Automatic train operation with position stop and velocity control

In an automatic control system for a train of one or more wheeled vehicles traveling on a fixed guideway along which a plurality of wayside signal devices are located at different predetermined distances from a desired stopping point for providing information to the train indicative of the distance from a signal device to the desired stopping point, an improved arrangement for effecting operation of the train on a predetermined velocity-distance profile comprising:

• (a) means for monitoring the rotational velocity of a selected wheel on a predetermined one of the vehicles and for producing a first signal representative of said rotational velocity;
• (b) means for producing a second signal representative of the diameter of said selected wheel;
• (c) means operative each time the train passes one of the wayside signal devices for generating a third signal that indicates the distance between the train position on the guideway and the desired stopping point;
• (d) addressable memory means for storing a plurality of values respectively representative of the number of revolutions that a wheel of various different diameters would turn in order for the train to move the different predetermined distances on the guideway;
• (e) logic control means responsive to said second and third signals for generating a memory address that causes said memory means to output the particular value stored at that address;
• (f) counter means connected for receiving said memory output, said counter means being set to the value represented by said memory output each time the train passes one of the wayside signal devices;
• (g) said counter means being responsive to said first signal for counting down from said set value in proportion to the actual revolutions of said selected wheel whereby the value remaining in said counter means is a continuous reference of the distance remaining to the desired stopping point;
• (h) means responsive to said first and second signals for producing a velocity signal representative of the linear velocity of the train of vehicles;
• (i) means for computing a value representative of the distance remaining to the desired stopping point as a function of the linear velocity of the train and a desired deceleration rate;
• (j) means for comparing said computed distance value with said reference distance value and for producing an error signal representative of the difference therebetween;
• and
• (k) means responsive to said error signal for varying the actual velocity of the train in a manner to minimize said error signal and thereby stop said train at the desired stopping point.