US 5,471,387 AGranted

Method of and apparatus for the combined detection of speed varying energy level wheel slip detection and determination of wheel slip intensity of a railway vehicle brake system

AssigneeWestinghouse Air Brake Company

InventorsJames A. Wood, David A. Greer

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Abstract

A method of and an apparatus for controlling wheel slip in a railway vehicle brake system which includes: determining whether the axle rate is in the slippage range, and generating a first output logical signal indicative thereof; comparing the axle rate and the first output logical signal to determining an energy summation value indicative of the wheel/axle set's loss of energy due to braking wheel slippage, and generating an energy summation signal indicative thereof; determining an energy loss limit and generating an energy loss limit signal at which wheel slippage has little potential for self correction; comparing the energy summation signal and the energy loss limit signal to generate a second logical output signal indicative of whether the wheel/axis set is in a slip condition that needs correction; comparing the axle rate signal, the energy summation signal and the second logical output signal to generate a wheel slip intensity signal; converting the wheel slip intensity signal to a command signal; and utilizing the command signal in a force modulation interface to vary the rate of braking force reduction.

Claims20

Dependent claims

A method of controlling wheel slip in a passenger transit type railway vehicle brake system, said method comprising the steps of:

(a) monitoring a speed of a wheel/axle set to produce an axle speed signal indicative of said speed of said wheel/axle set being monitored, and an axle rate signal indicative of acceleration/deceleration of said wheel/axle set being monitored;
(b) determining whether said axle rate is in a slippage range, and generating a first output logical signal indicative of whether said axle rate is in said slippage range;
(c) comparing said axle rate and said first output logical signal to determine an energy summation value indicative of said wheel/axle set's loss of energy due to braking wheel slippage, and generating an energy summation signal;
(d) determining an energy loss limit on a basis of said axle speed signal, and generating an energy loss limit signal at which wheel slippage has little potential for self correction, said energy loss limit signal having numerical value no greater than zero;
(e) comparing said energy summation signal and said energy loss limit signal to determine a slip enablement output indicative of whether said wheel/axle set being monitored is in a slip condition that must be corrected, and generating a second logical signal indicative of whether such correction is needed;
(f) comparing said axle rate signal, said energy summation signal and said second logical output signal to determine wheel slip intensity, and generating a wheel slip intensity signal which has a numerical value equal to said axle rate if said second logical output signal transitions from an indication that no wheel slip correction is needed to an indication that a wheel slip correction is needed, and which has an unchanging value if said second logical output signal remains unchanged or transitions from an indication that wheel slip correction is needed to an indication that no wheel slip correction is needed;
(g) converting said wheel slip intensity signal to a command signal;
and
(h) utilizing said command signal in a force modulation interface to vary a rate of braking force reduction.

6 more elements

A slip control system for a passenger transit type railway vehicle brake system, said slip control system comprising:

(a) a means for monitoring a speed of a wheel/axle set to produce an axle speed signal indicative of said speed of such wheel/axle set being monitored, and an axle rate signal indicative of acceleration/deceleration of such wheel/axle set be monitored;
(b) a means for determining whether said axle rate signal is in a slippage range, and generating a first output logical signal indicative of whether said axle rate signal is in said slippage range;
(c) a means for comparing said axle rate signal and said first output logical signal to determine an energy summation value indicative of such wheel/axle set's loss of energy due to braking wheel slippage, and generating an energy summation signal;
(d) a means for determining an energy loss limit on a basis of said axle speed signal, and generating an energy loss limit signal at which wheel slippage has little potential for self correction, said energy loss limit signal having a numerical value no greater than zero;
(e) a means for comparing said energy summation signal and said energy loss limit signal to determine a slip enablement output indicative of whether such wheel/axle set being monitored is in a slip condition that must be corrected, and generating a second logical signal indicative of whether such correction is needed;
(f) a means for comparing said axle rate signal, said energy summation signal and said second logical output signal to determine wheel slip intensity, and generating a wheel slip intensity signal which has a numerical value equal to said axle rate signal if said second logical output signal transitions from an indication that no wheel slip correction is needed to an indication that wheel slip correction is needed, and which has an unchanging value if said second logical output signal remains unchanged or transitions from an indication that wheel slip correction is needed to an indication that no wheel slip correction is needed;
(g) a means for converting said wheel slip intensity signal to a command signal;
and
(h) a force modulation interface responsive to said command signal to vary a rate of braking force reduction.

6 more elements

A slip control system for a passenger transit type railway vehicle brake system, said slip control system comprising:

(a) a means for monitoring a speed of a wheel/axle set to produce an axle speed signal and an axle rate signal;
(b) a rate band detector responsive to said axle rate signal and a deceleration rate signal, to produce a first logical output signal indicative of whether said axle rate signal is in a slippage range;
(c) an energy summation means responsive to said first logical output logical signal to produce an energy summation signal;
(d) an energy constant means responsive to said axle speed signal to determine an energy loss limit value indicative of a loss of energy due to braking wheel slippage of such wheel/axle set being monitored, and to produce an energy loss limit signal defining an energy loss limit value;
(e) a slip detector, responsive to said energy summation signal to determine whether such wheel/axle set being monitored is in a slip condition that must be corrected, and to produce a second logical signal indicative of whether such correction is needed;
(f) a wheel slip intensity detector responsive to said axle rate signal, said energy summation output signal, and said second logical output signal, to produce a wheel slip intensity signal having a value of "0" if said second logical output signal indicates that no correction is needed, and if said second logical signal indicates that correction is needed, said intensity output signal will have a value equal to said axle rate signal;
(g) a release rate determination means responsive to said intensity output signal to convert said intensity output signal to a command signal;
and
(h) a force modulation interface responsive to said command signal to vary the a rate of braking force reduction.

6 more elements

Dependencies are inferred from the claim text.