Vehicle control apparatus

Claim 2

Control apparatus for use in a vehicle, for controlling the vehicle in a transport system wherein the vehicle will travel over given paths or tracks, comprising: means for receiving command signals representing desired progress of the vehicle, a first servo-control means, having an input connected to the receiving means, for deriving modified speed-demand signals which depend on the said command signals but also take account of prescribed headway-distance, maximum acceleration and maximum deceleration limitations, and a second servo-control means, connected to the first servocontrol means and responsive to the modified speed demand signals, for controlling the speed of the vehicle; the said first servo-control means comprising: progress-signal deriving means for deriving demanded-progress signals substantially representing the progress demanded by said modified speed-demand signals, first differencing means, having a first input connected to the command signal receiving means and a second input connected to the progress signal deriving means, for deriving a position-lag signal dependent on the difference between the desired progress represented by the command signals and the demanded progress represented by the demanded progress signals, headway distance computer means, connected to receive the said modified speed-demand signals for deriving a headway-distance signal representing a desirable headway distance corresponding to the speed represented by the said modified speed-demand signals, second differencing means, having a first input connected to receive the said position-lag signal and a second input connected to receive the said headway-distance signal, for deriving a control signal dependent on the difference between the distance represented by the position-lag signal and the distance represented by the headway-distance signal, and integrating and limiting means, connected to receive the said control signal from the said second differencing means, for deriving the said modified speed-demand signal from the said control signal and for limiting the range of values of the said modified speed-demand signal in accordance with the said maximum acceleration and maximum deceleration limitations.

Claim 3

Apparatus as claimed in claim 1 wherein the said second servo-control means comprises a progress feedback means and a rate-of-progress feedback means, for making the actual rate-of-progress of the vehicle follow the said modified speed-demand signal with negligible error.

Claim 4

Apparatus as claimed in claim 2 wherein the said modified speed-demand signal is made available as an analogue voltage signal, and the said progress-signal deriving means comprises a voltage-to-frequency converting means having an input connected to receive the said modified speed-demand signal and an output connected to the said second input of the said first differencing means.

Claim 5

Apparatus as claimed in claim 1 wherein the said command signals are made available as a sequence of pulses wherein each pulse represents an increment of desired progress, the said demanded-progress signals being made available as a sequence of pulses wherein each pulse represents an increment of progress demanded by the said modified speed-demand signals, and the said first differencing means comprises a reversible counter circuit means, for providing a position-lag signal dependent on the difference between the cumulative total number of command signal pulses received and the cumulative total number of progress signal pulses received.

Claim 6

Apparatus as claimed in claim 1 wherein the said position-lag signal and the said headway-distance signal are made available as analogue voltage signals, and the said second differencing means comprises a differential direct-current amplifier having a first input connected to receive the said position-lag signal and a second input connected to receive the said headway-distance signal.

Claim 7

Apparatus as claimed in claim 1 wherein the said integrating and limiting means comprises: threshold circuit means for developing a first predetermined voltage output whenever the headway-distance represented by the headway-distance signal is less than the position-lag represented by the position-lag signal, and for developing a second predetermined voltage output whenever the headway-distance represented by the headway-distance signal is greater than the position-lag represented by the position-lag signal; cumulative integrating means, for developing a speed-demand signal dependent on a cumulative integration of the voltages developed on the output of the threshold circuit means; and limiting means, for limiting the speed-demand signal to a predetermined range of values.

Claim 8

Apparatus as claimed in claim 1, for use in a vehicle having at least one wheel continuously in rolling engagement with the track or path on which the vehicle runs, wherein the said second servo control means comprises wheel speed transducer means for providing a signal dependent on the rate of rotation of the said wheel, track marker detector means for providing a pulse whenever the vehicle passes a marker device in the path on which it travels, and first combining means connected to the said wheel speed transducer means and the said track marker detector means for combining their outputs to form an actual speed signal, dependent on the output of the wheel speed transducer means and also dependent on the pulse rate of the output of the track marker detector means.

Claim 9

Apparatus as claimed in claim 7 wherein the said first combining means comprises an integrating circuit connected to receive the pulses from the track marker detector means, an amplifier having a signal input connected to receive the output of the wheel speed transducer means and also having a gain control input and an output, a low-pass filter connected to the output of the amplifier, and means connected to the integrating circuit, the low-pass filter and the gain-control input, for controlling the gain of the amplifier so as to reduce the difference between the output of the low-pass filter and the output of the integrating circuit.

Claim 10

Apparatus as claimed in claim 7 comprising means for deriving progress signals from the said modified speed-demand signal, and wherein the said speed control means comprises: a third differencing means for deriving a signal dependent on the difference between the progress represented by the said progress signals and the progress represented by the output pulses of the track marker Detector; a second combining means for combining the actual speed signal from the first combining means with the modified speed-demand signal to form a signal dependent on the difference between the speeds which they represent; and a third combining means for additively combining the outputs of the said third differencing means and the said second combining means to form a signal for controlling the speed of the vehicle.

Claim 11

Apparatus as claimed in claim 9 wherein the progress signals are made available in the form of pulses each representing an increment of progress, and the said third differencing means comprises a reversible counter circuit means, for providing a signal dependent on the difference between the total number of progress signal pulses and the total number of the track marker detector pulses applied to it.

