Control device with learning function for electric motors

A control device for electric motors, for moving one workpiece to be moved by using two electric motors based on periodically repeated commands, the control device comprising:

• positional deviation calculating parts for calculating positional deviations of the electric motors, respectively;
• learning control parts for applying a learning control to control the electric motors, the learning control parts calculating amounts of correction of the positional deviations so that the positional deviations calculated by the positional deviation calculating parts are minimized, respectively, such that the positional deviations are converged to predetermined values, respectively;
• and
• positional deviation correcting parts for correcting the positional deviations based on the amounts of correction calculated by the learning control parts, respectively, wherein
• each learning control part is arranged to act independently for each of the electric motors,
• a parameter defining response of learning control in one of the learning control parts is equal to a parameter defining response of learning control in the other learning control part, and
• each learning control part includes
• a low-pass filter having the same cut-off frequency as that of the other learning control part,
• a memory for storing periodic positional deviation data having the same period of time as the periodically repeated commands, and
• a phase-lead compensating part for independently leading a phase of each electric motor based on the characteristic of the electric motor.