Electronic Brake System Ball Screw Control for Kick-Back Prevention
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Solution Overview
Problem
In electronic brake systems with an electrically-driven booster, the kick-back phenomenon occurs during ABS mode, causing pulsation in the brake pedal due to irregular pressure fluctuations in the master cylinder, leading to an unpleasant driving experience.
Innovation Solution
An electronic brake system with a control method that uses sensors to monitor the isolation gap between the input and output rods and an electronic control unit to stop the backward movement of the ball screw before collision, thereby preventing the output rod from colliding with the input rod, thus maintaining stable pressure and reducing kick-back.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If the ball screw is moved backward to decrease master cylinder pressure in ABS mode, then the pressure control function is improved, but the output rod collides with the input rod causing kick-back phenomenon
Solution Approach 1:
The electronic control unit performs preliminary action by stopping the ball screw's backward movement before the output rod collides with the input rod. This is achieved by monitoring the position of the ball screw and the isolation gap, and issuing a stop command in advance to prevent the harmful collision while still achieving pressure reduction
Solution Approach 2:
The system uses feedback control by continuously monitoring the position of the ball screw and the isolation gap between the input and output rods. The electronic control unit adjusts the ball screw movement based on real-time position feedback to stop before collision occurs, preventing the kick-back phenomenon while maintaining pressure control
2Object-affected harmful factors
If the isolation gap is reduced to prevent collision, then the kick-back phenomenon is prevented, but the pressure adjustment range is limited
Solution Approach 1:
The system dynamically adjusts the ball screw movement based on real-time conditions. The electronic control unit calculates the remaining isolation gap and determines the appropriate stop position dynamically, allowing maximum pressure adjustment range while preventing collision. The control parameter is adjusted based on the current position and gap size
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
Prevents the kick-back phenomenon by controlling the ball screw's movement, enhancing ride comfort and driving stability by avoiding collisions between the output and input rods, thereby maintaining consistent brake pedal pressure.
Implementation Method 1
a ball screw to move the output rod, and a motion converting unit to move the ball screw forward and backward by converting rotational movement of the motor into linear movement of the ball screw
Implementation Method 2
a master cylinder including a piston to generate hydraulic pressure by applying pressure to brake oil
Data Source
AI summary
Disclosed are an electronic brake system and a control method thereof. The electronic brake system includes a master cylinder including a piston, an output rod contacting the piston, an input rod configured to be moved forward by a driver's manipulation of a brake pedal and arranged coaxially to the master cylinder and spaced a predetermined isolation gap apart from the output rod, an electrically-driven booster including a motor, a ball screw to move the output rod, and a motion converting unit to move the ball screw forward and backward by converting rotational movement of the motor into linear movement, and an electronic control unit (ECU) to control operation of the motor based on the size of the isolation gap. When the ball screw is moved backward in an ABS mode, the ECU stops backward-movement of the ball screw before the output rod collides with the input rod.