Electronic Speed Control for Locomotives

Patent metadata

Field	Value
Publication number	US-2016347315-A1
Application number	US-201514722831-A
Country	US
Kind code	A1
Filing date	May 27, 2015
Priority date	May 27, 2015
Publication date	Dec 1, 2016
Grant date	—

Abstract

A drivetrain system for a machine includes an engine, a brake, and a controller operatively coupled to the engine and the brake. The controller is configured to generate a first speed error based on a first speed command signal and a first ground speed signal; generate a first engine speed command signal based on the first speed error; send the first engine speed command signal to the engine; compare the first speed error to an upper threshold; set a brake command signal to an engagement value when a magnitude of the first speed error is greater than a magnitude of the upper threshold; engage the brake in response to setting the brake command signal to the engagement value; and increase a speed of the engine in response to the first engine speed command signal while the brake command signal is set to the engagement value.

First claim

We claim:

1 . A drivetrain system for a machine, the drivetrain system comprising:
an engine operatively coupled to means for propelling the machine over a work surface; a brake operatively coupled to the means for propelling the machine over the work surface; and a controller operatively coupled to the engine and the brake, the controller being configured to:
generate a first speed error based on a first speed command signal and a first ground speed signal;
generate a first engine speed command signal based on the first speed error;
send the first engine speed command signal to the engine;
compare the first speed error to an upper threshold;
set a brake command signal to an engagement value when a magnitude of the first speed error is greater than a magnitude of the upper threshold;
engage the brake in response to setting the brake command signal to the engagement value; and
increase a speed of the engine in response to the first engine speed command signal while the brake command signal is set to the engagement value.

2 . The system of claim 1 , wherein the controller is further configured to:
generate a second speed error based on a second speed command signal and a second ground speed signal; generate a second engine speed command signal based on the second speed error; send the second engine speed command signal to the engine; compare the second speed error to a lower threshold; set the brake command signal to a disengagement value when a magnitude of the second speed error is less than a magnitude of the lower threshold; disengage the brake in response to setting the brake command signal to the disengagement value; and adjust a speed of the engine in response to the second engine speed command signal while the brake command signal is set to the disengagement value.

3 . The system of claim 1 , further comprising a throttle input device operatively coupled to the controller, wherein the controller is further configured to:
generate a fuel command signal based on a throttle setting of the machine; and override the fuel command signal with the first engine speed command signal.

4 . The system of claim 2 , wherein a value of the upper threshold equals a value of the lower threshold.

5 . The system of claim 2 , wherein a magnitude of the upper threshold is greater than a magnitude of the lower threshold.

6 . The system of claim 2 , wherein a value of the first ground speed signal equals a value of the second ground speed signal, and a value of the first speed command signal does not equal a value of the second speed command signal.

7 . The system of claim 2 , wherein a value of the first ground speed signal does not equal a value of the second ground speed signal, and a value of the first speed command signal equals a value of the second speed command signal.

8 . The system of claim 1 , wherein the first speed command signal corresponds to a desired ground speed of the machine.

9 . The system of claim 1 , wherein the first engine speed command signal is contained in a speed data field of a Torque/Speed Control # 1 (TSC 1 ) message of an SAE J1939 data bus communication standard.

10 . The system of claim 1 , wherein the controller is further configured to determine the first engine speed command signal with a PID controller.

11 . The system of claim 1 , wherein a value of the first speed command signal is lower than a steady-state idle ground speed of the machine.

12 . The system of claim 2 , wherein the controller is further configured to adjust at least one of the upper threshold and the lower threshold based on a user input.

13 . A method for controlling a ground speed of a machine, the method comprising:
generating a first speed error based on a first speed command signal and a first ground speed signal; generating a first engine speed command signal based on the first speed error; sending the first engine speed command signal from an engine speed controller to an engine of the machine; comparing the first speed error to an upper threshold via a brake controller; setting a brake command signal to an engagement value, via the brake controller, when a magnitude of the first speed error is greater than a magnitude of the upper threshold; engaging a brake of the machine in response to the setting the brake command signal to the engagement value; and increasing a speed of the engine in response to the first engine speed command signal while the brake command signal is set to the engagement value.

14 . The method of claim 13 , further comprising:
generating a second speed error based on a second speed command signal and a second ground speed signal; generating a second engine speed command signal based on the second speed error; sending the second engine speed command signal from the engine speed controller to the engine of the machine; comparing the second speed error to a lower threshold via the brake controller; setting the brake command signal to a disengagement value, via the brake controller, when a magnitude of the second speed error is less than a magnitude of the lower threshold; disengaging the brake of the machine in response to the setting the brake command signal to the disengagement value; and adjusting a speed of the engine in response to the second engine speed command signal while the brake command signal is set to the disengagement value.

15 . The method of claim 13 , further comprising:
generating a fuel command signal based on a throttle setting of the machine, via the engine speed controller; and overriding the fuel command signal with the first engine speed command signal.

16 . The method of claim 14 , wherein a value of the upper threshold equals a value of the lower threshold.

17 . The method of claim 14 , wherein a magnitude of the upper threshold is greater than a magnitude of the lower threshold.

18 . The method of claim 13 , wherein the first engine speed command signal is contained in a speed data field of a Torque/Speed Control # 1 (TSC 1 ) message of an SAE J1939 data bus communication standard.

19 . The method of claim 13 , wherein a value of the first speed command signal is lower than a steady-state idle ground speed of the machine.

20 . An article of manufacture comprising non-transitory machine-readable media having instructions encoded thereon for causing a controller to:
generate a first speed error based on a first speed command signal and a first ground speed signal; generate a first engine speed command signal based on the first speed error; send the first engine speed command signal from an engine speed controller to an engine of a machine; compare the first speed error to an upper threshold via a brake controller; set a brake command signal to an engagement value, via the brake controller, when a magnitude of the first speed error is greater than a magnitude of the upper threshold; engage a brake of the machine in response to setting the brake command signal to the engagement value; and increase a speed of the engine in response to the first engine speed command signal while the brake command signal is set to the engagement value.

Assignees

• Caterpillar Inc

Inventors

• Ngo Khanh
• Ryerson Cody
• Fossum Joshua

Classifications

• B60W2510/0604

  Throttle position · CPC title

• B60L15/2063

  for creeping · CPC title

• B60L50/10

  using propulsion power supplied by engine-driven generators, e.g. generators driven by combustion engines · CPC title

• B60W10/06 Primary

  including control of combustion engines · CPC title

• B60W30/18063

  Creeping · CPC title