Vehicle Control Device Using Dynamic Acceleration Thresholds
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Solution Overview
Problem
Conventional vehicle control systems fail to adjust driving performance in real-time to match driver preference, leading to either insufficient or excessive agility shifts, and may shift modes unintentionally due to temporary acceleration or deceleration, affecting drivability and comfort.
Innovation Solution
A vehicle control system that adjusts driving modes based on a calculated index of longitudinal and lateral acceleration, shifting between a moderated and enhanced driving force mode when the acceleration index exceeds a threshold value set within the range of 3.5m/s² to 4.5m/s², allowing for a seamless transition within 500 milliseconds to align with human perception of acceleration changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the threshold value is set to a larger value, then the driving mode will not be shifted to the sporty mode unintentionally, but the driving mode will not be shifted to the sporty mode promptly
Solution Approach 1:
The patent applies parameter changes by using a time-varying threshold value that decreases over time after an acceleration event. Initially, the threshold is set high to prevent unintentional mode shifts, then gradually lowered to allow prompt mode shifting if the acceleration condition persists. This dynamic parameter adjustment resolves the contradiction between reliability and response speed.
2Speed
If the threshold value is set to a relatively smaller value, then the driving mode will be shifted to the sporty mode promptly, but the driving mode may be shifted to the sporty mode unintentionally by temporal acceleration
Solution Approach 1:
The patent applies preliminary action by setting an initial high threshold value before the acceleration event occurs. This pre-set threshold prevents unintentional mode shifts during temporary accelerations. The threshold is then adjusted based on the duration and magnitude of the acceleration, allowing prompt mode shifting only when the acceleration is sustained and significant.
3Adaptability or versatility
If the vehicle control system adjusts driving mode frequently to match driver preference, then the driving performance will be adjusted in real-time, but the driver will feel strangeness about driving performance due to excessive shifts
Solution Approach 1:
The patent applies periodic action by using time-based threshold adjustment where the threshold value changes in a structured temporal pattern after an acceleration event. The threshold starts high and decreases over defined time intervals, allowing the system to adjust driving mode only when the acceleration condition persists through multiple time periods. This periodic threshold adjustment prevents frequent unnecessary mode shifts while maintaining real-time adaptability.
Data Source
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AI summary
A vehicle control system for adjusting control characteristics governing behaviors of a vehicle in accordance with a driving preference of a driver. The vehicle control system is comprised of a shifting means that shifts a driving mode of the vehicle between a first mode in which a driving force to be generated is moderated and a second mode in which a driving force to be generated is larger than that generated under the first mode, upon exceedance of a predetermined threshold value by an index that is changed according to a change in a behavior of the vehicle resulting from an accelerating or a decelerating operation executed by the driver. The threshold value is set to a limit value of acceleration for human beings to sense a linear change in the acceleration from zero.