Electric motor control device
AssigneeOkuma Corporation
InventorsTakeshi Sakai, Akiyoshi Satake
Life of this patent
Estimating the term…
Abstract
An electric motor control device for performing tandem control for driving one movable component includes, for each electric motor, a position controller, a speed controller, and a current controller. Further, each electric motor also has a preload controller for adding a preload torque to a torque command Tm calculated by the speed controller, and to a torque command Ts calculated by the speed controller. The preload controller calculates a minimum necessary preload torque for eliminating backlash in accordance with a position of the movable component.
Claims5
An electric motor control device for performing tandem control for driving a movable component for which an amount of load caused by gravity varies in accordance with a position of the movable component, using a main electric motor and an auxiliary electric motor, the electric motor control device comprising, for each of the electric motors:
- a position controller configured to calculate a speed command for a corresponding electric motor based on a common position command and to control the position of a movable component for which an amount of load caused by gravity varies in accordance with a position of the movable component;
- a speed controller configured to calculate a torque command for the corresponding electric motor based on the speed command calculated by the position controller;
- a preload controller configured to apply a preload torque to the torque command calculated by the speed controller, the preload torque having opposite polarities for the main electric motor and the auxiliary electric motor;
- and
- a current controller configured to calculate a current command for the corresponding electric motor based on the torque command,
- wherein the preload controller is configured to vary the preload torque based on the position of the movable component.
An electric motor control device for performing tandem control for driving a movable component using a main electric motor and an auxiliary electric motor, the electric motor control device comprising, for each of the electric motors:
- a position controller for calculating a speed command for a corresponding electric motor based on a common position command for controlling a position of the movable component;
- a speed controller for calculating a torque command for the corresponding electric motor based on the speed command calculated by the position controller;
- a preload controller for applying a preload torque to the torque command calculated by the speed controller, the preload torque having opposite polarities for the main electric motor and the auxiliary electric motor;
- a current controller for calculating a current command for the corresponding electric motor based on the torque command;
- and
- a torque arbitrator configured to calculate a torque arbitration value for performing arbitration on a difference between the torque command calculated by the speed controller for the main electric motor and the torque command calculated by the speed controller for the auxiliary electric motor in accordance with at least a time that has elapsed from application or removal of the preload torque, and adding the torque arbitration value to the torque command before the torque command is input to the current controller for the auxiliary electric motor.
Dependencies are inferred from the claim text.