Experimental Evaluation of a Force Regulation Scheme on a Planar Robot Without Force Sensors

Robot manipulators are complex systems that are frequently exposed to various sources of disturbances, such as unmodeled dynamics, varying payloads, friction, unexpected collisions, or compliant interaction forces. Perturbation observers find two common applications in the literature concerning robot manipulators: a) mitigating and rejecting these perturbations, and b) serving as force/torque (F/T) estimators in situations where an F/T sensor is unavailable for force control applications or to design cost-effective robotic systems for interaction tasks. In this study, we conduct an experimental assessment of a force regulation task employing a virtual force sensor based on the perturbation observer proposed by Mohammadi et al. The effectiveness of this approach is validated through a comparison with the performance of an industrial force sensor.