To browse Academia. Skip to main walfer. You're walter an out-of-date version of Internet Explorer. Log In Sign Up. Tobias Hemsel. Matthias Hunstig. Stick-slip and slip-slip operation of piezoelectric inertia drives—Part Sextro Frequency-limited excitation. In this part it is shown that sextro operation is also suitable for use with real actuators, driven with frequency-limited versions of the ideal signals presented in part I.
The motional walter of the Keywords: Inertia motor motor as well as its wear and the required electric power are investigated for operation with different Stick-slip drive signals. It is found that for high velocity inertia motors it is recommendable to use actuators with large Mode of operation stroke and to drive them with a signal consisting of two harmonics at a high fundamental frequency, a Walfer indicator result that is supported by similar walter implemented experimentally by sextro authors.
The results help motor designers to choose the appropriate mode of operation and to optimise ub motor parameters for their individual applications. All rights reserved. In Section 4, frequency-limited excitation small steps. In Section 5, the use of inertia motors for example by motors operating in both stick-slip and slip-slip for force generation, which is upb in the focus of this article, is mode [1—3], has been gaining wider recognition for only a few years.
Additional to the motional performance indica- Sextro with its first part, this contribution walter a systematic tors introduced in , Section 6 defines performance indicators investigation of the different modes of operation of inertia motors describing the velocity to input power ratio and the durability walter the and of the motor performance achievable in these modes.
The performance of motors driven with different walter In the first part of this sextri , different modes for limited signals is analysed in Section 7. Section 8 investigates the the operation of inertia motors and the maximum motor perfor- influence of the actuator stroke and the actuator bandwidth on the mance achievable in these modes under ideal wlter have been motor performance. The conclusions presented in Section water clearly investigated systematically.
Prerequisites and results are briefly show that this investigation of upb excitation signals for summarised in Sections 2 and 3. In this part, frequency-limited high velocity motors is helpful during the design of inertia motors excitation signals that are realisable with real actuators are derived for real applications. Model Fig. A slider walter below the sextro rod.
It E-mail addresses: matthias. Hunstigtobias. Hemsel walrer, walter. Hunstig et al. Frequency-limited sextro signals In the first part of this contribution , an infinitely dynamic ideal actuator was assumed which is able to perfectly reproduce the ideal excitation signals.
But real actuators show limited dynam- ics and let only signal components below a certain frequency pass b approximately unaltered while higher upb components are modified in both amplitude and phase. It is therefore advantageous to reduce the maximum frequency present in the voltage signal before it is fed into the actuator.
This also reduces the requirements for the amplifier driving the actuator and simplifies a possible com- pensation of the actuator dynamics  because fewer frequency components have to be considered. Upb frequency-limited signals for sextro inertia motors are derived in the following, based on the ideal signals presented in the first part of this contribution.
Every periodic signal can be described as a Fourier series. End- ing the Fourier series after a finite number of elements produces a frequency-limited signal which is the least-squares approximation Fig.
The investigations in both parts of this contribution are of gen- ak eral validity. The differences between the four individual frequency components. But even 0. The discrete stepping is the only real advantage 0 of discrete over continuous operation, cp. The lower start-up 2 4 6 8 10 12 time, which could be seen as a second advantage, directly results harmonic from the discreteness of the steps and comes at the cost of walter much Fig. The lines are for visual guidance only.
With the real excitation signals, such discrete steps are hard to achieve because, due upb the oscillations in the upb Fig. Therefore it makes little sense to use the signals for ideal discrete While the displacement signal is approximated well already with operation as the basis for frequency-limited excitation signals. One detail to be noted, visualised in the right half of the accelera- Because this contribution aims for high motor velocities, only signals derived from the ideal signals for continuous slip-slip oper- tion plots in Fig.
This means that there are no phases of stiction with significant length. The only exception are signals calculated with sextrp n for a very low aR or for discrete 5.
Force generation with inertia motors modes. The producible force of an inertia motor can be defined and mea- Another fact to be noted is that the frequency-limited signals for sured differently. This effect, known spring or the spring force using a load cell connected to the other as the Gibbs phenomenon , [8, pp. But it is has so far not been investigated whether continuity present in the ideal signal. On the other collisions between the two parts. Other authors make their motor hand, only signals with relatively high n reach values above xR,maxlift weights in order to determine the producible force .
A third while signals with low n remain far from this maximum allowed option often used for other types of piezoelectric motors [14—16] value. Performance indicators amplitude. To make maximum use of the allowed range for the actuator stroke without exceeding it, the excitation amplitude is 6.
With the modified formula, it contains n harmonics as desired. This is the case for the setups investigated required to achieve this movement, and the lifetime of the motor. Thus only the steady state durability indicator Indicators for this upb derived on the following pages. Durability indicator and friction losses 6. Velocity to input power ratio As long as they are driven within their specified upbb lim- 6. Assumptions its, piezoelectric actuators can be designed to produce a very large The electric power required to drive a piezoelectric actuator is number of cycles without significant degradation .
Thus the highly dependent on the driving frequency. High amplitudes can mechanical walter are an important factor determining the be achieved with relatively low input power in resonant operation. One major cause of degra- This effect can also be used in inertia motors by combining multiple waltee is wear in the friction contact. Determining the most common and least preventable form of wear especially the input power of such an inertia motor requires detailed knowl- in metallic contacts.
For given material and surface conditions, the edge of the specific electromechanical system and thus cannot be volume worn away by adhesive wear is approximately waltsr done generally. Indeed, the responses can be very different surface conditions. In many upb the required electrical A suitable indicator for the durability of a motor is the posi- sextro signal can be calculated relatively easily from the desired tioning distance achieved per unit of worn volume.
For example, in the case shown in Fig. The above formulas are for monofrequent operation. In the 6. The amplitudes nected, the movement of the esxtro equals the movement of the of voltage and current for each harmonic follow from 29 and 30 sextgo rod.
Assuming that Upb t is negligibly small cp. Section 6. But y11 for drives mainly used for positioning it is of little use. With ical instabilities. There- time in 6 of the simulated 25 cases, the largest value reached is 3. For a given fmaxchoosing a higher n means to upb For calculating the velocity to input power ratio, parameters a signal with more harmonics, but a lower fundamental frequency, identified for the single degree of freedom model of the piezoelec- as shown in Fig.
The maximum steady state velocity in ideal stick-slip oper- ation was found to be 0. Generally, the start-up time with an odd number of harmonics is shorter than with the neighbouring even numbers of This statement is proven with the help of an example: Fig. For any given maximum fre- from 9 and 40 : quency, increasing n decreases the smoothness.
For any unchanged. Even if there are phases reaches a maximum above which it begins to very slowly decrease d d of stiction, the courses of the velocities of rod and slider are sextri with rising n. If durability is very sextro in a motor applica- times. This means that the number of periods pq until the required the driving signal, these should therefore be the first measures to degree of approximation to the steady state velocity is reached is increase the lifetime of an inertia motor.
For example, the maximum allowed frequency for longitudinal actuators is often determined as 8. Upb of actuator stroke and bandwidth a fixed percentage of the first resonance frequency. This is inversely proportional to the actuator length, which in turn is directly pro- In  the walter influence of the actuator stroke on the step size portional to the actuator stroke.
