Speed control system

Abstract

In a speed control system for a carriage movable along a predetermined path, light beams originating at the ends of the path are deflected by light conductors aboard the carriage so that they are interrupted, as the carriage moves, by a slotted plate extending along the path. The light beams are then deflected by light conductors so that they are directed along the carriage path to light receivers situated at the ends of the path. Electrical pulses from the light receivers are ORed together and converted by a transducer to a signal representative of the actual carriage speed, and by a counter to a signal representative of the carriage position. The carriage position signal is converted, in accordance with a predetermined functional relationship, to a speed set signal which is compared with the actual carriage speed. A signal, representative of the difference between the actual speed and the set speed is used to control the driving motor for the carriage. The speed and position determination achieved by the control system makes it possible to stop the carriage at a predetermined fixed position regardless of the speed of the carriage by initiating braking at different carriage positions, depending on carriage speed.