Patent ID: 7971496
Filing Date: 2011-07-05
Classification: B25J,B66C,B66F,G05B

Abstract:
1. A method for determining and possibly compensating for the elastic deformation between a fixed and a movable platform of a parallel-kinematic device under load, comprising the steps of: determining and storing the geometry of the hinge points on the fixed platform and on the movable platform or possibly on an intermediate platform; determining and storing the equivalent spring constants of the mountings in the foundation and of the movable or possibly of the intermediate platform; determining and storing the equivalent spring constants of the actuators; determining and storing the equivalent spring constants of the bearings; determining the instantaneous theoretical lengths of the actuators based on the settings of their drives; determining the theoretical positions in space of all the hinge points or of all the actuators based on the theoretical lengths; determining the forces acting on the individual actuators, joints, and bearings based on the determined geometry and known or determined load; determining the real, instantaneous position of the bearings and the lengths and positions of the actuators to determine the real, instantaneous geometric model and thus the real, instantaneous position of the movable platform; and comparing the real, instantaneous position of the movable platform with the previously calculated theoretical position and actuating the appropriate actuator to bring the real, instantaneous position into agreement with the theoretical position, if necessary.