Electronic Parking Brake Duty Control for Wheel Slip Stability
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Solution Overview
Problem
Existing electronic brake systems without torque sensors experience large brake torque variations (BTV) during emergency braking, leading to increased wheel slip and decreased deceleration, which can cause vehicles to spin or fail to stop within a short distance.
Innovation Solution
A sensor system detects wheel speeds and deceleration to calculate wheel slip rate, adjusting the duty ratio of the parking brake application based on deceleration and slip rate to stabilize brake control during emergency braking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If emergency braking is performed in an electronic brake system without a torque sensor, then the braking response is fast, but large brake torque variation occurs causing wheel slip and vehicle spin
Solution Approach 1:
The control apparatus continuously monitors wheel speeds of front and rear wheels, calculates wheel slip rates in real-time, and uses this feedback to dynamically adjust the parking brake duty ratio. This closed-loop feedback mechanism prevents wheel slip and maintains stable brake control during emergency braking without requiring a torque sensor.
Solution Approach 2:
The system dynamically adjusts the parking brake duty ratio based on real-time wheel slip rate calculations. Rather than using a fixed braking force, the duty ratio is modulated according to the calculated slip rate, creating a dynamic braking control that adapts to changing wheel conditions and prevents wheel lockup.
2Speed
If feedback control is performed using large brake torque variation, then the control system responds quickly, but the amplitude increases causing decreased deceleration and increased stopping distance
Solution Approach 1:
The system changes the duty ratio parameter of the parking brake based on the calculated wheel slip rate. By modulating this parameter dynamically, the system optimizes the braking force to maintain effective deceleration while preventing wheel slip that would reduce stopping efficiency.
3Productivity
If the parking brake is applied with high duty ratio to achieve short stopping distance, then the stopping distance is reduced, but wheel lockup occurs causing vehicle spin
Solution Approach 1:
The system uses real-time wheel speed feedback to detect wheel slip conditions and adjusts the parking brake duty ratio accordingly. This feedback control prevents wheel lockup that would cause vehicle spin while maintaining effective braking force for short stopping distance.
Solution Approach 2:
The system applies partial braking force through duty ratio modulation rather than full brake application. By using controlled partial action based on wheel slip rate, the system achieves effective stopping while preventing the excessive braking force that would cause wheel lockup and vehicle instability.
Data Source
AI summary
An apparatus and method for controlling electronic brake of a vehicle is disclosed. The apparatus for controlling electronic brake of a vehicle according to an aspect of the present disclosure includes a sensor that detects a deceleration corresponding to a wheel speed of a front wheel and a rear wheel of the vehicle or driver's brake power, and a processor that slows down a parking brake application by determining a wheel slip rate based on the wheel speed of the front wheel and the wheel speed of the rear wheel, and by adjusting a first duty ratio of the parking brake application within the deceleration change section based on the determined wheel slip rate and the detected deceleration.