Digital high-resolution controller

• US 20050156545A1
• Filed: 01/17/2005
• Published: 07/21/2005
• Est. Priority Date: 01/21/2004
• Status: Active Grant

• Current Assignee: Peaktronics, Inc.
• Original Assignee: Peaktronics, Inc.
• Inventors: Leason, Jack M., Mueller, Peter W.
• Granted Patent: US 7,466,100 B2
• Time in Patent Office: Days
• US Class Current: 318/273
• CPC Class Codes: G05B 19/291 the positional error is used to control continuously the servomotor according to its magnitude
• CPC Class Codes: G05B 2219/42115 Switch from continuous drive to pwm, near stop or out of acceleration period
• CPC Class Codes: H02P 1/44 by phase-splitting with a capacitor
• CPC Class Codes: H02P 3/18 for stopping or slowing an ac motor
• CPC Class Codes: Y10S 388/934 Thermal condition

Abstract

Kinematic control of an electronic positioner and its associated actuator is effected through a control algorithm that delivers energy to the actuator based on observed motion produced by a previous delivery of energy. The algorithm achieves control based on a desired or user-specified resolution. Electronic braking between energy delivery intervals improves the speed at which the desired position is achieved. Temperature of the force producing mechanism is determined, as by monitoring energy consumed, and used to control how power is delivered to the actuator.

Claims

1. An electronic positioning system for an actuator, comprising:

an actuator operator configured to produce motion in an actuator in at least a first direction;

a sensor to ascertain the position of the actuator;

a controller that variably applies electrical power to said actuator operator to induce motion to be produced in said at least a first direction, wherein said variable application of electrical power is determined by motion sensed from at least one previous application of electrical power.

2. The electronic positioning system of claim 1 further comprising a braking system that impedes motion of said actuator prior to said application of electrical power.

3. The electronic positioning system of claim 1 further comprising an electronic braking system that applies alternating power in at least one of first and second directions.

4. The electronic positioning system of claim 1 wherein said controller determines an inertial compensation value according to coast of the actuator.

5. The electronic positioning system of claim 4 wherein said controller causes a braking sequence based at least in part on the inertial compensation value.

6. The electronic positioning system of claim 4 wherein said controller causes a braking sequence based at least in part on the inertial compensation value and on a desired position of the actuator.

7. The electronic positioning system of claim 1 wherein said controller applies a pulse of electrical power with a duty cycle that is determined according to motions sensed from at least one previous application of electrical power.

8. The electronic positioning system of claim 1 wherein said controller applies a pulse of electrical power with a duty cycle and frequency that is determined according to motions sensed from at least one previous application of electrical power.

9. The electronic positioning system of claim 8 wherein the controller determines a rate of change in frequency of applied pulses according to motions sensed from at least one previous application of electrical power.

10. The electronic positioning system of claim 1 wherein said controller applies power at a rate that is inversely proportional to the temperature of a force producing device that produces said induced motion.

11. The electronic positioning system of claim 9 wherein said controller determines temperature according to the amount of electrical energy applied over a given period of time.

12. The electronic positioning system of claim 1 wherein said controller includes analog to digital converter that provides a first faster and lower resolution conversion for motions above a predetermined size and a second slower and higher resolution conversion for motions below a predetermined size.

13. The electronic positioning system of claim 11 wherein said controller is configured to reject electrical noise in said second resolution conversion according to the number of consecutive conversions having a given differential value from an average value of previous conversion values.

14. The electronic positioning system of claim 1 wherein said controller is configured to inhibit application of power to the actuator according to a lack of motion over a given period of time.

15. The electronic positioning system of claim 1 wherein said controller is configured to determine an association between a desired direction and power applied to a given direction.

16. The electronic positioning system of claim 1 wherein the actuator operator is configured to produce motion in first and second directions and the controller applies power to the appropriate direction according to a desired direction.

17. The electronic positioning system of claim 1 wherein said controller is configured to automatically produce a desired output signal that is proportional to the difference of any two selected positions, where such proportionality remains the same regardless of the difference between the selected positions.

19. The method of claim 17 further comprising controlling the time interval between supplying said first and second quantities of energy.

20. The method of claim 17 further comprising controlling the time interval between supplying said first and second quantities of energy based on assessed distance from said desired motor position.

21. The method of claim 19 further comprising controlling the time interval such that said time interval is first value when the assessed distance is within a first proximity range and a second value when the assessed distance is within a second proximity range.

22. The method of claim 20 wherein said second proximity range is closer to said desired motor position than said first proximity range and said second value is greater than said first value.

23. The method of claim 17 further comprising engaging a braking system after supplying said first quantity of energy to inhibit movement prior to supplying said second quantity of energy.

24. The method of claim 17 wherein said at least one of said first quantity of energy and said second quantity of energy is supplied as a measured quantity of energy.

25. The method of claim 17 wherein said at least one of said first quantity of energy and said second quantity of energy is supplied as a measured quantity of energy pulses.

18. A method of controlling a motor comprising:

supplying a first quantity of energy to said motor to produce motion;

observing the motion produced thereby; and

supplying a second quantity of energy to said motor,

wherein the second quantity is determined based on the motion observed.