Trajectory planning strategy is proposed to jump over an obstacle integrated three various dynamics in one-legged multi-joint hopping robot. A concept of inertia matching ellipsoid and directional manipulability are extended to optimize take-off postures. Optimized results have been used to plan hopping trajectory. Aimed at the sensitivity of motion trajectory to constraint conditions, a 6th polynomial function is proposed to plan hopping motion and it has a better robustness to the parameters change of constraint conditions than traditional 5th polynomial function. During flight phase, an iterative method and angular momentum theory are used to control posture to a desired configuration. In order to lift foot over an obstacle, correction functions are constructed under unchanged boundary constraint conditions. During stance phase, robot trajectories are planned based on internal motion dynamics and steady-state consecutive hopping motion principle. A prototype model is designed, and the effectiveness of the proposed method is confirmed via simulations and experiments.
multi-joint hopping robot; trajectory planning; inertia matching ellipsoid; iterative method
