Redundant Brake-by-Wire Control for Sensor and Controller Failures
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Solution Overview
Problem
Electric vehicles equipped with a single brake-by-wire system face increased driving risks due to undetectable faults in components like the brake pedal or central controller, leading to potential brake failures.
Innovation Solution
Implementing a brake system with control redundancy, featuring a central controller and four wheel end brake apparatuses, each with a wheel end controller and brake actuator, utilizing dual channels of brake pedal travel and force sensors to ensure accurate detection and redundancy in case of sensor or central controller failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single brake-by-wire system is equipped, then the device complexity is reduced, but the reliability deteriorates due to undetectable faults and potential brake failures
Solution Approach 1:
The patent implements local quality by creating two distinct control channels with different sensor configurations. The first channel uses brake pedal travel sensors while the second channel uses brake pedal force sensors, allowing each channel to have specialized detection capabilities suited to its function, thereby improving overall system reliability without requiring a completely redundant complex system
Solution Approach 2:
The patent applies beforehand cushioning by pre-configuring dual independent control channels that can compensate for each other in case of failure. The system designates one channel as primary and the other as backup, with predetermined failure detection mechanisms that activate the backup channel before complete system failure occurs, thus cushioning against potential brake failures
2Reliability
If dual channels of sensors are implemented, then the reliability is improved through redundancy, but the device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the control system into two independent channels with different sensor types. Instead of duplicating the entire system, it segments the sensor function into travel-based detection and force-based detection, reducing complexity compared to full redundancy while maintaining reliability through diversification
Solution Approach 2:
The patent implements universality by designing the controller to handle multiple sensor types and control modes through a unified control logic. The same controller processes signals from both travel sensors and force sensors, and can switch between different control strategies, reducing overall system complexity while maintaining redundant functionality
3Ease of operation
If the central controller fails, then the ease of operation is maintained, but the reliability deteriorates due to loss of centralized control
Solution Approach 1:
The patent applies preliminary action by pre-configuring the wheel end controllers with the capability to independently execute control functions. The distributed control architecture is established in advance, so that upon central controller failure, the wheel end controllers can immediately take over without requiring complex reconfiguration or manual intervention, thus maintaining ease of operation while improving reliability
Data Source
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AI summary
A brake system with control redundancy provided in this application includes a central controller (12) and four wheel end brake apparatuses (13). The central controller receives one channel of brake pedal travel signal from a brake pedal travel sensor (PTS) and one channel of brake pedal force signal from a brake pedal force sensor (PFS). A wheel end controller is configured to receive the other channel of brake pedal travel signal from the brake pedal travel sensor and the other channel of brake pedal force signal from the brake pedal force sensor. One of the sensors fails, and the other sensor can still detect a motion state of a brake pedal, to improve operational reliability of the brake system with control redundancy. In addition, even when the central controller fails, the four wheel end brake apparatuses can be controlled, based on the other channel of brake pedal travel signal and the other channel of brake pedal force signal, to output brake forces, to avoid a failure of the entire brake system with control redundancy caused by the failure of the central controller, and improve safety and reliability of the brake system.