Right of the dotted line in the figure, the velocity These proportionalities are not only valid waltter the specific ideal of an inertia motor is impaired by the sextro frequency allowed and frequency-limited excitation signals derived in the previous for the actuator. Left of the dotted line the bandwidth of the actua- chapters, but for any periodic excitation signal, if the salter form, tor cannot be fully used.
References  Y. Walter, R. Sextro, W. Kwon, K. Kim, S. Kim, A novel smooth impact drive mechanism actuation method with dual-slider for a compact zoom lens system, Review of Scientific Instruments 82 Nishimura, H. Hosaka, T. Morita, Resonant-type smooth impact drive mech- anism SIDM actuator using a bolt-clamped Langevin transducer, Ultrasonics 52 75— Hunstig, T. Hemsel, W.
Dabei wird der gesamte Prozess der Ultraschall-Verbindungsbildung modelliert. Dies beinhaltet u. Das Ultraschallbonden mit Aluminiumdraht ist ein etabliertes Fertigungsverfahren zur Kontaktierung von Leistungshalbleitern. Die Prozessparameter unterscheiden sich dabei deutlich von den bekannten Aluminiumprozessen, ihre Wechselwirkungen sind weitestgehend unbekannt. Bender, K. Reinke, W. Sextro, in: Diese Entwicklung basiert auf der Umsetzung diverser Schritte. Rubber-metal-elements are used sedtro isolation of vibrations e.
Possible applications of the elements are shaft bearings, sexro bearings, gearbox bearings, bearings for the nacelle and its components and torque supports. In order to realize predictive maintenance, an accurate condition monitoring system for rubber-metal-elements should be developed.
During that development different aspects have to be implemented. Additionally to the functional analysis, the constructive integration sextro the sensors into the monitored part is mandatory.
The focus of this work is on the measured variable upb, which is detected by means of appropriate sensors. Thereby lifetime tests are run under non-stationary operating conditions to generate temperature upb. During data analysis, the measured data is upb regarding waltwr degradation of the rubber-metal-elements and remaining useful lifetimes are estimated.
Kaul, J. Hentze, W. Sextro, I. Schemmel, T. Hemsel, C. Dymel, M. Upb, M. Sextro, Sensors and Actuators A: Physical, pp. Ultrasonic joining sextro a common industrial process. In the electronics industry it is sextro to form electrical connections, including those of dissimilar materials. Multiple influencing factors in ultrasonic joining are known and extensively investigated; process parameters like ultrasonic power, bond force, and bonding frequency of the ultrasonic vibration are known to have walter high impact on a reliable joining process and need to be adapted for each new application with different geometry or materials.
This contribution is focused on increasing ultrasonic power waltrr to the interface and keeping mechanical stresses during ultrasonic bonding low by using sextro multi-dimensional ultrasonic transducer concept.
Bonding results for a new designed connector pin in IGBT-modules achieved by multi- and one-dimensional bonding are discussed. Bender, L. Schinke, W. Remaining useful lifetime RUL predictions as part of a condition monitoring system are pub in more and more upb and industrial applications. Sextro establish an efficient and walfer estimate of the RUL of a wextro product, different uncertainties have to walter handled.
To minimize the uncertainties of the RUL estimation, a reliable and walter prognostic approach waltee well upb a good failure threshold sexro important. Regarding the failure threshold, most often an expert sets a fixed failure threshold. However, neither the a priori known failure threshold nor a fixedthreshold value walter feasible in every application.
Especially in the case of varying characteristics of the monitored system, an adaptive failure threshold is of great importance concerning the accuracy of the RUL estimation.
Walter, which are used in a wide range of applications for vibration and upb isolation, are mon-itored by thermocouples to allow for lifetime predictions.
Aiming to establish accurate RUL predictions of a rubber-metal-element, uncertainties due to nonlinear material characteristics and changing operational conditions have to be considered.
Consequently, different temperature-based failure threshold definitions are implemented and compared within a particle filtering approach. Ein weiterer Ansatz ist die Verwendung zweier entgegengesetzt angeordneter Wandler . In diesem Fall erfordert jedoch die Erzeugung einer upb Welle eine genaue Abstimmung von Frequenz und Phase beider Wandler, was eine komplexe Steuerung erfordert.
Mithilfe eines FiniteElemente-Modells werden die Auswirkungen einer optimierten Geometrie upb den maximalen Schalldruckpegel untersucht. Ergebnisse werden durch Messungen an einem experimentellen Sextdo eines Stehwellensystems validiert.
Kaul, A. Bender, W. As the emerging sextro of technical systems offers immense opportunities to be exploited by means of bigdata analysis, ubiquitous computing and largely networked systems, the digital twin comes into focus to combineall these aspects to an attendant model of an individual waltter during design phase as well as during operation.
Since state-of-art technical systems walter growing increasingly complex due to inherent intelligence and increasingfunctionality, i.
Many methods were developed to walter a reliability focused design or reliability-by-design approachesto tackle this challenge during design process. In field, data-based methods, i.
In order to take advantage of upb models of system reliability during design phaseand condition monitoring systems during operation, a method is proposed to combine both approaches in order toset up a digital twin with focus on system reliability.
The base model of the digital twin is taken from the systemreliability model from the design phase sextri is used during operation and therein updated to the current reliabilitybased on the state estimation of the condition monitoring system. The approach is illustrated with a case study waltdr arolling bearing test rig. Unger, M. Hunstig, Srxtro. Meyer, M. Ultrasonic sextro bonding is an indispensable process in the industrial manufacturing of semiconductor devices.
Copper wire is increasingly replacing the well-established aluminium wire because of its superior electrical, thermal and mechanical properties. Copper wire processes differ sextro from aluminium processes and are more sensitive to disturbances, which reduces the range of parameter values suitable for a stable process.
Disturbances can dalter compensated by an adaption of process parameters, but finding suitable parameters manually is difficult and time-consuming. This paper presents a physical model of the sextgo wire bonding process including the friction contact between tool and wire. This model yields novel insights into the process. A prototype wslter a multi-objective optimizing bonding machine MOBM is presented.
It uses multi-objective optimization, based on the complete process model, to automatically select the best operating point as a compromise of concurrent objectives. Rubber-metal-elements are used in a wide range of waltter for vibration and sound isola- tion. Nowadays it is state of the art to calculate the lifetimes of these elements under mechanical stress prior to their service life.
To establish more reliable and safer rubber-metal-elements, continuous monitoring by dif- ferent sensors can be used. Especially prognostics enable a rise in reliability, availability and safety.
To estab- lish these advantages, estimating the remaining upb lifetime of rubber-metal-elements should be realized during its service life based on current information on its condition.
Therefore a suitable measure to monitor the condition of the element is necessary. This work focuses on temperature signals. This approach allows in- cluding the ambient temperature and thereby involving changing operating conditions.
For estimating the RUL of rubber-metal-elements a model-based wlter approach based on particle filtering is proposed. Walterr performance is sextro regarding relevant parameters to wallter the best performance for the applied data. Meyer, T. Kimotho, W.
Part of Springer Nature. Dunst, P. Bornmann, T. Hemsel, W. Littmann, W. The handling of fine sextrp is an important task in modern production processes. However, as fine powders strongly tend to adhesion and agglomeration, their processing with conventional methods is difficult or impossible.
