Cascaded PID Trajectory Tracking Control for Quadruped Robotic Leg

—This paper presents a cascaded Proportional Integral Derivative (PID) trajectory tracking controller to control the foot's tip of a quadruped robotic leg. The proposed robotic leg is designed and developed using electric Quasi-Direct Drive (QDD) actuators with high efficiency and torque density. Both the forward and inverse kinematics of the robotic leg are introduced to generate the desired path with the associated velocity of the foot's tip. Furthermore, the cascaded PID trajectory tracking controller is developed as a low-level controller to control the position and angular velocity of each leg's joint. Both the numerical simulation and experimental results showed that the proposed controller succeeded in tracking the desired trajectory with high accuracy and robustness of two different types of trajectories.