Body state estimation in a quasi-passive bipedal robot during dynamic walking

The authors present a body state estimator for a quasi-passive bipedal robot with dynamic gaits, to estimate the key performance parameters of the robot during stable walking motion. Based on the traditional inertial measurement unit, this approach integrates accurate pitch and roll measurement result to correct the impact for acceleration by gravity, in order to improve the performance of the body state estimator. The method implements the estimation procedure off-line, using data extracted from various repeated walking motion of the robot and evaluates its performance with reference to a visual ground-truth measurement system. Satisfactory results are obtained by using body state estimator to analyze both robot walking and human walking. The results can be used as feedback to improve the stability of the walker.