MOTOR CONTROLLER

• US 20100039059A1
• Filed: 07/17/2009
• Published: 02/18/2010
• Est. Priority Date: 08/12/2008
• Status: Active Grant

• Current Assignee: Okuma Corporation
• Original Assignee: Okuma Corporation
• Inventors: Ando, Toru, Kameyama, Tomohisa
• Granted Patent: US 8,076,891 B2
• Time in Patent Office: Days
• US Class Current: 318/591
• CPC Class Codes: G05B 19/404 characterised by control arrangements for compensation, e.g. for backlash, overshoot, tool offset, tool wear, temperature, machine construction errors, load, inertia G05B19/19, G05B19/41 take precedence
• CPC Class Codes: G05B 2219/42197 Brake as function of machining load, to keep total load on tool constant, avoid oscillation
• CPC Class Codes: H02P 29/04 by means of a separate brake
• CPC Class Codes: H02P 6/20 Arrangements for starting H02P6/08 takes precedence

Abstract

A motor controller is provided which has a function to prevent the falling of a shaft when the power supply to a motor is turned on.

The motor controller includes a PI control unit 1 which controls the velocity of a motor 4; a brake 8 which prevents the falling of the shaft in accordance with a brake signal; and a storage unit 7 which detects the brake signal input to the brake 8, and on the basis of the state of the detected brake signal, stores a torque command value T* calculated by the PI control unit 1. The storage unit 7 stores the torque command value T* when the brake signal has changed from off to on, and the storage unit 7 sets the stored torque command value T* to an integral component of the PI control unit 1 when the brake signal has changed from on to off. Thus, the falling of the shaft at the start of power application can be prevented.

Claims

1. A motor controller which drives and controls a motor to drive a shaft subject to gravity, the motor controller comprising:

a PI control unit which controls the velocity of the motor;

a brake which prevents the falling of the shaft in accordance with a brake signal; and

a storage unit which detects the brake signal input to the brake, and on the basis of the state of the detected brake signal, stores a torque command value calculated by the PI control unit,

wherein the storage unit stores the torque command value when the brake signal has changed from off to on, and the storage unit sets the stored torque command value to an integral component of the PI control unit when the brake signal has changed from on to off.