Control device of the stop for large masses are provided with a high speed

摘要

1,208,820. Controlling braking electrically. SOC. ALASACIENNE DE CONSTRUCTIONS ATOMIQUES DE TELECOMMUNICATIONS ET D'ELECTRONIQUE "ALCATEL". May 31, 1968 [June 2, 1967], No.26368/68. Heading G1N. An arrangement for stopping an aircraft arriving at the end of a runway at a speed higher than that corresponding to the stopping distance comprises a net 3 and two restraining straps 1, 2 which are retarded by brakes 4, 5 in dependence on control signals derived from measurements of the strap speed and the length of strap unwound. As shown in Fig. 5, the slider of a potentiometer 27 having a desired non-linear characteristic is moved in dependence on the length of strap 2 unwound and a tachometer 28 generates a voltage proportional to the speed of the strap. The output of a difference amplifier 30 is fed to servomechanisms 14, 15 to control the brakes. The voltage applied to the potentiometer 27 is set in accordance with the arrival speed of the aircraft. Initially, relays 19, 25 are in their rest positions R and a voltage source 20, the voltage of which corresponds to the highest anticipated arrival speed, is connected through an operational amplifier 22 to the potentiometer 27. When an aircraft arrives at the net and the straps have started to unwind, relay 19 is energized so that a capacitor 23 in the feedback circuit of amplifier 22 is charged from a voltage source 26 whereby the voltage applied to the potentiometer 27 decreases. When the output of a difference amplifier 29 becomes slightly positive, relay 25 is energized thereby disconnecting the source 26 so that the voltage fed to the potentiometer 27 remains constant from then on at a value appropriate to the arrival speed of the aircraft. Each strap may have its own control circuit, the brakes being controlled independently or by the average of the outputs of the control circuits. By comparing the lengths of the straps unwound, action may be taken to correct the direction of travel of the aircraft. A plurality of arrangements may be used having different characteristics.