Controller for machine effecting end

• US 7,205,743 B2
• Filed: 12/16/2005
• Issued: 04/17/2007
• Est. Priority Date: 12/16/2004
• Status: Active Grant

• Current Assignee: Fanuc Ltd (Fanuc Corporation)
• Original Assignee: Fanuc Ltd (Fanuc Corporation)
• Inventors: Iwashita, Yasusuke, Toyozawa, Yukio, Sonoda, Naoto
• Primary Examiner(s): Donovan; Lincoln
• Assistant Examiner(s): GLASS, ERICK DAVID
• Application Number:
  US11/304,572
• Publication Number:
  US 20060132078A1
• Time in Patent Office: 487 Days
• Field of Search: None
• US Class Current: 318/568.18
• 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

Abstract

A controller for controlling a position of a driven element with respect to a machine effecting end so as to be in accord with a command. An acceleration sensor is mounted to a member of the machine effecting end to which a tool is attached. Acceleration detected by the sensor is subjected to second-order integration by a torsion estimator to obtain displacement Δθ of the machine effecting end from the original position. Position feedback P1 of a driven element is subtracted from position command Pc to obtain first position deviation ε1. The displacement Δθ is added to the first position deviation ε1 to obtain second position deviation ε2. The second position deviation ε2 is subjected to learning control of a learning controller to obtain a correction value, which is added to the first position deviation ε1 to obtain velocity command Vc. The second position deviation is the sum of the displacement ε1 of the driven element from the commanded position and the displacement Δθ of the machine effecting end relative to the driven element, and thus signifies a positional displacement of the machine effecting end from the commanded position. The second position deviation is subjected to the learning control so as to converge to “0”, whereby the position of the driven element with respect to the machine effecting end becomes in accord with the command.

Claims

1. A controller having a position control section and a velocity control section for respectively controlling position and velocity of a motor, to control relative motion of a driven element driven by the motor with respect to a machine effecting end of a machine tool, said controller comprising:

position detecting means for detecting a position of the motor or the driven element;

means for obtaining a first position deviation between a position command for the motor and the position of the motor detected by said position detecting means;

acceleration detecting means for detecting an acceleration of the machine effecting end;

conversion means for determining a position of the machine effecting end by converting the acceleration detected by said acceleration detecting means;

means for obtaining a second position deviation by adding the obtained first position deviation and the determined position of the machine effecting end; and

learning control means for calculating and outputting a correction value for converging the second position deviation to zero,

wherein the correction value is added to the first position deviation and the sum obtained is multiplied by a position gain and the product obtained is outputted to the velocity control section as a velocity command.

2. A controller according to claim 1, wherein the position obtained by converting the acceleration of the machine effecting end by said conversion means is subjected to filtering by a high-pass filter.

3. A controller having a position control section and a velocity control section for respectively controlling position and velocity of a motor, to control relative motion of a driven element driven by the motor with respect to a machine effecting end of a machine tool, said controller comprising:

position detecting means for detecting the position of the motor or the driven element;

means for obtaining a first position deviation between a position command for the motor and the position of the motor detected by said position detecting means;

velocity detecting means for detecting the velocity of the motor or the driven element;

estimating means for estimating an amount of torsion of the machine effecting end based on the velocity detected by said velocity detecting means and a torque command outputted from the velocity control section;

means for obtaining a second position deviation by adding the obtained first position deviation and the estimated amount of torsion; and

learning control means for calculating and outputting a correction value for converging the second position deviation to zero,

wherein the correction value is added to the first position deviation, the sum obtained is multiplied by a position gain and the product obtained is outputted to the velocity control section as a velocity command.

4. A controller according to claim 3, wherein the torsion amount of the machine effecting end estimated by said estimating means is subjected to filtering by a high-pass filter.