Dither magnitude control

• US 5,673,166 A
• Filed: 09/20/1996
• Issued: 09/30/1997
• Est. Priority Date: 05/17/1995
• Status: Expired due to Term

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Hoffman, J. Paul
• Primary Examiner(s): FLEMING, FRITZ M
• Application Number:
  US08/717,145
• Time in Patent Office: 375 Days
• Field of Search: 361/152-156, 361/160
• US Class Current: 361/160
• CPC Class Codes: H01H 47/325 by switching regulator

Abstract

Apparatus and method for controlling dither in a solenoid actuator. Circuitry produces a frequency command signal in response to a measured dither parameter and produces a current command signal. A solenoid actuator input signal is delivered to a solenoid actuator, said solenoid actuator input signal having a frequency determined in response to the frequency command signal and a magnitude of current determined in response to a current command signal.

Claims

1. An apparatus for controlling dither in a solenoid actuator, comprising:

a microprocessor adapted to produce a current command signal;

dither parameter means for measuring a dither parameter and producing a dither parameter signal that is indicative of a desired dither frequency, wherein the microprocessor receives the dither parameter signal and responsively produces a dither command signal;

frequency producing means for receiving the dither command signal and producing a frequency command signal that is responsive to the dither parameter; and

solenoid driver means for receiving the current command and frequency command signals and producing a solenoid actuator input signal to drive the solenoid actuator to a desired position, wherein the frequency of the solenoid actuator input signal is a function of the frequency command signal and the magnitude is a function of the current command signal.

2. An apparatus, as set forth in claim 1, wherein said dither parameter is responsive to hydraulic oil temperature.

3. An apparatus, as set forth in claim 1, wherein said dither parameter is responsive to the length of solenoid actuator usage.

4. An apparatus, as set forth in claim 1, wherein said dither parameter is an identification code.

5. An apparatus, as set forth in claim 4, wherein said identification code corresponds to a preselected type of solenoid actuator.

6. A method for controlling dither in a solenoid actuator, comprising the steps of:

producing a current command signal of a preselected magnitude;

measuring a dither parameter and producing a dither parameter signal that is indicative of a desired dither frequency;

producing a dither command signal in response to the dither parameter signal;

producing a frequency command signal in response to the dither command signal;

generating a solenoid actuator input signal whose frequency is a function of the frequency command signal and whose magnitude is a function of the magnitude of current command signal; and

delivering the solenoid actuator input signal to the solenoid actuator.

7. A method, as set forth in claim 6, wherein said dither parameter is responsive to hydraulic oil temperature.

8. A method, as set forth in claim 6, wherein said dither parameter is responsive to the length of solenoid actuator usage.

9. A method, as set forth in claim 6, wherein said dither parameter is an identification code.

10. A method, as set forth in claim 9, wherein said identification code corresponds to a preselected type of solenoid actuator.