GB1332136A - Method and apparatus for controlling movement of a device to a desired position - Google Patents

Abstract

1332136 Acoustic control of speed VMEI "LENIN" NIS 26 Oct 1970 50796/70 Heading H4D The speed of a horizontally travelling mechanism, specifically the gantry or hoist trolley of a crane, is controlled in accordance with the phase difference between sonic or ultrasonic signals transmitted from the destination point and received by two microphones mounted on the mechanism and spaced in the directions of motion. Fig. 1, shows a trolley carrying two microphones B spaced by distance 2a in the direction of motion towards the vertical from the destination point A at which a pulsed ultrasonic radiator (Fig. 5, not shown) is located. The microphones 1, 2 (Fig. 3) receive pulses of ultrasonic waves which, depending on whether Z = (Z 1 -Z 2 ) is positive or negative (trolley to the left or right of vertical H) are as shown at 1U (Fig. 4) and after filtering by filters 2, 5 are amplified in 3 and 6 which produce outputs 3U 1 3U and 6U 1 6U respectively. These outputs are then supplied, as shown, to AND gates 7 and 8 the outputs of which comprising pulses 7U, 8U width modulated in accordance with the phase differences in the received pulse trains are supplied to further AND gates 10, 11 having as second inputs the output of a trigger 9 (waveform 9U) controlled by the 3U and 6U outputs of amplifier 3 and 6 respectively. The gates 10 and 11 are thus controlled such that when Z is positive gate 10 produces an output whilst when Z is negative gate 11 produces an output (waveforms 10U and 11U) and these outputs after amplification in 12, 13 are supplied by reversing contactors 14, 15 to a motor speed regulator 17 also supplied via OR gate 16 with the output of gates 7 and 7. Regulator 17 then supplies the required width modulated control signal to the driving motor 18.