Traction Control Device Wheel Slip Detection
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Solution Overview
Problem
Existing traction control systems for construction machines fail to effectively distribute driving force among wheels during slip conditions, leading to reduced acceleration and course traceability, especially when multiple wheels slip or when right and left front and rear wheels simultaneously slip.
Innovation Solution
A traction control device that monitors rotation speed differences between right and left wheels and front and rear wheels, using a common index to determine when to activate the braking mechanism and differential adjusting mechanism, ensuring appropriate force distribution based on slip conditions and adjusting control thresholds according to articulate angle and lockup conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the target speed is calculated based on the average speed of each wheel considering articulate angle, then the control accounts for vehicle turning conditions, but the TCS control cannot be smoothly started when multiple wheels slip simultaneously
Solution Approach 1:
The patent segments the wheel speed monitoring into individual wheel detection rather than average speed calculation. The control start determination is divided into: (1) detecting rotation speeds of right and left wheels separately, (2) calculating rotation speed difference between them, and (3) comparing against threshold. This segmentation allows reliable detection even when multiple wheels slip, as long as there is a speed difference between right and left wheels.
Solution Approach 2:
Instead of determining control activation based on whether wheel speed matches the calculated target speed (which fails when multiple wheels slip), the patent inverts the approach by detecting slip conditions directly through rotation speed difference between right and left wheels. When the speed difference exceeds the threshold, slip is detected and control is activated, regardless of whether the speed matches the target.
2Measurement precision
If the TCS control activation is delayed to calculate target speed accurately, then the control accuracy improves, but the acceleration performance deteriorates
Solution Approach 1:
The patent performs preliminary action by pre-setting the rotation speed difference threshold before control activation is needed. The threshold is determined in advance based on vehicle parameters and road conditions, allowing immediate comparison and control activation without delayed calculation. When slip occurs, the system immediately compares the measured speed difference against the pre-set threshold and activates control without waiting for target speed calculation.
Solution Approach 2:
The patent skips the complex target speed calculation process and rushes directly to control activation by using rotation speed difference detection. Instead of calculating target speed from average wheel speed and articulate angle, then comparing actual speed to target, the system rushes through to activation by simply comparing right-left wheel speed difference against threshold, significantly reducing response time.
3Measurement precision
If the rotation speed difference threshold is set low for sensitive slip detection, then the slip detection precision improves, but false activation during normal turning increases
Solution Approach 1:
The patent applies dynamics by making the rotation speed difference threshold variable rather than fixed. The threshold is dynamically adjusted based on the articulate angle of the vehicle. When the articulate angle is large (sharp turning), the threshold is increased to allow greater speed difference without activation. When the articulate angle is small (straight or gentle turning), the threshold is decreased for sensitive slip detection. This dynamic adjustment prevents false activation during normal turning while maintaining precision during slip conditions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system ensures sufficient acceleration and course traceability by reliably initiating control measures based on wheel slip conditions, preventing premature or delayed TCS activation and maintaining stable traction force distribution across the wheels.
Implementation Method 1
a rotation speed detector that detects a rotation speed of each wheel
Implementation Method 2
a braking mechanism that applies a braking force to the wheel
Implementation Method 3
a differential adjusting mechanism that adjusts a differential between front and rear wheels
Data Source
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AI summary
A traction control device includes: rotation speed detectors (43FL to 43CR) provided to wheels; a control-start determiner (82) that determines whether or not to control a braking mechanism and a differential adjusting mechanism based on rotation speeds; a braking mechanism controller (84) that controls the braking mechanism based on a result of the determination of the control-start determiner (82); and a differential adjusting mechanism controller (85) that controls the differential adjusting mechanism based on the result of the determination of the braking-start determiner (82), in which the control-start determiner (82) includes: a right-left-wheel rotation speed difference calculating section (822); a front-rear-wheel rotation speed difference calculating section (823); and a control-start determining section (825) that determines whether or not to start controlling at least one of the braking mechanism and the differential adjusting mechanism when one of rotation speed differences reaches or exceeds a predetermined threshold.