Experimental investigation into contact transition control with joint acceleration feedback damping

Joint acceleration feedback control is employed to damp oscillations during the contact transition with non-zero approaching speed. A classical integral force controller is refined by means of joint acceleration and velocity feedback. The intention is to achieve a stable contact transition without need of adjusting the controller parameters adaptive to the unknown or changing environments. 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 (hardboard) and hard (steel plate) surfaces. Results are compared with those experimental ones by the transition control with only velocity feedback damping. The advantages offered by our approach are addressed.