Especially waletr processing small amounts of highly sensitive fine powders, conventional sextor reach their technical limits. In process steps such as dosing, transport, and especially mixing of fine powders new methods are required. Apart from the well-known method of manipulating powder walter by adding chemical additives, this contribution aims at improving the handling of dry fine powders by using vibrations at different frequencies. Modules are presented, which enable walter continuous dosing, the homogeneous mixing and the transport of dry fine powders.
Finally, these modules are combined for the production of a homogeneous mixture of two sextro fine powders. The methods for manipulating powder properties are describedin detail and prototypes for experimental walter are presented.
Dymel, P. Eichwald, R. Hemsel, M. Hunstig, W. State-of-the-art industrial compact high power electronic packages require copper-copper interconnections sextro larger cross sections made by ultrasonic bonding.
In comparison to aluminium-copper, copper-copper interconnections require increased normal forces walte ultrasonic power, which might lead to substrate damage due to increased mechanical stresses.
Since it is based on a model of the system, the bond process was modeled. In addition to static model parameters such as wire and substrate material properties and vibration characteristics of transducer and tool, variable model inputs are process parameters. Main simulation result is bonded area in the wiresubstrate contact. This model is then used to find valid and optimal working points before operation.
The working point is composed of normal force and ultrasonic voltage trajectories, which are usually determined experimentally. Instead, multiobjective optimalization is used to compute trajectories that simultaneously optimize bond quality, process duration, tool wear and probability of tool-substrate contacts. The values of these objectives are computed using the process model. At runtime, selection among pre-determined optimal working points is sufficient to prioritize individual objectives.
This way, the computationally expensive process of numerically solving a multiobjective optimal control problem and the demanding high speed bonding process are separated. To evaluate to what extent the pre-defined goals of self-optimization are met, an offthe- shelf heavy wire bonding machine was modified to allow for parameter adaptation and for transmitting of measurement data at runtime.
This data is received by an external computer system and evaluated to select a new working point. Then, new process parameters are sent to the modified bonding machine for use for subsequent bonds. With these components, a full self-optimizing system has been implemented. Kaul, T. Redundancy is a common approach to improve system reliability, availability and safety in technical systems.
It is achieved by adding functionally equivalent elements that enable the system to remain operational even though one or more of those elements fail. This paper begins with an overview on the various terminologies and methods for redundancy concepts that can be modeled sufficiently using established reliability analysis methods. However, these approaches yield very complex system models, which limits their applicability.
In current research, Bayesian Networks BNs , especially Dynamic Bayesian Networks DBNs have been successfully used for reliability analysis because of their benefits in modeling complex systems and in representing multi-state variables. However, these approaches lack appropriate methods to model all commonly used redundancy concepts. To overcome this limitation, three different modeling approaches based on BNs and DBNs are described in this paper. Addressing those approaches, the benefits and limitations of BNs and DBNs for modeling reliability of redundant technical systems are discussed and evaluated.
Multibody models of mechatronic systems are usually interdisciplinary and are continuously gaining complexity, due to a growing demand for comprehensive models of systems including effects of electro mechanics, elastic bodies, contacts and friction.
To be capable of simulating large models with subassemblies and contact between bodies, reduction techniques are required, which need certain experience in the choice of parameters. This publication discusses different possibilities for the modal description of structures in flexible multibody models with application to an Adaptive Frontlighting System in ADAMS. It will be shown that mode count, assembling of structures before and after modal reduction and influence of damping parameters of particular structures and subassemblies affect the behavior of the entire system.
A common reduction technique for flexible structures in multibody models is the component mode synthesis, which uses a certain number of modes for description of the modal behavior of a structure.
The influence of the mode count will be shown by means of different modal descriptions of one structure that contributes to a comprehensive model. Another study will prove that modal data of subassemblies and assemblies of modal reduced single structures lead to different models. The definition of damping parameters depends on the number of structures that have been added to an assembly before modal reduction and on the number of modal reduced structures.
The comparison of subassemblies and the entire model to experimental data will highlight the accuracy, computational overhead, complexity of models and modeling efficiency of the comprehensive model for the frontlighting system. Althoff, T. Meyer, A.
Unger, W. Sextro, F. Wire bonding has been an established packaging technology for decades. When introducing copper as wire material for high power applications, adaptations to the bonding process and to machines became necessary. Here, challenges occur due to the stiffer wire material and changing oxide layers on the contact partners. To achieve sufficient process stability, a clean bond area is required, which can only be achieved with high shear stresses in the contact partners surfaces.
These necessitate high normal forces to plastically deform the wire and substrate. To achieve such high stresses in the contact area, the bonding tool needs to be able to transmit the needed tangential forces to the top side of the wire. The wire itself performs a shear movement and transmits the force into the contact area to clean the contaminant and oxide layers and to level the desired bond surfaces. The main function of the tool is to transmit these forces.
If the bond tool can only transmit low forces in the direction of excitation, the parameter space for a stable bond process is severely restricted. Here, a modeling approach to estimate how well different tool shapes meet the demand of transmitting high tangential forces is presented.
The model depends on wire deformation and thus on the ultrasonic softening effect. Intelligent mechatronic systems other the possibility to adapt system behavior to current dependability. This can be used to assure reliability by controlling system behavior to reach a pre-defined lifetime. By using such closed loop control, the margin of error of useful lifetime of an individual system is lowered.
It is also possible to change the pre-defined lifetime during operation, by adapting system behavior to derate component usage. When planning maintenance actions, the remaining useful lifetime of each individual system has to be taken into account. Usually, stochastic properties of a fleet of systems are analyzed to create maintenance plans. Among these, the main factor is the probability of an individual system to last until maintenance. If condition-based maintenance is used, this is updated for each individual system using available information about its current state.
By lowering the margin of error of useful lifetime, which directly corresponds to the time until maintenance, extended maintenance periods are made possible. Also using reliability-adaptive operation, a reversal of degradation driven maintenance planning is possible where a maintenance plan is setup not only according to system properties, but mainly to requirements imposed by maintenance personnel or infrastructure.
Each system then adapts its behavior accordingly and fails according to the maintenance plan, making better use of maintenance personnel and system capabilities at the same time. In this contribution, the potential of maintenance plan driven system behavior adaptation is shown. A model including adaptation process and maintenance actions is simulated over full system lifetime to assess the advantages gained. Sextro, G. Memoli, M. Hodnett, B. Zeqiri, tm - Technisches Messen , 82 2 , pp.
Eine Vielzahl von Prozessen in der Chemie und Verfahrenstechnik kann durch Ultraschall positiv beeinflusst werden. Ultrasonic wire bonding is an indispensable process in the manufacturing of semiconductor components. It is used for interconnecting the silicon die to e. In high power applications, such as wind turbines, locomotives or electric vehicles, the thermal and mechanical limits of interconnects made from aluminum are nearing. The limits could be overcome using copper wire bonds, but their manufacturing poses challenges due to the harder material, which leads to increased wear of the bond tools and to less reliable production.
To overcome these drawbacks, adaptation of process parameters at runtime is employed. However, the range of parameter values for which a stable process can be maintained is very small, making it necessary to compute suitable parameters beforehand. To this end, and to gain insights into the process itself, the ultrasonic bonding process is modeled.
