Parallel visual-force control

Visual servos are inherently inaccurate due to lower resolution of reasonably priced cameras and poor calibration of robot-camera relative position and robot kinematic model. Instead of trying to improve those factors the paper presents an alternative solution in which the grasping operation is aided by force control which accommodates positional inaccuracies. The developed control law utilizes the superposition of visually generated desired position and desired mechanical impedance of the manipulator.