PhD Projects

The PhD projects are accomplished in cooperation with the University of Rostock, Clausthal University, Liverpool John Moores University and industrial partners.

  • Modeling and Control in Breathing Therapy
    in cooperation with HOFFRICHTER GmbH Schwerin & University of Rostock
    M.Eng. Mathias Scheel
     
  • Modeling and Control in Heart Assistent Devices
    in cooperation with University of Rostock 
    MSc Alexander Sievert
     
  • Application of ILC-Methods for Optimization of Motion-Sequences in Service-Robot Systems
    in cooperation with University of Rostock 
    M.Eng. Sandra Baßler 
    since September 2014
     
  • Application of Subspace Identification Methods for Self-Adjustment of Controls in Embedded Systems
    in cooperation with University of Rostock 
    M.Eng. Mathias Marquardt
    since September 2014
     
  • Reactive and Cooperative Robot Controls Based on the SBC Framework 
    M.Eng. Birger Freymann
    in cooperation with Clausthal University
    since February 2014
    poster & video (work in progress)
     
  • Determination of Physical Process States Based on High Resolution Time Measurements
    in cooperation with University of Rostock and IAV GmbH
    M.Eng. Rocco Reinhardt
    since January 2014
  • Variant Management in Modeling and Simulation Using the SES/MB Framework
    M.Eng. Artur Schmidt
    in cooperation with University of Rostock
    (Thesis submitted 10/2018)
Project description

Project description

Modeling and Simulation (M&S) forms the basis of the modern development and planning process in engineering. Modeling deals with the abstraction of essential aspects of technical systems and their implementation in a model. During simulation the implemented model is executed aiming to gain knowledge about the system behavior. A single model execution is called a simulation run. A simple simulation experiment comprises many simulation runs with varied input variables. Complex simulation-based experiments are characterized by the integration of simulation with numerical methods such as optimization, screening or sensitivity analysis. Highly complex simulation experiments investigate the different model structures in addition to the parameter space.
The classical M&S approach is increasingly reaching its limits in engineering. One reason is the growing customers demand for customized products. This increases the variety and often the complexity of technical systems as well as of the resulting models and investigation objectives. This means that the specification and execution of simulation experiments includes not only a set of model variants with their parameter settings, but also combinations with numerical methods and their configuration. Furthermore, the sequence of variants to be investigated or numerical methods to be applied often arise from previously determined experiment results.
Accordingly, this work contributes to the development of general methods for variant management in M&S up to the simulation experiments’ level and their automated execution.
The proposed solutions are developed based on the ASIM procedure model, the modular-hierarchical modeling approach and the System Entity Structure/Model Base (SES/MB) framework. The variant management is based on different phases: variant analysis, variant formalization, variant implementation and variant generation. Furthermore, a modular-hierarchical structuring for simulation experiments is developed. By extending the SES/MB framework, not only model variants but complete experiment variants can be specified, implemented and generated. Moreover, a framework for automated experimentation based on the extended SES/MB framework is proposed. Finally, the methods are presented using an application example from the field of production and logistics.

 

  • New Control Strategies for a Pneumatic Driven Ventricular Assistant Device, VAD
    M.Sc. Alexander Sievert
    in cooperation with University of Rostock
    since May 2010
     
  • Reactive and Task-Oriented Robot Controls Using the SES/MB-Framework and the SBC Process Model
    (Former Working Title: Flexible Task-Oriented Multi-Robot Controls on the Basis of the SES/MB and DEVS Formalism)
    M.Eng Tobias Schwatinski
    in cooperation with University of Rostock
    since September 2009
    Task-oriented programming methods for offline robot control development are subject of many research activities. In this context task-oriented is understood as only specifying what task a robot should process and not how this task is being executed. In general simple task-based controls have several limitations e.g. that control structures and parameterisation of basic tasks are time invariant. The whole flexibility has to be implemented inside these basic tasks. This project focuses on the development of a time variant control system. Therefore any control strategy has to be specified in a declarative way. During real-time execution temporary controls are synthesised reiteratively and generated depending on actual process states and objectives. The SES/MB framework is used for this purpose. In future this approach will be generalised for cooperate robot controls. 
    poster (work in progress)
     
