Vehicle Road Step Detection Using Brake Input Compensation
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Solution Overview
Problem
Existing vehicle brake control systems have limitations in accurately determining the presence of road surface steps, as they rely solely on wheel deceleration, which can be influenced by both road surface features and driver braking actions, leading to reduced determination accuracy.
Innovation Solution
A step determination device that utilizes both wheel speed and braking operation amount sensors to calculate actual and estimated variable amounts, determining the presence of a road surface step by evaluating the deviation between these values, thereby considering the impact of driver braking on wheel deceleration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If wheel deceleration is used to determine road surface steps, then the detection capability is provided, but the determination accuracy deteriorates due to interference from driver braking operations
Solution Approach 1:
The invention extracts and separates the component of wheel deceleration caused by driver braking operations from the total wheel deceleration. By calculating the estimated variable amount based on braking operation amount and subtracting it from the actual variable amount, the system isolates the portion of deceleration caused by road surface steps, thereby eliminating the interference effect and improving determination accuracy.
Solution Approach 2:
The invention introduces the braking operation amount as an intermediary parameter to mediate between the driver's braking action and the wheel deceleration measurement. This intermediary allows the system to quantify and account for the driver's influence on wheel deceleration, enabling accurate separation of braking-induced deceleration from step-induced deceleration.
2Device complexity
If only wheel speed is used for step determination, then the system simplicity is maintained, but the determination accuracy is insufficient due to inability to distinguish driver braking effects
Solution Approach 1:
The invention makes the wheel speed sensor and controller serve multiple functions: they not only monitor wheel speed for basic brake control but also calculate actual variable amount for step detection. By combining this with the braking operation amount from the operation amount sensor, the system achieves both brake control and accurate step determination without adding dedicated hardware for each function.
Data Source
AI summary
A step determination device includes an operation amount sensor that detects an operation amount of a braking operation member, and a controller that determines a step by using the wheel speed and the operation amount. In the step determination device, the controller calculates an actual variable amount by using the wheel speed, calculates an estimated variable amount corresponding to the actual variable amount by using the operation amount, and executes the determination of the step by using the actual variable amount and the estimated variable amount. For example, the controller determines the presence of the step when the deviation between the actual variable amount and the estimated variable amount is not less than a predetermined value, and determines the absence of the step when the deviation is less than the predetermined value.