Automated vehicle guidance system and method for automatically guiding a vehicle

• US 5,875,408 A
• Filed: 07/17/1995
• Issued: 02/23/1999
• Est. Priority Date: 07/17/1995
• Status: Expired due to Fees

• Current Assignee: IMRA America Incorporated (Aisin Corp.)
• Original Assignee: IMRA America Incorporated (Aisin Corp.)
• Inventors: Aral, Alan Y., Bendett, Mark P.
• Primary Examiner(s): Louis-Jacques, Jacques H.
• Assistant Examiner(s): Pipala, Edward J.
• Application Number:
  US08/503,049
• Time in Patent Office: 1,317 Days
• Field of Search: 364/424.027, 364/424.029, 364/460, 180/167, 180/169, 250/559.29, 250/559.33, 250/559.37, 250/559.38, 356/3, 356/3.01, 356/3.1, 356/3.11, 356/5.01, 356/5.02, 356/5.1, 701/23, 701/25, 701/300
• US Class Current: 701/23
• CPC Class Codes: B62D 1/28 non-mechanical , e.g. following a line or other known markers
• CPC Class Codes: G01S 17/10 using transmission of interrupted, pulse-modulated waves determination of distance by phase measurements G01S17/32
• CPC Class Codes: G01S 17/87 Combinations of systems using electromagnetic waves other than radio waves
• CPC Class Codes: G01S 17/931 of land vehicles
• CPC Class Codes: G05D 1/0234 using optical markers or beacons optical beacons per se G01S1/70
• 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: G05D 1/0263 using magnetic strips

Abstract

An automated vehicle guidance system for guiding a movable vehicle along a predetermined desired path over a surface that is provided with at least one reference marking includes a laser radar for emitting laser pulses towards the reference marking and for receiving laser pulses reflected from the reference marking, a steering actuator for steering the vehicle, and a computer connected to the laser radar and the steering actuator. The laser radar is designed to determine the distance between the vehicle and the reference marking and that distance is used by the computer to determine the lateral position of the vehicle relative to the desired path of vehicle travel. The computer then controls the steering actuator in the manner necessary to effect guidance of the vehicle along the desired path. A method for automatically guiding a vehicle along a desired travel path involves determining the distance from a point on the vehicle to the reference marking by emitting a laser pulse and receiving the laser pulse reflected from the reference marker, determining the lateral position of the vehicle relative to the desired path based on the determined distance, and controlling the steering actuator when the lateral position of the vehicle is offset from the desired path to guide the vehicle along the desired path. The reference marking can be in the form of reflective stripes painted on the surface or white strips disposed on barriers positioned along the desired path.

Claims

1. Automated vehicle guidance system for guiding a movable vehicle having a vehicle axis along a predetermined desired path over a surface that is provided with first and second desired path references positioned on opposite sides of the desired path, comprising:

a first laser pulse transmitter positioned on the vehicle on one side of the vehicle axis for transmitting laser pulses towards an opposite side of the vehicle and towards the first desired path reference;

a second laser pulse transmitter positioned on the vehicle on the opposite side of the vehicle axis for transmitting laser pulses towards the one side of the vehicle and towards the second desired path reference;

a first laser pulse receiver positioned on the vehicle and operatively associated with the first laser pulse transmitter for receiving laser pulses transmitted by the first laser pulse transmitter and reflected from the first desired path reference;

a second laser pulse receiver positioned on the vehicle and operatively associated with the second laser pulse transmitter for receiving laser pulses transmitted by the second laser pulse transmitter and reflected from the second desired path reference;

a steering actuator mounted on the vehicle for steering the vehicle;

a control device connected to the steering actuator and to the first and second laser pulse receivers for controlling the steering actuator based on reflected laser pulses received by the first and second laser pulse receivers to guide the vehicle along the predetermined desired path.

2. Automated vehicle guidance system according to claim 1, wherein said control device includes one time measurement system connected to said first laser pulse receiver for producing a signal indicative of a time differential between when a laser pulse is transmitted by said first laser pulse transmitter and when the transmitted laser pulse reflected from said first desired path reference is received by the first laser pulse receiver and another time measurement system connected to said second laser pulse receiver for producing a signal indicative of a time differential between when a laser pulse is transmitted by said second laser pulse transmitter and when the transmitted laser pulse reflected from said second desired path reference is received by the second laser pulse receiver.

3. Automated vehicle guidance system according to claim 2, wherein said control device includes a computer operatively associated with said time measurement systems for determining, on the basis of said signals, the distance between a predetermined point on the vehicle and the desired path references.

4. Automated vehicle guidance system according to claim 1, wherein said control device includes a computer for determining a yaw angle of the vehicle.

5. Automated vehicle guidance system according to claim 1, wherein said first and second laser pulse transmitters each include a beam splitter for splitting the laser pulse transmitted by each respective laser pulse transmitter into two laser pulses which are each oriented at a different angle with respect to the vehicle axis.

