Guide wire communication system and method

• US 4,902,948 A
• Filed: 07/01/1988
• Issued: 02/20/1990
• Est. Priority Date: 05/02/1985
• Status: Expired due to Fees

• Current Assignee: HK Systems Incorporated (KION GROUP AG)
• Original Assignee: Eaton-Kenway Incorporated
• Inventors: Whatcott, Gary L., Madsen, David C., Sherman, Leigh E., Dicks, Richard M.
• Primary Examiner(s): Ro, Bentsu
• Application Number:
  US07/214,242
• Time in Patent Office: 599 Days
• Field of Search: 318/580, 318/587, 180/168, 343/741, 343/742, 343/855, 343/866, 343/867
• US Class Current: 318/580
• CPC Class Codes: G05D 1/0265 using buried wires
• CPC Class Codes: G05D 1/0297 by controlling means in a control room

Abstract

A guidance system for guiding a plurality of unmanned vehicles along guide wires. A plurality of data communication circuits are provided which form an extensive network. A traffic control computer composes a coded vehicle instruction for assigning tasks and allocates resources to said unmanned vehicles. The traffic control computer polls the status of each vehicle at varying time intervals and receives a response from said vehicle.

The network connecting the computer and the communication circuits prevents reception of data transmissions from more than one vehicle at a time. Other messages are temporarily stored.

Data transmitters generate low frequency, low power signals which have a high data transmission rate.

Digital data is converted at the transmitters into cosine waveforms of selected frequencies. The cosine waveforms are transposed into sine waveforms at receivers. Low impedance or high impedance characteristics are imposed upon the guide wires.

A low frequency, high gain transmit antenna for each vehicle is prorated.

Claims

1. A system for controlling at least one unmanned, task-performing vehicle including vehicle portion and non-vehicle portion, comprising:

at least one stationary guide wire essentially defining a path to be traversed by the vehicle;

the vehicle portion and the non-vehicle portion of the system each comprising substantially the same electrical means, each of the electrical means transmits and receives substantially the same communicating data signals, comprising signal generating means and antenna means for transmitting generated signal from the vehicle to the guide wire, and vice versa;

the antenna means in the vehicle portion comprising at least two opposed conductive loops, each conductive loop comprising a plurality of turns.

2. The system according to claim 1 wherein the loops of the antenna means collectively comprise an essentially symmetrical figure 8 configuration which is essentially symmetrically located along the center line of the vehicle and wound to steer all current flow unidirectionally along a central bar of the figure 8 configuration.

3. The system according to claim 1 wherein the signals are in the order of 9,600 Hz-19,200 Hz with data transmission rates up to 9,600 BAUD.

4. The system according to claim 1 wherein each conductive loop comprises a printed circuit deposited on a printed circuit board.

5. The system according to claim 1 wherein the antenna means comprises at least two sets of two opposed conductive loops, one set of the opposed conductive loops being carried by the vehicle at one location so as to be essentially symmetrically disposed in respect to the center line of the vehicle, and the second set of the conductive loops being carried by the vehicle at another location so as to be also essentially symmetrically disposed in respect to the center line of the vehicle.

6. A communication system for controlling an unmanned task-performing vehicle caused to traverse a path defined by guide wire means, comprising:

a source of control data;

vehicle receiver means;

transmitter means to which the control data from said source is communicated;

guide wire means to which the transmitter means sends control signals corresponding to the control data received from the source;

at least one unmanned task-performing vehicle which carries the vehicle receiver means and travels along the guide wire means responsive to the control signals received by the vehicle receiver means from the guide wire means;

the transmitter means comprising;

means which receives the control data from the source;

means comprising memory in which sets of information are respectively stored, each set of information representing a distinct waveform cycle;

means which addresses the memory in response to the control data received from the source;

means for timely outputting the addressed set of information representative of the distinct waveform cycle desired;

means for converting said representative information into the desired waveform cycle; and

means for outputting the waveform cycle to the guide wire means and along the guide wire means to the vehicle receiver means whereby the rate of data transmission is greatly increased.

7. The communication system according to claim 6 wherein each waveform cycle comprises one or more full cosine waveform cycles whereby the distinct nature of each waveform cycle is preserved.

8. The communication system according to claim 7 wherein the vehicle receiver means comprises means for transforming the cosine waveform cycles received from the guide wire means to one or more full sine waveform cycles whereby decoding errors are less likely.

9. The communication system according to claim 7 further comprising:

means for producing at least one complete waveform cycle of at least two different and distinguishable frequencies which produce digital data representing at least two logical states such that the transmission rate is the same as the lowest frequency used.

10. The communication system according to claim 6 further comprising:

a source of data carried by the vehicle;

control receiver means for two-way transmission;

means interposed between the control receiver means and the transmitter means at control site for disabling the control receiver means when the transmitter means is transmitting.

11. The communication system according to claim 6 wherein the sets of information stored in the memory each represents a distortion of a distinct sinusoidal waveform cycle and wherein inductance characteristics of the guide wire means are such that each distorted sinusoidal waveform cycle outputted to and communicated along the wire guide means is altered by said inductance characteristics into an exact sinusoidal waveform cycle and the transition between any two such exact sinusoidal waveform cycles is essentially instantaneous and any signal distortion at said transition is essentially avoided.

