Self-commissioning electronic motor controller determination

• US 7,606,624 B2
• Filed: 09/03/2008
• Issued: 10/20/2009
• Est. Priority Date: 01/14/2003
• Status: Expired due to Fees

• Current Assignee: Christopher P. Cullen
• Original Assignee: Christopher P. Cullen
• Inventors: Cullen, Christopher P.
• Primary Examiner(s): Barnes-Bullock; Crystal J
• Assistant Examiner(s): Norton; Jennifer L
• Application Number:
  US12/203,577
• Publication Number:
  US 20090021205A1
• Time in Patent Office: 412 Days
• Field of Search: 700/29, 700/30, 700/31, 318/439, 318/561, 703/2
• US Class Current: 700/29
• CPC Class Codes: G05B 17/02 electric
• CPC Class Codes: H02P 2209/07 Trapezoidal waveform
• CPC Class Codes: H02P 23/14 Estimation or adaptation of motor parameters, e.g. rotor time constant, flux, speed, current or voltage
• CPC Class Codes: H02P 6/16 Circuit arrangements for detecting position

Abstract

A control system for any type of electric motor that automatically learns the characteristics of the motor and computes a motor model for the motor. The control system uses the computed motor model to produce a closed-loop control design that achieves a particular resolution. The control system also uses the motor model to automatically construct efficient motion profiles for a variety of motion commands. The control system may also include an encoder interface device that provides highly accurate motor position information.

Claims

1. A method for calculating a derivative term in a closed-loop controller that receives position error information at each servo processing interval, the method comprising computer-implemented steps of:

performing a self-commissioning process to compute a motor model that relates a motor control signal applied by a first controller to a motor to a motion of the motor, where the self-commissioning process is automatically performed in response to receipt of a first user input and the motor model is computed without requiring second user input, and the self-commissioning process includes;

determining a number of position error readings to be supplied to the closed-loop controller for use in computing a derivative term; and

supplying the determined number of position error reading to the closed-loop controller;

computing a derivative term in the closed-loop controller, where the computer-implemented steps of calculating the derivative term includes computer-implemented code for the computer-implemented steps stored on a computer-readable medium for;

recording three or more position error readings at different servo processing intervals;

computing a derivative estimate by;

summing two or more of the position error readings; and

subtracting an equal number of different position error readings than used in the summing step; and

then

computing the derivative term based on the derivative estimate; and

generating a motor control signal based in part on the computed derivative term.

2. The method of claim 1, wherein the position error readings are recorded at successive servo processing intervals.