Electro-Mechanical Brake Current Limiting for Smooth Clamping
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Solution Overview
Problem
The electro-mechanical brake apparatus experiences sudden clamping force generation and associated shock and noise during braking due to air gaps and rapid current fluctuations in the motor.
Innovation Solution
A method and apparatus for controlling the electro-mechanical brake that includes a current sensor and a motor rotation angle sensor, allowing for the generation of a clamping force feedback, measurement of piston stroke, and variable limiting of motor current to prevent sudden clamping force and reduce noise and shock.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an air gap is maintained between the pressing unit and brake disc to prevent friction pad wear and overheating, then the friction pad is protected from wearing and overheating when braking is not performed, but sudden clamping force is generated when the piston stroke passes the air gap section, causing shock and noise
Solution Approach 1:
The controller performs preliminary action by detecting when the piston stroke is about to pass the air gap section and applies a current limit to the motor in advance. This prevents sudden clamping force generation when the piston contacts the brake disc, thereby eliminating shock and noise while maintaining the protective air gap during non-braking conditions
2Speed
If rapid current fluctuation is applied to the motor to overcome temporal error between control command and response, then the temporal error is reduced, but shock and noise are generated due to rapid change in electrical resistance and magnetic resistance of the motor
Solution Approach 1:
The system dynamically adjusts the current limit applied to the motor based on the real-time piston stroke position. By making the current limit variable rather than fixed, the system achieves rapid response when needed while preventing harmful current fluctuations that cause shock and noise, thus resolving the contradiction between response speed and harmful factors
3Speed
If target clamping force is generated immediately when braking is commanded, then braking responsiveness is improved, but sudden clamping force generation occurs at the braking start stage due to air gap closure
Solution Approach 1:
The controller uses feedback from the piston stroke detection to dynamically control the motor current. By continuously monitoring the piston position and adjusting the current limit accordingly, the system achieves responsive braking while preventing sudden clamping force generation, thus resolving the contradiction between braking responsiveness and harmful factors
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables improved force responsiveness without sudden clamping force at the braking start stage, reduces shock and noise by limiting rapid current fluctuations, and enhances the overall quality of the electro-mechanical brake apparatus.
Implementation Method 1
The electro-mechanical brake apparatus uses a motor to generate the clamping force corresponding to the target clamping force
Implementation Method 2
A method and apparatus for controlling the electro-mechanical brake that includes a current sensor and a motor rotation angle sensor
Implementation Method 3
The vehicle braking apparatus uses friction force to perform a braking operation
Data Source
AI summary
An electro-mechanical brake control method and apparatus are disclosed. An embodiment of the present disclosure provides a method of controlling an electro-mechanical brake(EMB), using a controller, wherein the electro-mechanical brake includes a current sensor and a motor rotation angle sensor, the method comprising: receiving a target clamping force generated based on a pedal stroke value; generating a clamping force feedback in response to the target clamping force and calculating a force error by comparing the clamping force feedback with the target clamping force; measuring an stroke of a piston using the motor rotation angle sensor; controlling the motor so that the stroke of the piston is located at a contact point by applying a current to the motor; and controlling the electro-mechanical brake for reducing noise and shock generated in the electro-mechanical brake by variably limiting a maximum or minimum amount of current applied to the motor based on the stroke of the piston.