Vehicle Braking Apparatus Piston Position Initialization
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Solution Overview
Problem
Conventional vehicle braking systems face issues with misjudgment and failure to provide necessary braking force when the piston position is not initialized correctly, leading to abnormal actuator determination and insufficient braking force generation.
Innovation Solution
A braking apparatus and method that utilize a controller to determine if the piston has reached its end point by analyzing the rate of change in its position and motor current, setting the piston displacement as maximum when initialization is incomplete, and performing backward pressure control to ensure accurate positioning and prevent misjudgment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the piston position is not initialized correctly before braking, then the system can still generate braking force based on driver input, but the piston may not reach the correct direction change displacement leading to actuator misjudgment and failure to provide necessary braking force
Solution Approach 1:
The system performs preliminary piston position initialization by detecting the end point position before normal braking operation. The controller moves the piston to identify the end point (maximum displacement position) and stores this information for subsequent braking operations, ensuring accurate position measurement from the start of braking.
Solution Approach 2:
The system uses feedback from motor current and piston position rate of change to detect when the piston reaches the end point. The controller continuously monitors these parameters during piston movement and uses the feedback signal to determine the end point position, enabling accurate position measurement without requiring pre-initialization.
2Measurement precision
If the system continuously monitors piston position and motor current to detect end point, then accurate position determination is achieved, but the control complexity and computational load increase
Solution Approach 1:
The system uses the existing motor and its current characteristics to perform both the positioning function and the position detection function. The motor serves itself by providing the current signal that the controller uses to detect the end point, eliminating the need for separate sensors or complex measurement systems.
Solution Approach 2:
The system detects the end point by monitoring changes in motor current and piston position rate of change parameters. When these parameters reach specific thresholds or exhibit characteristic patterns, the controller identifies the end point, providing accurate detection through parameter analysis rather than complex hardware.
3Speed
If the piston starts moving from a middle position rather than the starting position, then the system can respond quickly to braking input, but the piston does not reach the direction change displacement and braking force is insufficient
Solution Approach 1:
The system performs preliminary detection of the end point position and calculates the correct displacement required to reach the direction change point. This preliminary information allows the controller to adjust the piston movement profile, ensuring the piston reaches the correct position even when starting from a middle position, thereby maintaining sufficient braking force.
Solution Approach 2:
The system dynamically adjusts the piston control based on the detected end point position and the current piston position. The controller calculates the required displacement in real-time and adjusts the motor control accordingly, enabling the piston to reach the correct direction change displacement regardless of the starting position, thus maintaining both response speed and braking force sufficiency.
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 ensures smooth control and accurate determination of piston position, preventing actuator failure and providing the necessary braking force based on the driver's intention, thereby enhancing braking system stability and robustness in failure diagnosis.
Implementation Method 1
a motor that controls pressure transmitted to a wheel brake side by moving a piston included in a master cylinder
Implementation Method 2
a conventional braking apparatus for a vehicle increases a pedal operating force of a driver through a booster using a hydraulic system, and provides the pedal operating force to a master cylinder, and generate a braking force by transmitting, to a wheel cylinder of each wheel, braking pressure formed by the master cylinder
Data Source
AI summary
A braking apparatus for a vehicle and a method for controlling the same. The braking apparatus includes a master cylinder configured to form braking pressure based on an input to a brake pedal and transmit the braking pressure to a wheel brake side, a motor configured to control the pressure transmitted to the wheel brake side by moving a piston included in the master cylinder, and a controller configured to control the motor. The controller determines whether the piston reaches an end point of travel, based on a rate of change in a position of the piston and a current of the motor, and sets a displacement of the piston as a maximum displacement when it is determined that the piston has reached the end point and position initialization for the piston has been completed.