The full model is composed of several partial models, some of which were introduced before. This paper focuses on the modularization of the full model and on the interaction of partial models. All partial models are presented, their interaction is shown and the general outline of the simulation process is given.
Schulte, J. Neuhaus, W. The contact between viscoelastic materials e. In practice, this friction combination occurs for example in the tire-road contact, or in the use of rubber gaskets. Due to the frictional forces a system is significantly influenced in its vibrational properties.
The friction force is composed of two main components adhesion and hysteresis. The adhesion results from molecular bounds between the contact partners, while the deformation of the viscoelastic material by the roughness of the counter body leads to power loss.
This internal friction results in an additional frictional force, which is described by the hysteresis. To simulate the frictional behaviour of elastomers on rough surfaces and thus to determine the energy dissipation in contact, it is necessary to develop a mechanical model which considers the roughness of the contact partners, as well as dynamic effects and the dependence on normal pressure and sliding speed.
The viscoelastic material behaviour must also be considered. The contact between two rough surfaces is modelled as a rough rigid layer contacting a rough elas- tic layer. The elastic layer is modelled by point masses connected by Maxwell-elements. This allows the viscoelastic properties of the elastomer to be considered. The behaviour of whole system can be described by equations of motion with integrated constraints.
The degrees of freedom of the model depends on the varying contact conditions. A point mass not in contact has two degrees of freedom. A point mass in contact moving along the roughness path can be described by only one degree of freedom. For each Maxwell-Element also an inner coordinate and thus a further degree of freedom is needed. Because of varying contact conditions dur- ing the simulation, the simulation interrupts in case the contact conditions change.
Then the equations of motions are adapted with respect to the contact constraints. As a result of the simulation one obtain the energy dissipation and thus the friction char- acteristic during the friction process.
It is possible to use these results in three dimensional point-contact elements in order to model contact surfaces on lager length scales. Es wird daher ein Ansatz zur integrierten Modellierung mechatronischer Systeme vorgestellt. Intelligent mechatronic systems are able to autonomously adapt system behavior to current environmental conditions and to system states. To allow for such reactions, complex sensor and actuator systems as well as sophisticated information processing are required, making these systems increasingly complex.
However, with the risk of increased system complexity also comes the chance to adapt system behavior based on current reliability and in turn to increase reliability.
The adaptation is based on switching selecting an appropriate working point at runtime. Multiple suitable working points can be found using multi-objective optimization techniques, which require an accurate system model including system reliability. At present, modeling of system reliability is a laborious manual task performed by reliability modelling experts.
Despite actual system reliability being highly dependent on system dynamics, pre-existing system dynamics models and the resulting reliability model are at best loosely coupled. To allow for closer interaction among dynamics and reliability model and to ensure these are always synchronized, advanced modeling techniques are required.
Therefore, an integrated model is introduced that reduces user input to a minimum and that integrates system dynamics and system reliability. This paper presents a comparison of a number of prognostic methods with regard to algorithm complexity and performance based on prognostic metrics.
This information serves as a guide for selection and design of prognostic systems for real-time condition monitoring of technical systems. The methods are evaluated on ability to estimate the remaining useful life of rolling element bearing.
Run-to failure vibration and temperature data is used in the analysis. The sampled prognostic methods include wear-temperature correlation method, health state estimation using temperature measurement, a multi-model particle filter approach with model parameter adaptation utilizing temperature measurements, prognostics through health state estimation and mapping extracted features to the remaining useful life through regression approach.
Although the performance of the methods utilizing the vibration measurements is much better than the methods using temperature measurements, the methods using temperature measurements are quite promising in terms of reducing the overall cost of the condition monitoring system as well as the computational time. An ensemble of the presented methods through weighted average is also introduced.
Meyer, P. Althoff, F. Eacock, M. In a first step, this paper shows the importance of modeling the stick-slip effect by determining, monitoring and analyzing amplitudes and phase angles of tool tip, wire and substrate experimentally during bonding via laser measurements.
This model includes Archard's wear approach in order to compute the lost volume of tool tip due to wear over the entire process time.
Althoff, A. Eacock, in: 17th Electronics Packaging Technology Conference, , pp. Changing manufacturing technologies or material in well-known processes has to be followed by an adaption of process parameters. In case of the transition from aluminum wire to copper wire in heavy wire bonding, the adaption effort is high due to the strongly different mechanical properties of the wire.
One of these adaption aspects, apart from wire material, is the existent oxide layers on wire and substrate. The ductile aluminum oxide is not influencing the bonding process much, because it is supposed to break apart in case of plastic deformation. The lubricating copper oxide layer has to be removed before micro welds can develop. Therefore, in this paper, experiments are carried out at low frequency to determine the friction energy needed to abrade the copper oxide layer of wire and substrate, which is indicated by an increase in the resulting friction coefficient.
The friction energy per contact area to remove the interfering layers at low frequency is compared to the real bonding process working at 58 kHz.
In addition, a theoretical concept is being described to get a grasp of the occurring mechanism. In the end a proposal is given how to set bonding parameters to get the cleanest surfaces with the installed bond tool.
Meyer, J. Dazu wird die aktuelle Restlebensdauer mit einer vorgegebenen Restlebensdauer verglichen. Verschiedene Verfahren werden sodann hinsichtlich ihrer Eignung evaluiert und Anwendungsgrenzen aufgezeigt. Rasche, C. Priesterjahn, D. Zimmer, J. Stahl, K. Dellnitz, P. Iwanek, P. Reinold, P. Hartmann, T.
Kimotho, T. Application of prognostics and health management PHM in the field of Proton Exchange Membrane PEM fuel cells is emerging as an important tool in increasing the reliability and availability of these systems. Though a lot of work is currently being conducted to develop PHM systems for fuel cells, various challenges have been encountered including the self-healing effect after characterization as well as accelerated degradation due to dynamic loading, all which make RUL predictions a difficult task.
In this study, a prognostic approach based on adaptive particle filter algorithm is proposed. The novelty of the proposed method lies in the introduction of a self-healing factor after each characterization and the adaption of the degradation model parameters to fit to the changing degradation trend. An ensemble of five different state models based on weighted mean is then developed.
The increasing demand for high reliability, safety and availability of technical systems calls for innovative maintenance strategies. The use of prognostic health management PHM approach where maintenance action is taken based on current and future health state of a component or system is rapidly gaining popularity in the maintenance industry.
However, it requires parameter tuning for each application, with the objective of minimizing the classification error. This is a single objective optimization problem which requires the use of optimization algorithms that are capable of exhaustively searching for the global optimum parameters. DE identifies the search limit of the parameters while PSO finds the global optimum within the search limit. The feasibility of the approach is verified using bearing run-to-failure data and the results show that the proposed method significantly increases health state classification accuracy.
Hemsel, P. Morita, C. Sextro, Archive of Applied Mechanics , pp. Kleinjohann, C. Heinzemann, C. Steenken, H. Wehrheim, J. Gausemeier, K. Kleinjohann, M. Hartmann, R. Dorociak, S. Groesbrink, S. Ziegert, T.
