Electro-Mechanical Brake Control for Air Gap Response Delay
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Solution Overview
Problem
The electro-mechanical brake in existing systems experiences a delay due to an air gap, leading to a discrepancy between target and actual braking forces, causing abrupt braking and discomfort.
Innovation Solution
A control method and apparatus that measures pedal stroke values to generate a first braking force to minimize the air gap and adjust the target braking force based on hydraulic brake simulation, using a control unit to manage a motor for precise force application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a motor is used to directly drive a brake actuator in an electro-mechanical brake, then braking force control precision and responsiveness are improved, but an air gap between the friction pad and disc causes time delay and reduces actual braking responsiveness
Solution Approach 1:
The control unit performs preliminary action by generating a first braking force to minimize the air gap between the friction pad and disc before actual braking occurs. This pre-positioning of the friction pad eliminates the time delay caused by the air gap during actual braking operations.
Solution Approach 2:
The control unit continuously monitors the air gap distance and adjusts the braking force accordingly. When the air gap exceeds a reference value, the control unit generates additional braking force to reduce the gap, creating a feedback loop that maintains optimal braking readiness and eliminates response delays.
2Measurement precision
If the braking force is abruptly generated to overcome the error between target braking force and actual braking force, then braking force accuracy is improved, but an impact occurs in the vehicle causing uncomfortable braking
Solution Approach 1:
The control unit applies beforehand cushioning by generating a first braking force that gradually minimizes the air gap before full braking force is applied. This preliminary cushioning force prevents abrupt changes in braking force, thereby eliminating impacts and uncomfortable sensations during braking.
Solution Approach 2:
The control unit dynamically adjusts the braking force in two stages: first applying a gradual first braking force to minimize the air gap, then transitioning to the target braking force. This dynamic, multi-stage approach replaces abrupt force application with a smooth transition, eliminating vehicle impacts while maintaining braking accuracy.
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
Minimizes the sense of abrupt braking by reducing the air gap and aligning the target braking force with actual force, providing smoother and more responsive braking.
Implementation Method 1
a motor is used to directly drive a brake actuator
Implementation Method 2
a friction pad and a disc... a clamping force is formed
Data Source
AI summary
A method and apparatus for controlling an electro-mechanical brake are disclosed. An embodiment of the present disclosure provides a method for controlling an electro-mechanical brake (EMB) of a vehicle, comprising: measuring a pedal stroke value; determining whether the pedal stroke value exceeds a first threshold; in response to determining that the pedal stroke value does not exceed the first threshold, generating a first braking force for reducing an air gap of the EMB; in response to determining that the pedal stroke value exceeds the first threshold, setting a target braking force for decelerating the vehicle; and after setting the target braking force, generating a second braking force based on the target braking force, wherein a magnitude of the first braking force is determined based on an increase rate of the pedal stroke value over time, and wherein the target braking force is proportional to the pedal stroke value.