Patent GB-1334694-A (GB)
Title: Method and system for speed control for vehicles
IPC: B60K31/00
Filed: 1970-11-03
Abstract: 1334694 A/D converters SANYO MACHINE WORKS Ltd 3 Nov 1970 52253/70 Heading G4H [Also in Divisions G3 and B7] A voltage corresponding to a preset vehicle speed is determined by variable resistor 3, and is opposed by a voltage corresponding to actual speed, provided by A.C. generator 1, and rectifier 2. The resultant voltage is fed to amplifier 5 where it is compared with a fixed reference voltage E/2, and, if it is greater than the latter, transitors 6, 7 and 8 conduct to drive servomotor 9 with a driving voltage proportional to the excess over the value E/2 to close motor throttle 29, and vice-versa via transistors 10, 11 and 12, when the resultant voltage is less than E/2, to open motor throttle 29. The reference voltage E/2 is provided by circuit 13, and energization of a relay coil 14 causes contacts 15-17 to close enabling the circuit and actuating a control clutch 18 to connect the motor 9 to throttle 29. The circuit is disenabled if any of contacts 22-24 open, corresponding to brake actuation, or disengagement of the vehicle clutch, or disengagement of top gear, respectively. A feedback voltage representing the number of revolutions of motor 9 and produced by generator 28 increases the magnitude of the driving voltage for faster system response, the strength of the feedback being increased by utilizing the relay (38, 39), Figs. 2, 3 (not shown), to change the value of resistor 40 when the driving voltage exceeds a threshold value (V B ), Fig. 3 (not shown). In the embodiment of Figs. 4-6 (not shown) the desired speed voltage (3, Fig. 4) always lies between E/2 and E, and the actual speed voltage opposes if the comparison between the resultant and the reference voltage E/2 being made by differential amplifier (46, 47, Fig. 5). The resultant signal causes either the conduction of transistors (51, 76-78) causing servomotor (74) to close the throttle, or the conduction of transistors (50, 71-73) to open the throttle, Figs. 7, 8 (not shown). Diode 52 prevents both of transistors 50, 51 being conducting at once. The circuit is set for constant speed operation by pressing button (53, Fig. 6) energizing relay coil 55, opening contacts (57, Fig. 5) and operating control clutch (64, Fig. 6) via transistors (61- 63). For operation of the vehicle in a speed limited mode, contacts (57) are closed to cut off transistor (72, Fig. 5), the motor (74) then being controlled only to close the throttle, Fig. 8 (not shown), clutch (64) being energized via the collector of transistor (51). For extra acceleration during passing, signals from the "winkers" of the vehicle (79, 80, Fig. 4) may via transistors (81, 82, 38), increase the control voltage at (a<SP>1</SP>, a<SP>11</SP>). Remote control by wireless, Figs. 9-12 (not shown).-The desired vehicle speed is set by variable resistor (100, Fig. 9) which varies the oscillation rate of unijunction transistor oscillator (100, 101, 102) governing the rate of flipflops (104) modulating transmitter (105). A receiver (Fig. 10) on the vehicle provides an analogue voltage at (112), fed to terminal (201, Fig. 11) connected to a set of differential amplifiers, of graded switch-on voltages, whose outputs (219-222, Fig. 11) are connected to a relay operating circuit (227), causing successive operation of single relay coils (238-235) for increasing voltage at (201) all the outputs (219-222) but one being short circuited by one or more of transistors (232-234). The relay coils operate contacts (241-244, Fig. 12) to change the set resistance on the vehicle. A receiver gate signal (113, Fig. 10) enables transistor (239, Fig. 11) in the relay circuits.