Claim 12

Control apparatus for use in a vehicle, for controlling the vehicle in response to command signals in a transport system wherein the vehicle will travel over given paths or tracks, comprising servo-control means for deriving modified speed-demand signals dependent on said command signals but also taking account of prescribed headway-distance, maximum-acceleration and maximum-deceleration limitations, the said servo-control means comprising: progress-signal deriving means for deriving demanded-progress signals substantially representing the progress demanded by said modified speed-demand signals, first differencing means, having a first input for receiving said command signals and a second input connected to the progress signal deriving means, for deriving a position-lag signal dependent on the difference between the desired progress represented by the command signals and the progress represented by the demanded-progress signals, headway distance computer means, connected to receive the said modified speed-demand signals, for deriving a headway-distance signal representing a desirable headway distance corresponding to the speed represented by the said modified speed-demand signal, second differencing means, having a first input connected to receive the said position-lag signal and a second input connected to receive the said headway-distance signal, for deriving a control signal dependent on the difference between the distance represented by the position-lag signal and the distance represented by the headway-distance signal, and integrating and limiting means, connected to receive the said control signal from the said second differencing means, for deriving the said modified speed-demand signal from the said control signal and for limiting the range of values of the said modified speed-demand signal in accordance with the said maximum acceleration and maximum deceleration limitations.

Claim 13

Control apparatus for use in a vehicle, for controlling the vehicle in response to command signals in a transport system wherein the vehicle will travel over given paths or tracks, comprising servo-control means for deriving modified speed-demand signals dependent on said command signals but also taking account of prescribed headway-distance, maximum-acceleration and maximum-deceleration limitations, the said servo-control means comprising: progress-signal deriving means for deriving demanded-progress signals substantially representing the progress demanded by said modified speed-demand signals, first differencing means, having a first input for receiving said command signals and a second input connected to the progress signal deriving means, for deriving a position-lag signal dependent on the difference between the desired progress represented by the command signals and the progress represented by the demanded-progress signals, headway distance computer means, connected to receive the said modified speed-demand signals, for deriving a headway-distance signal representing a desirable headway distance corresponding to the speed represented by the said modified speed-demand signal, second differencing means, having a first input connected to receive the said position-lag signal and a second input connected to receive the said headway-distance signal, for deriving a control signal dependent on the difference between the distance represented by the position-lag signal and the distance represented by the headway-distance signal, and integrating and limiting means, connected to receive the said control signal from the said second differencing means, for deriving the said modified speed-demand signal from the said control signal and for limiting the range of values of the said modified speed-demand signal in accordance with the said maximum acceleration and maximum deceleration limitations.

Claim 14

Control apparatus for use in a vehicle for controlling the vehicle in a transport system wherein the vehicle will travel over given paths or tracks, comprising: means for receiving command pulses representing desired increments of progress of the vehicle; a first servo-control means, having an input connected to the receiving means, for deriving modified speed-demand signals which depend on the said command signals, but also take account of prescribed headway-distance, maximum acceleration and maximum deceleration limitations; second servo-control means connected to the first servo-control means and responsive to the modified speed-demand signals, for controlling the speed of the vehicle; the said first servo-control means comprising: progress-signal deriving means for deriving progress-signal pulses substantially representing the progress demanded by said modified speed-demand signals; reversible counter means having a first input connected to receive the said command pulses and a second input connected to receive the said progress signal pulses, for deriving a position-lag signal dependent upon the difference between the number of command pulses and the number of progress signal pulses applied to its inputs; HEADWAY distance computer means, connected to receive the said modified speed-demand signals for deriving a headway-distance signal representing a desirable headway distance corresponding to the speed represented by the said modified speed-demand signals; comparison means, having a first input connected to receive the said position-lag signal and a second input connected to receive the said headway-distance signal, for providing a first predetermined voltage output when the headway distance represented by the said headway-distance signal is greater than the position-lag represented by the said position-lag signal, and providing a second predetermined voltage output when the headway distance represented by the said headway-distance signal is less than the position-lag represented by the said position-lag signal; and cumulative integrating means, connected to the said comparison means, for developing a modified speed-demand signal dependent upon a cumulative integration of the voltages developed on the output of the said comparison means, and limiting the said modified speed-demand signal to a predetermined range of values, in accordance with the said maximum acceleration and maximum deceleration limitations.

Claim 15

Control apparatus for use in a vehicle for controlling the vehicle in a transport system wherein the vehicle will travel over given paths or tracks, comprising: means for receiving command pulses representing desired increments of progress of the vehicle; a first servo-control means, having an input connected to the receiving means, for deriving modified speed-demand signals which depend on the said command signals, but also take account of prescribed headway-distance, maximum acceleration and maximum deceleration limitations; second servo-control means connected to the first servo-control means and responsive to the modified speed-demand signals, for controlling the speed of the vehicle; the said first servo-control means comprising: progress-signal deriving means for deriving progress-signal pulses substantially representing the progress demanded by said modified speed-demand signals; reversible counter means having a first input connected to receive the said command pulses and a second input connected to receive the said progress signal pulses, for deriving a position-lag signal dependent upon the difference between the number of command pulses and the number of progress signal pulses applied to its inputs; HEADWAY distance computer means, connected to receive the said modified speed-demand signals for deriving a headway-distance signal representing a desirable headway distance corresponding to the speed represented by the said modified speed-demand signals; comparison means, having a first input connected to receive the said position-lag signal and a second input connected to receive the said headway-distance signal, for providing a first predetermined voltage output when the headway distance represented by the said headway-distance signal is greater than the position-lag represented by the said position-lag signal, and providing a second predetermined voltage output when the headway distance represented by the said headway-distance signal is less than the position-lag represented by the said position-lag signal; and cumulative integrating means, connected to the said comparison means, for developing a modified speed-demand signal dependent upon a cumulative integration of the voltages developed on the output of the said comparison means, and limiting the said modified speed-demand signal to a predetermined range of values, in accordance with the said maximum acceleration and maximum deceleration limitations.