Automatic steering system for standing-crop harvester

• US 3,946,825 A
• Filed: 08/12/1974
• Issued: 03/30/1976
• Est. Priority Date: 08/14/1973
• Status: Expired due to Term

• Current Assignee: Maschinenfabrik Fahr AG
• Original Assignee: Maschinenfabrik Fahr AG
• Inventors: Gail, Josef
• Primary Examiner(s): Wood, Jr., M. H.
• Assistant Examiner(s): Pekar, John A.
• Application Number:
  US05/496,743
• Time in Patent Office: 596 Days
• Field of Search: 180/79.2 R, 180/79.2 D, 180/79.1, 180/79, 180/98, 56/10.2, 56/DIG. 15, 172/4.5, 94/84
• US Class Current: 180/401
• CPC Class Codes: A01B 69/008 automatic
• CPC Class Codes: A01D 41/1278 for automatic steering
• CPC Class Codes: B62D 1/28 non-mechanical , e.g. following a line or other known markers
• CPC Class Codes: G05D 1/0227 using mechanical sensing means, e.g. for sensing treated area
• CPC Class Codes: G05D 1/0238 using obstacle or wall sensors G05D1/0246 and G05D1/0289 take precedence; lidar systems designed for anti-collision purposes G01S17/93
• CPC Class Codes: Y10S 56/15 Condition responsive

Abstract

A standing-crop harvester has a chassis adapted to be displaced along the ground in a transport direction and carrying a pair of guide wheels which are normally controlled from a steering wheel. A sensor carried on an arm in front of the machine detects the edge of a swath in a standing crop and generates an output which varies the impedance of one element of a bridge circuit. Another element of this bridge circuit has its impedance varied in accordance with inclination of the harvester on the ground, another element is varied in accordance with the speed of the harvester on the ground, and a fourth element is varied in accordance with the position of the wheels of the harvester relative to the direction of travel. A zerovoltage detector connected across this bridge operates an electromechanical valve which steers the vehicle automatically, compensating for inclination of the ground under the harvester and speed of the harvester along the ground, and using the feedback signal from the wheel positions so as to accurately guide the harvester along the edge of the swath. The steering wheel is provided with an electrical capacitative sensor which shuts off the automatic steering system immediately when the operator touches the wheel so that he can readily take over manual operation of the machine. In addition a double check valve is provided between the power steering system and the hydraulic cylinder serving to steer the wheel so as to prevent rotation of the steering wheel when the automatic pilot is in operation.

Claims

1. An automatic steering system for a standing-crop harvester having a chassis adapted to travel in a transport direction along the ground and carrying guide wheels operated by a steering element on the chassis, said system comprising:

sensor means at a forward location of said chassis in said transport direction and mounted on said chassis for detecting the edge of a swath cut in a standing crop and generating an output corresponding to the position of said edge relative to said chassis;

actuation means independent of said steering element and connected to said sensor means for receiving said output and controlling said guide wheels in accordance with said output; and

means for altering said output before reception thereof by said actuation means in accordance with the inclination of the ground under said chassis for biasing said chassis directionally in an uphill direction.

2. An automatic steering system for a standing crop harvester having a chassis displaced by a drive having a speed-control element along the ground in a transport direction and carrying guide wheels operable by a steering element on the chassis, said system comprising:

sensor means ahead of said chassis in said transport direction and mounted on said chassis for detecting the edge of a swath cut in a standing crop and generating an output corresponding to the position of said edge relative to said chassis;

actuation means independent of said steering element and connected to said sensor means for receiving said output and controlling said guide wheels in accordance therewith; and

means connected to said speed-control element and to said sensor means for altering said output in accordance with displacement speed of said chassis along the ground for reducing the steering response of said guide wheels in response to said output with increased displacement speed.

3. An automatic steering system for a standing crop harvester having a chassis displaceable along the ground in a transport direction and carrying guide wheels operable by a steering element on said chassis, said system comprising:

sensor means ahead of said chassis in said transport direction and mounted on said chassis for detecting the edge of a swath cut in a standing crop and generating an output corresponding to the position of said edge relative to said chassis;

actuation means independent of said steering element and connected to said sensor means for receiving said output and controlling said guide wheels in accordance therewith; and

means responsive to the position of said guide wheels relative to said chassis and to said transport direction for altering said output so as to control displacement of said guide wheels by feedback once said guide wheels are set thereby in an orientation to bring said chassis into a predetermined position relative to said edge.

4. The system defined in claim 3 wherein said means responsive to said guide wheels includes a variable impedance having a portion connected to a one of said guide wheels and displaceable thereby so as to have an impedance dependent on wheel position.

5. A steering system for a harvesting-machine chassis displaceable along the ground in a transport direction and having at least one guide wheel operable by a steering element, said system comprising:

a crop-swath sensor on said chassis;

automatic steering means connected to said guide wheel and connected to said sensor for steering said chassis along the ground according to a predetermined path corresponding to a swath independent of displacement of said steering element;

means for operatively coupling said steering element to said guide wheel to terminate operation of said automatic steering means; and

pump means connected to said steering element and cylinder means connected to said pump means and to said guide wheel for hydraulic actuation of said cylinder means by said pump means on actuation of said steering element, said means for coupling including at least one check valve between said pump means and said cylinder means, said automatic steering means being connected to said cylinder means and means for controlling said check valve to prevent displacement of said steering element by movement of said guide wheel.

6. The system defined in claim 5 wherein said check valve includes a double check valve only allowing fluid flow between said pump means and said cylinder means on actuation of said steering element.

7. An automatic steering system for a chassis displaceable along the ground and having at least one guide wheel directable by a steering element, said system comprising:

automatic steering means connectable to said guide wheel for steering said chassis along the ground according to a predetermined path independent of displacement of said steering element, said steering element comprising a steering wheel and a spinner knob on said wheel; and

a capacitive switch on said knob responsive to the grasping of said knob by the driver of said chassis for uncoupling said automatic steering means from said guide wheel.

8. A method of guiding a standing-crop harvester comprising the steps of:

sensing the edge of a swath in said standing crop and generating an impedance output;

detecting the speed of displacement of said harvester along the ground and generating an impedance output corresponding to said speed;

generating an impedance output having a magnitude corresponding to the side-to-side inclination of the ground under said harvester; and

combining said impedance outputs and controlling the orientation of guide wheels of said harvester in accordance with the combined outputs.

9. The method defined in claim 8 wherein said outputs are signals derived from respective resistors.