Patent GB-1361750-A (GB)
Title: Vehicle control system
IPC: B61L3/22
Filed: 1972-03-30
Abstract: 1361750 Vehicle control GENERAL SIGNAL CORP 30 March 1972 [1 April 1971] 15092/72 Heading B7N In apparatus for controlling the movement of a vehicle along a track, e.g. an air supported vehicle driven by a linear induction motor, a cable loop with transpositions extends along a track and co-operates with location sensing apparatus to provide continuously an indication of the apparent location of the vehicle by counting the pulses produced by its passage over the transpositions, in addition location checking apparatus is provided including a series of trackside markers spaced along the track and responsive to vehicle passage to provide a wayside marker signal which is applied to control means arranged to provide an alarm signal if the marker signal is not received when the location indicated by the location sensing apparatus corresponds to the location of one of the marker signals. As described the transpositions are detected in trackside apparatus by detector 14 from a signal transmitted from the vehicle via cable 13 and central control receiver 11 and the transpositions are counted in counter 15 which supplies a signal indicative of the distance travelled between check points to threeway check unit 16 to which location check point 17 supplies a signal on passage of the vehicle and to which the vehicle supplies a signal via the cable 13 and the receiver 11 when it passes the location check point 17. The output of the three-way check unit holds off system trip unit 18 if the three signals are received in a predetermined period of time. When actuated the trip unit can bring part or the whole of the system to a halt. A transmit-receive channel is provided via the cable loop 13 for each vehicle which also has a particular one of the counters 15 associated therewith for storing the current position of the vehicle. This information is supplied to computer 10 which derives a safe speed for the vehicle from the information and that relating to an ahead vehicle, compares this with a local speed limit for the vehicle position and then compares the lower of these two limits with vehicle actual speed. The computation is repeated on a second computer and if this gives the same result and the actual speed is below the limit a 'go' signal is transmitted via transmitter 12 to the vehicle to hold off the vehicle braking system; the 'go' signal is also returned from the vehicle and routed to a 2-way check unit 19 which again can operate a system trip 21 in the event of a discrepancy. The vehicle position, speed and speed limit are also applied to a 'thrust' controller 21 which also receives an input from a velocity profile store 22 and provides speed and direction information for the vehicle via transmitter 12. Stopping is controlled in response to information from line supervision computer 23 which selects the stopping profile from store 22, this computer, which has access to a stored time table schedule in unit 24, also controls vehicle departure from the stopping places. A manual control console 26 is also provided. On the vehicle the transmitter provides a channel for motor check, a speech channel and a channel for checking communication and the receiver provides a speech channel and a speed control information channel. Means are provided in the vehicle for controlling the reverse thrust applied to the linear motor for stopping the vehicle and for ensuring that this does not lead to acceleration of the vehicle in the reverse direction.