Vorrichtung zum Verfolgen einer ebenen Trasse oder Umrisslinie

摘要

1,227,880. 880. Photo-electric edge followers. COMPAGNIE D'ETUDES ET DE REALISATIONS DE CYBERNETIQUE INDUSTRIELLE. July 19, 1968 [July 27, 1967] No.34651/68. Heading G1A. [Also in Division G3] Apparatus for following a boundary between light and dark comprises a television camera scanning across the boundary, means for measuring the durations of the light portions of at least two line scans, a motor rotating the camera until the deviations are equal and traversing motors driving the camera along the boundary. The camera 16 is mounted in a scanning head 5 for rotation by a step-by-step motor 15, Fig. 4, through a pulley band 17. Offset of the line tracing is provided by a screw 19 which shifts the camera axis Z1 Z1 relative to the axis of rotation ZZ. Potentiometers 21, 22 generate Πsin # and Πcos # signals where # is the angle of the axis 23 of the camera field relative to the X co-ordinate drive of the scanning head. | cos#| and | sin#| signals are applied to amplitude/frequency converters 26, 27 Fig. 5 by diodes which pass whichever of the Πcos# and Πsin# signals is positive. The converters 26, 27 respectively produce pulse trains of frequency 2,000 cos# Hz and 2,000 sin# Hz which are applied to the traversing motors Mx, My in senses determined by the signs of the + cos# and + sin# signals. The camera video signals a, b, c corresponding to the lines A B C, Fig. 6, are fed to comparators 24, 25. So long as the video signals indicate that the boundary coincides with a predetermined axis 23 of the camera tracing continues, but when the a or b signal has too long or short a "light" portion, a signal from comparator 24 switches the pulses from converters 26, 27 via frequency dividers 41, 42 to reduce the tracing speed. When signal c has too long or short a light portion a signal from comparator 25 stops motors Mx and My and transfers the frequency divided pulses to the motor 15 (M # ) to rotate the camera until the boundary coincides with the axis 23. A flip-flop set by the start of a line scan and re-set by the boundary may provide an artificial "light" portion for the video signal to cope with re-entrant curves. The line follower may be used for controlling or making a control tape for machine tools or planimetry. A relay reverses the connections to motors M # , Mx and My to cope with internal and external machining.