System, and method for enabling a vehicle to track a path

• US 5,680,306 A
• Filed: 05/01/1995
• Issued: 10/21/1997
• Est. Priority Date: 02/05/1990
• Status: Expired due to Fees

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Whittaker, William L., Shin, Dong Hun, Devier, Lonnie J., Singh, Sanjiv J.
• Primary Examiner(s): PARK, COLLIN
• Application Number:
  US08/431,591
• Time in Patent Office: 904 Days
• Field of Search: 364/424.02, 364/443, 364/444, 364/449, 180/167, 180/168, 180/169
• US Class Current: 701/213
• CPC Class Codes: B60K 31/0008 including means for detecting potential obstacles in vehicle path
• CPC Class Codes: B60K 31/04 and means for comparing one electrical quantity, e.g. voltage, pulse, waveform, flux, or the like, with another quantity of a like kind, which comparison means is involved in the development of an electrical signal which is fed into the controlling means
• CPC Class Codes: B62D 1/28 non-mechanical , e.g. following a line or other known markers
• CPC Class Codes: G01S 17/42 Simultaneous measurement of distance and other co-ordinates indirect measurement G01S17/46
• CPC Class Codes: G01S 17/86 Combinations of lidar systems with systems other than lidar, radar or sonar, e.g. with direction finders
• CPC Class Codes: G01S 17/931 of land vehicles
• CPC Class Codes: G01S 19/11 wherein the cooperating elements are pseudolites or satellite radio beacon positioning system signal repeaters
• CPC Class Codes: G01S 19/27 creating, predicting or correcting ephemeris or almanac data within the receiver
• CPC Class Codes: G01S 19/41 Differential correction, e.g. DGPS [differential GPS]
• CPC Class Codes: G01S 19/46 the supplementary measurement being of a radio-wave signal type
• CPC Class Codes: G01S 19/47 the supplementary measurement being an inertial measurement, e.g. tightly coupled inertial
• CPC Class Codes: G01S 19/52 Determining velocity
• CPC Class Codes: G01S 5/009 Transmission of differential positioning data to mobile
• CPC Class Codes: G01S 7/4811 common to transmitter and receiver
• CPC Class Codes: G05D 1/0011 associated with a remote control arrangement
• CPC Class Codes: G05D 1/024 in combination with a laser lasers per se H01S
• CPC Class Codes: G05D 1/0242 using non-visible light signals, e.g. IR or UV signals
• CPC Class Codes: G05D 1/0268 using internal positioning means
• CPC Class Codes: G05D 1/027 comprising intertial navigation means, e.g. azimuth detector inertial navigation G01C21/16; inertial navigation combined with non-inertial navigation instruments G01C21/165
• 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
• CPC Class Codes: G05D 1/0278 : using satellite positioning signals, e.g. GPS
• CPC Class Codes: G05D 1/0297 : by controlling means in a control room
• CPC Class Codes: G08G 1/202 : Dispatching vehicles on the basis of a location, e.g. taxi dispatching

Abstract

A system (400) for positioning and navigating an autonomous vehicle (310) allows the vehicle (310) to travel between locations. Position information (432) is derived from global positioning system satellites (200, 202, 204, and 206) or other sources (624) when the satellites (200, 202, 204, and 206) are not in the view of the vehicle (310). Navigation of the vehicle (310) is obtained using the position information (432), route information (414), obstacle detection and avoidance data (416), and on board vehicle data (908 and 910).

Claims

1. A system for enabling a vehicle to track a preset path comprising:

means for executing vehicle commands that cause the vehicle to attempt to follow the preset path;

means for periodically calculating errors in following the preset path; and

means for adjusting said vehicle commands based on said calculated errors to reduce said calculated errors,

wherein said means for adjusting includes means for constructing a smooth path back to the preset path using a quintic polynomial.

2. The system of claim 1, wherein said means for adjusting further comprises means for compensating for vehicle response characteristics, said vehicle response characteristics including latency of vehicle control commands, system response delay and vehicle dynamics.

3. The system of claim 2, wherein said vehicle dynamics includes vehicle-ground interaction, slip angle and under/over steering.

4. The system of claim 1, wherein said means for adjusting further comprises means for compensating for sensing and actuation timing characteristics of said system.

5. The system of claim 1, wherein said means for adjusting further comprises means for varying a look-ahead distance based on a speed of travel of said vehicle.

6. The system of claim 1, wherein said means for adjusting further comprises means for adjusting control of the vehicle using an optimal control system.

7. The system of claim 1, wherein said vehicle commands include steering control aspects and speed control aspects, and wherein said means for executing comprises:

means for executing said steering control aspects; and

means for executing said speed control aspects,

wherein steering and speed control of the vehicle are decoupled.

8. A method for enabling a vehicle to track a preset path comprising the steps of:

executing vehicle commands that cause the vehicle to attempt to follow the preset path;

periodically calculating errors in following the preset path; and

adjusting said vehicle commands based on said calculated errors to reduce said calculated errors,

wherein said step of adjusting includes the step of constructing a smooth path back to the preset path using a quintic polynomial.

9. The method of claim 8, wherein said step of adjusting further comprises the step of compensating for vehicle response characteristics, said vehicle response characteristics including latency of vehicle control commands, system response delay and vehicle dynamics.

10. The method of claim 9, wherein said vehicle dynamics includes vehicle-ground interaction, slip angle and under/over steering.

11. The method of claim 8, wherein said step of adjusting further comprises the step of compensating for sensing and actuation timing characteristics of said system.

12. The method of claim 8, wherein said step of adjusting further comprises the step of varying a look-ahead distance based on a speed of travel of said vehicle.

13. The method of claim 8, wherein said step of adjusting further comprises the step of adjusting control of the vehicle using an optimal control system.

14. The method of claim 8, wherein said vehicle commands include steering control aspects and speed control aspects, and wherein said step of executing comprises the steps of:

executing said steering control aspects, and

executing said speed control aspects,

wherein steering and speed control of the vehicle are decoupled.