Biologically motivated push recovery strategies for a 3D bipedal robot walking in complex environments

Abstract

Though balancing is a fundamental part of human walking, it has been a challenging topic for bipedal robot. Compared to the versatile strategies of handling disturbances of human, current bipedal robots possess limited skills of managing external disturbances. Among them the capabilities of push recovery and maintaining balance are obviously of prior importance for a bipedal robot to walk in an unknown environment. Existing solutions, such as, capture point, walking phase modification, foot placement estimator and etc, are mostly based on simplifying a bipedal robot as a linear inverted pendulum, which result in omitting the effects of knee and ankle joints, natural dynamics, ground reaction forces and interaction between joints in sagittal and frontal planes in a 3D bipedal robot. To overcome those drawbacks, this paper presents a work that it classifies push types, presents a push detector, and proposes control strategies for managing continuous strong pushes occurring during walking. Based on biological and biomechanical research, more efficient strategies, e. g., hip and ankle strategy, a bent-knee strategy, can be transferred to control methods for bipeds. Through generating required torques and/or regulating joint positions in order to stabilize bipedal robot, a push recovery controller is proposed in this paper. Simulation results demonstrate that a 3D physically simulated anthropomorphic biped with 21 degrees of freedom can succeed in recovering from a strong push of up to 200 N during walking in different walking scenarios.

A Bio-Inspired Behavior Based Bipedal Locomotion Control — B4lc Method for Bipedal Upslope Walking

“…α target ankle y,f ore = 90 • + α hip y,f ore − α knee,f ore − β actual − θ sg (5) In walking phase 5 (Heel Strike), the posture reflex Lateral Foot Placement Slope and the local reflex Lock Hip Slope continues functioning. The posture reflex Weight Acceptance Slope described in the Weight Acceptance takes the charge of the knee control from the Lock Knee Slope.…”

“…Again, those ZMP-based control methods have many drawbacks as mentioned in. 4,5 Looking over the mentioned studies on the upslope walking for bipedal robots, the achievement is yet limited. Current research focus only on the modification of ZMP based on the pre-defined trajectories, a more systematic solution for this situation is still missing.…”

A Mechanism of Particle Swarm Optimization on Motor Patterns in the B4lc System

“…The optimization scenario is set up on the simulated robot with 21 degrees of freedom and 1.8m height. 7 The robot is designed to start the experiments with a stable walking on a flat ground. The parameters generated by Optimization Module known as the position of a particle are fed into Leg P ropel and Active Hip Swing.…”

Dynamically Stepping Over Large Obstacle Utilizing Pso Optimization in the B4lc System

“…changing speed locomotion, cyclic walking on even terrain and uneven terrain with small obstacles, as well as locomotion with external pushes. 2,3 However, compared to humans superior mobility in uneven ground, the B4LC system shows limited capability of large obstacle avoidance.…”