Electro-Mechanical Brake Control for Sensorless Braking Force Estimation
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Solution Overview
Problem
Existing electro-mechanical brakes without braking force sensors face challenges in accurately estimating braking force, especially when brake pad wear occurs, affecting safety and requiring frequent calibration.
Innovation Solution
The electro-mechanical brake employs a control unit to detect the contact point between the piston and brake pad and generate a second force map based on changing stiffness, allowing for accurate braking force estimation without a braking force sensor, using a series of current commands to position the piston and correct stiffness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a braking force sensor is used to measure braking force, then measurement accuracy is improved, but device cost and complexity increase
Solution Approach 1:
The patent extracts the measurement function from a dedicated braking force sensor and relocates it to the motor controller by utilizing existing motor current detection capabilities. The controller estimates braking force by detecting motor current during regenerative braking, eliminating the need for a separate expensive braking force sensor while maintaining measurement accuracy.
Solution Approach 2:
The motor controller is designed to perform multiple functions: it controls motor operation during propulsion and simultaneously measures braking force during regenerative braking using the same current detection hardware. This multi-functional approach eliminates the need for dedicated sensing equipment for braking force measurement.
2Measurement precision
If calibration is performed frequently to account for brake pad wear, then braking force estimation accuracy is improved, but loss of time increases
Solution Approach 1:
The system performs preliminary calibration by detecting the contact point between the brake pad and rotor before normal operation begins. This preliminary action establishes baseline parameters that are then used for continuous braking force estimation without requiring frequent recalibration, reducing time loss while maintaining accuracy.
Solution Approach 2:
The system continuously monitors motor current and compares it against stored calibration data to estimate braking force in real-time. This feedback mechanism allows the system to adapt to brake pad wear progressively rather than requiring periodic complete recalibration, reducing the frequency and duration of calibration interruptions.
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
This method enables quick and accurate estimation of braking force, ensuring safety by accurately detecting the contact point and correcting stiffness, even with worn brake pads, without the need for a braking force sensor, thus enhancing operational efficiency and safety.
Implementation Method 1
a motor to move the piston forward or backward
Implementation Method 2
a piston to press the brake pad against a rotor
Implementation Method 3
the brake pad against a rotor
Data Source
AI summary
An electro-mechanical brake including: a wheel disc; a brake pad configured to press the wheel disc; a piston configured to press the brake pad; a motor configured to move the piston forward or backward when a current is applied; and a control unit configured to apply a current to the motor, detect a contact point on the basis of a position of the piston when forward movement of the piston due to the current ends, and estimate braking force corresponding to the position of the piston on the basis of the position of the piston, wherein the contact point is a position of the piston when the piston starts to move forward due to the motor and the piston and the brake pad start to come into contact with each other.