Vehicle Brake Torque Control for Smooth Stops Within Target Distance
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Solution Overview
Problem
Existing brake control systems for vehicles fail to smoothly stop a vehicle while considering jerk without increasing the stop distance, which affects the braking feeling for occupants.
Innovation Solution
A brake control apparatus that adjusts braking torque based on a target deceleration profile with an upwardly curving and downwardly curving characteristic, ensuring the estimated stop distance is equal to or less than the requested stop distance, thereby avoiding increased stop distance and providing a smooth braking experience.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the vehicle is stopped by simply curbing the fluctuation component vibrating due to pitching, then the stop distance can be controlled, but the braking feeling for occupants deteriorates due to high jerk
Solution Approach 1:
The patent applies parameter changes by modifying the deceleration profile parameters (curvature characteristics) to simultaneously achieve smooth braking feeling and accurate stop distance control. The upwardly and downwardly curving characteristics of the deceleration profile adjust the rate of change of deceleration, reducing jerk while maintaining stop precision
Solution Approach 2:
The patent implements dynamics by transitioning from static deceleration control to dynamic profile-based control. The deceleration profile with upwardly and downwardly curving characteristics dynamically adjusts the deceleration rate over time, creating a smooth braking experience while achieving the target stop distance
2Ease of operation
If a standard deceleration profile is used to provide smooth braking feeling, then the braking comfort improves, but the stop distance may exceed the requested stop distance
Solution Approach 1:
The patent modifies the deceleration profile parameters (curvature and timing) to balance comfort and stop distance. By adjusting the upwardly and downwardly curving characteristics, the system optimizes the trade-off between smooth braking feeling and achieving the requested stop distance
Solution Approach 2:
The patent employs feedback control by comparing the estimated stop distance with the requested stop distance and adjusting the deceleration profile accordingly. This ensures that the vehicle stops at or before the requested position while maintaining smooth braking characteristics
Data Source
AI summary
Braking torque is automatically applied based on requested deceleration and requested distance from a driving assistance device. Standard deceleration decreases in an “upwardly curved” form and then decreases in a “downwardly curved” form over time in a standard deceleration profile, and a standard speed profile corresponds to the standard deceleration profile. In the present calculation period, target deceleration and target speed profiles are set by adjusting the standard deceleration/standard speed profiles to satisfy the relationship between deceleration and vehicle body speed. The estimated distance from the reference speed to the vehicle stop is calculated based on the target speed profile. In a condition that the estimated distance is equal to/less than the requested distance is denied, braking torque is adjusted based on requested deceleration. After first satisfying the condition that the estimated distance is equal to/less than the requested distance, braking torque is adjusted according to the target deceleration profile.