Servomotor control device

A servomotor control device comprising:

• a servomotor;
• a driven body that is driven by way of the servomotor;
• a connection mechanism. that connects the servomotor and the driven body to transmit power of the servomotor to the driven body;
• a first position detection section that detects a position of the servomotor;
• a second position detection section that detects a position of the driven body;
• and
• a motor control unit that controls the servomotor,
• wherein the motor control unit includes:
• a force estimation section that estimates a drive force acting on the driven body at a connection part between the connection mechanism and the driven body;
• a rigidity estimation section. that estimates a magnitude of rigidity of the connection mechanism based on a position of the servomotor detected. by the first position detection section, a position of the driven body detected. by the second position detection section, and a drive force estimated by the drive force estimation. section;
• and
• a rigidity variation detection section that detects a change in rigidity of the connection mechanism, based on the magnitude of rigidity estimated by the rigidity estimation section.