Electronic Parking Brake Inrush Current Modeling for Clamping Force Estimation
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Solution Overview
Problem
Existing electronic parking brake systems face challenges in accurately estimating inrush currents during motor operation, leading to misdiagnosis of clamping force and actuator malfunctions due to the inability to distinguish between inrush currents and actual driving currents.
Innovation Solution
An electronic parking brake system that models and removes inrush currents by calculating an Nth order function based on repeated measurements of inrush currents in no-load conditions, allowing for precise estimation of clamping force and actuator performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If inrush current is not distinguished from driving current, then the system can operate continuously, but measurement precision of clamping force deteriorates
Solution Approach 1:
The current signal is segmented into inrush current component and driving current component. The controller separates these components by comparing the detected current with the modeled inrush current, allowing independent analysis of each component to achieve precise clamping force measurement while maintaining continuous operation
Solution Approach 2:
An inrush current model serves as an intermediary between the raw current detection and clamping force calculation. This model acts as a mediator that filters out the inrush current effect, enabling accurate clamping force measurement without interrupting system operation
2Device complexity
If inrush current is not removed from current signal, then the system structure remains simple, but measurement precision of motor state deteriorates
Solution Approach 1:
The system performs self-service by using its own current detection capability to generate the inrush current model internally. The controller utilizes the detected current data to build and update the inrush current model, eliminating the need for external sophisticated filtering devices while achieving precise motor state measurement
3Measurement precision
If inrush current model is calculated based on repeated measurements, then measurement precision of inrush current improves, but loss of time increases
Solution Approach 1:
The inrush current model is built in advance during system initialization or idle periods using repeated measurements. By performing this time-consuming modeling action preliminarily, the system achieves high measurement precision without incurring time loss during critical braking operations
Solution Approach 2:
The system performs repeated current measurements at periodic intervals to build the inrush current model. This periodic sampling approach captures the inrush current characteristics efficiently, achieving accurate modeling while minimizing total measurement time through optimized sampling frequency
Data Source
AI summary
The present disclosure relates to an electronic parking brake system and a control method thereof. The electronic parking brake system includes an electronic parking brake that includes an electronic parking brake actuator applied by a motor. The electronic parking brake system includes a current sensor configured to detect a current flowing in the motor. The electronic parking brake system includes a processor configured to control a parking apply operation of the electronic parking brake. The electronic parking brake system includes a memory configured to store an inrush current generated during the parking apply operation of the electronic parking brake in a no-load condition. The processor calculates an inrush current model based on the inrush current and may accurately estimate and remove the inrush current generated during the parking apply operation by modeling the inrush current when there is no external load.