Brake-By-Wire Force Estimation for Low-Cost Caliper Control
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Solution Overview
Problem
Modern vehicles with BBW electronic braking systems face high costs due to the need for expensive force sensors to ensure precise force modulation and compliance with stringent safety requirements, which are essential for systems like ABS and ESC.
Innovation Solution
A method and system that estimates braking force using vehicle dynamics and sensor data to control the braking system, potentially reducing the reliance on high-cost force sensors by incorporating low-cost sensors with lower safety integrity levels and validating their readings through redundant estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If expensive force sensors with high safety integrity levels are used to ensure precise force measurement and compliance with safety requirements, then measurement precision and reliability are improved, but system cost increases significantly
Solution Approach 1:
The patent creates a virtual copy of the force sensor measurement through software estimation algorithms. Instead of relying solely on expensive physical force sensors, the system generates an estimated force value through mathematical models that replicate the measurement function, thereby reducing hardware costs while maintaining measurement precision
Solution Approach 2:
The patent replaces the mechanical force sensing system with a software-based estimation system. By substituting the physical measurement mechanism with computational algorithms that process other sensor data, the system eliminates the need for expensive force sensors while achieving comparable measurement precision
2Reliability
If expensive force sensors are used to meet functional safety requirements, then reliability is improved, but system cost increases
Solution Approach 1:
The patent implements a feedback mechanism where the estimated force value is continuously compared with the actual force sensor reading. This feedback loop validates the estimation algorithm and ensures reliability by detecting deviations that could indicate sensor failure or estimation errors, thereby maintaining functional safety without requiring expensive high-integrity sensors
Solution Approach 2:
The patent prepares for potential sensor failures by having a pre-developed estimation algorithm ready to take over or validate sensor readings. This beforehand cushioning ensures that if the force sensor fails, the system can maintain reliable operation through the estimation method, thereby ensuring functional safety without requiring expensive redundant high-integrity sensors
3Manufacturing precision
If high-performance force sensors are used to ensure accurate force modulation, then control precision is improved, but device complexity increases
Solution Approach 1:
The patent makes the estimation algorithm serve multiple functions: it acts as a backup when sensors fail, provides continuous validation of sensor readings, and can even replace sensors entirely in cost-sensitive applications. This multi-functionality reduces device complexity by eliminating specialized high-performance sensors while maintaining force modulation precision through the versatile software solution
Data Source
AI summary
A method for controlling a vehicle braking system may include receiving a braking request, and first input information representative of the vehicle. The method may also include determining first intermediate information on the basis of first input information and determining a reference force value on the basis of the first input information and of the braking request. The method may also include detecting second input information representative of the braking system at the corner of the vehicle. The method may also include determining an estimated force value on the basis of the first intermediate information and the second input information and determining a control quantity. The method may also include determining a control signal of an electro-mechanical actuator of a braking system brake caliper based on the control quantity and the reference force value. The method may also include providing the control signal to the electro-mechanical actuator.