Machine learning device, servo control device, servo control system, and machine learning method

A machine learning device that performs machine learning with respect to a servo control device comprising a velocity feedforward calculation unit configured to create a velocity feedforward value on the basis of a position command, the machine learning device comprising:

• a state information acquisition unit configured to acquire from the servo control device, state information including a servo state including at least position error, and combination of coefficients of a transfer function of the velocity feedforward calculation unit, by causing the servo control device to execute a predetermined machining program;
• an action information output unit configured to output action information including adjustment information of the combination of coefficients included in the state information, to the servo control device;
• a reward output unit configured to output a reward value in reinforcement learning based on the position error included in the state information;
• and
• a value function updating unit configured to update an action value function on the basis of the reward value output by the reward output unit, the state information, and the action information.