Electro-Mechanical Brake Calibration Without Clamping Force Sensors
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Solution Overview
Problem
Existing electro-mechanical brake systems lack effective methods for calibrating braking parameters due to friction pad wear or thermal deformation during vehicle operation without relying on expensive and space-consuming force sensors, leading to reduced reliability and stability.
Innovation Solution
A calibration method using a main controller to determine vehicle states and generate commands for calibrating parameters related to friction pad wear or thermal deformation, employing torque blending, contact point measurement, and error correction without a force sensor, ensuring high reliability and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a force sensor is used to measure actual clamping force for calibration, then measurement accuracy is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts and removes the force sensor from the brake apparatus, eliminating the complex measurement component while maintaining calibration capability through alternative means (motor current and rotation angle measurements)
Solution Approach 2:
The patent replaces the mechanical force sensor measurement system with an electrical measurement system that uses motor current and rotation angle sensors to infer clamping force, thereby simplifying the mechanical structure
2Reliability
If calibration is performed only during initialization, then device complexity is reduced, but reliability deteriorates due to inability to compensate for wear and thermal deformation during operation
Solution Approach 1:
The patent enables continuous calibration capability during vehicle operation by utilizing the motor's existing sensors (current and rotation angle) to perform calibration at any time, not just during initialization, ensuring ongoing compensation for friction pad wear and thermal deformation
Solution Approach 2:
The calibration system uses the motor's own operational parameters (current and rotation angle) to perform self-calibration, eliminating the need for external force sensors or complex additional calibration equipment
3Reliability
If motor pressing/reducing is performed during driving to collect calibration data, then calibration capability is improved, but driving safety deteriorates due to potential conflict with driver's braking intentions
Solution Approach 1:
The patent performs calibration using partial motor operations (pressing and reducing) that are sufficient to collect necessary calibration data without fully engaging the braking system, thereby minimizing impact on driver's perceived driving experience while maintaining calibration accuracy
Data Source
AI summary
A method comprising: determining whether a state of the vehicle is a non-braking state and a non-accelerating state; in response to determining that a state of the vehicle is a braking state or an accelerating state, generating and transmitting, to the EMB, a calibration stop command; in response to determining that the state of the vehicle is the non-braking state and the non-accelerating state, determining whether it is necessary to calibrate the parameter; in response to (1) determining that it is necessary to calibrate the parameter or (2) receiving a calibration request signal from an EMB controller, generating and transmitting, to the EMB, a calibration start command; and in response to (1) determining that it is not necessary to calibrate the parameter and (2) not receiving the calibration request signal from the EMB controller, generating and transmitting, to the EMB, the calibration stop command.