Automatic steering apparatus for crop vehicle

• US 4,967,362 A
• Filed: 01/30/1989
• Issued: 10/30/1990
• Est. Priority Date: 01/30/1989
• Status: Expired due to Fees

• Current Assignee: Eaton Corp. (Wisconsin) (Eaton Corporation PLC.)
• Original Assignee: Eaton Corp. (Wisconsin) (Eaton Corporation PLC.)
• Inventors: Stephenson, Dwight B., Schutten, Herman P., Johnson, Oliver W.
• Primary Examiner(s): Black, Thomas G.
• Application Number:
  US07/302,889
• Time in Patent Office: 638 Days
• Field of Search: 364/424.01, 364/424.02, 364/424.07, 56/DIG. 15, 56/10.2, 180/131
• US Class Current: 701/50
• CPC Class Codes: A01B 69/008 automatic
• CPC Class Codes: G05D 1/0227 using mechanical sensing means, e.g. for sensing treated area
• CPC Class Codes: G05D 1/0272 comprising means for registering the travel distance, e.g. revolutions of wheels measuring distance traversed on the ground by vehicles, e.g. using odometers G01C22/00

Abstract

Apparatus for automatically steering a farm crop vehicle into rows of corn by sensing the locations of the rows ahead of the vehicle on both sides of the vehicle. The apparatus senses the plants of each row by means of contact sensors that touch the plants as the crop vehicle approaches them. The data thus obtained are processed by an on-board microcontroller to determine the lateral location of the crop vehicle relative to the rows. Also, the frequencies of encountering plants in laterally spaced-apart rows provided information regarding turning of the vehicle, i.e., incipient changes of lateral position. This is used to produce a further feedback signal that improves the automatic steering, especially where the rows are curved. Having the turning-feedback signal in the servo loop also permits higher loop gain without instability, which reduces tracking error even further. The microcontroller provides steering commands that automatically maintain the crop vehicle on a proper course for stripping the corn, cutting the crop, etc. The control system also provides indications for the operator of single row dropout, vehicle out of field, and field entry.

Claims

1. A guidance system that automatically steers a vehicle to track rows of spaced-apart plants, comprising:

first plant-contact sensor means mounted on the vehicle to intercept a row of plants as the vehicle moves, for sensing the position of the row laterally relative to the vehicle and for providing a lateral error signal indicative of said position;

said first plant-contact sensor means comprising means for sensing individual plants encountered on the rows and for providing signals indicative of the rates of encountering the plants;

at least one additional plant-contact sensor means on the vehicle spaced apart laterally from said first plant-contact sensor means so that it intercepts a different row of plants, for sensing individual plants encountered on its row and for providing signals indicative of the rates of encountering plants;

means for producing a turning-feedback signal based on the difference between the rate at which plants are encountered by said first sensor and the rate at which plants are encountered by said additional sensor;

signal-processing means receiving both said lateral error signal and said turning-feedback signal and responsive to both, for providing steering command signals;

steering-actuator means receiving said steering command signals and responsive thereto for steering the vehicle on a course having a predetermined lateral position relative to said rows.

2. A guidance system that automatically steers a vehicle to track rows of spaced-apart plants and provides an out-of-field signal, comprising:

means for detecting the plants of each of two rows as the vehicle encounters them and for signaling occurrences of the encounters;

means for measuring indicia of the cyclic spacing between neighboring plants and providing data indicative of the spacing accordingly, for each row;

means for detecting that an absence of a plant has occurred, including;

means for establishing, based upon said spacing data, a time-interval window in which a plant would be detected if a plant were present;

means responsive to said means for detecting the plants and responsive to said time-interval window for ascertaining whether or not a plant was detected within that time-interval window and producing a signal indicative of plant presence or absence;

means responsive to plant-absence signals for determining when simultaneous absences occur during overlapping cycles on both rows and for determining when the number of contiguous simultaneous-absences reaches a predetermined number and responsive thereupon to provide an alarm for the operator of the vehicle indicating that the vehicle may be out of the field.

3. A guidance system as in claim 2 and wherein said means for detecting the plants of a row as the vehicle encounters them comprises means contacted by the plants as the vehicle arrives at them and producing signals in response to being contacted.

4. A guidance system as defined in claim 2 and wherein said means for establishing a time-interval window comprises:

means responsive to said data indicative of the cyclic spacing between plants for (a) establishing a window starting-time at a time a fraction of a cycle before the most recent plant encounter and at later times whole cycles apart, and (b) establishing a window stopping-time at a time a fraction of a cycle after the most recent plant encounter and at later times whole cycles apart.

