An intuitive approach for quadruped robot trotting based on virtual model control

This article presents an intuitive approach based on virtual model control for quadrupedal dynamic locomotion, aiming at simple and robust trotting control. The controller consists of two main modules: stance phase virtual model control for full control of the robot body and swing phase virtual model control for control of swing legs. We combine the decomposed virtual model control with Raibert's method to intuitively regulate the height, speeds and attitude of the body during stance phase, with special attention to the rotation about the body diagonal line. To unify the control law and further simplify the controller, virtual model control is also implemented for swing legs to follow the planned swing foot trajectories that are self-adapting depending on the speeds of the robot. Simulations including forward trotting, lateral push recover, and lateral travel are presented to demonstrate the effectiveness and robustness of our controller.