Patent ID: 6943519

Claim:
A method of compensating for position-dependent length changes in a plurality of closed kinematic chains that connect a stationary first element to a movable second element, with a weight acting on the second element, comprising the steps of: assigning to the kinematic chains respective actuators which define a relative movement between the first and the second element based on a freely definable sequence of control instructions, determining corresponding positions of the respective actuators required for desired positions of the movable element via a back transformation, distributing the weight acting on the movable element over the respective kinematic chains by applying rules associated with the back transformation to thereby determine forces acting on the respective kinematic chains, determining from the forces acting on the respective kinemetic chains length changes of the kinematic chains in accordance with respective compliance values of the kinematic chains, and applying to the actuators corresponding compensation values which compensate for the respective length changes, wherein each kinematic chain comprises links and connecting elements of constant length.