Virtual Variable Stiffness Control Method for Quadruped Robot Leg based on Contact Event

Aiming at the variation of different task focuses of the quadruped robot in response to different contact events, this paper proposes a virtual stiffness adaptive compensation strategy that introduces the perception of proprioceptive disturbance dynamics. The method first relies on floating base dynamics and generalized momentum to establish the estimation method of the disturbance force of the quadruped robot. Then the method of recognizing different contact events in the base and legs of the quadruped robot is established by building band pass filter and isolation filter for estimating the force and by classifying the contact events into hard and soft contacts. Then by combining the method with the virtual model control method of the quadruped robot and swing leg, the recognized contact events can help the robot to change the virtual coefficients, and realized more accurate leg trajectory tracking.