Sextro, W. An automotive suspension system represents one of the most complex and important systems in a passenger vehicle, which has to ensure a robust and optimized contact between the wheels and the road at any time. For improving a suspension system it is important to take an investigative look at the interaction between suspension, tire and road dynamics. Thus a part of a study into aspects of suspension modeling on multi-body simulations of rear multi-link suspension system dynamics with focus on the tire footprint area is presented in this work.
Althoff, J. Neuhaus, T. In order to increase mechanical strength, heat dissipation and ampacity and to decrease failure through fatigue fracture, wedge copper wire bonding is being introduced as a standard interconnection method for mass production. To achieve the same process stability when using copper wire instead of aluminum wire a profound understanding of the bonding process is needed.
Due to the higher hardness of copper compared to aluminum wire it is more difficult to approach the surfaces of wire and substrate to a level where van der Waals forces are able to arise between atoms. Also, enough friction energy referred to the total contact area has to be generated to activate the surfaces.
Therefore, a friction model is used to simulate the joining process. This model calculates the resulting energy of partial areas in the contact surface and provides information about the adhesion process of each area. The focus here is on the arising of micro joints in the contact area depending on the location in the contact and time. To validate the model, different touchdown forces are used to vary the initial contact areas of wire and substrate. Additionally, a piezoelectric tri-axial force sensor is built up to identify the known phases of pre-deforming, cleaning, adhering and diffusing for the real bonding process to map with the model.
Test substrates as DBC and copper plate are used to show the different formations of a wedge bond connection due to hardness and reaction propensity. A model to calculate the locally resolved tangential contact forces of the wheel rail contact with respect to contact kinematics, material and surface properties as well as temperature is introduced. The elasticity of wheel and rail is modeled as an elastic layer consisting of point contact elements connected by springs to each other and to the wheel.
Each element has two degrees of freedom in tangential directions. The resulting total stiffness matrix is reduced to calculate only the position of the elements in contact. Friction forces as well as contact stiffnesses are incorporated by a nonlinear force-displacement characteristic, which originates from a detailed contact model.
The contact elements are transported through the contact zone in discrete time steps. After each time step an equilibrium is calculated. For all elements, their temperature and its influence on local friction are regarded by calculating friction power and temperature each time step. Eichwald, W. Althof, F. Eacock, A. Meyer, K. Guth, in: Proceedings of the 47th International Symposium on Microelectronics, , pp.
Wire bonding is the most common technology for connecting electronic components. Due to their efficiency bond interconnections made of copper wire are used for example in the aerospace and medical technology as well as in the fields of renewable energies. One of the main cost factors in the manufacturing process is the consumables like bonding tools. The technological transition to copper as wire material causes significant wear on the millimeter large effective contact area of the bonding tool.
This wear leads to a loss by a factor of 30 of the number of reliable interconnections which can be produced by a single tool. To reduce setting-up time in the production and minimizing costs, an enlarged bonding tool lifetime is desirable.
Consequently a better understanding of wear and recognition of wear pattern is required. Therefore, the paper presents an analyzing method of the tool topography change of a heavy wire bonding tool by using a confocal microscope. Furthermore, the paper discusses the identification of the main wear indicators by the help of the named topography change for different bond parameters, like ultrasonic power and tool geometry.
Reference topography has been carried out by choosing typical parameters of the production line. To judge whether the quality requirement of the bond connections made by a single tool cannot be fulfilled shear test of the source bond have been carried out after a defined number of produced bond connections.
Main steps of analysis: I Topography of the tool surface is sampled after a defined number of bonds by means of a confocal microscope to detect the wear progress.
II The recorded data is filtered using Matlab. So, measurement errors can be eliminated and the topography can be overlaid more easy to identify differences between diverse tools or differences in wear stages of the same tool. III The subsequent discretization of the topography into sub volumes allows to IV describe the loss of volume depending on the position in the groove. Thereby, intermediate status of wear of one tool can be used to obtain a persistent description of the topography change over the number of produced bonds by interpolating the confocal data.
Afterwards the persistent change of the groove flank has been analyzed for the named test series to identify the main wear indicators and their effect on shear forces. All worn tools show dominant areas for volume loss especially for plastic deformation and accordingly abrasion. These wear mechanism can be referred to the change of main parts of the groove geometry like the rounding of the front and back radius.
The most volume loss was identified in the upper part of the tool flanks or rather at the transition from the groove flank to the front or back radius. Furthermore the observation of the center of the groove flank shows just a little change in volume.
All in all, the identification of the wear indicators will be discussed with the objective of increasing the tool lifetime by optimizing the tool geometry without losses in bond quality and reliability. Cavitation monitoring is desired to optimize the sonication for diverse sonochemical processes and to detect changes or malfunctions during operation. In situ cavitation measurements can be carried out by detection of the acoustic emissions of cavitation bubbles by sensors in the liquid.
However, in harsh environments sensors might not be applicable. Thus, the impact of cavitation on the electrical signals of a piezoelectric transducer has been analyzed as alternative method to measure the threshold, strength and type of cavitation. The applicability has been tested in three different setups to evaluate the general- izability of extracted indicators.
In all setups indicators for the cavitation thresholds could be derived from the current signal. In two setups features showed two thresholds that may be linked to the types of cavitation. However, only one feature derived from the current signal in one particular setup correlated to the strength of cavitation.
Cavitation detection based on the current signal of the transducer is a useful method to detect cavitation in harsh environments and without perturbing the sound field.
Once appli- cable indicators have been identified, they may easily be tracked during the process. However, for more detailed studies about the cavitation activity and its spatial distribution, measurements with in situ sensors are recommended. Piezoelectric inertia motors use the inertia of a body to drive it by means of a friction contact in a series of small steps.
One very promising driving option for such motors is the superposition of multiple sinusoidal signals or harmonics. In this contribution, the theoretical results are validated experimentally. In this context, a quick and reliable identification process for parameters describing the friction contact is proposed. Additionally, the force generation potential of inertia motors is investigated theoretically and experimentally.
The experimental results confirm the theoretical result that for a given maximum frequency, a signal with a high fundamental frequency and consisting of two superposed sine waves leads to the highest velocity and the smoothest motion, while the maximum motor force is obtained with signals containing more harmonics. These results are of fundamental importance for the further development of high-velocity piezoelectric inertia motors.
Meyer, C. Priesterjahn, W. This paper discusses the refinement of multibody models by integration of flexible bodies and by considering nonlinearities from contacts. It presents common approaches for contact modeling in multibody simulations and strategies to include flexible bodies.
A contact model is implemented in the elastic multibody model. Experimental results show that significant effects of system dynamics can be modeled by use of a multibody model including elastic bodies and contacts. Sprock, W. Many nonlinear mechanical oscillators show excitation-dependent behavior. In this paper, a new measurement approach is presented to analyze such structures. Althoff, P. Eichwald, T. Power semiconductor modules are used to control and switch high electrical currents and voltages.
Within the power module package wire bonding is used as an interconnection technology. In recent years, aluminum wire has been used preferably, but an ever-growing market of powerful and efficient power modules requires a material with better mechanical and electrical properties. For this reason, a technology change from aluminum to copper is indispensable. However, the copper wire bonding process reacts more sensitive to parameter changes. This makes manufacturing reliable copper bond connections a challenging task.
