Contact transition and force tracking control with joint acceleration feedback damping

Joint acceleration feedback control of high bandwidth is employed to damp oscillations during both the contact transition and force tracking phase. In this control scheme, a classical integral force controller is refined by means of joint acceleration and velocity feedback. This is intended to achieve a stable contact transition without need for adjusting the controller parameters adaptive to the unknown or changing environments, and also to stabilize the force tracking control in the presence of abrupt disturbances during the post-contact phase. Extensive experiments are conducted on the third joint of a three-link direct-drive robot to verify the proposed scheme for various stiffness of the contacted environments, including elastic (sponge) less elastic (cardboard) and hard (steel plate) surfaces. Results are compared with experimental ones by transition control without acceleration feedback.