Motor controller, positioning apparatus, and motor control method

A positioning apparatus comprising:

• an apparatus frame;
• a movable object installed movably relative to the apparatus frame;
• a motor mechanically connected to the movable object;
• a camera to capture an image of a target position;
• movable object position command generation circuitry to generate a movable object position command to stop the movable object at a predetermined position relative to the target position;
• a motor position receiver to acquire a motor position detection value that is a time waveform of a position coordinate of the motor;
• frame vibration estimation circuitry to calculate a frame vibration estimate value obtained by estimating vibration of the apparatus frame, based on thrust generated by the motor and a frame weight that is a weight of the apparatus frame;
• vibration error compensation signal calculation circuitry to calculate, based on the frame vibration estimate value, a vibration error compensation signal to reduce an error due to the vibration of the apparatus frame included in a relative position of the movable object relative to the target position;
• motor drive control circuitry to generate a motor thrust command to control the thrust generated by the motor, based on the movable object position command, the motor position detection value, and the vibration error compensation signal;
• relative position acquisition circuitry to acquire, from the image captured by the camera, a movable object relative position detection value that is a time waveform of a position coordinate of the movable object relative to the target position;
• frame vibration calculation circuitry to calculate a frame vibration calculation value from the movable object relative position detection value;
• and
• frame weight estimation circuitry to calculate a frame weight estimate value obtained by estimating the weight of the apparatus frame from the frame vibration calculation value and the thrust generated by the motor, wherein
• the frame vibration estimation circuitry calculates the frame vibration estimate value, using the frame weight estimate value estimated by the frame weight estimation circuitry.

A motor control method for a motor controller to control, based on a motor thrust command, thrust generated by a motor to thereby stop a movable object at a predetermined position relative to a target position, the motor being mechanically connected to the movable object, the movable object being installed movably relative to an apparatus frame, the motor control method comprising:

• acquiring a position coordinate of the movable object relative to the target position from a captured image of the target position, and calculating a frame vibration calculation value of vibration occurring in the apparatus frame;
• calculating a frame weight estimate value obtained by estimating a weight of the apparatus frame from the frame vibration calculation value and the thrust generated by the motor;
• estimating the vibration of the apparatus frame from the frame weight estimate value and the thrust generated by the motor;
• and
• calculating a vibration error compensation signal to reduce an error due to the vibration of the apparatus frame included in a relative position of the movable object relative to the target position, and changing the motor thrust command based on the vibration error compensation signal.