US 4,235,403 AGranted

Speed control apparatus and method for railroad car retarders

AssigneeAmerican Standard Inc.

InventorsHarold C. Gillen, Donald R. Little

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Abstract

An acceleration servo control system for railroad car retarders in which a computed desired instantaneous deceleration signal and a measured actual deceleration signal are compared and any resulting error signal is fed back through the servo network to adjust retarder braking pressures to achieve and/or hold the desired deceleration rate which will allow the cut of cars to leave the retarder at a selected speed. The desired instantaneous deceleration is computed using an algorithm incorporating actual measured speed, the selected exit speed, the number of axles in the retarder, and the remaining distance-to-go for all axles of the cut over which retarder braking will be effective, and based on the principle of braking each axle-wheel unit throughout the entire retarder length.

Claims11

Dependent claims

A speed control arrangement for a railroad car retarder, to achieve a selected leaving speed for each cut of cars as it exits the retarder, comprising:

(a) speed measuring means operable for producing signals representing actual speed and deceleration of a particular cut moving through said retarder and other pulse signals representing successive incremental distances traveled within said retarder by that cut,
(b) distance register means coupled to receive wayside cut detection signals and said incremental distance signals and jointly responsive thereto and to previously registered signals of retarder length and total axles on said particular cut for continuously producing a signal representing the instantaneous remaining axle braking distance within said retarder for said particular cut,
(c) processing means coupled for receiving the actual speed signal, the selected leaving speed signal, and the corresponding remaining braking distance for said particular cut and operable in response for generating an output signal representing the desired instantaneous deceleration for said particular cut, and
(d) a servo control means coupled for comparing the desired deceleration signal from said processing means and the actual deceleration signal from said speed measuring means and connected for controlling the retarder braking force to equalize the two deceleration signals to achieve said desired leaving speed for said particular cut as the last axle exits said retarder.

1 more element

An apparatus arrangement for controlling the braking pressure of a railroad car retarder to reduce the speed of a cut of cars traversing said retarder using substantially constant braking pressure over the entire length of said retarder so that a preselected desired leaving speed is achieved as the last axle of a cut leaves said retarder, comprising:

(a) speed measuring means responsive to movement of a particular cut in said retarder for continuously generating an actual speed signal and an actual deceleration signal,
(b) a first counter means coupled for registering the instantaneous number of axles of said particular car within said retarder,
(c) a first source generating a signal representing the total distance all axles of said particular cut will travel while moving through said retarder,
(d) a second counter means coupled to said speed measuring means, said first counter means, and said first source and responsive to a selected output from each for generating an output representing the total remaining instant axle distance-to-go for said retarder to control the speed of said particular cut.
(e) a second source providing a signal representing the desired retarder leaving speed for said particular cut,
(f) signal processing means coupled to receive an actual speed signal from said speed measuring means, said desired leaving speed signal from said second source, the instant axle distance-to-go signal from said second counter means, and the instant axle count from said first counter means and responsive to said signals for producing a signal representing a desired instantaneous deceleration for said particular cut required to achieve said desired leaving speed when the last axle exists from said retarder, and
(g) a servo network coupled to said speed measuring means and said processing means and responsive to the actual and desired deceleration signals for controlling said retarder to equalize the actual and desired deceleration of said particular cut.

4 more elements

A method of controlling a railroad car retarder to achieve a desired leaving speed for each car cut traversing the retarder, using substantially the entire length of the retarder to continuously brake the cut wheels to achieve said leaving speed when the last axle exits, said retarder comprising the steps of:

(a) continuously measuring actual speed and deceleration of a car cut moving through said retarder,
(b) continuously determining the instant remaining axle distance-to-go within said retarder for braking said cut moving through said retarder,
(c) mathematically processing the actual and desired leaving speed data and remaining axle distance-to-go for said cut moving through said retarder to continuously produce a desired deceleration value which will achieve the desired leaving speed as the last axle of said cut exits from said retarder, and
(d) comparing said actual and desired deceleration values and controlling the braking pressures of said retarder in accordance with detected differences to equalize the two deceleration values.

1 more element

Dependencies are inferred from the claim text.