Helmut Hoyer

Architectural Concepts of a Semi-autonomous Wheelchair

A new smart, sensor-assisted wheelchair system for the vocational rehabilitation of people with severe and multiple handicap has been developed in the research project OMNI within the CEC TIDE programme. The project finished in December 1996. The objective of the project was the development of an advanced wheelchair with omnidirectional manoeuvrability and navigational intelligence that is well suited for vocational rehabilitation. It provides an opportunity of intuitive wheelchair control to people with severe physical or multiple (incl. mental) handicap. Cramped offices are made accessible by the small outline, high mobility and navigational support of the chair. The users safety and driving accuracy are guaranteed by a novel sensor system and navigation modules. A wide range of control devices can be used with the adaptable human-machine interface which also controls environmental devices. Within this project, the user focused principle has strongly been followed (this includes the involvement of users from the preparatory work to the evaluation of the results).

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.

Autonomous robot technology for advanced wheelchair and robotic aids for people with disabilities

Abstract The use of robotic technology in assistive devices opens new opportunities for people with severe disabilities (tetraplegia, spinal cord injuries, etc.) at work and in their private homes. It can reduce social exclusion and assist social and vocational integration. Highly manoeuvrable wheelchairs for indoor use and wheelchair mounted arms are of particular importance. Due to their mobility, they are available on different locations, e.g. in different rooms of a dwelling for use in activities of daily living (ADL). Practical experiences and tests of a wheelchair mountable robot by users with disability are reported. This user analysis leads to further development of the human-machine interface and system integration towards an improved usability. A new type of highly manoeuvrable wheelchair is introduced. The modular software design provides comfortable means of integration. Parts of the work described are carried out within the ESPRIT project PMMA, the SPRINT project IMMeDIAte and the TIDE project OMNI.

Planning of optimal paths for autonomous agents moving in inhomogeneous environments

Long-range route planning is an important feature of autonomous agents guidance and control during out-door missions. Offline path planning for any manoeuvres in cluttered environments depends on the pre-mission knowledge about the topographical features of the landscape between the agents start position and goal position. A topographical landscape consists of regions with different traversal costs, and it is not binary in nature (in terms of passable/impassable). For certain extraterrestrial or cross-country missions, where a lack of vehicular resources has to be handled, there is a strong need to calculate an optimal path according to a given optimization criterion. This paper presents an optical approach to find optimal paths in inhomogeneous environments, which follows from FERMATs principle. It is derived from the beam propagation method, which is commonly used in optical research areas.

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.

Online collision avoidance for two robots in 3D-space

Previously presented methods for online collision avoidance for robots in a two-dimensional space are extended to the third dimension. Even if global planning and programming are done in multi-robot workcells, in real-world applications it is important to supervise the actual movements and to influence them if necessary, due to sensor-driven changes of the trajectories, incomplete information on the environment, and possible failures in mechanical or electrical devices. Therefore, precautions have to be taken for online collision detection and avoidance. Besides the considerations of dynamics for online collision avoidance in 3-D space, attention is given to the online computing of the algorithms and their execution on parallel hardware.

Regelungstechnik multimedial, Lernen am PC (Multimedia for Control Theory, PC-based Learning)

Abstract Dieser Beitrag beschreibt einen multimedialen Lernkurs zur Regelungstechnik, so wie sie in Grundlagenvorlesungen an wissenschaftlichen Hochschulen gelehrt wird. Der Lernkurs wird ergänzt durch eine Simulationsumgebung, die zu Übungszwecken und für praktische Anwendungen einsetzbar ist. Dieser multimediale Kurs dient als Unterstützung bei der heimischen Nachbearbeitung von Lerninhalten durch Studierende sowie zur Wiederauffrischung von Wissensinhalten bei bereits berufstätigen Ingenieuren. Daher berücksichtigt er die speziellen Bedürfnisse sowohl der Fernlehre als auch des lebenslangen Lernens. Die auf einer CD-ROM basierende Version dieser Lernumgebung wird hier vorgestellt. Wir berichten von methodischen Aspekten und gewonnenen Erfahrungen während ihrer Erstellung und geben Resultate aus einer studentischen Evaluation wieder.

Minimum Time Pole Assignment Control of a Position System Servo-Drive

Abstract This paper demonstrates by experimental results properties of the minimum time pole assignment control algorithms applied to positioning the cart of a gantry crane laboratory model driven by a DC motor. This new type of controllers for constrained systems is tuned by a simple procedure based on generalisation of the method by Ziegler and Nichols. It shows that the control design problem may be treated in a simple and direct way - much more efficiently as it is usual by means of two step procedure based on standard linear techniques extended by some anti-windup measures.

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.