Magnetically guided vehicle

• US 4,990,841 A
• Filed: 09/19/1989
• Issued: 02/05/1991
• Est. Priority Date: 09/19/1989
• Status: Expired due to Fees

• Current Assignee: Apogee Robotics
• Original Assignee: Apogee Robotics
• Inventors: Elder, Mark
• Primary Examiner(s): Shoop, Jr., William M.
• Assistant Examiner(s): IP, SHIK LUEN PAUL
• Application Number:
  US07/409,063
• Time in Patent Office: 504 Days
• Field of Search: 318/139, 318/587, 318/568, 318/580, 364/424.01, 364/424.02, 340/825.05, 180/167, 180/168, 180/169, 901/1, 901/7, 901/14, 901/46, 901/47, 901/50, 358/103
• US Class Current: 318/587
• CPC Class Codes: G05D 1/0263 using magnetic strips

Abstract

Disclosed is a computer control device designed to be incorporated in a vehicle such as, for example, a robotic vehicle, which device is designed to be used to guide the vehicle in a desired path. The device includes a multiplicity of Hall effect sensors designed to sense a permanent magnet tape placed on a floor surface and extending along the desired path of motion. A permanent magnet bar code may also be installed on the floor surface and the device includes a reader to read the bar code and transmit read information to the computer, with the computer storing pathway information based upon the bar code. Other aspects are disclosed.

Claims

1. An improved guidance system, comprising:

(a) a tape having permanent magnet material incorporated therein, said tape being attachable to a floor surface, said tape, when attached to said floor surface, defining a desired guide path;

(b) a device adapted to travel over said floor surface along said guide path, said device having a guidance system, comprising;

(i) at least three Hall effect sensors arranged in a linear array, said device being oriented with respect to said guide path such that said array is maintained, by operation of said guidance system, substantially perpendicular to said guide path;

(ii) a controller electrically connected to said sensors and receiving first signals therefrom indicative of the position of said array with respect to said tape, each said sensor being electronically connected to said controller via a corresponding sub-circuit including a comparator which compares said first signals with a variable reference signal, said controller varying said reference signal from a first high voltage downwardly in stepped fashion until said first signals exceed said reference signal whereupon said first signals are transmitted to said controller;

(iii) motive means on said device for moving said device along said guide path, said controller emitting second signals to control said motive means;

(c) a code on said floor surface, said guidance system having a code reader adapted to read said code when said device travels thereover, said code reader sending third signals to said controller indicative of said code, said third signals accessing a memory means of said controller wherein information is stored regarding specifics of said guide path, said controller comparing said information with said first signals to verify movements of said device along said guide path.

2. The invention of claim 1, wherein said linear array includes seven Hall effect sensors.

3. The invention of claim 1, wherein said motive means includes a plurality of servo amplifier operated motors.

4. The invention of claim 1, wherein said code comprises a magnetic code.

5. The invention of claim 4, wherein said code reader comprises a magnetic code reader.

6. The invention of claim 4, wherein said code comprises a bar code.

7. The invention of claim 1, wherein said device comprises a vehicle.

8. The invention of claim 1, wherein outputs from at least two of said comparators are inputted into an OR gate.

9. In a magnetically guided vehicle having motive means to move said vehicle over a floor surface following a magnetic pathway of predetermined width, the improvement comprising a guidance system for controlling said motive means to follow said magnetic pathway, said guidance system comprising:

at least three Hall effect sensors arranged in a linear array, said linear array having a length greater than the width of said magnetic pathway, said linear array arranged on said vehicle so as to be substantially perpendicular to a direction of travel of said vehicle;

a controller electronically connected to said sensors and receiving first signals therefrom indicative of the position of said array with respect to said magnetic pathway, each said sensor being electronically connected to said controller via a corresponding sub-circuit including a comparator which compares said first signals with a variable reference signal, said controller varying said reference signal from a first voltage downwardly in stepped fashion until said first signals exceed said reference signal whereupon said first signals are transmitted to said controller, said controller emitting second signals to control said motive means.