EPB Motor Failure Detection via Current Change Rate
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Solution Overview
Problem
Conventional electronic parking brake systems struggle to accurately and reliably determine motor failures, particularly when the stall current threshold value is within the target current range, leading to potential misclassification of motor stuck failures as normal parking completion.
Innovation Solution
The system incorporates a current sensing unit and electronic control unit that accumulate electric charge during a parking operation based on motor current change rates, determining a motor stuck failure if the accumulated charge exceeds a preset amount, thereby distinguishing between normal and faulty states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the stall current threshold value is set lower to improve motor failure detection sensitivity, then detection precision improves, but false positives increase when the threshold falls within the target current range
Solution Approach 1:
The patent transitions from one-dimensional current magnitude detection to two-dimensional detection by incorporating both current magnitude and current change rate. This dimensional expansion allows the system to distinguish between normal high-current operations and actual motor failures, resolving the contradiction between detection sensitivity and false positive rates
Solution Approach 2:
The patent introduces dynamic monitoring of current change rate (dI/dt) alongside static current threshold comparison. By detecting the rate of change rather than relying solely on absolute current values, the system can dynamically identify motor failures even when current magnitudes overlap with normal operating ranges, thereby improving detection precision without increasing false positives
2Ease of operation
If conventional current threshold comparison is used, then the system is simple to operate, but it cannot accurately distinguish between motor stuck failure and normal parking completion
Solution Approach 1:
The patent introduces current change rate as an intermediary parameter that mediates between the simple current threshold comparison and accurate failure detection. This intermediary metric enables the system to maintain operational simplicity while achieving precise failure identification by analyzing the temporal dynamics of current variation
Data Source
AI summary
Disclosed are an electronic parking brake system and a control method thereof. The electronic parking brake system according to an embodiment of the present disclosure which comprises an EPB (Electronic Parking Brake) actuator operated by an electric motor, comprises a motor driving unit for driving the electric motor of the EPB actuator, a current sensing unit for sensing a current flowing in the electric motor, and an electronic control unit for accumulating an electric charge amount put into the electric motor from the time when a motor current change rate is higher than a preset change rate if the motor current change rate according to the motor current sensed through the current sensing unit during a parking operation is higher than the preset change rate and determining a stuck failure of the electric motor based on the accumulated electric charge amount.