5. A guidance system that automatically steers a vehicle to track rows of spaced-apart plants and steers automatically even through a limited dropout, comprising:

means for detecting the plants of a row as the vehicle encounters them and for signaling occurrences of the encounters;

means for measuring indicia of the spacing between neighboring plants and providing data indicative of the spacing;

means for ascertaining a running average of said spacing data for a predetermined number N of plants, wherein, when a new spacing datum is included in the average the oldest datum is dropped, and for outputting a value signal indicative of said N-fold running average of spacings;

means for detecting that a dropout of a plant has occurred, including;

means for establishing a time-interval window in which a plant would be detected if a plant were present;

means responsive to said means for detecting the plants and responsive to said time-interval window for ascertaining whether or not a plant was detected within said time-interval window;

means for loading a substitute value in lieu of a measured spacing datum when a dropout occurs;

means for counting contiguous occurrences of such loadings of substitute values;

means for discontinuing the substitution process when the occurrences reach a predetermined number M;

whereby said means for ascertaining a running average puts out a value signal even while the vehicle travels through a limited dropout, enabling the vehicle to be steered automatically through the dropout.

6. A guidance system as in claim 5 and wherein said means for detecting the plants of a row as the vehicle encounters them comprises means contacted by the plants as the vehicle arrives at them and producing signals in response to being contacted.

7. A guidance system as defined in claim 5 and wherein said means for establishing a time-interval window comprises:

means responsive to said data indicative of the cyclic spacing between plants for (a) establishing a window starting-time at a time a fraction of a cycle before the most recent plant encounter and at later times whole cycles apart, and (b) establishing a window stopping-time at a time a fraction of a cycle after the most recent plant encounter and at later times whole cycles apart.

8. A guidance system as in claim 5 and wherein said means for loading a substitute value comprises means for storing and loading an average value of a plurality of previous values in lieu of a measured spacing datum when a dropout occurs.

9. A guidance system as in claim 5 and further comprising means responsive to said occurrence-counting means for providing a dropout indication for the operator of the vehicle when a predetermined number of contiguous dropouts occurs.

10. A guidance system that automatically guides a vehicle to track rows of spaced-apart plants and automatically initiates automatic guidance of the vehicle when it enters a field of plants, comprising:

(A) means defining the lateral span of a left-hand sector of the vehicle that extends across a left-hand row of plants as the vehicle moves to enter a field, said left-hand sector including within it a left-hand subsector and a right-hand subsector;

sensor means for sensing the arrival of a plant within said left-hand sector and left-hand subsector and for providing a signal L_L indicative of said arrival;

sensor means for sensing the arrival of a plant within said left-hand sector and right-hand subsector and for providing a sign L_R indicative of said arrival;

(B) means defining the lateral span of a right-hand sector of the vehicle that is spaced apart from said left-hand sector and that extends across a right-hand row of plants, said right-hand sector including within it a left-hand subsector and a right-hand subsector;

sensor means for sensing the arrival of a plant within said right-hand sector and left-hand subsector and for providing a signal R_L indicative of said arrival;

sensor means for sensing the arrival of a plant within said right-hand sector and right-hand subsector and for providing a signal R_R indicative of said arrival;

(C) means for, when only said L_L signal is present, steering hard left until initiation of automatic guidance is detected;

means for, when only said L_R signal is present, steering straight ahead until a L_L signal starts, then for steering hard left until initiation of automatic guidance is detected;

means for, when only said R_L signal is present, steering straight ahead until a R_R signal starts, then for steering hard right until initiation of automatic guidance is detected;

means for, when only R_R signal is present, steering hard right until initiation of automatic guidance is detected;

(D) means for detecting when initiation of automatic guidance is complete, comprising logic means for detecting when at least one of the L_L and L_R signals is present AND at least one of the R_L and R_R signals is present.

11. A guidance system that automatically steers a vehicle to track rows of spaced-aprt plants, comprising:

means for sensing the lateral locations of the rows relative to the vehicle and providing lateral information signals based thereon;

spaced-apart means on the vehicle contacting the plants for sensing the difference in the velocities at spaced-apart plant rows and providing feedback signals, said feedback signals being affected by the angular rate of turning of the vehicle;

steering command means receiving said lateral information signals and said feedback signals and responsive thereto to provide command signals for steering the vehicle to follow a course tracking said rows;

steering-actuator means receiving said command signals, and responsive thereto for steering the vehicle.

12. A guidance system that automatically steers a vehicle to track a right-hand row and a left-hand row of spaced-apart plants, comprising:

plant-contact sensor means on the vehicle for sensing plants that the sensor means encounter and for providing plant-indicating signals thereupon;

means utilizing said plant-indicating signals for providing lateral-position information signals indicating the lateral position of the plants relative to the vehicle;

means utilizing said plant-indicating signals for providing frequency-difference information signals regarding the difference between the frequency of encountering plants at the right row relative to that of the left row, to ascertain the rate of change of the vehicle'"'"'s heading;

means receiving at least said lateral-position information signals and said frequency-difference information signals, and responsive thereto for providing steering command signals;

steering-actuator means receiving said steering command signals and responsive thereto for steering the vehicle to track said rows.