Andreas Jochheim

The Virtual Lab for controlling real experiments via Internet

The aim of the Virtual Lab project is to provide students access via the Internet to various experiments in control engineering, which are situated in control laboratories at several universities. Three German universities are currently developing the Virtual Lab as a network of remotely accessible laboratories in order to set up a prototype experimental environment. Students under consideration are usually located at geographically distributed location (e.g. at home) and have remote access to our experiments. The Virtual Lab is based on a distance education concept due to the fact that certain students (e.g. professionals) may be interested in studying even at places which are far away from campus eliminating the necessity to be there in person. In the Virtual Lab they are able to gain some practice in control theory at their convenience thereby saving travel time and cost. An approach based on a client/server architecture written in Java is proposed. This paper discusses the requirements of remote experimentation and presents the technical structure and first results of the project.

A multiuser virtual-reality environment for a tele-operated laboratory

In engineering studies, concepts taught through lectures are often complemented by laboratory experimentation. This contribution presents a collaborative virtual environment for a tele-operated laboratory. Students have access to the tele-operated laboratory via the Internet from anywhere at any time. They control the experiments exclusively with their standard Web browser; no additional software is needed. The collaborative environment allows the experimentation in a team. Group members are able to interact and discuss the results of their work. A real collaboration, such as in local experimentation, is possible. The tele-operated laboratory is based on a client/server architecture, which is implemented in the Java programming language.

Java-based Framework for Remote Access to Laboratory Experiments

Abstract This paper presents a platform independent approach to remote experimentation. It addresses a wide area of problems occurring in conjunction with remote laboratory experiments, starting with access management procedures via remote control to network- based analysis of measured data. It presents the architecture of the remote laboratory at the University of Hagen. Students have access to the experiments via Internet from anywhere at any time. They control the experiments exclusively with their standard Web browser, no additional software is needed. The remote laboratory is based on a client/server architecture, which is mainly implemented in the Java programming language. The methods and software modules developed for the lab are generic and frequently used in several remote experiments at some German universities. Furthermore the paper discusses the motivation of remote experimentation.

Identification and compensation of force ripple in linear permanent magnet motors

The main problem in improving the tracking performance of linear permanent magnet motors is the presence of force ripple caused by the irregular magnetic field of the permanent magnets and inaccuracy in electronic commutation by the servo amplifier. The paper presents a method to identify and compensate the effect of the force ripple in servo control. A physical model of the linear motor and the force ripple is derived first. The identification of the model parameters is done in a closed position control loop by measurement of the control signal for movements with different load forces. No additional sensors are necessary. A comparison of the tracking performance with and without ripple compensation is given.

The Virtual Lab for teleoperated control of real experiments

The Virtual Lab is an experimental setup for students in control systems engineering, which is accessible via Internet. The experimental system is an omnidirectional vehicle; several different tasks can be carried out with this vehicle ranging from kinematics and dynamics analysis to controller design and system identification. Teleoperation control options for these experiments have been chosen in addition to conventional practice because of the following two major reasons: to share this experimental setup with other universities, and to simplify experiments for home-learners and professionals in a distance teaching environment.

Group-based learning using a remote laboratory

Presents a collaborative learning environment for a remote laboratory. Students have access to the remote laboratory via the Internet from anywhere at any time. They control the experiments exclusively with their standard Web browser, no additional software is needed. The learning environment allows experimentation in a team. The group is able to interact and to discuss the results of their work. A real collaboration like in local experimentation is possible. The remote laboratory is based on a client/server architecture, which is mainly implemented in the Java programming language. Furthermore the contribution discusses the motivation of group-based learning using remote experiments.

MOTION CONTROL OF LINEAR SYNCHRONOUS MOTORS WITH FORCE RIPPLE COMPENSATION USING CURRENT SHAPING

Abstract The main problem in improving the tracking performance of linear synchronous motors is the presence of force ripple caused by the irregular magnetic field of the permanent magnets and inaccuracy in electronic commutation by the servo amplifier. In this paper a method to compensate the force ripple based on shaping of the phase current waveforms is presented. The method generates optimized current waveforms which produces minimal copper losses and maximize motor efficiency. The current waveforms are based on a Fourier series approximation. A comparison of the tracking performance with and without force ripple compensation is given.

Multiuser Environment for a Teleoperated Laboratory

Abstract In engineering education, concepts taught through lectures are often complemented by laboratory experimentation. This contribution presents a collaborative virtual environment for a teleoperated laboratory. Students have access to the teleoperated laboratory via Internet from anywhere at any time. They control the experiments exclusively with their standard Web browser, no additional software is needed. The collaborative environment allows the experimentation in a team. The group is able to interact and to discuss the results of their work. A real collaboration like in local experimentation is possible. The teleoperated laboratory is based on a client/server architecture, which is mainly implemented in the Java programming language.

Teleoperation von Laborexperimenten (Teleoperation of Laboratory Experiments)

Laborexperimente sind integrale Bestandteile in natur- und ingenieurwissenschaftlichen Studiengängen. Ihre Zielsetzung ist die Umsetzung und Verifizierung der Theorien an realen Systemen sowie das Erlernen der Handhabung technischer Versuchsanlagen. Durch Teleoperation von Laborexperimenten können die zeitlichen und räumlichen Einschränkungen von lokalen Experimenten überwunden werden. Der Beitrag beschreibt einen plattformübergreifenden Ansatz der Teleoperation von Laborexperimenten über das Internet, der an der FernUniversität Hagen in Kooperation mit den Universitäten Bochum und Dortmund entwickelt und erprobt wurde.

Virtuelles Labor-Nutzung vernetzter Multimediatechnologie

Die didaktischen Hauptelemente einer Universitat sind Vorlesungen, Ubungen, Laborpraktika und Seminare. An Fernuniversitaten werden die Vorlesungsunterlagen und entsprechende Ubungen zu den Studierenden nach Hause geschickt, wo die Unterlagen studiert und die Ubungen bearbeitet werden, bevor sie zur Korrektur zuruckgesandt werden. Ublicherweise werden die Studienmaterialien und Ubungen den Studierenden in gedruckter Form zugesandt, woraufhin diese ihre Antworten ebenfalls per Post zuruckschicken.