METHOD FOR GUIDING VEHICLES AUTOMATICALLY ALONG A PREDETERMINED PATH

• US 3,696,882 A
• Filed: 01/27/1971
• Issued: 10/10/1972
• Est. Priority Date: 02/13/1970
• Status: Expired due to Term

• Current Assignee: Kabelmetal Electro GmbH Kabelkamp
• Original Assignee: Helmut Martin
• Inventors: Martin, Helmut
• Primary Examiner(s): Betts, Kenneth H.
• Application Number:
  US05/110,063
• Time in Patent Office: 622 Days
• Field of Search: 180/98,82,15E 246/29,30,182R,167R 340/22,23,32
• 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 1/0259 using magnetic or electromagnetic means
• CPC Class Codes: G05D 1/0265 using buried wires

Abstract

Low rate propagation of descrete phase points between two oppositely propagation and slightly detuned frequencies is used for motion control of vehicles along a prescribed path.

Claims

1. A method of controlling the motion of vehicles along a prescribed path comprising the steps of:

providing a high frequency cable for developing partial external field along said path to radiate high frequency energy along that path;

feeding h.f. energy of a first frequency into the cable, from one end thereof and to propagate therein in a direction away from the feed-in point;

feeding h.f. energy of a second frequency into the cable from the opposite end to propagate therein in the opposite direction, the first and second frequencies both being approximately subharmonics of a particular frequency, the total deviation of both of the first and second frequencies from respectively being a true subharmonic of the particular frequency representing a phase point velocity along the cable;

detecting, in a vehicle in the vicinity of the cable, signals of the first and second frequencies;

detecting, in the vehicle, particular harmonics in each of the detected signals and comparing the phase between the separately detected harmonics; and

controlling motion of the vehicle in response to the phase comparison.

2. A method as in claim 1, wherein the motion of the vehicle is controlled to maintain a constant phase between the harmonic as derived from the signal of the first frequency and the harmonic as derived from the signal having the second frequency.

3. A method as in claim 2, wherein the motion is controlled to maintain a + 90* phase difference.

4. A method as in claim 2, wherein the motion is controlled to maintain a - 90* phase difference.

5. The method as in claim 1, wherein the first frequency is a true subharmonic of the particular frequency, the second frequency is a composite frequency that includes another true harmonic of the particular frequency and an incremental component representing the phase point velocity.

6. The method as in claim 5, wherein the incremental component is equal to twice the second frequency multiplied by the ratio of phase point velocity and wave propagation velocity in the cable.

7. The method as in claim 5, providing the second frequency by first providing an h.f. rotating field having frequency of the other true harmonic, and providing a rotating coil in the field, to derive therefrom the composite frequency as second frequency to be transmitted through the cable.

8. The method as in claim 1, wherein the particular frequency is selected to be equal to the propagation speed of high frequency energy within the cable divided by four times the distance to be maintained between two succeeding vehicles.

9. The method as in claim 1, comprising the step of selecting a relatively reduced wave propagation velocity in portions of the high frequency cable as compared with the wave propagation velocity in other portions of the cable, in accordance with a reduced desired phase velocity in the vicinity of the cable.