Abstract: A control device includes: a command generating unit that generates a command for a motor, a correction-amount calculating unit that performs correction-amount calculation processing for calculating a correction amount for the command on the basis of elastic parameters of elastic elements; and a stage detecting unit that detects the fact that a transition has been made from a first stage in which a driving force generated by the motor acts on the first elastic element to a second stage in which the driving force acts on the second elastic element via the first elastic element. When the transition from the first stage to the second stage is detected, the correction-amount calculating unit switches from first correction-amount calculation processing based on the first elastic parameter of the first elastic element to second correction-amount calculation processing based on the second elastic parameter of the second elastic element and the first elastic parameter.

Abstract: Regarding a backlash amount measurement system provided in the servo control device of the drive motor of machine tools and industrial machines, a technical problem is to accurately measure the backlash amount at the time of inversion of a drive shaft by means of a backlash amount measurement system having a simpler configuration with a small number of detectors. The above technical problem can be solved by a backlash amount measuring unit equipped with an inversion detection unit which detects the start of inversion of the shaft, an arrival detection unit which detects that the backlash end has been reached from the start of inversion, and a time/distance measurement unit which measures the time from when the inversion detection unit detects the start of inversion until the arrival detection unit detects that the backlash end has been reached, or the movement distance.