Vehicle Speed Control for Curve Negotiation
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Solution Overview
Problem
Conventional vehicle control systems fail to comprehensively assist drivers in navigating curves by not setting target vehicle speeds for safe deceleration and acceleration, leading to potential undue deceleration or lack of assistance when vehicle speed exceeds or falls below possible traveling speeds.
Innovation Solution
A vehicle control system that includes a distance obtaining means, an evaluation index calculating means, a curvature radius obtaining means, a target vehicle speed setting means, a vehicle speed obtaining means, and a vehicle control means to calculate and apply target deceleration or acceleration, ensuring the vehicle travels safely along curves by adjusting speed based on the approaching/separating state evaluation index, current speed, and curvature radius.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the vehicle speed control means automatically decelerates the vehicle when the vehicle speed V0 is larger than the possible traveling vehicle speed, then the vehicle can travel safely along the curve, but the vehicle may be unduly decelerated
Solution Approach 1:
The system calculates the possible traveling vehicle speed in advance based on curve parameters (curvature radius, gradient, allowable lateral acceleration) before the vehicle enters the curve. This preliminary calculation allows the control system to prepare appropriate speed adjustments, preventing undue deceleration by having the target speed ready before the maneuver begins.
Solution Approach 2:
The control system continuously monitors the actual vehicle speed and compares it with the calculated possible traveling vehicle speed. Based on this feedback, the system adjusts the automatic speed control to maintain the vehicle speed within the safe range without causing undue deceleration. The feedback mechanism ensures that speed adjustments are precise and tailored to actual driving conditions.
2Adaptability or versatility
If the vehicle speed control means does not automatically accelerate the vehicle when the vehicle speed V0 is smaller than the possible traveling vehicle speed, then the system remains simple, but the vehicle cannot be comprehensively assisted in drive operation
Solution Approach 1:
The vehicle speed control means is designed to perform multiple functions: it can both automatically decelerate the vehicle when speed is too high and automatically accelerate when speed is too low. This multi-functionality provides comprehensive drive assistance throughout the entire curve negotiation process, rather than only limiting speed from above.
3Ease of operation
If conventional vehicle control systems do not set target vehicle speed for automatic deceleration, then the control logic is simpler, but the vehicle may be unduly decelerated or lack comprehensive assistance
Solution Approach 1:
The system pre-calculates the possible traveling vehicle speed based on curve parameters before the vehicle enters the curve. This preliminary action provides a clear target speed that simplifies the control logic during actual curve negotiation, as the controller only needs to compare actual speed with the pre-determined target and make appropriate adjustments.
Data Source
AI summary
When a vehicle travels along a curve of a road, a target vehicle acceleration/deceleration that is used for accelerating/decelerating the vehicle to a target vehicle speed, which is set for the curve, is calculated. Based on a comparison between a present vehicle speed of the vehicle and the target vehicle speed, the vehicle is controlled such that an acceleration/deceleration of the vehicle coincides with the target vehicle acceleration/deceleration.