Brake Pressure Estimation for Wheel Sensor Failure Control
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Solution Overview
Problem
Modern brake systems face challenges in maintaining vehicle stability and deceleration capacity during autonomous driving due to potential failures in wheel speed sensors, which are costly and structurally complex to redundantly address.
Innovation Solution
A method and brake device that estimates brake pressure for wheels without functional wheel speed sensors by using brake pressure from other wheels, considering factors like axle load distribution and μ-split situations, to ensure stability control even with sensor failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If redundant wheel speed sensors are configured to prevent sensor failure, then system reliability is improved, but device complexity and cost increase
Solution Approach 1:
The patent uses brake pressure data from wheels with functional sensors as a substitute copy for the missing sensor data. Instead of physically duplicating sensors, the system creates a virtual sensor reading by copying and adapting brake pressure information from other wheels, thereby maintaining reliability without adding physical redundancy components.
Solution Approach 2:
The patent introduces brake pressure as an intermediary parameter to bridge the gap between functional sensors and the wheel where sensor data is missing. By using brake pressure (which can be measured or estimated from other wheels) as a mediator, the system can infer wheel speed information without requiring a direct sensor connection to the affected wheel.
2Reliability
If redundant wheel speed sensors are configured to prevent sensor failure, then system reliability is improved, but cost increases
Solution Approach 1:
The patent uses brake pressure data from wheels with functional sensors as a substitute copy for the missing sensor data. Instead of physically duplicating sensors, the system creates a virtual sensor reading by copying and adapting brake pressure information from other wheels, thereby maintaining reliability without adding physical redundancy components.
Solution Approach 2:
The patent employs a software-based estimation algorithm that uses readily available brake pressure data (which is already present in the system for other control functions) to replace expensive redundant sensor hardware. This approach treats the estimation algorithm as a low-cost virtual solution compared to the high cost of physical sensor redundancy.
3Measurement precision
If wheel speed sensor fails, then measurement precision is maintained, but reliability deteriorates
Solution Approach 1:
The patent uses brake pressure data from wheels with functional sensors as a substitute copy for the missing sensor data. Instead of physically duplicating sensors, the system creates a virtual sensor reading by copying and adapting brake pressure information from other wheels, thereby maintaining reliability without adding physical redundancy components.
Solution Approach 2:
The system continuously monitors brake pressure data from functional sensors and uses this feedback to dynamically adjust and refine the estimation of wheel speed for the affected wheel. This feedback mechanism ensures that the substituted measurement remains accurate and reliable even as operating conditions change.
4Reliability
If control is concentrated on wheels with functional sensors, then reliability is improved, but stability deteriorates
Solution Approach 1:
The patent uses brake pressure data from wheels with functional sensors as a substitute copy for the missing sensor data. Instead of physically duplicating sensors, the system creates a virtual sensor reading by copying and adapting brake pressure information from other wheels, thereby maintaining reliability without adding physical redundancy components.
Solution Approach 2:
The patent makes the brake pressure measurement system universal by using it for multiple purposes: both for its original function of brake control and as a substitute for wheel speed sensing. This multi-functionality allows the same sensor data to serve both braking and stability control functions, even when wheel speed sensors fail.
Data Source
AI summary
Methods for determining or estimating a first brake pressure for a first brake actuator. Methods are directed towards, for example, situations where a pressure-medium-actuated brake device of at least one first wheel, at which a brake-pressure buildup is necessary during a braking operation, at which for example, there is no first wheel-speed sensor. Methods are also directed towards situations, for example, where a first wheel-speed sensor does not produce a first wheel-speed signal. Methods include determining, measuring, or estimating, during the braking operation and/or during the execution of the controlling operation, a second brake pressure for a second brake actuator.