Force/motion control of robotic manipulator in end milling process

In robotic contour cutting, the tracking accuracy tolerance is very important. The tracking accuracy in contour paths is studied as a function of the commanded trajectory step resolution and the natural frequency of the reference model.;Three-dimensional cutting force dynamics of end milling is developed, and position error sources of robotic machining are studied. A strategy to compensate cutting force in force/motion control of robotic machining is established.;Position error is evaluated at the cutting tool end through reference points. The unique character of the proposed approach is that the wrist-force sensor is used not only for force measurement and compensation, but also to detect the position error between the actual and kinematically calculated positions. Position error compensation is feedforwarded to improve accuracy in robotic contour end-milling.;A nonlinear model-reference adaptive control system based on Liapunov stability consideration is proposed for robotic manipulators. Asymptotic stability of the computed torque method is proven using model reference formulation. Robustness of the control system against model uncertainties are studied.