Variable Leg Stiffness Walking Control for the Biped Robot with Torso

The planar stable walking control of the biped robot with torso is studied in this paper. Firstly, improve the spring-mass model by adding a rigid torso to the hip joint and then get the spring-mass model with torso. Secondly, control the torque applied to the hip joint and regulate the stiffness of the springy leg to make the robot converge to the desired gait. Due to the nonlinear and strong coupling characteristics of the system model, use the feedback linearization to transform the nonlinear model into a linear model. Thirdly, the robot's torso angle and hip joint trajectory are controlled overall using PD control and P control. Finally, based on the theoretical analysis, the control method is simulated. The simulation results show that the feedback linearization and variable leg stiffness control methods used in this paper can achieve stable walking of the biped robot with torso, and have good anti-disturbance performance.