Vehicle Braking Control Apparatus Dynamic Deceleration
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Solution Overview
Problem
Existing vehicle braking systems often fail to allow the driver of a following vehicle to perform appropriate operations when a lead vehicle executes automatic braking to avoid an obstacle, as the braking behavior can be unpredictable and may not account for the driver's ability to respond effectively.
Innovation Solution
A vehicle braking control apparatus that includes an obstacle detection unit and an electronic control unit to automatically generate a braking force based on detected distance and relative speed, with the deceleration amount increasing over time to ensure the driver of a following vehicle can safely respond to the lead vehicle's braking actions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the vehicle executes automatic braking with a high deceleration amount to avoid collision, then the collision avoidance effectiveness is improved, but the driver of a following vehicle cannot perform appropriate driving operations
Solution Approach 1:
The patent applies dynamics by making the upper-limit deceleration amount variable rather than fixed. The control unit adjusts the upper-limit deceleration amount based on elapsed time since braking start, increasing it after a predetermined first time period. This dynamic adjustment allows the braking force to be manageable initially while achieving effective collision avoidance over time, resolving the contradiction between high deceleration effectiveness and driver response capability.
Solution Approach 2:
The patent changes the parameter of deceleration amount over time. By setting the upper-limit deceleration amount to increase with elapsed time, the system transforms a static braking parameter into a dynamic one. This parameter change enables the braking force to start at a manageable level for following drivers while progressively increasing to achieve effective collision avoidance, thus resolving the technical contradiction.
2Loss of time
If the braking force is increased immediately to avoid collision, then the response time is reduced, but the following vehicle driver cannot react appropriately
Solution Approach 1:
The patent applies preliminary action by setting an initial upper-limit deceleration amount during a first predetermined time period that is lower than subsequent limits. This preliminary, more conservative braking phase allows following drivers time to react and perceive the lead vehicle's braking action, while still initiating the collision avoidance process. The braking force is not immediately maximized but starts at a manageable level.
Solution Approach 2:
The system dynamically adjusts the braking characteristics over time. The upper-limit deceleration amount is not fixed but changes based on elapsed time, transitioning from a lower initial limit to higher subsequent limits. This dynamic approach balances immediate collision avoidance needs with following driver reaction time, resolving the contradiction between rapid response and driver reactability.
3Ease of operation
If the deceleration amount is kept low to allow following drivers to respond, then driver response is improved, but collision avoidance effectiveness is reduced
Solution Approach 1:
The patent resolves this contradiction through dynamic time-based adjustment of the upper-limit deceleration amount. During the initial first predetermined time period, a lower deceleration limit protects following drivers' ability to respond. After this period expires, the upper-limit deceleration amount increases, enabling the braking force to reach levels sufficient for effective collision avoidance. This dynamic progression ensures both driver response capability and collision avoidance effectiveness are achieved at different phases.
Solution Approach 2:
The patent implements periodic action by dividing the braking process into distinct time periods. The first predetermined time period uses one deceleration limit, while subsequent periods use higher limits. This periodic structure allows the system to prioritize driver response capability initially, then transition to prioritizing collision avoidance effectiveness, thus resolving the contradiction between these two opposing requirements.
Data Source
AI summary
A vehicle braking control apparatus includes an obstacle detection unit configured to detect an obstacle ahead of a vehicle, and to detect a distance to the obstacle from the vehicle, and a relative speed of the obstacle with respect to the vehicle; an electronic control unit configured to generate a braking force of the vehicle automatically based on the distance and the relative speed, and to weaken the braking force when a value subtracting a deceleration amount of a vehicle speed of the vehicle since a start of generating the braking force, from a predetermined upper-limit deceleration amount is less than or equal to a predetermined threshold. The upper-limit deceleration amount is set to increase while an elapsed time increases since the start of generating the braking force, at least after a predetermined first time has passed since the start of generating the braking force.