12. A low frequency, low power communication system for controlling at least one unmanned, task-performing vehicle by at least one non-vehicle means, comprising:

vehicle portion and non-vehicle portion, each comprising substantially the same electrical means, each of the electrical means transmits and receives substantially the same communicating data signals having low frequency and low power;

said at least one unmanned, task-performing vehicle comprising signal detecting and tracking means;

at least two sources of signals;

at least one guide wire loop;

means for outputting the signals from the source to and along the guide wire loop;

the guide wire loop having characteristics such that said outputted signals are detected by the vehicle signal detecting and tracking means used to cause the vehicle to substantially follow the path defined by the guide wire loop;

means for reducing the impedance of the guide wire loop whereby amplitude deterioration in the signals on the guide wire loop, which would otherwise occur, is alleviated.

13. The low frequency, low power communication system according to claim 12 wherein the impedance reducing means comprises opposed inductor means respectively in electrical communication with the guide wire loop and capacitor means interposed between the opposed inductor means.

14. The low frequency, low power communication system according to claim 12 further comprising a receiver, a resistor means in electrical communication with the receiver and the guide wire loop for increasing the impedance of and decreasing the current flow in the guide wire loop to accommodate improved reception at the receiver whereby the resistor means accommodates accurate detection of the low power signal.

15. A method for controlling an unmanned task-performing vehicle caused to transverse a path defined by guide wire means comprising the steps of:

generating data at at least one source;

communicating said data from said source to at least one control transmitter site;

transforming said data at said control transmitting site into corresponding signals by;

receiving the data from the source;

addressing memory in response to the data received from the source in which sets of information are respectively stored, each set of information representing a distinct predetermined low frequency waveform;

timely outputting the addressed set of information representative of the distinct waveform corresponding to the data received;

converting said set of information into desired waveform;

outputting the desired waveform to and along the guide wire means; and

receiving said desired waveform at a vehicle receiver site whereby the rate of data transmission is greatly increased.

16. The method according to claim 15 wherein the step of outputting the addressed set of information comprises the step of outputting an addressed representation of one or more full cosine waveform cycles.

17. The method according to claim 16 wherein the outputted cosine waveform cycles are communicated along the guide wire means and are transformed at the vehicle receiver site to one or more full sine waveform cycles whereby decoding errors are less likely.

18. The method according to claim 15 wherein the step of addressing the memory comprises the steps of:

determining the status of at least three data states, and, on the basis of said data states,

addressing the memory in which sets of information are stored, each representing a predetermined distortion of a distinct sinusoidal waveform cycle; and

wherein inductance characteristics of the guide wire means are such that each distorted sinusoidal waveform cycle outputted to and communicated along the guide wire means is altered by said inductance characteristics into nondistorted sinusoidal waveform cycle and the transition between any two such nondistorted sinusoidal waveform cycles is essentially instantaneous and any signal distortion of said transition is essentially avoided.

19. The method according to claim 15 wherein the step of outputting the desired waveform to and along the guide wire means comprises the step of disabling a control receiver associated with a control transmitter when the control transmitter site is transmitting.

20. The method according to claim 15 wherein the step of communicating said data further comprises the step of temporarily storing said data.

21. A method for controlling at least one unmanned, task-performing vehicle by at least one non-vehicle means, comprising the steps of:

outputting data signals from a source to and along a guide wire;

communicating substantially the same data signals bidirectionally between the vehicle and the non-vehicle means;

reducing the impedance of the guide wire whereby amplitude deterioration in the data signals on the guide wire, which would otherwise occur, is alleviated;

detecting the data signals by vehicle signal detecting and tracking means, causing the vehicle to substantially follow the path defined by the guide wire.

22. The method according to claim 21 wherein the step of reducing the impedance of the guide wire comprises the step of positioning an inductor means in opposed relationship in electrical communication with the guide wire and interposing a capacitor means between the inductor means.

23. The method according to claim 21 further comprising the steps of:

increasing the impedance of and decreasing the current flow in the guide wire adjacent the vehicle;

producing improved reception at the vehicle, and accurate detection of a low power signal.

24. A communication system for controlling an unmanned task-performing vehicle caused to traverse a path at a control site defined by guide wire means, comprising:

at least one source of data;

at least one receiver means;

at least one transmitter means to which the data from said source is communicated;

guide wire means to which the transmitter means sends signal corresponding to the data received from the source;

at least one vehicle which travels along the guide wire means;

the transmitter means comprising;

means which receives the data from the source;

means comprising memory in which sets of information are respectively stored, each set of information representing a distinct waveform cycle;

means which addresses the memory in response to the data received from the source;

means for timely outputting the addressed set of information representative of the distinct waveform cycle desired;

means for converting said representative information into the desired waveform cycle; and

means for outputting the waveform cycle to the guide wire means and along the guide wire means to the receiver means.

25. The communication system according to claim 24 wherein each waveform cycle comprises one or more full cosine waveform cycles.

26. The communication system according to claim 25 wherein the receiver means comprises means for transforming the cosine waveform cycle received from the guide wire means to one or more fully sine waveform cycles.

27. The communication system according to claim 24 wherein the sets of information stored in the memory each represent a distortion of a distinct sinusoidal waveform cycle and wherein inductance characteristics of the guide wire means are such that each distorted sinusoidal waveform cycle outputted to and communicated along the guide wire means is altered by said inductance characteristics into an exact sinusoidal waveform cycle and the transition between any two such exact sinusoidal waveform cycles is essentially instantaneous and any signal distortion at said transition is essentially avoided.

28. The communication system according to claim 24 wherein the at least one source of data comprises two sources of data, one at the control site and the other on the vehicle;

wherein the at least one receiver means comprises two receivers, one at the control site, and the other on the vehicle;

wherein the at least one transmitter means comprises two transmitters, one at the control site, and the other on the vehicle for two-way transmission; and

said system further comprising means interposed between the receiver and the transmitter at the control site and at the vehicle for disabling the associated receiver when the associated transmitter is transmitting.