Parallel Stiffness Actuators with Six Degrees of Freedom for Efficient Force/Torque Control Applications

On-line knowledge acquisition and enhancement in robotic assembly tasks

“…Vibration at the peg's tip has been employed following an elliptical trajectory using a piezoelectric vibrator with frequencies in excess of 7 kHz [20]. High stiffness provided by a parallel actuator at the robot's wrist in conjunction with force/torque (F/T) sensing has also been used so that stable contact with stiff environments can be obtained [21]. Learning by demonstration has also been tested using a dextrous hand and tele-operation [22].…”

Hybrid Position-Force Control of a Cable-Driven Parallel Robot with Experimental Evaluation

“…There exist solutions like air controlled cylinders or stiffness actuators, which can be installed at the robot's platform to enable for the control of process forces. Osypiuk and Kröger (2011) The drawback is that the system adds additional weight to the platform and the direction of the force is typically fixed w.r.t. the platform frame.…”