Speed and height control for a special class of running quadruped robots

In this work a novel control method is presented for controlling the forward speed and apex height of a special class of running quadruped robot, with a dimensionless inertia of 1, and one actuator per leg. Seeking to minimize the parasitic pitching motion in running, pronking is used as the target gait. The control design is based on the robot dynamics, allowing its application to a wide range of robots of the class studied. Moreover, the controller adjusts the robot speed and height, requiring knowledge only of the robot physical parameters. The control ensures that negative actuator work during the stance phase is zero, thereby reducing the power expenditure. Small, off-the-shelf DC motors are adequate for the control implementation, while results of application to a detailed robot model show good performance even when including leg mass, foot collision, motor limitations, foot slipping and other factors.