Method for controlling parallel kinematic mechanism machine and control apparatus therefor

A control apparatus for a parallel kinematic mechanism machine comprising:

• 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, wherein the apparatus comprises:
• an actuator command value computing means to determine 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 resultant force computing means that computes the force and the moment exerted to each of the second universal joints using the rotational resistance values obtained by rotational resistance value storage means, and determines the resultant force and the resultant moment exerted to the end-effector from the computed force and the moment exerted to each of the second universal joints;
• a compensation amount computing means that computes an elastic deformation amount of a mechanism by using the resultant force and the resultant moment exerted to the end-effector, and computes the compensation amounts of the actuator command values using that amount;
• and
• the control means that updates the actuator command values determined by the actuator command value computing means taking the compensation amounts determined by the compensation amount computing means into account.

A method for controlling a parallel kinematic mechanism machine having a base fixed to the outside;

• a plurality of struts each being connected to the base via first universal joints;
• respective actuators for driving each strut;
• an end-effector connected to each strut via respective second universal joints;
• and load detectors that detect a load of each actuator, the method comprising the step of:
• estimating rotational resistance values of the first universal joints and/or the second universal joints on the basis of the load detected by the load detectors.

A method for controlling a parallel kinematic mechanism machine having a base fixed to the outside;

• a plurality of struts each being connected to the base via first universal joints;
• respective actuators for driving each strut;
• an end-effector connected to each strut via respective second universal joints;
• and load detectors that detect a load of each actuator, the method comprising the step of:
• estimating rotational resistance values of first universal joints and/or second universal joints as composing elements of rotational resistance vectors,
• by finding relevant rotational resistance vectors of first universal joints and/or second universal joints from load vectors configured by loads detected by the load detectors,
• in conformity to the fact that
• the equation that expresses the internal force exerted to the end-effector by rotational resistance of the first universal joint and/or second universal joint,
• by the use of the Jacobian matrix related to each leg unit and rotational resistance vectors of first universal joint and/or second universal joint by regarding each leg unit including each first universal joint, corresponding strut, and corresponding second universal joint as a serial link mechanism,
• is equal to
• the equation that expresses the internal force exerted to the end-effector by the rotational resistance of the first universal joint and/or second universal joint by the use of the Jacobian matrix of the parallel link mechanism and load vectors of each actuator from the statics relationship of the parallel link mechanism.

A control apparatus for a parallel kinematic mechanism machine, comprising:

• a base fixed to the outside;
• a plurality of struts each being connected to the base via first universal joints;
• respective actuators for driving each strut;
• an end-effector connected to each strut via respective second universal joints;
• and
• load detectors that detect a load of each actuator, wherein
• rotational resistance values of the first universal joint and/or the second universal joint are estimated on the basis of the load detected by the load detector.

A control apparatus that controls actuators in a parallel kinematic mechanism machine, comprising:

• a base fixed to the outside;
• a plurality of struts each being connected to the base via first universal joints;
• respective actuators for driving each strut;
• an end-effector connected to each strut via respective second universal joints;
• and
• load detectors that detect a load of each actuator, wherein rotational resistance values of first universal joints and/or second universal joints as composing elements of rotational resistance vectors are estimated,
• by finding relevant rotational resistance vectors of first universal joints and/or second universal joints from load vectors configured by loads detected by the load detectors,
• in conformity to the fact that
• the equation that expresses the internal force exerted to the end-effector by rotational resistance of the first universal joint and/or the second universal joint,
• by the use of the Jacobian matrix related to each leg unit and rotational resistance vectors of the first universal joint and/or second universal joint by regarding each leg unit including each first universal joint, corresponding strut, and corresponding second universal joint as a serial link mechanism,
• is equal to
• the equation that expresses the internal force exerted to the end-effector by the rotational resistance of the first universal joint and/or the second universal joint by the use of the Jacobian matrix of the parallel link mechanism and load vectors of each actuator from the statics relationship of the parallel link mechanism.