Electronic Parking Brake Controller With Cross-MCU Crash Recovery
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Solution Overview
Problem
The existing automobile electronic parking brake control systems are prone to crash faults and failures due to the reliance on a single microcontroller unit (MCU), which can compromise safety and reliability.
Innovation Solution
A double-MCU redundancy design is implemented, where a monitoring MCU U1 monitors the system and quickly restores the main MCU U2 in case of failure, enabling the parking brake control to resume operation, along with a relay DC motor drive unit using single-pole double-throw relays and MOS power switches for PWM control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single MCU is used as the control device, then the device complexity is reduced, but the reliability of the parking brake system deteriorates due to crash fault risks
Solution Approach 1:
The control system is segmented into two independent MCUs: a main MCU (U2) responsible for normal parking brake control operations, and a monitoring MCU (U1) dedicated to monitoring the main MCU's running state and restoring it when abnormal. This segmentation allows the monitoring function to operate independently, improving system reliability without significantly increasing overall complexity.
Solution Approach 2:
The monitoring MCU U1 acts as an intermediary between the main MCU U2 and the rest of the system. It monitors the main MCU's state and intervenes by restoring the main MCU when a crash fault is detected, thereby improving reliability while maintaining a relatively simple overall architecture through this dedicated intermediary component.
2Reliability
If a monitoring MCU is added to restore the main MCU when abnormal, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The monitoring MCU U1 is designed to autonomously monitor the main MCU U2's running state and automatically restore it when a crash fault is detected, without requiring external intervention. This self-service capability improves reliability while keeping the system relatively simple by eliminating the need for additional external monitoring equipment or complex manual restoration procedures.
3Ease of manufacture
If a relay DC motor drive unit with SPDT relays and MOS power switches is used, then the cost is reduced, but the manufacturing precision requirements increase
Solution Approach 1:
The patent employs relay-based motor control components and MOS power switches that are cost-effective and widely available, replacing more expensive integrated H-bridge drive circuits. While these components require precise wiring and assembly, their individual low cost and availability make the overall system easier and more economical to manufacture.
Data Source
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AI summary
The present invention discloses an automobile electronic parking execution controller with a double-MCU redundancy design, relates to the technical field of electrical automobile control, and solves the problems that since a single MCU is used as a mainstream control device, there are certain crash fault and failure risks, which may affect the safety of an automobile parking brake. The automobile electronic parking execution controller comprises a parking switch circuit, a biaxial acceleration sensor unit, a main micro control unit (MCU) U2 and a monitoring MCU U1, wherein the main MCU U2 controls a parking motor by means of detecting signals of the parking switch circuit and the biaxial acceleration sensor; the monitoring MCU U1 monitors a running state of a whole control system and restores the main MCU U2 when the main MCU U2 is abnormal; and the main MCU U2 restores the monitoring MCU U1 when the monitoring MCU U1 is abnormal. The following effect is achieved: After the main MCU U2 crashes, the main MCU U2 can still be quickly stored through the monitoring MCU U1, so that the main MCU U2 quickly enters a response state to recover the parking brake control ability, which improves the safety of the system.