  • Contribution to the Control of the Air Ratio of a Gasoline Engine, Taking Into Account the Dynamics of a Three-way Catalyst
    (Beitrag zur Regelung des Luftverhältnisses eines Ottomotors unter Berücksichtigung der Dynamik des Dreiwege-Katalysator)
    Dr.-Ing. Michael Tomforde
    in cooperation with University of Rostock and IAV
    (Thesis submitted 2014, PhD examination 10/2014)
    In practical control systems, deadzone characteristics are encountered in a wide range of mechanical and electrical components, such as valves or DC servo motors. Another process that exhibits a deadzone characteristic is the three-way catalyst. Due to its oxygen storage ability, the normalized air-fuel ratio post catalyst remains at one despite air-fuel mixture variations pre catalyst, as long as certain levels of the oxygen storage state are not exceeded. 
    The aim of this project is to reduce the exhaust emissions produced by cars equipped with a three-way catalyst by improving the control of the air-fuel mixture. Low emissions are reached if post-catalyst air-fuel ratio remains at one despite large air-fuel mixture variations and a biased measurement of pre-catalyst air-fuel ratio. Typically, the aim of a controller for deadband processes is to overcome the deadzone in an optimal way, commonly by employing the deadzone inverse to cancel it. For this project, however, the aim of the controller is to keep the oxygen storage state within the deadzone. 
    In order to control the oxygen storage state (and pre-catalyst air-fuel ratio which is connected to the storage state via the deadzone), a model-based approach is proposed, since the storage state cannot be measured directly by a sensor. Thus, the project includes i) the development of a control-oriented model of a three-way catalyst, which has to be both accurate and simple enough to be calculated on the vehicles electronic control unit, and ii) the design of a suitable control strategy. 
     
  • Torque Coordination of Spark Ignition Engine - Control of Processes with Auxiliary Actuating and Control Variables
    Dr.-Ing Christian Steinbrecher
    in cooperation with University of Rostock and IAV
    July 2006 - 2010
    (Thesis submitted 03/2010, PhD examination 11/2010)
    Due to increasing demands on driving comfort, consumption and emission of modern combustion engines new combustion processes came to introduction of series production in the last years. The potential of these combustion processes in general can only be utilized by introduction of additional actuating and measure variables. Thereby an increasing complexity from control viewpoint is almost unavoidable. The choice of particular actuating variables has decisive influence on efficiency, comfort and waste gas emission. Besides the main manipulated variables, as e.g. the throttle position, there are some more different actuating variables that are in many cases only effective for limited operating ranges of the engine with different effects.
    The cooperative graduation project deals with the general problem of control with auxiliary actuating and control variables. Application emphasis of the procedures to be developed is located in the field of combustion engine controllers.
    One aim is to find the best compromise between efficiency, driving comfort and waste gas emission. This is achieved by an optimized choice, according to several criteria, of available actuating variables for the realization of the driving torque. 
    thesis
     
  • Application of sophisticated algorithms for spark ignition engine control
    M.Eng. Stefan Behrendt
    in cooperation with University of Rostock and IAV
    since March 2006
    The coordination of available actuators in modern engine control units (ECUs) is a challenging task. The broad variety of signals (e.g. throttle, advance angle, exhaust gas recirculation, injection, etc.) to influence the momentum and engine speed are coupled. Therefore a multi-variable control should manage these actuators to fulfill the control aim in an efficient manner. A compromise respecting further aims like comfort issues and exhaust gas emissions must be found. An available scheme to cope with these requirements is model predictive control (MPC). The incorporated optimization ensures the optimal selection of actuator signals under their constraints. 
    The cooperative graduation project is concerned with the development of a suitable quadratic program that solves the optimization within the MPC algorithm. It needs to fulfill the real-time requirements when run on high-potential micro-controllers (e.g. Infineon Tricore) that are incorporated in modern ECUs. 
     
  • Parallel and Distributed Simulation of Discrete-Event Systems within Engineering Applications
    M.Eng. Christian Stenzel
    in cooperation with University of Rostock and MTG Marinetechnik GmbH
    since March 2006
    Parallel and distributed simulation techniques of discrete-event systems evolved since the end of the 70s. Sophisticated synchronization algorithms mainly developed in the High Performance Computing (HPC) commmunity help to reduce the execution time of complex discrete-event simulation within a parallel execution. On the other hand, distributed simulation techniques, mainly developed within the military domain, allow the concurrent execution of interconnected simulation components in heterogeneous soft- and hardware environments. The union of these both historically and technically very different developments succeeded through the introduction of the standard High Level Architecture through the American Department of Defense since the mid-90s. 
    From the vantage point of the engineering domain only a few application fields can benefit from parallel and distributed simulation techniques of discrete-event systems. Especially for automation engineering a systematic analysis of the pros and cons of such techniques can not be found througout the literature. Due to this fact the project pursues three objectives: 
    (i) Evaluation of parallel discrete-event simulation methods in the field of automation engineering and related domains, (ii) evaluation of the standard HLA as military innovation in the field of automation engineering and related domais and (iii) statements to the practical relevance of parallel and distributed simulation methods and HLA. 
    Therefore, this project introduces basics in parallel and distributed simulation techniques. As a second step concepts and implementations to realize parallel and distributed simulations within often-used engineering tools, namely so-called Scientific and Technical Computing Environments (SCEs), are proposed. Upon this basis, the value of such simulation methods can be examined in detail at typical applications of automation engineering and related domains.
     
