Energy-Optimal Design of Walking Machines

In a general definition of robot components given by Wolfram Stadler, communications and power supply are included showing the close relation between robots and walking machines. Both of them are based on mechatronics allowing variable programmable operations.Biped walking represents a complex motion of sophisticated systems in nature as well as in engineering. A young human requires more than 1 year to learn walking while old humans need additional devices for save walking. While passive machines walk only on inclined planes, active machines may walk in all kinds of terrains. However, the active devices known from literature consume so much energy that their operation time is very restricted.In this paper the modeling of walking systems using the method of multibody dynamics is presented including the contact and impact problem inherent to biped walking. The limit cycle of passive motions is investigated as well as the related stability using shooting approaches with optimization techniques. The active machines proposed are controlled using the principles of inverse dynamics and advanced linear control strategies. In particular, the energy consumption between passive and active walking machines is compared by a coefficient of efficiency. At the time being human walking is still the most efficient and it is considered as a benchmark for the mechatronic design of walking machines.