Motor control system which corrects backlash

A motor control system which corrects a backlash between a moving part which is driven by a motor and a driven part which is driven by that moving part, comprising:

• a first position detecting part which detects a position of said moving part,
• a second position detecting part which detects a position of said driven part,
• a difference calculating part which calculates a difference between a first position detection value which said first position detecting part detects and a second position detection value which said second position detecting part detects,
• a judging part which judges if said moving part has engaged with said driven part when said moving part is made to move from any initial position in a first drive direction and in a second driven direction opposite to said first drive direction,
• a holding part which holds said difference calculated by said difference calculating part as initial difference linked with said first drive direction or said second drive direction, when said judging part judges that said moving part has engaged with said driven part, and
• a correction amount calculating part which calculates a backlash correction amount of said backlash,
• wherein said correction amount calculating part using the difference calculated by said difference calculating part based on the current positions of said moving part and said driven part and said initial difference held by said holding part to calculate said backlash correction amount;
• and
• wherein said backlash correction amount is added to a first position difference between a position command value of the moving part and the first position detection value or is added to a speed command value of the moving part.