Electrical Parking Brake Redundancy for EPB ECU Failure
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Solution Overview
Problem
The existing Electrical Parking Brake (EPB) systems face challenges in ensuring fail-safe performance without increasing hardware costs or the system's bulk, particularly in scenarios where the EPB Electronic Control Unit (ECU) fails.
Innovation Solution
The proposed solution involves an electrical parking brake system with a vehicle control unit, a main parking brake controller, and an auxiliary parking brake controller. The system utilizes dual CAN communication channels and a hardwired connection as a spare communication channel to ensure fail-safe operation by switching to the auxiliary controller in case of communication failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an EPB ECU is added separately to prevent P-gear parking failures, then the fail-safe performance is improved, but hardware costs and the size of the EPB system are increased
Solution Approach 1:
The patent integrates the EPB control function into the existing IEB controller, which already handles brake control functions. This allows the IEB controller to perform multiple functions (integrated brake control and EPB control) without adding a separate dedicated EPB ECU, thereby improving fail-safe performance while avoiding increased hardware costs and system size
Solution Approach 2:
The patent combines the EPB control functionality with the IEB controller into a single integrated unit. By merging these control functions, the system achieves redundant control pathways for P-gear parking without requiring separate hardware components, thus resolving the contradiction between reliability and device complexity
2Reliability
If dual CAN communication channels are used for the main parking brake controller, then the communication reliability is improved, but the device complexity is increased
Solution Approach 1:
The system pre-configures dual CAN communication channels (first and second CAN networks) for the main parking brake controller before any failure occurs. This preliminary setup ensures that redundant communication pathways are already in place, allowing immediate switching if one channel fails, thereby improving communication reliability without requiring complex real-time decision-making
Solution Approach 2:
The vehicle control unit acts as an intermediary that manages the dual CAN communication channels. It monitors the communication status and can switch between the first and second CAN networks, simplifying the complexity by centralizing the management of redundant communication pathways in a single control unit
Data Source
AI summary
In an electrical parking brake system and a control method thereof, the electrical parking brake system includes: a vehicle control unit electrically connected to a shift by wire of a vehicle, and configured to receive a shift command entered by a driver from the shift by wire, and periodically transmitting a parking request signal at a predetermined transmission time interval; a main parking brake controller electrically connected to the vehicle control unit through a first communication channel and a second communication channel, and configured to execute a main parking brake control based on the parking request signal received from the vehicle control unit; and an auxiliary parking brake controller electrically connected to the vehicle control unit through the first communication channel and a third communication channel, and configured to execute an auxiliary parking brake control based on the parking request signal received from the vehicle control unit.