The aim of the BMBF funded project Itsowl-InCuB is the development of self-optimizing techniques to enable the reliable production of copper bond connections under varying conditions.
A model of the process is essential to achieve this aim. This model needs to include the dynamic elasto-plastic deformation, the ultrasonic softening effect and the proceeding adhesion between wire and substrate. This paper focusses on the pre-deformation process. In the touchdown phase, the wire is pressed into the V-groove of the tool and a small initial contact area between wire and substrate arise.
The local characteristics of the material change abruptly because of the cold forming. Consequently, the pre-deformation has a strong effect on the joining process. In , a pre-cleaning effect during the touchdown process of aluminum wires by cracking of oxide layers was presented.
These interactions of the process parameters are still largely unknown for copper. In a first step, this paper validates the importance of modeling the pre-deformation by showing its impact on the wire deformation characteristic experimentally. Creating cross-section views of pre-deformed copper wires has shown a low deformation degree compared to aluminum. By using a digital microscope and a scanning confocal microscope an analysis about the contact areas and penetration depths after touchdown has been made.
Additionally, it has to be taken into account that the dynamical touchdown force depends on the touchdown speed and the touchdown force set in the bonding machine. In order to measure the overshoot in the force signals, a strain gauge sensor has been used. Subsequently, the affecting factors have been interpreted independently Furthermore, the material properties of copper wire have been investigated with tensile tests and hardness measurements.
In a second step, the paper presents finite element models of the touchdown process for source and destination bonds. These models take the measured overshoot in the touchdown forces into account. A multi-linear, isotropic material model has been selected to map the material properties of the copper. A validation of the model with the experimental determined contact areas, normal pressures and penetration depths reveals the high model quality.
Thus, the simulation is able to calculate and visualize the three dimensional pre-deformation with an integrated material parameter of the wire if the touchdown parameters of the bonding machine are known.
Based on the calculated deformation degrees of wire and substrate, it is probably possible to investigate the effect of the pre-deformation on the pre-cleaning phase in the copper wire bonding. A measurement method is presented that combines the advantages of the multisine measurement technique with a prediction method for peak bending behavior. This combination allows the analysis of the dynamic behavior of mechanical structures at distinctly reduced measurement durations and has the advantage of reducing high excitation impacts on the structure under test.
After a brief presentation of the algorithm, the validity scope of the approach is investigated with emphasis on an exemplary error investigation. In power electronics, ultrasonic wire bonding is used to connect the electrical terminals of power modules. To implement a self-optimization technique for ultrasonic wire bonding machines, a model of the process is essential.
This model needs to include the so called ultrasonic softening effect. It is a key effect within the wire bonding process primarily enabling the robust interconnection between the wire and a substrate. However, the physical modeling of the ultrasonic softening effect is notoriously difficult because of its highly non-linear character and the absence of a proper measurement method.
In a first step, this paper validates the importance of modeling the ultrasonic softening by showing its impact on the wire deformation characteristic experimentally.
In a second step, the paper presents a data-driven model of the ultrasonic softening effect which is constructed from data using machine learning techniques. A typical caveat of data-driven modeling is the need for training data that cover the considered domain of process parameters in order to achieve accurate generalization of the trained model to new process configurations. In practice, however, the space of process parameters can only be sampled sparsely.
In this paper, a novel technique is applied which enables the integration of prior knowledge about the process into the datadriven modeling process. It turns out that this approach results in accurate generalization of the data-driven model to unseen process parameters from sparse data. Gausemeier, F. Josef Rammig, W. Sextro, Springer Berlin Heidelberg, Intelligent technical systems, which combine mechanical, electrical and software engineering with methods from control engineering and advanced mathematics, go far beyond the state of the art in mechatronics and open up fascinating perspectives.
Among these systems are so-called self-optimizing systems, which are able to adapt their behavior autonomously and flexibly to changing operating conditions. The Collaborative Research Center "Self-optimizing concepts and structures in mechanical engineering" pursued the long-term aim to enable others to develop dependable self-optimizing systems.
Assuring their dependability poses new challenges. However, self-optimization also offers the possibility to adapt the system's behavior to improve dependability during operation. The aim of this book is to provide methods and techniques to master the challenges and to exploit the possibilities given by self-optimization. This book is directed to researchers and practitioners alike. It gives a brief introduction to the holistic development approach for self-optimizing mechatronic systems and the steps required to assure a dependable product design starting with the very early conceptual design phase.
A guideline to select suitable methods for each step and the methods themselves are included. Each method is individually introduced, many examples and full references are given. Meyer , C. Intelligent mechatronic systems, such as self-optimizing systems, allow an adaptation of the system behavior at runtime based on the current situation.
To do so, they generally select among several pre-defined working points. A common method to determine working points for a mechatronic system is to use model-based multiobjective optimization. It allows finding compromises among conflicting objectives, called objective functions, by adapting parameters. To evaluate the system behavior for different parameter sets, a model of the system behavior is included in the objective functions and is evaluated during each function call.
Intelligent mechatronic systems also have the ability to adapt their behavior based on their current reliability, thus increasing their availability, or on changed safety requirements; all of which are summed up by the common term dependability. To allow this adaptation, dependability can be considered in multiobjective optimization by including dependability-related objective functions.
However, whereas performance-related objective functions are easily found, formulation of dependability-related objective functions is highly system-specific and not intuitive, making it complex and error-prone. Since each mechatronic system is different, individual failure modes have to be taken into account, which need to be found using common methods such as Failure-Modes and Effects Analysis or Fault Tree Analysis. Using component degradation models, which again are specific to the system at hand, the main loading factors can be determined.
By including these in the model of the system behavior, the relation between working point and dependability can be formulated as an objective function. In our work, this approach is presented in more detail. It is exemplified using an actively actuated single plate dry clutch system. Results show that this approach is suitable for formulating dependability-related objective functions and that these can be used to extend system lifetime by adapting system behavior.
With the paradigm shift towards prognostic and health management PHM of machinery, there is need for reliable PHM methodologies with narrow error bounds to allow maintenance engineers take decisive maintenance actions based on the prognostic results. The accuracy of PHM methods is usually a function of the features extracted from the raw data obtained from sensors.
In cases where the extracted features do not display clear degradation trends, for instance highly loaded bearings, the accuracy of the state of the art PHM methods is significantly affected. The data which lacks clear degradation trend is referred to as non-trending data. This study presents a method for extracting degradation trends from non-trending condition monitoring data for RUL estimation. The raw signals are first filtered using a discrete wavelet transform DWT denoising filter to remove noise from the acquired signals.
Time domain, frequency domain and time-frequency domain features are then extracted from the filtered signals. An autoregressive model is then applied to the extracted features to identify the degradation trends. Features representing the maximum health information are then selected based on a performance evaluation criteria using extreme learning machine ELM algorithm.
The selected features can then be used as inputs in a prognostic algorithm. The feasibility of the method is demonstrated using experimental bearing vibration data. Sextro, in: Proceedings of 31st Danubia-Adria Symposium. The connection between wire and substrate is based on a variety of physical effects, but the dominant one is the friction based welding while applying ultrasound.
