Motor control device for compensating backlash

A motor control device for compensating backlash between a movable unit driven by a motor and a driven unit driven by the movable unit, the motor control device comprising:

• a position command generating unit for generating a position command for the driven unit;
• a first position detecting unit for detecting a position of the movable unit;
• a second position detecting unit for detecting a position of the driven unit;
• a difference calculating unit for calculating a difference between a first positional detection value detected by the first position detecting unit and a second positional detection value detected by the second position detecting unit;
• a judging unit for judging whether or not the movable unit is engaged with the driven unit when the movable unit is driven in a first direction and in a second direction opposite to the first direction;
• a retaining unit for retaining the difference calculated by the difference calculating unit as an engaging difference, in association with the first direction or the second direction, when the judging unit determines that the movable unit is engaged with the driven unit;
• and
• a compensation amount calculating unit for calculating a backlash compensation amount, based on the difference calculated by the difference calculating unit, and the engaging difference retained by the retaining unit,
• wherein the judging unit is adapted to determine that the movable unit is engaged with the driven unit when a movement amount of the driven unit exceeds a threshold.