Patent ID: 7706922

Claim:
A method for controlling a parallel kinematic mechanism machine having: a base fixed to the outside; a plurality of struts connected to the base via first universal joints; actuators which drive each strut; an end-effector connected to each strut via second universal joints; a control means for giving actuator command values to control each actuator; and a rotational resistance value storage means provided with the control means for storing rotational resistance values of the first universal joints and/or the second universal joints, the method comprising the steps of: a first step that determines each actuator command value for end-effector position command values and posture command values on the basis of predetermined kinematic parameters in the parallel kinematic mechanism machine; a second step that obtains rotational resistance values of first universal joints and/or second universal joints from the rotational resistance value storage means; a third step that computes the force and the moment exerted to each of the second universal joints by using the rotational resistance values; a fourth step that determines the resultant force and the resultant moment exerted to the end-effector from the force and the moment exerted to each of the second universal joints; a fifth step that computes an elastic deformation amount of a mechanism by using the resultant force and the resultant moment exerted to the end-effector and that computes the compensation amounts of the actuator command values using that amount; and a sixth step that updates the actuator command values determined in the first step with the compensation amounts determined in the fifth step taken into account, wherein in the third step, links comprising struts, first universal joints and second universal joints are regarded as independent serial link mechanisms, respectively, and the force and the moment exerted to connections between the strut and the end-effector by rotational resistance of universal joints in relevant serial link mechanisms are computed.