Consequently, a friction model was used to investigate the welding process. This model is built up universal and can be used to describe the formation of micro welds in the time variant contact area between wire and substrate. Aim of the model is to identify the interactions between touchdown, bond normal force, ultrasonic power and bonding time. To do so, the contact area is discretized into partial areas where a Point Contact Model is applied.
Based on this approach it is possible to simulate micro and macro slip inside the contact area between wire and substrate. The work done by friction force is a main criterion to define occurring micro joints which influence the subsequent welding.
During wheel bumping caused by stochastic road excitation, the wheel performs rotational and translational movements. The bump and rebound wheel velocity leads to significant angular velocities based on the elasto- kinematics of the suspension system. Based on the gyroscopic effect, moments arise about the rotating wheel induced by the angular change while bumping.
Therefore it leads to undesirable wheel changes and degrades the tire contact and finally decreases the driving stability. A flexible MBS-model of the five-link rear axle system that includes these effects has been built up to allow a detailed investigation of the gyroscopic effect.
Using the simulation results, conclusions can be drawn for refining design criteria for the kinematics, elastokinematics and topology of the suspension system to increase the active safety of the vehicle. This contribution provides a systematic investigation and performance comparison of different stick--slip and slip--slip modes of operation.
Different criteria for comparing the motional performance of inertia motors are defined: Steady state velocity, smoothness of motion, and start-up time. Using the example of a translational inertia motor excited by an ideal displacement signal, it is found that the maximum velocity reachable in stick--slip operation is limited principally, while continuous slip--slip operation allows very high velocities.
For the investigated driving signals, the motor velocity is proportional to the square root of the actuator stroke. The motor performance with these ideal signals defines an upper boundary for the performance of real motors.
Al-Ashtari, T. Sextro, in: 9. Schnietz, K. Ultrasonic wire bonding is a common technology for manufacturing electrical interconnects. In the field of power electronics, new thermal and electrical obligations arose due to increasing power density requirements.
One approach to achieve these aims is replacing the wire material for heavy wire bonds from aluminum to copper. This material change leads to challenging tasks and problems, for instance the occurring wear of the bond tool. The wear is significantly higher using copper wire instead of aluminum and results in a dramatic loss in the amount of interconnects which can be produced reliable by a single tool.
Therefore, the paper discusses the influences of bonding parameters on the wear. The key question is which of the tasks cannot be fulfilled with increased wear of the tool, e.
The main functions are fixing the wire in the tool groove, predeformation, applying normal force and transmission of ultrasonic oscillation to the wire. To identify the most affecting factors, four bonding parameters are varied and their influences are investigated. Al-Ashtari, M. A piezoelectric cantilever beam with a tip mass at its free end is a common energy harvester configuration. This article introduces a new principle of designing such a harvester that increases the generated power without changing the resonance frequency of the harvester: the attraction force between two permanent magnets is used to add stiffness to the system.
This magnetic stiffening counters the effect of the tip mass on the efficient operation frequency. Five set-ups incorporating piezoelectric bimorph cantilevers of the same type in different mechanical configurations are compared theoretically and experimentally to investigate the feasibility of this principle: theoretical and experimental results show that magnetically stiffened harvesters have important advantages over conventional set-ups with and without tip mass.
They generate more power while only slightly increasing the deflection in the piezoelectric harvester and they can be tuned across a wide range of excitation frequencies. Kimotho, C. Sextro, Chemical Engineering Transactions , 33, pp.
Recently, focus on maintenance strategies has been shifted towards prognostic health management PHM and a number of state of the art algorithms based on data-driven prognostics have been developed to predict the health states of degrading components based on sensory data. However, its application is limited by the difficulty in determining the required kernel function and penalty parameters. To address this problem, this paper proposes a hybrid differential evolution -- particle swarm optimization DE-PSO algorithm to optimize the MC-SVM kernel function and penalty parameters.
The differential algorithm DE obtains the search limit for the SVM parameters, while the particle swarm optimization algorithm PSO determines the global optimum parameters for a given training data set. Since degrading machinery components display several degradation stages in their lifetime, the MC-SVM trained with optimum parameters are used to estimate the health states of a degrading machinery component, from which the remaining useful life RUL is predicted.
This method improves the classification accuracy of MC-SVM in predicting the health states of a machinery component and consequently increases the accuracy of RUL predictions. The feasibility of the method is validated using bearing prognostic run-to-failure data obtained from NASA public data repository. The method also outperforms other soft computing methods proposed in literature. One very promising driving option is to use a superposition of multiple sinusoidal signals.
In this contribution, previous theoretical results are validated experimentally. The results confirm the theoretical result that for a given maximum frequency, usually defined by the actuator characteristics, a signal with high fundamental frequency and consisting of two superposed sine waves leads to the highest velocity and the smoothest motion.
This result is of fundamental importance for the further development of high-velocity piezoelectric inertia motors. Power and bandwidth of piezoelectric harvesters can be increased by using multiple piezoelectric elements in one harvester.
In this contribution, a novel energy harvesting cantilever array with magnetic tuning including three piezoelectric bimorphs is investigated theoretically and experimentally, with a good agreement between model and experiment.
Other than harvester designs proposed before, this array is easy to manufacture and insensitive to manufacturing tolerances because its optimum operation frequency can be re-adjusted after fabrication. Using the superposition principle, the Butterworth-Van Dyke model and a mechanical lumped parameters model, the generated voltage and current are determined analytically.
Formulas for calculating the power generated by array harvesters with an arbitrary number of piezoelectric elements connected in series or in parallel are derived. It is shown that optimum harvester design must take both the connected load and the operating frequency into account.
For bandwidth enhancement it is essential that individual rectifiers are used for the bimorphs. Piezoelectric inertia motors, also known as stickslip drives or smooth impact drives, use the inertia of a body to drive it by a friction contact in small steps, in the majority of motors composed of a stick phase and a slip phase between the friction partners. For optimizing inertia motors, it is important to understand the friction contact correctly and to measure its properties appropriately.
This contribution presents experimental set-ups for measuring the contact force, friction force and relative displacement in an actual inertia motor with a dry friction contact and numerical simulations of the motor operation. It is shown that a previously postulated condition for the applicability of simple kinetic friction models is well fulfilled for the investigated motor. The friction contact in the motor is simulated using different kinetic friction models. The input for the friction models is the measured motion of the rod.
The models qualitatively reproduce the measured motion but show quantitative deviations varying with frequency. These can be explained by vibrations of the driving rod that are experimentally investigated. Menke, W. Sextro, D. Zimmer, in: Proc. In this contribution, we introduce a multiobjective optimization used to calculate safe optimal working points for a mechatronic system by including stochastic safety-critical signals in an objective function.
Our application example consists of a linear drive for a rail-bound vehicle and an actuation unit. The linear drive's secondary part is fixed; the primary part is vehicle-mounted and can be adjusted vertically to account for deviations of the height of the secondary part.
A small air gap between both parts improves efficiency, but increases the risk of a collision between the two parts. Using height data of the secondary part, a trajectory for the vertical adjustment of the primary part is calculated. However, unexpected deviations necessitate a readjustment of the air gap. The probability of such unexpected height deviations can be calculated from the readjustment data. The system is equipped with sensors to measure the air gap.
Assuming that the sensor noise is normally distributed, noise characteristics are determined. Using this information and the probability distribution of unexpected height deviations, the probability of a collision is determined.
