Brake Pressure Abnormality Detection via Dynamic Threshold Adjustment
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Solution Overview
Problem
Existing brake system abnormality detection devices face challenges in accurately setting determination areas, leading to inadequate abnormality detection when the control target hydraulic pressure is in a maintaining state.
Innovation Solution
An abnormality detection device that calculates control target braking force-related physical amounts, obtains braking force-related physical amounts, determines the state of control target hydraulic pressure, sets and adjusts threshold values to define permissible divergence ranges, and determines abnormalities based on deviations from these ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed determination area is set for abnormality detection, then the device complexity is reduced, but the measurement precision of abnormality detection deteriorates when control target hydraulic pressure is in a maintaining state
Solution Approach 1:
The patent applies dynamics by making the threshold value adjustable based on the operational state of the brake system. The threshold value changing portion dynamically modifies the threshold value in response to state determination (maintaining, increasing, or decreasing states of control target hydraulic pressure), transforming a static determination area into a dynamic one that adapts to different operating conditions, thereby improving abnormality detection accuracy without excessive complexity
Solution Approach 2:
The patent changes the parameter of the threshold value based on the operational state. When the control target hydraulic pressure is in a maintaining state, the threshold value is adjusted to a smaller value compared to when it is in increasing or decreasing states. This parameter change allows the determination area to be appropriately narrowed or widened according to the system state, improving measurement precision while maintaining reasonable device complexity
2Adaptability or versatility
If the threshold value is set to a larger value to cover more operating states, then the adaptability improves, but the measurement precision of abnormality detection deteriorates in maintaining state
Solution Approach 1:
The system dynamically adjusts the threshold value based on the determined state of the control target hydraulic pressure. The threshold value changing portion responds to state determination by selecting appropriate threshold values, enabling the system to adapt to different operating states (maintaining, increasing, decreasing) while maintaining high measurement precision in each state through state-appropriate threshold selection
Solution Approach 2:
The patent implements parameter changes by modifying the threshold value according to the operational state. In the maintaining state, a smaller threshold value is applied for precise abnormality detection, while in increasing or decreasing states, a larger threshold value is used to accommodate normal variations. This conditional parameter change resolves the contradiction between adaptability and precision
Data Source
AI summary
An abnormality detection device includes a control target hydraulic pressure calculating portion that calculates a control target hydraulic pressure according to an operation state of a brake pedal, the hydraulic pressure obtaining portion that obtains the hydraulic pressure of the operating fluid controlled to become the control target hydraulic pressure calculated by the control target hydraulic pressure calculating portion from the pressure sensor; a second determination threshold value changing portion that changes a threshold value to be closer to the control target hydraulic pressure calculated by the control target hydraulic pressure calculating portion in a stepwise manner when a state determining portion determines that the control target hydraulic pressure is in a maintaining state, and the abnormality determining portion that determines the hydraulic pressure braking force generating device is abnormal when the hydraulic pressure obtained by the hydraulic pressure obtaining portion deviates from the permissible divergence range.