Agricultural harvester ground tracking control system and method using fuzzy logic

• US 5,704,200 A
• Filed: 11/06/1995
• Issued: 01/06/1998
• Est. Priority Date: 11/06/1995
• Status: Expired due to Fees

• Current Assignee: Control Concepts, Inc.
• Original Assignee: Control Concepts, Inc.
• Inventors: Colavito, Leonard Raymond, Chmielewski, Thomas A. Jr.
• Primary Examiner(s): MELIUS, TERRY L
• Application Number:
  US08/554,432
• Time in Patent Office: 792 Days
• Field of Search: 56/10.2 E, 56/208, 56/10.2 D, 56/10.2 F, 56/DIG. 15
• US Class Current: 56/10.20E
• CPC Class Codes: A01D 41/141 Automatic header control
• CPC Class Codes: Y10S 56/15 Condition responsive

Abstract

A method and control system for an agricultural harvester having a frame and a cut crop receiving header coupled to a hydraulic cylinder. The header has a cutter pivotably mounted on its bottom. The header has a height relative to the frame that is adjusted by applying fluid under pressure to the cylinder. A first control valve is fluidly coupled to the cylinder and responsive to a first input signal for increasing fluid pressure in the cylinder to raise the header. A second control valve is fluidly coupled to the cylinder and responsive to a second input signal for reducing fluid pressure in the cylinder to lower the header. An electrical flex angle signal is produced, representing a flex angle between the bottom of the header and the cutter. A plurality of local maximum and minimum values of the flex angle signal are measured as the cutter passes over respective maxima and minima of a height of the ground relative to the frame. The local maximum and minimum values are identified and stored. A fuzzy inferring device determines the first and second input signals by fuzzy inference based on the plurality of local maximum and minimum values.

Claims

1. A control system for an agricultural harvester having a frame and a cut crop receiving header coupled to a hydraulic cylinder, the header having a cutter pivotably mounted on a bottom thereof, the header having a height relative to the frame that is adjusted by applying fluid under pressure to the cylinder, comprising:

first control valve means fluidly coupled to the cylinder responsive to a first input signal for supplying fluid to the cylinder to raise the header;

second control valve means fluidly coupled to the cylinder responsive to a second input signal for removing fluid from the cylinder to lower the header;

means for producing an electrical flex angle signal that represents a flex angle between the bottom of the header and the cutter;

means for identifying and storing a plurality of local maximum and minimum values of the flex angle signal which are measured as the cutter passes over respective maxima and minima of a height of the ground relative to the frame; and

fuzzy inferring means for determining the first and second input signals by fuzzy inference based on the plurality of local maximum and minimum values.

2. A control system according to claim 1, further comprising means for receiving and storing an operator defined closeness value, representing an operator'"'"'s desired flex angle, wherein the fuzzy inferring means include:

means for establishing a plurality of closeness membership functions of said closeness value, and

means for determining said first and second signals from said plurality of local maximum and minimum values and said plurality of closeness membership functions by fuzzy inference.

3. A control system according to claim 1, wherein the fuzzy inferring means include:

means for establishing a plurality of flex angle membership functions which represent the distribution of the local maximum and local minimum values, and

means for determining said first and second signals from said plurality of flex angle membership functions by fuzzy inference.

4. A control system according to claim 3, further comprising means for determining a top margin value representing an average of the local maximum values measured within a predetermined number of most recent flex angle signal values,

wherein the establishing means include means for establishing a top margin membership function of said top margin value.

5. A control system according to claim 3, further comprising means for determining a bottom margin value representing an average of the local minimum values measured within a predetermined number of most recent flex angle signal values,

wherein the establishing means include means for establishing a bottom margin membership function of said bottom margin value.

6. A control system according to claim 3, further comprising means for determining a maximum peak value representing a smallest one of the local minimum values measured within a predetermined number of most recent flex angle signal values,

wherein the establishing means include means for establishing a maximum peak membership function of said maximum peak value.

7. A control system according to claim 3, further comprising means for determining a minimum peak value representing a largest one of the local maximum values measured within a predetermined number of most recent flex angle signal values,

wherein the establishing means include means for establishing a minimum peak membership function of said minimum peak value.

8. A control system for an agricultural harvester having a frame, a feeder house coupled to a hydraulic cylinder, and a cut crop receiving header, the header having a height relative to the frame that is adjusted by applying fluid under pressure to the cylinder, comprising:

first control valve means fluidly coupled to the cylinder responsive to a first input signal for supplying fluid to the cylinder to raise the header;

second control valve means fluidly coupled to the cylinder responsive to a second input signal for removing fluid from the cylinder to lower the header;

means for receiving and storing an input value that is used to control the rate of change of header acceleration while raising or lowering the header;

means for producing an electrical feeder house angle signal that varies as a function of an angle between the feeder house and the frame;

fuzzy inferring means for determining the first and second input signals by fuzzy inference based on the input value and the feeder house angle signal.

9. A system according to claim 8, further comprising means for determining a velocity of the header based on:

the feeder house angle signal, and

a velocity error formed by subtracting the velocity from a desired velocity of the header,

wherein the fuzzy inferring means include means for establishing a membership function of said velocity error.

10. A system according to claim 8,

wherein the fuzzy inferring means include means for establishing a membership function of said input value.

11. A control system for an agricultural harvester having a frame and a cut crop receiving header coupled to a hydraulic cylinder, the header having a cutter pivotably mounted on a bottom thereof, the header having a height relative to the frame that is adjusted by applying fluid under pressure to the cylinder, comprising:

first control valve means fluidly coupled to the cylinder responsive to a first input signal for supplying fluid to the cylinder to raise the header;

second control valve means fluidly coupled to the cylinder responsive to a second input signal for removing fluid from the cylinder to lower the header;

means for producing an electrical flex angle signal that represents a flex angle between the bottom of the header and the cutter;

means for identifying and storing recent values of the flex angle signal which are measured as the cutter passes over the ground;

means for receiving and storing an operator defined value, and

means for determining the first and second input signals by fuzzy inference based on the stored values of the flex angle signal and the operator defined value.