ARRANGEMENT FOR CONTROLLING THE STEERING OF VEHICLES DIRECTED ALONG A PREDETERMINED PATH

• US 3,763,955 A
• Filed: 12/02/1971
• Issued: 10/09/1973
• Est. Priority Date: 10/23/1970
• Status: Expired due to Term

• Current Assignee: Karl-Heinz Schroder, Wolfgang Zwicker
• Original Assignee: Karl-Heinz Schroder, Wolfgang Zwicker
• Inventors: Schroder, Karl-Heinz, Zwicker, Wolfgang
• Primary Examiner(s): Betts, Kenneth H.
• Assistant Examiner(s): Silverstrim, John P.
• Application Number:
  US05/204,274
• Time in Patent Office: 677 Days
• Field of Search: 180/98,79.1 318/580,587
• US Class Current: 180/168
• CPC Class Codes: G05D 1/0265 using buried wires

Abstract

An arrangement for controlling unmanned vehicles to drive along a predetermined path on which a guide track is laid. The guide track has a border of electrically conductive and non-conductive material. The vehicle carries analog signal generators which emanate a magnetic field that is damped by the electrically conductive material. The signal generators provide positive or negative signals depending on the displacement of the projected border relative to the centerline of the active zone of the signal generators. The generators provide a zero signal when the projected border coincides with the centerline of the active zone.

Claims

1. A guided-vehicle system, comprising, in combination, at least one vehicle;

steering means for steering said vehicle;

guide track means comprised of a material capable of conducting electrical current but being electrically unconnected to a source of current, said guide track means having an edge constituting a border between the electrically conductive material of said guide track means and electrically non-conductive material and defining a path of travel for said vehicle;

field-generating means mounted on said vehicle spaced from said guide track means and operative for generating an A.C. magnetic field oriented to intersect the conductive material of said guide track means to an extent dependent upon the lateral deviation of said vehicle from the path defined by said edge, said field creating eddy currents in the conductive material of said guide track means resulting in dissipation of energy in said conductive material and causing said field to vary in strength in dependence upon said lateral deviation;

signal generating means responsive to variations in the strength of said field and operative for generating a control signal which varies in dependence upon said lateral deviation; and

control means connected to said steering means and to said signal generating means and operative for effecting steering of said vehicle in dependence upon said control signal in a direction reducing said lateral deviation so as to cause said vehicle to travel along the path defined by said edge.

2. A system as defined in claim 1, wherein said field-generating means has an active zone, and wherein said signal generating means comprises means for generating a control voltage having zero magnitude when the centerline of said active zone coincides with said edge, a positive magnitude proportional to said lateral deviation when the deviation is to one side of said edge and a negative magnitude proportional to said lateral deviation when the deviation is to the other side of said edge.

3. A system as defined in claim 1;

and further including means for stopping said vehicle when said deviation exceeds a predetermined value.

4. A system as defined in claim 1;

and further including a third field-generating means generating an A.C. magnetic field which intersects the material of said guide track means to an extent dependent upon said lateral deviation and creates eddy currents in said material producing a variation in the strength of the field produced by said third-generating means in dependence upon said lateral devIation; and

further including means cooperating with said third field-generating means for stopping said vehicle when said lateral deviation exceeds a predetermined value.

5. A system as defined in claim 1;

and further including auxiliary analog signal generator means arranged over said guide track means and registering variations in the spacing of said vehicle from said guide track means, said auxiliary analog signal generator means providing a compensating signal for compensating against variations in said spacing.

6. A system as defined in claim 1, wherein said signal generating means comprises operational amplifier means having two inputs and serving as an adder, means for applying to one of said inputs a signal indicative of the field strength of the activated one of said field-generating means and means for applying to the other of said inputs a nulling signal, so that the signal appearing at the output of the operational amplifier will have a desired predetermined null value when said lateral deviation is zero.

7. A system as defined in claim 1, wherein said guide track means comprises at least one metallic strip with a self-adhesive backing to facilitate laying of the strip upon a surface to form a guide track for said vehicle.

8. A system as defined in claim 7, wherein the material of said guide track means is electrically conductive and non-ferromagnetic.

9. A system as defined in claim 7, wherein the material of said guide track means is aluminum.

10. A system as defined in claim 1, wherein said signal-generating means is operative for generating a control signal having a first polarity when said deviation is to one side of said edge and for generating a control signal having an opposite second polarity when said deviation is to the other side of said edge, and wherein said control means includes diode means so connected to said signal-generating means as to separate control signals of said first polarity from control signals of said second polarity, said diode means being connected to said steering means for applying the separated control signals to said steering means for controlling the latter.

11. A system as defined in claim 10, wherein said steering means comprises steering motor means including one winding operative when energized for effecting turning of said vehicle in one direction and another winding operative when energized for effecting turning of said vehicle in the other direction, and wherein said control means comprises amplifier means and inverter means, and switch-over means operative when said control signal is of said first polarity for applying said control signal to said amplifier means via said inverter means and for connecting the output of said amplifier means to one of said windings for energizing the same, and operative when said control signal is of said second polarity for applying said control signal to said amplifier means without the intermediary of said inverter means and for connecting the output of said amplifier means to the other of said windings for energizing the same.

