In this paper, I suggest active suspension technique for a rapid mobile robot, KDMR-1. The major purpose of KDMR-1 is object delivery. The KDMR-1 is designed to have a maximum speed of 12.8 km/hr. At this high speed, ground disturbances caused the mobile robot to vibrate. To reduce vibration, we controlled the compliance of the active suspension. The active suspension, consisting of 3-DOF highly geared electric motors was controlled by the Cartesian computed torque (CCT) control. The CCT control method has been studied widely in the literature; however, there have been few experimental realizations in joint position controlled robots. The CCT control was used to improve joint compliance while maintaining position control accuracy. We reduced the Cartesian disturbances at high speeds successfully using joint compliance. We focused on the experimental evaluation of the ability of the CCT control to improve joint compliance in the position-controlled system equipped with highly geared electric motors. A rapid object delivery experiment demonstrated the effectiveness of the active suspension.