Biomedical subjects

Friedrich Pfeiffer

Publications and source records attributed to Friedrich Pfeiffer.

3 recordsLinked to original sources

PubMed2007

Walking: technology and biology.

If all the signs are to be believed, then the twenty-first century will technologically be characterized by machine walking and its relevant products, which possess all chances to become real bulk goods in the course of the next decades. With several university institutes and with Honda and Sony from the industrial side, Japan is today and without any doubt the leading nation in research and development of walking machines. The US and Europe follow at some distance. Walking machines will influence all areas of daily and industrial life and, with the fast evolution of artificial intelligence, will become a real partner of human beings. All relevant technologies are highly interdisciplinary, they will push the future technologies of all technical fields. The special issue on this topic gives a selection of walking machine research and development including some aspects from biology.

Artificial Intelligence↗

PubMed2007

The TUM walking machines.

This paper presents some aspects of walking machine design with a special emphasis on the three machines MAX, MORITZ and JOHNNIE, having been developed at the Technical University of Munich within the last 20 years. The design of such machines is discussed as an iterative process improving the layout with every iteration. The control concepts are event-driven and follow logical rules, which have largely been transferred from neurobiological findings. At least for the six-legged machine MAX, a nearly perfect autonomy could be achieved, whereas for the biped JOHNNIE, a certain degree of autonomy could be realized by a vision system with appropriate decision algorithms. This vision system was developed by the group of Prof. G. Schmidt, TU-München. A more detailed description of the design and realization is presented for the biped JOHNNIE.

Artificial Intelligence↗

PubMed1994

Unsteady processes in machines.

Couplings in machines and mechanisms always have play and friction. While under loading, stick-slip phenomena and impact events can take place. Such processes are modeled as multibody systems whose structure is time variant or unsteady. The time-variant number of degrees of freedom is due to stick-slip contacts. The coupling characteristics become unsteady, for instance there exist jumps in the loads, if impacts occur. For establishing a uniform theory for such phenomena we use a Lagrangian approach connecting the additional constraint equations and the equations of motion by Lagrange multipliers, which are proportional to the constraint forces. Stick-slip and impact events are evaluated by indicator functions leading to special numerical algorithms for the search of switching points. Contact problems are formulated as a complementarity problem which can be solved by efficient algorithms. The theory is applied to rattling in gears, impact drilling machines, turbine blade dampers, and a woodpecker toy. In some of these applications, chaos as a result of bifurcations is possible, which results from variations in the parameters. (c) 1994 American Institute of Physics.

Journal Article↗