Automatically guided vehicle having steering mechanism for enabling vehicle to follow guidance wire

• US 4,729,449 A
• Filed: 12/06/1985
• Issued: 03/08/1988
• Est. Priority Date: 12/06/1985
• Status: Expired due to Fees

• Current Assignee: Nationsbank Of North Carolina, N.A. (Bank of America Corp.)
• Original Assignee: Ndc Technologies Inc. (Nordson Corporation)
• Inventors: Holmquist, Fredrik
• Primary Examiner(s): Love, John J.
• Assistant Examiner(s): CULBRETH, ERIC D
• Application Number:
  US06/805,540
• Time in Patent Office: 823 Days
• Field of Search: 180/167, 180/168, 364/424, 364/426, 318/16, 318/17, 342/70, 342/71, 340/52 R, 446/135, 446/136, 446/441, 446/444
• US Class Current: 180/168
• CPC Class Codes: B62D 1/28 non-mechanical , e.g. following a line or other known markers
• CPC Class Codes: G05D 1/0231 using optical position detecting means position-fixing by using electromagnetic waves other than radio waves, e.g. optical position detecting means G01S5/16
• CPC Class Codes: G05D 1/0265 using buried wires

Abstract

An automatically guided vehicle (V) having a steering mechanism for enabling the vehicle to follow a guidance wire is disclosed. The vehicle includes a pair of spaced-apart steer drive antennas (S1, S2) and a pair of spaced-apart differential drive antennas (D1, D2). The steer drive antennas and differential drive antennas are in mutual perpendicular relation to each other and are stationarily mounted on the vehicle (V). In a steer drive mode, wheels (12) and (13) are separately controlled by steer drive antennas (S1) and (S2), respectively. The antennas cause the wheels to turn and therefore guides the vehicle (V) so that a wire (W) is followed.

In a differential drive mode, wheels (12) and (13) that are positioned in parallel driving relation to each other and are controlled by antennas (D1, D2) respectively by varying the speed of the wheels (12, 13) to cause the vehicle (V) to follow the wire (W).

Claims

1. A steering mechanism for enabling a vehicle to follow a guidance wire, said steering mechanism comprising:

(a) first and second cooperating steer drive antennas stationarily affixed in spaced-apart relation on said vehicle in wire sensing relation thereto;

(b) a differential drive antenna stationarily affixed on said vehicle in wire sensing relation thereto and oriented perpendicular to said first and second steer drive antennas;

(c) first drive wheel means including a first drive wheel mounted on said vehicle and having steering and driving means for propelling and steering said vehicle along a surface;

(d) second drive wheel means including a second drive wheel mounted on said vehicle in spaced-apart relation to said first drive wheel and having steering and driving means for propelling and steering said vehicle along a surface;

(e) control means operatively connecting the steering means of said first drive wheel to said first steer drive antenna and to said differential drive antenna, and, the steering means of said second drive wheel to said second steer drive antenna and said differential drive antenna;

said control means further including means for;

(f) in a steer drive mode, positioning said first and second drive wheels in front-to-back, driving and steering relation for steering movement of said first drive wheel in response to lateral relative movement between said guidance wire and said first steer drive antenna and steering movement of said second drive wheel in response to lateral relative movement between said guidance wire and said second steer drive antenna;

the steering movement of said first drive wheel being independent of the steering movement of the second drive wheel; and

(g) in a differential drive mode, rotating said first and second drive wheels into a position substantially perpendicular from the steer drive position and into mutual parallel relation whereby said vehicle may be moved in a direction substantially perpendicular to the direction of movement in the steer drive mode in a straight-line or sinuous path by differential speed control of said first and second drive wheels in response to lateral relative movement between said guidance wire and said second differential drive antenna;

whereby said vehicle can be guided along a straight or sinuous path by said first and second drive wheels in steer drive relation and then moved perpendicularly along a straight or sinuous path by said drive wheels in differential drive position.

2. A steering mechanism according to claim 1, wherein said control means includes a computer for receiving and processing first and second steer drive antenna input signals and outputting drive signals and steer signals.

3. A steering mechanism according to claim 2, wherein said steer signals comprise separate first and second steer signals for said first and second drive wheels, respectively.

