Force and contact transient control using nonlinear PD control

Describes the use of a nonlinear proportional and derivative (NPD) controller for both non-contact transition force control (NCTFC) (zero velocity when contact occurs) and contact transition force control (CTFC) (non-zero velocity when contact occurs). The authors present a gain design method for NCTFC. Simulations and experiments on the Sarcos Dextrous Arm show that PD control becomes unstable for CTFC while NPD control is stable and reaches the steady state quickly. Experiments with human subjects on NCTFC and CTFC are also presented