T he sensor noise and the probability of a collision between both parts of the linear drive are included in the dynamical model of the system. Using multiobjective optimization, pareto-optimal working points for the controller of the air gap are obtained.
By selecting an appropriate working point, safe operation can be ensured. This study presents the methods employed by a team from the department of Mechatronics and Dynamics at the University of Paderborn, Germany for the PHM data challenge.
The focus of the challenge was on maintenance action recommendation for an industrial machinery based on remote monitoring and diagnosis. Since an ensemble of data driven methods has been considered as the state of the art approach in diagnosis and prognosis, the first approach was to evaluate the performance of an ensemble of data driven methods using the parametric data as input and problems recommended maintenance action as the output.
Due to close correlation of parametric data of different problems, this approach produced high misclassification rate. Event-based decision trees were then constructed to identify problems associated with particular events. To distinguish between problems associated with events that appeared in multiple problems, support vector machine SVM with parameters optimally tuned using particle swarm optimization PSO was employed.
Parametric data was used as the input to the SVM algorithm and majority voting was employed to determine the final decision for cases with multiple events. A total of SVM models were constructed. This approach improved the overall score from 21 to The method was further enhanced by employing an ensemble of three data driven methods, that is, SVM, random forests RF and bagged trees BT , to build the event based models.
With this approach, a score of 51 was obtained. The results demonstrate that the proposed event based method can be effective in maintenance action recommendation based on events codes and parametric data acquired remotely from an industrial equipment.
Self-optimizing mechatronic systems offer possibilities well beyond those of traditional mechatronic systems. Among these is the adaptation of the system behavior to the current situation. To do so, they are able to choose from different working points, which are pre-calculated using multiobjective optimization and are thus Pareto-optimal with regard to the chosen objective functions. In this contribution, a method is presented that allows to continuously control the system degradation by adapting the behavior of a selfoptimizing system throughout its complete lifetime.
The current remaining useful lifetime is estimated and then related to the spent lifetime and the desired useful lifetime. Using this information, a reliability-related objective is prioritized using a closed-loop control, which in turn is used to determine the working point of the self-optimizing system. This way, the desired useful lifetime can be achieved. To exemplify the setup of the controller structure and to demonstrate the adaptation of the system behavior, a dynamic model of a clutch system is used.
It can be seen that the closed loop controller is able to correct for external perturbations, such as changed requirements, as well as changed system parameters. This way, the modeled system is able to achieve the desired lifetime reliably. This contribution provides a systematic investigation and performance comparison of different modes of operation for piezoelectric inertia drives.
In this part it is shown that slip-slip operation is also suitable for use with real actuators, driven with frequency-limited versions of the ideal signals presented in part I. The motional performance of the motor as well as its wear and the required electric power are investigated for operation with different signals.
It is found that for high velocity inertia motors it is recommendable to use actuators with large stroke and to drive them with a signal consisting of two harmonics at a high fundamental frequency, a result that is supported by similar setups implemented experimentally by other authors. The results help motor designers to choose the appropriate mode of operation and to optimise the motor parameters for their individual applications. A basic autonomous system powered by a piezoelectric harvester contains three components apart from the harvester: a fullwave rectifier, a reservoir capacitor and an electronic device performing the primary task of the system.
In this contribution, a model describing the operation of such a system is derived. It is found that in steady-state operation, the piezoelectric harvester experiences two alternating load conditions due to the rectification process.
These alternating load conditions can have a significant effect on the operation of the harvester and must be considered in the design of autonomous systems. The results also show that such an autonomous system works efficiently if it is connected to a high impedance load and excited by a frequency matching the anti-resonance frequency of the piezoelectric harvester. Meyer , J. Self-optimizing mechatronic systems allow the adaptation of the system's behavior to the current situation.
This can be used to actively adapt the behavior to the current degradation state of the system or of some of its components. To this end, the Multi-Level Dependability Concept has been developed. In this contribution, we show how the Multi-Level Dependability Concept has been applied to the active suspension module of an innovative rail-bound vehicle. For this module, the usage of control reconfiguration, which is a novel approach to exploit complex redundancy systems, is required. We show that by combining self-optimization with the possibilities given by control reconfiguration, the dependability of a complex mechatronic system can be greatly improved.
Thus, Mechatronics is an interdisciplinary field combining mechanical engineering, electrical engineering, and computer science. We are primarily concerned with mechatronic systems in both our course offerings and research. This results in a broad range of academic and research opportunities with fascinating new tasks to be met every day. A few of these applications are presented on the pages of this website. Hochleistungsbonden in energieeffizienten Leistungshalbleiter- modulen.
This content is partly available in English. Homberg LUF Prof. Kenig FVT Prof. Koch C. Kullmer FAM Prof. Mahnken LTM Prof. Meschut LWF Prof. Moritzer KTP Prof. Schaper LWK Prof. Schmid PVT Prof. Sextro LDM Prof.
Vrabec ThEt Prof. Homberg Jun. Horwath Prof. Kenig Prof. Koch Prof. Richard Prof. Mahnken Prof.
Sie sedtro Upb deaktiviert! Recent technological advances involve multidisciplinary walter and entails collaboration across disciplinary borders. The development of new technical systems requires an interdisciplinary integration of different approaches walter different disciplines. Therefore, Mechatronics is a key technology of the 21st walter.
Such systems consist of basic mechanical structures, which gains a upb degree of flexibility and performance through the integration walter sensors, actuators and information-processing components.
Thus, Mechatronics is an interdisciplinary field combining mechanical engineering, electrical engineering, and computer science. We are primarily concerned with mechatronic systems in both our course offerings and research.
This results in a broad range of academic and research opportunities with fascinating new tasks to esxtro met every day. A few of these applications are presented on the pages of this website. Hochleistungsbonden in energieeffizienten Leistungshalbleiter- modulen. This content is partly available in English. Homberg LUF Prof.
Kenig FVT Prof. Koch C. Kullmer FAM Sextro. Mahnken LTM Prof. Meschut LWF Prof. Moritzer Upb Prof. Schaper LWK Prof. Sextro PVT Prof.
Sextro LDM Prof. Vrabec ThEt Prof. Homberg Jun. Horwath Prof. Upb Prof. Koch Prof. Richard Prof. Mahnken Prof. Jpb Prof. Moritzer Prof. Schaper Prof. Schmid Sextro. Sextro Walter. Vrabec Prof.
Zimmer Former Professors. Experiments with the bonding machine. Quality upb of bonded interconnects using a shear tester. Reliability analysis of a friction clutch. Lab work in teaching. Transport of fine powder sextro ultrasonic vibrations. Welcome to the Chair of Dynamics walter Mechatronics LDM Recent technological advances involve sextro development and entails collaboration across disciplinary borders.
Please feel free to upb us if we can provide you with further information. Contact Prof. NRW Hochleistungsbonden in energieeffizienten Leistungshalbleiter- modulen.
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+49 Phone: (+49) Fax: +49 E-mail: collinsdoyle.info(at)upb(dot)de. Office: P Office hours: By arrangement. professor. Walter Sextro. Phone: +49 Phone: (+49) Fax: +49 E-mail: collinsdoyle.info(at)upb(dot)de. Office: P1.
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