12. A system as defined in claim 11, wherein said switch-over means comprises relay means.

13. A system as defined in claim 12, wherein said switch-over means comprises electronic switch means.

14. A system as defined in claim 10, wherein said control means further includes first amplifying means operative for amplifying control signals to said first polarity and second amplifying means operative for amplifying control signals of said second polarity, the outputs of said first and second amplifying means being connected to said steering means for controlling the latter.

15. A system as defined in claim 14, wherein said control means further includes inverter means connecting said diode means to said second amplifying means to invert the polarity of control signals having said second polarity prior to application to said second amplifying means.

16. A system as defined in claim 1, wherein said steering means includes sTeering motor means for changing the direction of movement of said vehicle, and wherein said control means is operative for controlling the energization of said steering motor means in dependence upon said control signal, and wherein said control means comprises means operative when said control signal reaches a predetermined value indicative of excessive lateral deviation for effecting supplemental energization of said steering motor means in addition to the aforementioned energization, so as to effect rapid reduction of such excessive lateral deviation.

17. A system as defined in claim 16, wherein said means for effecting supplemental energization comprises threshold-detecting means connected to said signal generating means to receive said control signal and relay means connected to the output of said threshold-detecting means for activation when said control signal reaches said predetermined value, and means operable when said relay means is activated for effecting said supplemental energization of said steering motor means.

18. A system as defined in claim 1, wherein said steering means includes at least one turnable wheel, and wherein said field-generating means is mounted for turning movement together with said wheel.

19. A guided-vehicle system comprising, in combination, at least one vehicle;

guide track means of electrically conductive material having two edges constituting borders between electrically conductive and electrically non-conductive material and each defining a respective path of travel for said vehicle;

two alternatively activatable analog signal generator means on said vehicle, one associated with one of said edges and the other associated with the other of said edges, and each operative for directing a high-frequency magnetic field towards said guide track means, said magnetic field being damped by said electrically conductive material, and each of said two analog signal generator means having an active operating zone; and

signal-furnishing means in said analog signal generator means for furnishing a voltage proportional to the projected displacement of the respective one of said borders relative to the centerline of the active zone of the activated one of said two analog signal generators, said voltage being positive when the displacement of said respective border is in one direction and negative when the displacement of said respective border is in direction opposite to said one direction, and said voltage being zero when the projection of said respective border coincides with the centerline of the active zone of the activated one of said two alternatively activatable analog signal generator means.

20. A system as defined in claim 19;

and further comprising steering means on said vehicle connected to said signal-furnishing means and responsive to said signal for steering said vehicle in dependence upon said signal to maintain the centerline of the active zone of the activated one of said analog signal generators coincident with the respective border.

21. A guided-vehicle system, comprising, in combination, at least one vehicle;

steering means for steering said vehicle;

guide track means comprised of a material capable of conducting electrical current but being electrically unconnected to a source of current, said guide track means having two spaced edges constituting borders between electrically conductive and electrically non-conductive material and each defining a respective path of travel for said vehicle;

two alternatively activatable field-generating means mounted on said vehicle spaced from said guide track means, one associated with one of said edges and the other associated with the other of said edges, and each operative when activated for generating an A.C. magnetic field oriented to intersect said guide track means to an extent dependent upon the lateral deviation of said vehicle from the path defined by the respective one of said edges, said A.C. magnetic field creating eddy currents in the conductive material of said Guide track means resulting in dissipation of energy in said guide track means causing said field to vary in strength in dependence upon said lateral deviation;

signal-generating means responsive to variations in the strength of said field and operative for generating a control signal which varies in dependence upon said lateral deviation; and

control means connected to said steering means and to said signal generating means and operative for steering said vehicle in dependence upon said control signal in a direction reducing said lateral deviation so as to cause said vehicle to travel along the path defined by that one of said edges associated with the activated one of said two alternatively activatable field-generating means.

22. A system as defined in claim 21, wherein said guide track means comprises at least one branched member of electrically conductive material defining a branched path having a stem portion and two branch portions with one of said edges being an edge of said stem portion and continuing as an edge of one branch portion, and the other of said edges being the other edge of said stem portion and continuing as an edge of the other branch portion;

and further including activating means for activating one or the other of said two alternatively activatable field-generating means to cause said steering means to steer said vehicle along the path defined by the edge associated with the activated one of said field-generating means, whereby to cause steering of said vehicle onto one or the other of said branch portions.

23. A system as defined in claim 21;

and further including mechanical activating means for activating one or the other of said two alternatively activatable field-generating means.

24. A system as defined in claim 21;

and further including electrical activating means for activating one or the other of said two alternatively activatable field-generating means.