Decentralized Wheel Controller for Friction Estimation
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Solution Overview
Problem
Current electronic braking and propulsion systems for vehicles lack accuracy in determining torque levels and propulsion capabilities for individual wheels, affecting vehicle stability and performance.
Innovation Solution
A decentralized wheel controller that calculates longitudinal wheel slip and estimates wheel force to generate a model representing the relationship between wheel slip and force, allowing for determination of absolute maximum wheel friction and capability, improving stability and performance by providing real-time data to centralized systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a centralized control system is used to evaluate parameter values for brake torque and propulsion, then system integration is simplified, but accuracy in determining individual wheel capabilities deteriorates
Solution Approach 1:
The control system is divided into decentralized wheel controllers (one per wheel) that independently calculate wheel slip and estimate wheel forces, rather than using a single centralized controller. This segmentation enables each wheel to have dedicated capability determination while maintaining overall system integration through standardized communication protocols.
Solution Approach 2:
The wheel controllers continuously receive feedback from wheel speed sensors and other sources, process this information locally to determine wheel capabilities, and adjust control signals accordingly. This closed-loop feedback mechanism at the wheel level improves accuracy while the standardized interfaces maintain system integration.
2Measurement precision
If more parameter values are used to generate the tire model, then model accuracy improves, but computational time increases
Solution Approach 1:
The system performs preliminary calculations of wheel slip and wheel force estimates using readily available sensor data before generating the tire model. By preparing these input parameters in advance and using efficient calculation methods, the system reduces the computational burden during model generation while maintaining high accuracy with sufficient parameter values.
3Speed
If real-time wheel capability determination is implemented, then vehicle responsiveness improves, but computational complexity increases
Solution Approach 1:
Each wheel controller independently performs wheel slip calculation and wheel force estimation without requiring complex centralized computation. The decentralized architecture allows each controller to serve its own wheel's capability determination needs, reducing overall computational complexity while achieving real-time responsiveness through parallel processing at multiple wheel controllers.
Data Source
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AI summary
The present invention relates to a wheel controller (108) for a vehicle (100), comprising a wheel slip calculation module (212) arranged to calculate a longitudinal wheel slip value for a wheel slip between a surface of the wheel (102) and a road surface thereof; a wheel force estimation module (214) arranged to estimate a longitudinal wheel force value for a wheel force between the surface of the wheel (102) and the road surface; a tire model generator (216) arranged to receive longitudinal wheel slip values from the wheel slip calculation module (212) and longitudinal wheel force values from the wheel force estimation module (214); said tire model generator (216) being configured to generate a model (300, 400) representing a relationship between the calculated longitudinal wheel slip and the estimated longitudinal wheel force by using at least three longitudinal wheel force values and three corresponding longitudinal wheel slip values; and a vehicle wheel capability module (218) arranged in communication with the tire model generator (216), said vehicle wheel capability module (218) being configured to determine an absolute maximum wheel friction level between the surface of the wheel (102) and the road surface thereof by means of acquiring, for a calculated wheel slip value, a longitudinal wheel force value from the model (300, 400) of the tire model generator.