EPB Motor Duty Ratio Control for Noise Reduction
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Solution Overview
Problem
Electronic parking brake systems generate noise during operation, which is particularly bothersome in luxury vehicles with numerous electric components, and existing systems lack effective noise reduction methods.
Innovation Solution
A control method that variably adjusts the duty ratio of voltage applied to the motor in an electronic parking brake system, switching between a first duty ratio of 50% to 80% during release and a second duty ratio of 90% to 100% based on motor locking status, utilizing sensors like encoders or hall sensors to determine motor locking and release conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If high duty ratio voltage is applied to the motor during parking brake release, then the release speed and torque are improved, but noise generation increases
Solution Approach 1:
The patent applies dynamic duty ratio adjustment by switching between first duty ratio (lower, for normal operation) and second duty ratio (higher, for locked condition) based on real-time motor locking status detection. This dynamic adaptation resolves the contradiction by providing high power only when necessary for release while maintaining low noise during normal operation.
Solution Approach 2:
The patent changes the voltage duty ratio parameter based on motor locking status. By detecting whether the motor is locked and adjusting the duty ratio accordingly (first duty ratio for normal, second duty ratio for locked), the system optimizes both noise levels and release effectiveness, resolving the contradiction between noise reduction and release performance.
2Reliability
If high duty ratio voltage is applied to ensure maximum torque for release, then the reliability of brake release is improved, but energy consumption increases
Solution Approach 1:
The system dynamically adjusts the duty ratio based on motor locking status, applying high energy consumption (second duty ratio) only when the motor is locked and release reliability is compromised. During normal operation with first duty ratio, energy consumption is reduced while maintaining adequate release reliability.
Solution Approach 2:
By changing the voltage duty ratio parameter according to motor locking detection, the system optimizes the balance between release reliability and energy consumption. The controller applies maximum torque (higher energy) only when necessary for locked motors, otherwise using lower energy consumption mode.
3Reliability
If the motor operates continuously at high duty ratio to prevent locking, then the reliability is improved, but noise and energy consumption increase
Solution Approach 1:
The system performs preliminary detection of motor locking status before applying high duty ratio voltage. By detecting the locked condition and then applying the second duty ratio, the system prevents prolonged high noise operation while maintaining reliability. The preliminary detection avoids continuous high-duty-ratio operation.
Solution Approach 2:
The system uses feedback from motor locking status detection to control duty ratio selection. The controller continuously monitors whether the motor is locked and adjusts the duty ratio accordingly, ensuring reliability only when needed while minimizing noise during normal operation. This feedback mechanism prevents continuous high noise generation.
Data Source
AI summary
Disclosed is a control method of an electronic parking brake system, which variably controls the duty of voltage applied to a motor upon release of the electronic parking brake system. The control method includes controlling voltage applied to a motor to a first duty ratio upon release of the electronic parking brake system, controlling the voltage applied to the motor to a second duty ratio greater than the first duty ratio if locking of the motor occurs and the motor is not operated, and controlling the voltage applied to the motor to the first duty ratio if locking of the motor is released and the motor begins to operate, after the control of voltage to the second duty ratio.