Constrained motion (force/position) control of flexible joint robots

The author develops a control scheme to perform force/position control with flexible joint robots when the end effector is constrained to move along a frictionless curved surface represented by algebraic constraints. The control scheme involves the exact cancellation of the nonlinear terms of the projected end effector dynamics in the position and force controlled directions. It is shown that it is not necessary to use end-effector force sensors in order to control a desired force trajectory in the force-controlled directions and a desired end-effector position trajectory along the position-controlled directions. Measurements of joint acceleration and jerk are also not necessary