Friction Compensation, Gain Scheduling and Curvature Control for a Flexible Parallel Kinematics Robot

For a parallel manipulator with a kinematic loop and a highly flexible link, a comprehensive control approach including friction compensation for the drive train, gain scheduling and active oscillation damping is considered. Friction compensation based on the Stribeck as well as the LuGre models and gain scheduling are used to improve the position control. A curvature controller, which is based on a nonlinear flexible multibody system and on an accurate position control, actively damps the oscillations of the parallel manipulator. First experimental results are presented to confirm the utility of the implemented concepts.