MOTOR CONTROLLER

• US 3,652,912 A
• Filed: 12/22/1969
• Issued: 03/28/1972
• Est. Priority Date: 12/22/1969
• Status: Expired due to Term

• Current Assignee: Michael P. Bordonaro
• Original Assignee: Michael P. Bordonaro
• Inventors: Bordonaro, Michael P.
• Primary Examiner(s): Dobeck, Benjamin
• Application Number:
  US04/887,156
• Time in Patent Office: 827 Days
• Field of Search: 318/599,681,227,612
• US Class Current: 318/599
• CPC Class Codes: G05D 3/18 delivering a series of pulses

Abstract

A polyphase bidirectional control system suitable for use with AC motors of the squirrel cage type. In response to applied actual and desired position signals, the present invention generates a position error signal and a motor speed control signal; the speed control signal having a variable pulse width and pulse repetition rate. The control signal is employed to supervise the application of power to the motor to be controlled while the position error signal is employed to control the direction of operation of the motor.

Claims

1. Apparatus for controlling an electrical actuator comprising:

means responsive to input signals commensurate with actual and desired actuator position for generating an error signal;

bistable switch means;

first pulse generator means responsive to said error signal for generating first switch control signals having a repetition rate directly proportional to the magnitude of the error signal;

second pulse generator means responsive to said error signal for generating second switch control signals having a repetition rate inversely proportional to the magnitude of the error signal;

means applying said first and second switch control signals to said bistable switch means, said first switch control signals causing said switch means to assume a first condition whereby actuator control pulses are initiated and said second switch control signals causing said switch means to assume a second condition whereby previously initiated actuator control pulses will be terminated, the width and repetition rate of the control pulses provided by said bistable switch means thereby varying directly with the magnitude of the error signal;

a source of power for the actuator to be controlled; and

means connected to said bistable switch means and to said power source and responsive to the control pulses provided by said switch means for applying power from said source to the actuator.

2. The apparatus of claim 1 further comprising:

synchronizing means responsive to the condition of said bistable switch means for preventing application of said second switch control signals to said switch means when said switch means is in said second condition.

3. The apparatus of claim 2 wherein the actuator is a bidirectional device having at least a pair of directional control terminals and wherein said means for applying control signal pulses to said actuator comprises:

means responsive to said error signals for generating directional control signals commensurate with the direction of the actuator position error;

first and second power switch means for applying power from said source to respective of said actuator directional control terminals, said power switch means being responsive to said first and second switch control signals; and

means responsive to said directional control signals for applying said switch control signals to the one of said power switch means commensurate with operation of said actuator in the proper direction to null the position error.

4. The apparatus of claim 3 wherein actuator has an electrically operated brake, said control apparatus further comprising:

a brake control circuit; and

means responsive to said directional control signals for generating brake control signals, application of said brake control signals to said brake control circuit causing release of the brake when the errOr signal exceeds a predetermined magnitude.

5. The apparatus of claim 3 wherein said means for generating directional control signals comprises:

first level detector means for generating a first directional control signal when the error signal exceeds a preselected magnitude; and

second level detector means for generating a second directional control signal when the error signal is less than a preselected magnitude, said first and second directional control signals being respectively commensurate with position errors of opposite polarity.

6. The apparatus of claim 4 wherein said means for generating directional control signals comprises:

first level detector means for generating a first directional control signal when the error signal exceeds a preselected magnitude; and

second level detector means for generating a second directional control signal when the error signal is less than a preselected magnitude, said first and second directional control signals being respectively commensurate with position errors of opposite polarity.

7. The apparatus of claim 6 wherein the control signals provided by said first and second level detector means are offset from one another to establish a deadband, said brake control signal generating means providing a brake energizing control signal to said brake control circuit when the error signal is within said deadband.

8. The apparatus of claim 7 further comprising:

means responsive to the output of said brake control signal generating means for disabling said first pulse generator means when said brake is in the energized state.

9. The apparatus of claim 1 wherein said bistable switch means comprises:

a bistable multivibrator circuit.

10. The apparatus of claim 9 wherein said first and second pulse generator means each comprise:

an oscillator circuit including an input capacitor; and

means responsive to the magnitude of the error signal for varying the charging rate of the input capacitor of said oscillator circuit.

11. The apparatus of claim 5 wherein said bistable switch means comprises:

a bistable multivibrator circuit.

12. The apparatus of claim 11 wherein said first and second pulse generator means each comprise:

an oscillator circuit including an input capacitor; and

means responsive to the magnitude of the error signal for varying the changing rate of the input capacitor of said oscillator circuit.

13. Apparatus for controlling a bidirectional electrical actuator, said actuator having at least a pair of directional control terminals, said control apparatus comprising:

means responsive to input signals commensurate with actual and desired actuator position for generating an error signal;

means responsive to said error signal for generating directional control signals commensurate with the direction of the actuator position error;

means responsive to said error signal for generating a pulsating control signal, the width and repetition rate of the pulses comprising said control signal varying directly with the magnitude of the error signal;

a source of power for the actuator to be controlled;

first and second power switch means for applying power from said source to respective of said actuator directional control terminals, said power switch means being responsive to said pulsating control signals; and

means responsive to said directional control signals for applying said pulsating control signals to the one of said power switch means commensurate with operation of said actuator in the proper direction to null the position error.

14. The apparatus of claim 13 wherein said means for generating directional control signals comprises:

first level detector means for generating a first directional control signal when the error signal exceeds a preselected magnitude; and

second level detector means for generating a second directional control signal when the error signal is less than a preselected magnitude, said fIrst and second directional control signals being respectively commensurate with position errors of opposite polarity.

15. Apparatus for controlling an electrical actuator, said actuator having an electrically operated brake, said control apparatus comprising:

means responsive to input signals commensurate with actual and desired actuator position for generating an error signal;

means responsive to said error signal for generating a pulsating control signal, the width and repetition rate of the pulses comprising said control signal varying directly with the magnitude of the error signal;

a source of power for the actuator to be controlled;

means responsive to said control signal pulses for applying power from said source to the actuator;

a brake control circuit; and

means responsive to the magnitude of said error signal for generating brake control signals, said brake control signals being applied to said brake control circuit and causing release of the brake when the error signal exceeds a predetermined magnitude.