Wheel Slip Feedback Control for Braking and Traction Stability
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Solution Overview
Problem
Current slip control algorithms in vehicles lack direct control over wheel slip, which hampers the optimization of tire potential for braking and traction, particularly in articulated vehicles where stability and maximum deceleration are critical.
Innovation Solution
A method involving sensors to measure or estimate wheel slip directly, with a vehicle control unit determining a desired slip value based on vehicle state parameters, and a braking/traction control unit adjusting wheel slip accordingly, ensuring real-time, accurate control of wheel slip ratio and angle to utilize peak tire forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If indirect closed loop slip control algorithms are used, then the control system is simpler to implement, but the wheel slip control accuracy is insufficient and tire potential cannot be fully optimized
Solution Approach 1:
The patent implements a closed-loop feedback control system where wheel slip is continuously measured by sensors, compared against a desired slip value, and the difference (error) is used to adjust braking or traction control. This feedback mechanism enables direct and accurate wheel slip control, allowing the system to fully optimize tire potential while maintaining manageable complexity through automated control.
2Measurement precision
If direct wheel slip measurement and control is implemented, then tire potential optimization is maximized, but the device complexity and measurement requirements increase
Solution Approach 1:
The patent replaces complex mechanical slip measurement mechanisms with electronic sensors and computational algorithms. Instead of using mechanical linkages to directly measure slip, the system uses sensors to collect wheel parameters and computationally determines slip, thereby achieving high measurement precision while reducing mechanical complexity.
Solution Approach 2:
The patent introduces an intermediary computational layer that processes sensor data to determine wheel slip. Rather than directly measuring slip with complex hardware, the system uses intermediate calculations based on readily available wheel parameters (speed, acceleration, steering angle) to derive slip information, simplifying the overall measurement system while maintaining accuracy.
3Reliability
If advanced slip control is applied to all wheels including trailer, then maximum deceleration and stability are achieved, but the control algorithm complexity increases
Solution Approach 1:
The patent divides the vehicle into separate controllable segments (tractor and trailer) with independent slip control for each. By segmenting the control system, each unit can be optimized independently with its own desired slip values and control algorithms, achieving overall vehicle stability and maximum deceleration while keeping individual control modules manageable in complexity.
Data Source
AI summary
A method for controlling braking and/or traction of a vehicle is provided. The methods includes determining by the vehicle control unit a desired slip value based on vehicle state parameters, the desired slip value being communicated to the braking control unit and to the traction control unit, measuring or estimating a slip measure or estimation from wheel parameters collected on the at least wheel tire by the sensor, the slip measure or estimation being communicated to the braking control unit and/or to the traction control unit controlling a wheel slip by the braking control unit and by the traction control unit, based on the desired slip value and the slip measure or estimation.