Electro-Mechanical Brake Wear Compensation for Precise Clamping Force
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Solution Overview
Problem
Conventional electric brake devices struggle with precise clamping force control due to friction pad wear during vehicle travel, leading to inaccurate compensation for the movement of the contact point between the friction pad and brake disc.
Innovation Solution
An electric brake device and control method that utilizes a current sensor and motor rotation angle sensor to measure actual motor current and stroke, determining friction pad wear and compensating for it by calculating a target stroke for each wheel, thereby improving clamping force control precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a force sensor is mounted on the EMB to detect actual clamping force, then measurement precision of clamping force is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent replaces the mechanical force sensor mounting structure with an electrical measurement approach. Instead of physically mounting a force sensor on the EMB caliper housing, the system uses existing electrical sensors (current sensor and motor rotation angle sensor) to indirectly measure clamping force through motor current and stroke calculations, thereby eliminating the complex mechanical mounting structure while maintaining measurement capability
Solution Approach 2:
The patent introduces motor current and motor rotation angle as intermediary parameters to indirectly represent clamping force. Rather than directly measuring clamping force with a force sensor, the system uses motor current and stroke (from rotation angle) as mediators to calculate and infer the actual clamping force, simplifying the overall measurement system
2Manufacturing precision
If reference data is collected at initialization to compensate for contact point movement, then manufacturing precision is improved, but reliability during vehicle travel deteriorates
Solution Approach 1:
The patent implements a feedback mechanism that continuously monitors motor current and motor rotation angle during vehicle travel, compares actual values with reference data, and dynamically compensates for friction pad wear. This continuous feedback loop maintains reliability by adapting to real-time wear conditions rather than relying solely on static initialization data
Solution Approach 2:
The patent collects reference data during initialization as a preliminary action, but enhances it by enabling continuous wear compensation during operation. The reference data serves as a baseline, and the system performs preliminary compensation calculations continuously during travel to maintain accuracy as friction pads wear
3Manufacturing precision
If friction pad wear compensation is performed continuously during vehicle travel, then clamping force control precision is improved, but use of energy increases
Solution Approach 1:
The patent implements a self-service wear compensation system that automatically monitors motor current and rotation angle, detects friction pad wear, and adjusts control parameters without requiring external intervention or additional heavy-duty sensors. The system uses the existing motor control sensors to self-diagnose and self-correct, minimizing additional energy consumption
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
Enhances the precision and quality of clamping force control by accurately accounting for friction pad wear, ensuring consistent braking performance.
Implementation Method 1
generating an actual motor current of each wheel and an actual stroke of each wheel by collecting a voltage signal from a current sensor
Implementation Method 2
a motor rotation angle sensor mounted on the electro-mechanical brake to detect a rotation angle of the motor and output a rotation angle signal
Implementation Method 3
a friction pad configured to press a brake disc of each wheel; a pressing unit configured to generate a clamping force by pressing the friction pad against the brake disc
Data Source
AI summary
The present disclosure provides an electric brake apparatus having an electro-mechanical brake disposed in each wheel of a vehicle and configured to perform braking control of the vehicle, the electric brake apparatus including a friction pad configured to press a brake disc of each wheel; a pressing unit configured to generate a clamping force by pressing the friction pad against the brake disc; a motor configured to generate a rotational force and transmit the rotational force to the pressing unit; a current sensor mounted on the electro-mechanical brake to measure current flowing through the motor; a motor rotation angle sensor mounted on the electro-mechanical brake to detect a rotation angle of the motor and output a rotation angle signal; and a main controller configured to calculate an actual motor current based on a voltage signal input from the current sensor, calculate an actual stroke using the rotation angle signal input from the motor rotation angle sensor, determine whether or not the friction pad is worn using the actual motor current and the actual stroke, calculate an amount of friction pad wear when determination is made that the friction pad is worn, calculate a target stroke using the amount of friction pad wear, and perform the braking control of the vehicle based on the target stroke.