4. A steering mechanism for enabling a vehicle to follow a guidance wire, said steering mechanism comprising:

(a) a steer drive antenna stationarily affixed on said vehicle in wire sensing relation thereto;

(b) a differential drive antenna stationarily affixed on said vehicle in wire sensing relation thereto and oriented perpendicular to said steer drive antenna;

(c) first drive wheel means including a first drive wheel mounted on said vehicle and having steering and driving means for propelling and steering said vehicle along a surface;

(d) second drive wheel means including a second drive wheel mounted on said vehicle in spaced-apart relation to said first drive wheel and having steering and driving means for propelling and steering said vehicle along a surface;

(e) control means operatively connecting the steering means of said first drive wheel to said steer drive antenna and to said differential drive antenna, and the steering means of said second drive wheel to said differential drive antenna;

said control means further including;

(f) in a steer drive mode, means for steering the first drive wheel in response to lateral relative movement between said guidance wire and said steer drive antenna;

(g) electrical motion transmitting means operativelyconnected to said first and second steer wheels for transmitting steering movement information from the leading drive wheel to the following drive wheel whereby when said leading wheel turns in a direction, the following drive wheel turns in the opposite direction to the corresponding degree; and

(h) in a differential drive mode, said control means including means to rotate said first and second drive wheels into a position substantially perpendicular from the position of the wheels in the steer drive mode and into mutually parallel relation whereby said vehicle may be moved in a direction substantially perpendicular to the direction of movement in the steer drive mode by differential speed control of said first and second drive wheels in response to lateral relative movement between said guidance wire and said differential drive antenna;

whereby said vehicle can be guided along a straight or sinuous path by said first and second drive wheels in steer drive relation and then moved perpendicularly along a straight or sinuous path by said drive wheels in differential drive position.

5. A steering mechanism according to claim 4, wherein said electrical motion transmitting means comprise first and second feedback potentiometers cooperating with said first and second drive wheels, respectively, wherein said first and second feedback potentiometers send a signal from the respective drive wheels to said controller representing the angular position of the respective wheels for addition to the antenna signal to control steering movement.

6. A steering mechanism for enabling a vehicle to follow a guidance wire, said steering mechanism comprising:

(a) first and second cooperating steer drive antennas stationarily affixed in spaced-apart relation on said vehicle in wire sensing relation thereto;

(b) first and second cooperating differential drive antennas stationarily affixed in spaced-apart relation on said vehicle in wire sensing relation thereto and oriented perpendicular to said first and second steer drive antennas;

(c) first drive wheel means including a first drive wheel mounted on said vehicle and having steering and driving means for propelling and steering said vehicle along a surface;

(d) second drive wheel means including a second drive wheel mounted on said vehicle in spaced-apart relation to said first drive wheel and having steering and driving means for propelling and steering said vehicle along a surface;

(e) control means operatively connecting said first drive wheel to said first steer drive antenna and to said first differential drive antenna, and said second drive wheel to said second steer drive antenna, and said second differential drive antenna;

said control means further including means for;

(f) in a steer drive mode, designating as a leading steer drive antenna that steer drive antenna on an end of the vehicle forward in the direction of movement on said vehicle, for steering movement of the corresponding drive wheel in response to said lateral relative movement between said guidance wire and said leading drive antenna;

(g) electrical motion transmitting means operatively connected to said first and second steer wheels for transmitting steering movement information from the leading drive wheel to the following drive wheel whereby when said leading wheel turns in a direction, the following drive wheel turns in the opposite direction to the corresponding degree; and

(h) wherein in the differential drive mode, said control means rotate said first and second drive wheels into a position substantially perpendicular from the steer drive position and into mutually parallel relation whereby said vehicle may be moved in a direction substantially perpendicular to the direction of movement in the steer drive mode by differential speed control of said first and second drive wheels in response to lateral relative movement between said guidance wire and said first differential drive antenna if the vehicle is moving in one direction and the second differential drive antenna if the vehicle is moving in the opposite direction;

whereby said vehicle can be guided along a straight or sinuous path by said first and second drive wheels in steer drive relation and then along a straight or sinuous path by said drive wheels in differential drive position.

7. A steering mechanism according to claim 6, wherein said electrical control means comprises first and second feedback potentiometers cooperating with said first and second drive wheels, respectively, wherein said first and second feedback potentiometers send a signal from the respective drive wheels to said controller representing the angular position of the respective wheels for addition to the antenna signal to control steering movement.