Vision/force control of parallel robots

In this paper, force and position control of parallel kinematic machines are discussed. Cartesian space computed torque control is applied to achieve force and position servoing directly in the task space within a sensor-based control architecture. The originality of the approach resides in the use of a vision system as an exteroceptive pose measurement of a parallel machine tool for force control purposes. Three different mechanical structures with different degrees of freedom are considered to validate the approach.

► Parallel vision/force control scheme is applied on three different mechanical structures of parallel robots.
► Vision sensor is used to measure Cartesian poses of the robots end-effectors.
► The effect of sensor resolution and calibration on the position and force tracking errors is analyzed.
► Tracking errors depend only on sensor performances and are not affected by the machine kinematics and dynamics complexity.