Speed controller for a self-traveling vehicle

• US 6,324,462 B1
• Filed: 08/24/1998
• Issued: 11/27/2001
• Est. Priority Date: 08/22/1997
• Status: Expired due to Term

• Current Assignee: Komatsu Ltd.
• Original Assignee: Komatsu Ltd.
• Inventors: Kageyama, Masato
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): To, Tuan C
• Application Number:
  US09/138,635
• Time in Patent Office: 1,191 Days
• Field of Search: 701/93, 701/41, 701/70, 701/301, 340/903, 382/104
• US Class Current: 701/93
• CPC Class Codes: B60W 2552/15 Road slope, i.e. the inclination of a road segment in the longitudinal direction
• CPC Class Codes: B60W 2552/30 Road curve radius
• CPC Class Codes: B60W 2554/802 Longitudinal distance
• CPC Class Codes: B60W 2720/10 Longitudinal speed
• CPC Class Codes: B60W 30/143 Speed control B60W30/16 takes precedence
• CPC Class Codes: G05D 1/0223 involving speed control of the vehicle vehicle fittings for automatically controlling, i.e. preventing speed from exceeding an arbitrarily established velocity or maintaining speed at a particular velocity, as selected by the vehicle operator B60K31/00
• 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 1/0278 using satellite positioning signals, e.g. GPS

Abstract

A speed controller for a self-traveling vehicle, capable of traveling at high speed along curves, downhill roads, and uphill roads without colliding with an object detected by an object detecting means, is provided. Therefore, a speed controller, equipped in the self-traveling vehicle, previously stores a detection limit area A, of an object detecting means 1, and speed at the start of braking Vmax of every braking stop distance La, receives information on detection distance L from the object detecting means 1; information on a predetermined course Co from a course storage means 2; and information on a current position Po from a current position defining means 3, limits the detection distance L from the object detecting means 1 by the detection limit area A from the current position Po and the predetermined course Co from the current position Po; computes the speed at the start of braking Vmax with a limited detection distance Ln as the breaking stop distance La; and controls actual speed Va by operating a speed control actuator 4 to make the speed at the start of braking Vmax the upper limit.

Claims

1. A speed controller for a self-traveling vehicle comprising:

an object detecting means for detecting an object, in a traveling direction of said vehicle, and a distance to said object;

a course storage means for storing a predetermined course in a coordinate system;

a current position defining means for receiving coordinate information on said predetermined course from said course storage means and defining a current position of said vehicle on said predetermined course; and

a speed control actuator,

wherein said vehicle is an unmanned vehicle;

wherein a detection limit area of said object detecting means is stored in advance, and speeds at the start of braking for respective braking stop distances are stored in advance;

wherein information on the detected distance from said object detecting means, information on the predetermined course from said course storage means, and information on the current position from said current position defining means are received respectively;

wherein the detection distance from said object detecting means to the object is a limited detection distance, which is limited by the detection limit area from the current position and the predetermined course from the current position;

wherein the speed at the start of braking is computed with the limited detection distance as the braking stop distance;

wherein actual vehicle speed is controlled by operating said speed control actuator to make the speed at the start of braking the upper speed limit; and

wherein said speed controller stores a speed control program corresponding to said predetermined course and said vehicle travels on said predetermined course while being speed-controlled by said speed control program.

2. A speed controller for the self-traveling vehicle, according to claim 1, wherein the limited detection distance is a distance between a nearest intersection point from the current position, out of intersection points of an outer edge of the detection limit area and an outer edge of the predetermined course, as seen from above, and the current position.

3. A speed controller for the self-traveling vehicle, according to claim 1, wherein a point is defined at a location where a height from a lower surface of the outer edge of the detection limit area to an upper surface of the predetermined course, as seen from a cross direction, is a predetermined height, and wherein a distance from the current position to the defined point is made the limited detection distance.

4. A speed controller for the self-traveling vehicle, according to claim 1, wherein a point is defined at a location where height from an upper surface of the outer edge of the detection limit area to an upper surface of the predetermined course, as seen from a cross direction, is a predetermined height, and wherein a distance from the current position to the defined point is made the limited detection distance.

5. A speed controller for the self-traveling vehicle, according to claim 1, wherein said speed controller updates information on vehicle speed at each position on the predetermined course in the speed control program to make the speed at the start of braking, computed by said speed controller, the upper speed limit.

6. A speed controller for a self-traveling vehicle, according to claim 1, further comprising:

a speed detector for detecting an actual speed of the vehicle;

a load gauge for detecting a state of a load on a load-carrying platform of the vehicle; and

storage means for storing parameters comprising a speed at the start of braking, a braking stop distance, and predetermined heights.

7. A speed controller for a self-traveling vehicle, according to claim 1, further comprising external input means for inputting correction factors to the speed controller.

8. A speed controller for a self-traveling vehicle, according to claim 1, further comprising information means for indicating the status of the speed controller.

9. A method of controlling a speed of an unmanned self-traveling vehicle, comprising the steps of:

determining a detection limit area;

determining a speed at a start of braking of said vehicle;

determining predetermined heights of said vehicle;

detecting a distance from said vehicle to an object;

determining a predetermined course of travel for said vehicle;

detecting a current position of said vehicle;

determining an actual speed of said vehicle;

determining a conjunction of said detection limit area and said predetermined course of travel;

determining a shortest distance from a plurality of farthest distances from said current position to points within said conjunction of said detection limit area and said predetermined course of travel;

defining a limited detection distance as said shortest distance;

determining a speed at a start of braking based on said limited detection distance;

storing a speed control program corresponding to said predetermined course of travel; and

controlling said actual speed of said vehicle according to said speed control program so that said actual speed does not exceed said speed at a start of braking.

10. A method of controlling a speed of an unmanned self-traveling vehicle, comprising the steps of:

determining a detection limit area and a speed at a start of braking corresponding to the detection limit area;

detecting an object in a traveling direction of said self-traveling vehicle and a distance to said object;

storing a predetermined course as coordinate information;

determining a current position of said self-traveling vehicle on said predetermined course;

determining a limited detection distance which is said distance to said object limited by said detection limit area from said current position of said self-traveling vehicle;

determining a speed at a start of braking with said limited detection distance being a braking stop distance;

storing a speed control program corresponding to said predetermined course; and

controlling said speed of said self-traveling vehicle according to said speed control program while said self-traveling vehicle is traveling along said predetermined course so that said speed at said start of braking is an upper speed limit.