Ultrasonic furrow or crop row following sensor

• US 5,410,479 A
• Filed: 08/17/1992
• Issued: 04/25/1995
• Est. Priority Date: 08/17/1992
• Status: Expired due to Fees

• Current Assignee: William B. Coker
• Original Assignee: William B. Coker
• Inventors: Coker, William B.
• Primary Examiner(s): Teska, Kevin J.
• Assistant Examiner(s): NGUYEN, TAN QUANG
• Application Number:
  US07/929,988
• Time in Patent Office: 981 Days
• Field of Search: 364/424.02, 364/447, 364/449, 364/424.05, 364/561, 364/167, 180/169, 180/168, 180/131, 180/98, 318/567, 318/587, 340/901, 340/988, 342/123, 342/438, 342/458, 342/463
• US Class Current: 701/23
• CPC Class Codes: G05D 1/0227 using mechanical sensing means, e.g. for sensing treated area
• CPC Class Codes: G05D 1/0255 using acoustic signals, e.g. ultra-sonic singals sonar systems designed for anti-collision purposes G01S15/93

Abstract

An automated ultrasonic guidance apparatus is adapted to be mounted on a vehicle having a guidance steering system for steering the vehicle on a desired track between adjacent crop rows or sides of a furrow. The apparatus includes first and second sensors for transmitting and receiving ultrasonic ranging signals. The sensors are mountable on a vehicle for directing the ranging signals downwardly and outwardly in opposite directions toward adjacent crop rows or sides of a furrow such that the ranging signals strike the rows or furrow and are reflected back into the respective sensor. Variable ranging outputs from the sensors are operatively associated with the guidance steering system to cause it to steer the vehicle toward the desired track.

Claims

1. A method of sensing lateral displacement of a vehicle having a guidance system relative to a desired track between two crop rows or along a furrow comprising:

providing a pair of ultrasonic sensor means for transmitting and receiving ultrasonic ranging signals;

mounting said pair of ultrasonic sensor means on a vehicle;

orienting said pair of ultrasonic sensor means on a vehicle such that said ranging signals are directed downwardly and outwardly in opposite directions from said vehicle and towards adjacent crop rows or sides of a furrow such that said ranging signals strike said rows or furrow and are reflected back into the respective sensor;

generating variable ranging outputs proportional to the distance of said sensor means from said row or furrow;

filtering said variable ranging outputs to produce filtered variable ranging outputs wherein erroneous data in said output is eliminated;

multiplying each said filtered variable ranging output by itself thereby producing squared ranging outputs and greatly increasing sensitivity to lateral displacements;

comparing said squared ranging outputs to determine the validity thereof by comparing the relative changes of the two signals wherein if both said squared ranging outputs indicate the same direction of movement, said vehicle is determined to be moving in a vertical direction and the output is not validated, and if said squared ranging outputs indicated different directions of movement, said output is validated;

computing from said validated squared ranging outputs, steering correction commands; and

transmitting said steering correction commands to said guidance system whereby the vehicle is steered toward the desired track.

2. An automated ultrasonic guidance apparatus, mountable on a vehicle having a guidance steering system for steering a vehicle on a desired track between adjacent longitudinal sides of a furrow, the ultrasonic guidance apparatus comprising:

first and second transducers, each operative to emit an ultrasonic ranging signal in the direction of a respective one of said sides of said furrow, to receive the reflection therefrom and to produce a variable ranging output voltage proportional to the distance of said transducer to said furrow;

input buffer means electrically connected to said first and second transducers, for adjusting the maximum level of said variable ranging output voltage;

mounting means for mounting said first and transducers to said vehicle such that said ranging signals of said first and second transducers are directed downwardly and outwardly in opposite directions whereby upon placement of the vehicle on the desired track, said ranging signals are directed from a respective one of said transducers towards adjacent sides of a furrow such that said ranging signals strike said furrow and are reflected back into said respective transducer; and

signal processing means electrically connected to said first and second transducers for receiving, combining and comparing said variable ranging outputs from said first and second transducers said signal processing means having;

