Traction control device

• US 8,463,511 B2
• Filed: 12/25/2009
• Issued: 06/11/2013
• Est. Priority Date: 12/26/2008
• Status: Active Grant

• Current Assignee: Komatsu Ltd.
• Original Assignee: Komatsu Ltd.
• Inventors: Uematsu, Koji, Hatake, Kazuhiro, Kusumoto, Yuya
• Primary Examiner(s): Trammell, James
• Assistant Examiner(s): Do, Truc M
• Application Number:
  US13/140,664
• Publication Number:
  US 20110251762A1
• Time in Patent Office: 1,264 Days
• Field of Search: 701/50, 701/48, 701/70, 701/78, 701/83
• US Class Current: 701/50
• CPC Class Codes: B60K 17/35 including arrangements for suppressing or influencing the power transfer, e.g. viscous clutches differential gearing with locking devices F16H48/20
• CPC Class Codes: B60T 10/00 Control or regulation for continuous braking making use of fluid or powdered medium, e.g. for use when descending a long slope
• CPC Class Codes: B60T 2201/14 Electronic locking-differential
• CPC Class Codes: B60T 2210/16 Off-road driving conditions
• 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 8/4809 Traction control, stability control, using both the wheel brakes and other automatic braking systems
• CPC Class Codes: B60W 10/14 Central differentials for dividing torque between front and rear axles
• CPC Class Codes: B60W 10/16 Axle differentials, e.g. for dividing torque between left and right wheels
• CPC Class Codes: B60W 10/184 with wheel brakes
• CPC Class Codes: B60W 2300/17 Construction vehicles, e.g. graders, excavators
• CPC Class Codes: B60W 2510/0233 of torque converter lock-up clutch
• CPC Class Codes: B60W 2520/263 Slip values between front and rear axle
• CPC Class Codes: B60W 2520/266 Slip values between left and right wheel
• CPC Class Codes: B60W 2520/28 Wheel speed
• CPC Class Codes: B60W 2720/403 between front and rear axle
• CPC Class Codes: B60W 2720/406 between left and right wheel
• CPC Class Codes: B60W 30/18172 Preventing, or responsive to skidding of wheels

Abstract

An object of the invention is to provide a traction control device capable of preventing a reduction in acceleration. A traction control device of the invention includes a braking mechanism controller that controls a braking mechanism. The braking mechanism controller includes: a target brake torque calculating section that calculates a target brake torque to each of wheels based on the rotation speed of the wheel and an estimated vehicle speed; a target brake torque determining section that determines whether or not the target brake torque reaches or exceeds a per-stored threshold; a reference wheel determining section that selects a reference wheel used as a reference for controlling the braking mechanism based on the target brake torque to each of the wheels; and a target brake torque reducing section that reduces the target brake torque in accordance with a difference between the target brake torque to the reference wheel and the threshold when the target brake torque to one of the wheels reaches or exceeds the threshold.

Claims

1. A traction control device of a construction machine comprising a braking mechanism provided to each of wheels, the traction control device controlling the braking mechanism, the traction control device comprising:

a rotation speed detector that detects a rotation speed of each of the wheels;

a vehicle speed estimator that estimates a vehicle speed of the construction machine; and

a braking mechanism controller that controls the braking mechanism, wherein the braking mechanism controller comprises;

a control deviation calculating section that calculates a control deviation based on the rotation speed and the vehicle speed;

a target brake torque calculating section that calculates a target brake torque applied to each of the wheels by the braking mechanism based on the control deviation;

a target brake torque determining section that determines whether or not the target brake torque reaches or exceeds a pre-stored threshold;

a reference wheel determining section that selects a reference wheel used as a reference for controlling the braking mechanism based on the target brake torque to each of the wheels; and

a target brake torque reducing section that reduces the target brake torque in accordance with a difference between the target brake torque to the reference wheel and the threshold when the target brake torque to one of the wheels reaches or exceeds the threshold.

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

the reference wheel determining section selects one of the wheels having a smallest target brake torque as the reference wheel.

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

the threshold comprises a front-wheel threshold and a rear-wheel threshold of the target brake torques,

the target brake torque determining section determines whether or not the target brake torques to both front ones of the wheels reach or exceed the front-wheel threshold and whether or not the target brake torques to both rear ones of the wheels reach or exceed the rear-wheel threshold, and

the target brake torque reducing section reduces the target brake torques in accordance with a difference between the target brake torque to the reference wheel and the front-wheel threshold when the reference wheel is one of the front wheels and reduces the target brake torques in accordance with a difference between the target brake torque to the reference wheel and the rear-wheel threshold when the reference wheel is one of the rear wheels.

4. The traction control device according to claim 1, wherein

the braking mechanism controller further comprises a traction force estimating section that estimates a traction force between each of the wheels and a road surface based on the control deviation, and

the target brake torque calculating section calculates the target brake torque to each of the wheels by using the estimated traction force.