Collision Avoidance Braking Control via Deceleration Feedback
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Solution Overview
Problem
Existing collision avoidance assist systems may perform either excessive or insufficient braking due to reliance on time to contact or relative speed alone for determining when to release braking assistance, leading to inadequate collision avoidance.
Innovation Solution
A collision avoidance assist apparatus that continuously brakes over a set time determined by the vehicle's deceleration ability, ensuring the relative speed with an object ahead reaches zero, thereby preventing excessive or insufficient braking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If braking is released after maximum contact prediction time elapses, then the system avoids excessive braking time, but insufficient braking may occur leading to collision
Solution Approach 1:
The control section continuously monitors the actual deceleration of the vehicle during braking and compares it with the predicted deceleration. Based on this feedback, the system adjusts the braking release timing to ensure sufficient braking duration while avoiding excessive braking time, thereby resolving the contradiction between time loss and collision avoidance reliability
Solution Approach 2:
The braking release condition is dynamically adjusted based on real-time vehicle deceleration characteristics rather than using a fixed time threshold. The system adapts the braking duration to actual vehicle performance, enabling optimal balance between minimizing braking time and ensuring sufficient collision avoidance
2Object-generated harmful factors
If braking is released when relative speed equals zero or distance begins to widen, then the system avoids excessive braking, but insufficient braking may occur
Solution Approach 1:
The system uses feedback from actual deceleration measurement to determine braking release timing, rather than relying solely on relative speed or distance thresholds. This ensures the braking continues long enough to be effective while stopping before excessive braking occurs
Solution Approach 2:
The braking release criterion transitions from static parameters (relative speed = 0, distance widening) to a dynamic parameter based on actual deceleration measurement, allowing the system to adapt to varying vehicle conditions and maintain optimal braking duration
3Device complexity
If braking is based only on relative speed condition, then the system simplifies control logic, but insufficient braking may occur
Solution Approach 1:
The system incorporates feedback from deceleration sensors to supplement the relative speed condition, creating a more reliable braking control without significantly increasing complexity. The braking releases only when both relative speed condition is met AND sufficient deceleration has been achieved
Solution Approach 2:
The control system integrates multiple functions: relative speed monitoring, deceleration measurement, and combined condition evaluation. This multi-functional approach ensures reliable braking sufficiency while keeping the overall control logic unified and manageable
Data Source
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AI summary
There is provided a collision avoidance assist apparatus that includes an object detection sensor 11 that detects a relative speed Vr between a vehicle and an object ahead, a brake unit 20 that brakes the vehicle so as to avoid collision with the object ahead, and a control unit 30 that sets a set braking time tbd that will be taken for the relative speed Vr to reach zero based on set deceleration dd determined depending on a braking ability of the vehicle, and controls the brake unit 20 such that the braking of the vehicle is continued over the set braking time tbd.