  • Simulation model-based Rapid Control Prototyping of Complex Robot Controls
    Dr.-Ing. Gunnar Maletzki
    in cooperation with University of Rostock
    since March 2005
    (Thesis submitted 06/2013, PhD examination 03/2014)
    Progressive robotics research opens up new application fields incessantly. Hence, demands on the development of robot controls are increasing. Easy programming and integration of different external hardware are of particular importance. The aim of every control implementation is to realise easy, safe, fast and cost-effective design and commissioning of robot applications. Therefore, it is essential to avoid re-implementations in the entire development process. 
    An approach for integrated modeling, simulation and operation, named "simulation model-based rapid control prototyping", is introduced and illustrated by the example of a sensor based robot control. It is discussed how simulation models have to be structured in the early system design stage in order to extend them to model-based control programs for the operation stage stepwise. 
    Objects of this research are (i) the prevention of re-implementations, (ii) the development of a task oriented programming approach, (iii) methods for an easy integration of different hardware and (iv) a concept for specification of high flexible and re-configurable controls. 
    thesis
     
  • Simulation Based Parameter and Structure Optimisation of Discrete Event Systems
    Dr. (PhD) Olaf Hagendorf
    in cooperation with Liverpool John Moores University and Syntax Software GbR
    July 2005 - July 2009
    (Thesis submitted 05/2009, PhD examination 07/2009)
    The research reported in this thesis details a new simulation based approach providing automatic reconfiguration and optimisation of both model structure and model parameters.This is achieved through a combination of simulation, optimisation and model management methods. Simulation is used to determine current model performance and an optimisation method, assistet by model management, searches for an optimal solution with repeated model parameter and model structure changes. The approach employs a meta-modeling method to define a set of model structure variants and includes a model base with pre-defined basic components. With the meta-modeling method the model management can determine specific model structures and create executeable models. 
    thesis
     
  • DEVS-Based Modeling and Simulation in Scientific and Technical Computing Environments
    Dipl.-Ing (FH) Christina Deatcu
    in cooperation with University of Rostock
    since January 2005
    Discrete Event System Simulation (DEVS) in our days is not widely accepted by engineers. This is mainly caused by the fact that engineers usually are rather familar with Scientific and technical Computing Environments (SCEs) than with the use of high level programming language simulation libraries. Furthermore, most of those comercial off-the-shelf tools are just suitable for specific application areas.
    One more aspect is that SCEs offer good opportunies to integrate DEVS modeling and simulation with other advanced techniques such as e.g. optimisation, ode solvers, data aquisition and analysis and integration of hardware.
    In this project main focus is put on modeling and simulation of hybrid system dynamic by utilisation of the features for solving ordinary differential equations within the most popular SCE Matlab. The approach includes modeling of structure variable systems, as well.
    A prototype for DEVS modeling and simulation is available here
     
  • Investigations on SCE Based Parallel Computing
    Dr.-Ing. René Fink
    in cooperation with University of Rostock and IAV
    March 2004 - December 2007 
    (Thesis submitted 07/2007, PhD examination 12/2007, honored with summa cum laude)
    Scientific and technical Computing Environments (SCEs) like Matlab are powerful tools for todays engineers, especially for desing problems. But the increasing complexity of calculations often lead to bottlenecks in interactive design processes. Parallel processing offers one possibility to bypass those bottlenecks. Within this research project, approaches for combining SCEs and parallel processing are investigated and classified. Several tools are examined with respect to their programming model, abstraction level and communication performance. Furthermore, several example programs are parallelized for runtime measurements and implementation effort investigations.
    posterthesis 
     
  • The Development of a Genetic Programming Method for Kinematic Robot Calibration
    Dr. (PhD) Jens-Uwe Dolinsky
    in cooperation with Liverpool John Moores University
    finished March 2001
    thesis 
M.Eng. Georg Kunert - Intelligent Control and Machine-Human Adaption of Jointed-Arm Robots

M.Eng. Georg Kunert - Intelligent Control and Machine-Human Adaption of Jointed-Arm Robots

since 2018

Project description is coming soon.