filtering means electrically connected to said input buffer means for receiving said variable ranging output from said transducers and filtering out all frequency components of said output below a predetermined adjustable value, producing a filtered variable ranging output, wherein erroneous data in the output is eliminated,

multiplier means electrically connected to said filter means for receiving said filtered variable ranging output from said filtering means and multiplying said output by itself thereby producing a squared ranging output signal, wherein any detected lateral deviations are greatly enhanced,

said signal processing means being operative determine from said variable ranging outputs lateral displacement of said vehicle from said desired track and to convert said displacement into steering correction output by generating a voltage, the value of which is indicative of the direction and magnitude of the correction necessary to return to said desired track, and to transmit said steering correction output to said guidance steering system.

3. The invention of claim 2 wherein said signal processing means further comprises a signal composition means electrically connected to said multiplier means for comparing said squared ranging output from each of said first and second sensor means and producing said steering correction output therefrom and wherein if both ranging outputs indicate the same direction of movement, said signal composition means determines said vehicle is moving in a vertical, rather than lateral, direction and the displacement is not converted into a steering correction output.

4. The invention of claim 3 further comprising multiplier switching means having OFF and ON positions and operatively associated with said signal processing means such that the filtered variable ranging output bypasses said multiplier means upon said switch means being in the OFF position thereby connecting said signal composition means to said filtering means and wherein said multiplier is utilized upon said switch being in the ON position.

5. The invention of claim 4 further comprising a signal selection switching means electrically connected to said signal composition means for selecting a single or dual sensor configuration.

6. An automated ultrasonic guidance apparatus, mountable on a vehicle having a guidance steering system for steering a vehicle on a desired track between adjacent longitudinal sides of a furrow, the ultrasonic guidance apparatus comprising:

first and second transducers, each operative to emit an ultrasonic sound in the direction of a respective one of said sides of a furrow, to receive the reflection therefrom and to produce a variable ranging output voltage proportional to the distance of said transducer to said respective side of said furrow said variable ranging output voltage varying between zero and a maximum voltage;

input buffer means electrically connected to said first and second transducers, for adjusting the maximum level of said variable ranging output voltage;

mounting means on said vehicle for mounting said first and second transducers thereto such that said variable ranging signals are directed downwardly and outwardly in opposite directions from said vehicle and towards adjacent crop rows or sides of a furrow such that said ranging signals strike said row or furrow and are reflected back into the respective transducer;

a first and second signal processing means electrically connected to said first and second transducers for receiving and processing said variable ranging outputs, generating processed ranging outputs;

a signal composition means for combining and comparing said processed ranging outputs from said first and second signal processing means said composition means being operative to determine from said processed ranging outputs and having;

a filtering means electrically connected to said input buffer means for receiving said variable ranging output from said sensor means and filtering out all frequency components of said variable ranging output below a predetermined adjustable value thereby producing a filtered variable ranging output, wherein erroneous data in the output is eliminated, and wherein said signal composition means compares said processed ranging outputs from each of said first and second signal processing means to determine the direction of movement away from said track based on the relative changes of the said filtered variable ranging outputs wherein if both said filtered variable ranging outputs indicate the same direction of movement, said signal composition means determines lateral displacement of said vehicle from said desired track converts said displacement into a steering correction output by generating a voltage, the value of which is indicative of the direction and magnitude of the steering correction necessary to return to said desired track, and transmit said steering correction output to said guidance steering system, whereby said vehicle is steered toward the desired track.

7. The invention of claim 6 wherein said signal processing means further comprises a multiplier means electrically connected to said filter means for receiving said filtered variable ranging output from said filtering means and multiplying said output by itself thereby producing a squared ranging output signal, wherein any detected lateral deviations are greatly enhanced.

8. The invention of claim 7 further comprising multiplier switching means having OFF and ON positions and operatively associated with said signal processing means such that the filtered variable ranging output will bypass said multiplier means when said switch means is in the OFF position thereby connecting said signal composition means to said filtering means and wherein said multiplier is utilized when said switch is in the ON position.

9. The invention of claim 8 further comprising a signal selection switching means electrically connected to said signal composition means for selecting a single or dual sensor configuration.