Boundary Condition Relaxation Method for Stepwise Pedipulation Planning of Biped Robots

A completely stepwise online pedipulation planning method is proposed. It is an analytical approach based on the general solution of the equation of motion of an approximate dynamical biped model whose mass is concentrated at the center of mass. A physically feasible referential trajectory with a constraint about the reaction force taken into account is planned only in one interval by relaxing the boundary condition, namely, by admitting a certain level of error between the desired and actually reached states, and discontinuity of zero-moment point at each end of the interval. It potentially creates responsive motions that require strong instantaneous acceleration. A semiautomatic continual pedipulation planning method is also presented. It generates a referential trajectory of the whole body only from the next desired foot placement. The validity of the proposed method is ensured through experiments with a small anthropomorphic robot.