6. Automated vehicle guidance system for guiding a movable vehicle having a vehicle axis along a predetermined desired path over a surface that is provided with at least one desired path reference, comprising:

a laser radar for emitting a laser pulse along a radar axis towards the at least one desired path reference, for receiving a laser pulse reflected from the at least one desired path reference and for determining the distance between the laser radar and the at least one desired path reference along the radar axis on the basis of time-of-flight of said laser pulse emitted towards and reflected from said at least one desired path reference;

a steering actuator for steering the vehicle; and

a computer connected to the laser radar and the steering actuator for determining, based on the distance determined by said laser radar, a lateral position of the vehicle relative to the desired path and for controlling the steering actuator to guide the vehicle along the desired path.

7. Automated vehicle guidance system according to claim 6, wherein said laser radar includes a laser pulse transmitter which emits a laser pulse and a laser pulse receiver which receives a laser pulse reflected from the at least one desired path reference.

8. Automated vehicle guidance system according to claim 7, wherein said laser pulse transmitter includes a beam splitter for splitting each laser pulse emitted by the laser pulse transmitter into two substantially simultaneously emitted laser pulses which are each oriented at a different angle with respect to the vehicle axis.

9. Automated vehicle guidance system according to claim 6, wherein said laser radar includes means for emitting substantially simultaneously first and second laser pulses along respective first and second radar axes which are each oriented at a different angle relative to the vehicle axis for determining a first distance between the laser radar and the at least one desired path reference along said first radar axis and a second distance between the laser radar and the at least one desired path reference along the second radar axis.

10. Automated vehicle guidance system according to claim 9, wherein said computer determines, on the basis of said first and second distances, a yaw angle of the vehicle relative to the desired path.

11. Automated vehicle guidance system according to claim 6, wherein said laser radar is a first laser radar that is adapted to emit a laser pulse along a first radar axis that crosses the vehicle axis and that is directed towards the at least one desired path reference, and including a second laser radar for emitting another laser pulse along a second radar axis that crosses the vehicle axis towards another desired path reference positioned on a side of the desired path opposite said at least one desired path reference and for receiving a laser pulse reflected from the another desired path reference to determine the distance between the second laser radar and the another desired path reference along the second radar axis.

12. Automated vehicle guidance system according to claim 6, wherein said laser radar includes a time measurement system for determining said distance along the radar axis based on a time differential between when the laser pulse is emitted and when said emitted laser pulse is reflected from the at least one desired path reference and received by the laser radar.

13. Automated vehicle guidance system according to claim 6, wherein said laser radar axis is obliquely oriented with respect to said vehicle axis.

14. Method for automated guidance of a movable vehicle having a vehicle axis along a predetermined desired path over a surface that is provided with at least one desired path reference, comprising:

determining a distance from a point on the vehicle to the at least one desired path reference along a radar axis by emitting a laser pulse along the radar axis towards the at least one desired path reference, receiving the laser pulse reflected from the at least one desired path reference and determining said distance to the at least one desired path reference on the basis of time-of-flight of the laser pulse;

determining a lateral position of the vehicle relative to the desired path based on said distance; and

controlling a steering actuator operatively associated with the vehicle when the lateral position of the vehicle is offset from the desired path to guide the vehicle along the desired path.

15. Method according to claim 14, wherein said distance is one distance, and including determining another distance from said point on the vehicle to the at least one desired path reference along another radar axis by emitting another laser pulse along the another radar axis towards the at least one desired path reference, receiving the another laser pulse reflected from the at least one desired path reference and determining said another distance to the at least one desired path reference on the basis of time-of-flight of the another laser pulse.

16. Method according to claim 15, including determining a yaw angle of the vehicle relative to the desired path based on said one distance and said another distance.

17. Method according to claim 14, wherein said distance is one distance, and including determining another distance from a point on said vehicle to another desired path reference positioned on a side of the desired path opposite said at least one desired path reference by emitting another laser pulse along another radar axis towards said another desired path reference, receiving the another laser pulse reflected from said another desired path reference and determining said another distance to the at least one desired path reference on the basis of time-of-flight of the another laser pulse.

18. Method according to claim 17, including determining a yaw angle of the vehicle relative to the desired path based on said one distance and said another distance.

19. Method according to claim 14, wherein said laser pulse is emitted towards a reflective stripe positioned on the surface along which the vehicle travels and is reflected from said stripe, said stripe being spaced from the desired path.

20. Method according to claim 14, wherein said laser pulse is emitted towards a reflective strip positioned on a barrier that is located at a spaced apart distance from the desired path and is reflected from said strip.

21. Method according to claim 14, wherein said step of controlling the steering actuator includes controlling the steering actuator to maintain the vehicle in a current lane in which the vehicle is travelling.