Vehicular Deceleration Control via Yaw Rate and Navigation Comparison
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Solution Overview
Problem
Existing vehicular running control systems face challenges in smoothly navigating curved roads, as they often result in abrupt acceleration or deceleration, leading to an unpleasant driving experience due to discrepancies between navigation information and actual road conditions.
Innovation Solution
A vehicular running control apparatus and method that includes a curved road detecting section, target vehicle speed calculating section, navigation target deceleration calculating section, yaw rate detecting section, and target deceleration selecting section, which calculate and compare navigation and yaw rate target decelerations to determine the optimal deceleration for smooth passage through curved roads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If navigation information is used to calculate target deceleration, then the vehicle can plan ahead for curved roads, but abrupt deceleration occurs when navigation information does not match actual road conditions
Solution Approach 1:
The system continuously monitors actual yaw rate and compares it with the yaw rate corresponding to the target vehicle speed from navigation information. This feedback mechanism allows the system to detect discrepancies between planned and actual road conditions, triggering corrective action by switching to actual road condition-based deceleration calculation when mismatch is detected.
Solution Approach 2:
The deceleration calculation method dynamically switches between two modes: navigation-information-based planning (for normal conditions) and actual-road-condition-based adjustment (when mismatch is detected). This dynamic adaptation allows the system to maintain both advance planning capability and responsiveness to actual conditions, preventing abrupt deceleration.
2Reliability
If target vehicle speed is calculated based on curved road state from navigation information, then vehicle can maintain safe speed, but smooth passage is compromised when navigation information is inaccurate
Solution Approach 1:
The system uses yaw rate feedback to continuously verify whether the vehicle is actually experiencing the curved road conditions predicted by navigation information. When the actual yaw rate matches the expected yaw rate (within a predetermined range), the navigation-based target speed is maintained. When mismatch occurs, the system switches to calculating target speed based on actual road conditions, ensuring both safety and smooth passage.
Solution Approach 2:
The system performs preliminary deceleration planning based on navigation information before entering curved roads. However, it prepares a backup calculation method based on actual road conditions that can be activated when the preliminary plan becomes inaccurate, ensuring continuous safe and smooth operation.
3Loss of time
If deceleration is calculated solely from navigation information, then advance deceleration planning is possible, but responsiveness to actual road conditions is reduced
Solution Approach 1:
The system uses yaw rate as a feedback parameter to continuously monitor actual road conditions. The detected yaw rate is compared with the yaw rate corresponding to the target vehicle speed from navigation information. This comparison provides real-time verification of road condition accuracy, allowing the system to switch calculation methods when discrepancy exceeds a predetermined range.
Solution Approach 2:
The deceleration calculation system serves multiple functions: it can operate in navigation-information-based mode for advance planning, and switch to actual-road-condition-based mode for precise responsiveness. This multi-functionality allows the single system to handle both advance planning and real-time accuracy requirements.
Data Source
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AI summary
In vehicular running apparatus and method, a yaw rate target deceleration calculated on a basis of a yaw rate and a preset lateral acceleration set value is compared with a navigation target deceleration calculated on a basis of a target vehicle speed calculated on a basis of a state of a curved road located in front of a running road on which the vehicle is running and the preset lateral acceleration to select a target deceleration from one of the yaw rate and navigation target decelerations which is lower than the other and a target vehicle speed command value is calculated on a basis of the selected target deceleration, the calculated vehicle speed command value being outputted to decelerating means of the vehicle.