Force-Control Capabilities for Lightweight Industrial Robots

This paper investigates the capabilities of lightweight industrial robots with respect to force/torque control. Two robots were chosen for this investigation. One robot was equipped with an internal force/torque sensor, while the other used motor current values to measure forces and torques. Many approaches of robot force control have been examined in the past. However, it is often difficult to implement these algorithms in commercial systems, as the robot controller lacks adequate programming features. The robotic system used in this paper included a precast functions for force control. It seems necessary to study the behavior of such robots when force control is activated. In particular, we analyzed the forces where the end-effector made contact with its environment (coming from free space). In the case of persistent contact, the desired contact force was altered, and the step responses were investigated. In addition, a more complex task involving force control was developed and presented to evaluate the quality of the precast force-control functions.