Traction control apparatus

• US 8,989,969 B2
• Filed: 03/12/2013
• Issued: 03/24/2015
• Est. Priority Date: 01/08/2009
• Status: Active Grant

• Current Assignee: Komatsu Ltd.
• Original Assignee: Komatsu Ltd.
• Inventors: Uematsu, Koji, Hatake, Kazuhiro
• Primary Examiner(s): Black, Thomas G
• Assistant Examiner(s): LI, CE LI
• Application Number:
  US13/796,298
• Publication Number:
  US 20130190992A1
• Time in Patent Office: 742 Days
• Field of Search: 701/50, 701 69- 71, 701 74- 75, 701/78, 701 82- 83, 701 89- 90, 180/197, 180/233, 180/244, 303/139, 303/144, 303/151, 303/163, 303/165, 303/113.2
• US Class Current: 701/50
• CPC Class Codes: B60T 2210/16 Off-road driving conditions
• CPC Class Codes: B60T 2270/202 for all-wheel drive vehicles
• CPC Class Codes: B60T 8/175 Brake regulation specially adapted to prevent excessive wheel spin during vehicle acceleration, e.g. for traction control safety devices for propulsion unit control responsive to, or preventing, skidding of wheels B60K28/16
• CPC Class Codes: B60T 8/1769 specially adapted for vehicles having more than one driven axle, e.g. four-wheel drive vehicles
• CPC Class Codes: E02F 9/2083 Control of vehicle braking systems
• CPC Class Codes: F02D 29/02 peculiar to engines driving vehicles; peculiar to engines driving variable pitch propellers

Abstract

An object of the invention is to provide a traction control apparatus capable of suitably controlling an error, if it occurs, between an estimation of a vehicle speed and an actual vehicle speed. A traction control apparatus according to the invention includes a vehicle speed estimator and a driving-force controller. The traction control apparatus includes a vehicle state determiner that determines whether the vehicle speed of the construction vehicle estimated by the vehicle speed estimator and the driving-force control by the driving-force controller are balanced, and a driving-force control changer that changes a driving-force control by the driving-force controller when the vehicle state determiner determines the vehicle speed and the driving-force control to be unbalanced.

Claims

1. A traction control apparatus, comprising:

a vehicle speed estimator that estimates a vehicle speed of a construction vehicle, the vehicle speed estimator comprising a rotation speed detector that detects a rotation speed of each of driving wheels of the construction vehicle and a reference wheel-speed calculator that calculates a reference wheel-speed based on the rotation speed detected by the rotation speed detector;

a driving-force controller that performs a driving-force control of the construction vehicle based on the vehicle speed estimated by the vehicle speed estimator, the driving-force controller comprising a braking mechanism controller that calculates an actual slip ratio of each of the wheels based on the rotation speed detected by the rotation speed detector and controls a braking mechanism of the construction vehicle so that the calculated actual slip ratio of each of the wheels converges to a predetermined target slip ratio;

a vehicle state determiner that determines whether or not the vehicle speed of the construction vehicle estimated by the vehicle speed estimator and the driving-force control by the driving-force controller are balanced based on deviations between each of the calculated actual slip ratios and the target slip ratio; and

a driving-force control changer that changes a driving-force control by the driving-force controller based upon a determination by the vehicle state determiner that the vehicle speed and the driving-force control are unbalanced,

wherein the vehicle state determiner is configured to determine that the vehicle speed and the driving-force control are unbalanced based on the slip ratios of both right and left ones of the wheels calculated by the braking mechanism controller being a predetermined threshold or less, and

wherein the braking mechanism controller is configured to keep an amount of braking control by the braking mechanism at the predetermined threshold or more for a predetermined time or more.

2. The traction control apparatus according to claim 1, wherein

the driving-force control changer changes the driving-force control by setting the vehicle speed estimated by the vehicle speed estimator at the reference wheel speed calculated by the reference wheel-speed calculator.

3. The traction control apparatus according to claim 1, wherein

the driving-force control changer changes the driving-force control by releasing the control by the driving-force controller.

4. A traction control method, comprising:

estimating a vehicle speed of a construction vehicle, detecting a rotation speed of each of driving wheels of the construction vehicle, and calculating a reference wheel-speed based on the detected rotation speed;

performing a driving-force control of the construction vehicle based on the estimated vehicle speed, calculating an actual slip ratio of each of the wheels based on the detected rotation speed, and controlling a braking mechanism of the construction vehicle so that the calculated actual slip ratio of each of the wheels converges to a predetermined target slip ratio;

determining whether or not the estimated vehicle speed and the driving-force control are balanced based on deviations between each of the calculated actual slip ratios and the target slip ratio; and

changing the driving-force control based upon a determination that the vehicle speed and the driving-force control are unbalanced,

wherein determining that the vehicle speed and the driving-force control are unbalanced is based upon a determination that the slip ratios of right and left ones of the wheels are both at a predetermined threshold or less and that an amount of braking control is kept at the predetermined threshold or more for a predetermined time or more.

5. The traction control method according to claim 4, wherein

changing the driving-force control includes setting the estimated vehicle speed at the calculated reference wheel speed.

6. The traction control method according to claim 4, wherein

changing the driving-force control includes releasing the control.

7. A traction control apparatus, comprising:

a vehicle speed estimator that estimates a vehicle speed of a construction vehicle, the vehicle speed estimator comprising a rotation speed detector that detects a rotation speed of each of driving wheels of the construction vehicle and a reference wheel-speed calculator that calculates a reference wheel-speed based on the rotation speed detected by the rotation speed detector;

a driving-force controller that performs a driving-force control of the construction vehicle based on the vehicle speed estimated by the vehicle speed estimator, the driving-force controller comprising a braking mechanism controller that calculates an actual slip ratio of each of the wheels based on the rotation speed detected by the rotation speed detector and controls a braking mechanism of the construction vehicle so that the calculated actual slip ratio converges to a predetermined target slip ratio;

a vehicle state determiner that determines whether or not the vehicle speed of the construction vehicle estimated by the vehicle speed estimator and the driving-force control by the driving-force controller are balanced based on a deviation between the calculated actual slip ratio and the target slip ratio; and

a driving-force control changer that changes a driving-force control by the driving-force controller when the vehicle state determiner determines that the vehicle speed and the driving-force control are unbalanced,

wherein the vehicle state determiner determines the vehicle speed and the driving-force control to be unbalanced when the slip ratios of right and left ones of the wheels calculated by the braking mechanism controller are both at a predetermined threshold or less, and the braking control amount of the braking mechanism by the braking mechanism controller is kept at the predetermined threshold or more for a predetermined time or more.