# US 5,994,865 A · Apparatus and method for control of an earth moving implement

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- Number: US 5,994,865 A
- Document ID: US5994865A
- Status: Granted
- Kind: A
- Application number: 08/996,045
- Filed: 1997-12-22
- Granted: 1999-11-30
- Earliest claimed: 1997-12-22
- Assignees: Caterpillar Inc.
- Inventors: Stephen K. Phelps; Robert R. Sychra
- Web page: https://patentgrep.com/patent/US5994865A

## CPC

- G05B 13/0275: {using fuzzy logic only}
- G05B 19/19: characterised by positioning or contouring control systems, e.g. to control position from one programmed point to another or to control movement along a programmed continuous path
- G05B 2219/34065: Fuzzy logic, controller
- G05B 2219/37269: Ultrasonic, ultrasound, sonar
- G05B 2219/42051: Fuzzy position controller
- G05B 2219/42134: Fuzzy logic tuning of controller as function of error
- Y10S 706/90: Fuzzy logic
- G05B: CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS (systems for controlling or regulating non-electric variables G05D; systems for regulating electric or magnetic variables G05F; control devices or systems insofar as characterised by mechanical features only G05G)
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## Abstract

An earth moving or construction equipment implement control system is disclosed. The control system includes a fuzzy logic controller that is connected to an electro-hydraulic valve. An implement position sensing system senses the height of the implement. A set point is compared to the implement position to produce an implement position error signal which is an input to the fuzzy logic controller.

## Claims

### Claim 1

An apparatus for controlling the position of an implement on construction equipment, said apparatus comprising:
a position sensing device associated with said implement, said position sensing device producing an implement position signal;
an operator input producing a desired position signal;
an electronic controller receiving said implement position signal and said desired position signal and producing an error signal;
wherein said electronic controller includes control logic with an associated system gain, a fuzzy logic controller receiving said error signal and responsively adjusting the system gain, said electronic controller producing an implement control signal as a function of said gain and said error signal;
an implement positioning device, said device responding to the implement control signal to move the implement.

### Claim 2 (depends on 1)

The apparatus according to claim 1, including an electronic controller, said electronic controller including said fuzzy logic controller.

### Claim 3

An apparatus for controlling the position of an implement on construction equipment, said apparatus comprising:
position sensing means for sensing the position of the implement above a surface and producing an implement position signal;
an electronic controller, said electronic controller producing an implement control signal in response to said implement position signal and a desired implement position;
implement position means for receiving the implement position signal and responsively positioning the implement;
wherein said electronic controller includes a fuzzy logic controller that adjusts a system gain in response to an error signal between said implement position signal and said desired implement position.

### Claim 4 (depends on 3)

The apparatus according to claim 3, wherein said position sensing means includes a ultrasonic sensing device.

### Claim 5 (depends on 3)

The apparatus according to claim 3, wherein said implement position means includes a hydraulic cylinder and an electro-hydraulic control valve.

### Claim 6

A method of controlling an implement on construction equipment, said method comprising:
determining an actual implement position;
comparing said implement position to a desired implement position;
producing an error signal in response to said step of comparing;
using fuzzy logic in connection with said error signal to produce a control signal;
controlling the implement position is response to said control signal; and
wherein said step of using fuzzy logic includes producing a fuzzified error signal, applying fuzzy rules to the fuzzified error signal, producing a fuzzy control signal in response to said step of applying, and adjusting a system gain based on said step of producing a fuzzy control signal.

### Claim 7

An apparatus for controlling the position of an implement on construction equipment, said apparatus comprising:
an implement position sensor;
an operator input;
an implement actuator;
an electronic controller connected with said implement position sensor, said operator input and said implement actuator;
wherein said electronic controller includes a fuzzier, fuzzy rules, a de-fuzzifier, and control logic having a system gain; and
wherein said de-fuzzifier produces an output signal that modifies the system gain.