Recovery of a Humanoid Robot from a Destabilising Impact

This paper examines the case of a bipedal robot under an external impact along the axis of the two supporting feet. The dynamics of the robot is modelled using the 3-Mass Linear Inverted Pendulum Model. The model shows that, for impacts below a given threshold, the robot recovers naturally and no corrective action is required. For larger, destabilising impacts, this paper described how to calculate a single or a sequence of corrective steps. The key information used for the calculations is the initial velocity generated by the impact. The behaviour of the model for various initial configurations and impact parameters is illustrated by simulations.