Adaptation to load variations of a planar biped: Height control using robust adaptive control

Abstract

“Turkey Walking” is a simple bipedal walking algorithm which is constructed using a control language called virtual model control. Three virtual components are used to achieve height, posture and speed control. The algorithm was successfully applied to steady dynamic walking of a planar biped. This paper explores the disturbance adaptation aspect of the algorithm, in particular, how to maintain the desired height when an external load is added to the system. This paper proposes to use a robust adaptive controller (RAC) to achieve the desired height control. The resulting control algorithm is applied to a simulated biped that walks over both level and rolling terrains while it adapts to discrete changes in payload. The capability to walk successfully over rolling terrain indirectly demonstrates the robustness of the implementation.