Electronic speed control for locomotives

• US 9,517,772 B1
• Filed: 05/27/2015
• Issued: 12/13/2016
• Est. Priority Date: 05/27/2015
• Status: Active Grant

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Ngo, Khanh, Ryerson, Cody, Fossum, Joshua
• Primary Examiner(s): Jabr, Fadey
• Assistant Examiner(s): SHUDY, ANGELINA M
• Application Number:
  US14/722,831
• Publication Number:
  US 20160347315A1
• Time in Patent Office: 566 Days
• Field of Search: 701/19, 701/20, 303/188
• US Class Current: 1/1
• CPC Class Codes: B60L 15/10 for automatic control superimposed on human control to limit the acceleration of the vehicle, e.g. to prevent excessive motor current electric devices for safety purposes B60L3/00
• CPC Class Codes: B60L 15/2063 for creeping
• CPC Class Codes: B60L 2200/26 Rail vehicles
• CPC Class Codes: B60L 2240/12 Speed
• CPC Class Codes: B60L 2240/441 Speed
• CPC Class Codes: B60L 2250/26 by pedal actuation
• CPC Class Codes: B60L 2260/40 Control modes
• CPC Class Codes: B60L 50/10 using propulsion power supplied by engine-driven generators, e.g. generators driven by combustion engines
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/184 with wheel brakes
• CPC Class Codes: B60W 2510/0604 Throttle position
• CPC Class Codes: B60W 2510/0638 Engine speed
• CPC Class Codes: B60W 2510/0657 Engine torque
• CPC Class Codes: B60W 2710/0644 Engine speed
• CPC Class Codes: B60W 30/18063 Creeping
• CPC Class Codes: B60W 30/188 Controlling power parameters of the driveline, e.g. determining the required power
• CPC Class Codes: B61C 15/00 Maintaining or augmenting the starting or braking power by auxiliary devices and measures; Preventing wheel slippage; Controlling distribution of tractive effort between driving wheels propelling locomotives or motor railcars by special means B61C11/00; driving wheels with non-slipping devices B60B; brakes B61H; wetting or lubricating rails B61K
• CPC Class Codes: Y02T 10/64 Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/72 Electric energy management in electromobility

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.

Claims

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 2, wherein a value of the upper threshold equals a value of the lower threshold.

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

5. 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.

6. 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.

7. 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.

8. 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.

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

10. 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 (TSC1) message of an SAE J1939 data bus communication standard.

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

12. 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.

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 14, wherein a value of the upper threshold equals a value of the lower threshold.

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

17. 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.

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 (TSC1) 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.