Controller

A controller for a machine tool having a feed shaft that moves a cutting tool and a workpiece relative to each other, the machine tool configured to cut the workpiece with the cutting tool while moving the feed shaft,

• wherein the controller is configured to function as:
• a command generator configured to output, in response to an instruction for oscillation cutting, a moving command to shift the feed shaft toward a feeding direction while allowing the feed shaft to oscillate in the feeding direction,
• a position controller configured to output a velocity command based on the moving command;
• a velocity controller configured to output a torque command based on the velocity command;
• a current controller configured to control motor line current based on the torque command;
• and
• an inversion compensation calculator configured to calculate a compensation amount for compensating for a tracking delay caused by inversion of a moving direction of the feed shaft, and to add the compensation amount to at least one of the moving command, the velocity command, and the torque command for inversion compensation,
• wherein the controller is configured not to perform the inversion compensation unless the feeding direction is inverted, in spite of inversion of the moving direction of the feed shaft due to oscillation.