Adaptive virtual model control of a bipedal walking robot

Abstract

The robustness of bipedal walking robots can be enhanced by the use of adaptive control techniques. We extend a previous control approach, virtual model control (VMC) (Pratt et al., 1997), to create adaptive virtual model control (AVMC). The adaptation compensates for external disturbances and unmodelled dynamics, enhancing robustness in the control of height, pitch, and forward speed. The state machine used to modulate the virtual model components and to select the appropriate virtual to physical transformations (as in traditional VMC) is also used to inform the adaptation about the robot's changing configuration. The design procedure for AVMC is described in this paper and simulation results are presented for a planar walking biped.