Roundabout Speed Control With Curvature-Based Entry Deceleration
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Solution Overview
Problem
Existing vehicle speed control methods do not effectively manage vehicle speed when entering a roundabout, as they exclude positions with significant changes in radius of curvature, leading to inadequate control during entry.
Innovation Solution
A vehicle speed control method that calculates a first vehicle speed based on roundabout curvature information, adjusts speed to a lower entry speed when entering the roundabout, and then returns to the initial speed after entry, using a combination of sensors and an Electronic Control Unit (ECU) to control powertrain, transmission, and brake actuator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If positions with significant changes in radius of curvature are excluded from calculation, then calculation accuracy is improved, but vehicle speed control capability at roundabout entry is worsened
Solution Approach 1:
The patent divides the roundabout entry process into two distinct phases: (1) entry phase where the vehicle approaches and enters the roundabout, requiring speed reduction to a second vehicle speed; and (2) traversal phase where the vehicle moves through the roundabout, requiring speed adjustment to a first vehicle speed based on curvature calculations. This segmentation allows the system to apply different control strategies for different phases, resolving the contradiction between excluding problematic positions for accuracy and including them for control capability.
Solution Approach 2:
The patent implements preliminary speed reduction before the vehicle actually enters the roundabout by detecting the entrance position and reducing speed to a second vehicle speed (lower than the first) in advance. This preliminary action ensures the vehicle is at an appropriate speed before encountering the curvature calculation challenges at the entrance, thereby maintaining both calculation accuracy and control capability.
2Device complexity
If a single vehicle speed is calculated based on curvature information, then control simplicity is improved, but adaptability to different driving phases is worsened
Solution Approach 1:
The patent implements a dynamic vehicle speed control system that adjusts the target vehicle speed based on the detected driving phase. The system transitions from a static single-speed approach to a dynamic two-speed approach: using a first vehicle speed during roundabout traversal and a second (lower) vehicle speed during entry. This dynamic adaptation allows the system to handle different phases appropriately while maintaining relatively simple control logic through phase detection.
Data Source
AI summary
A vehicle speed control method includes: a calculation step of calculating a first vehicle speed when a vehicle moves in a roundabout, on the basis of curvature information indicating curvature related to the roundabout; a first control step of bringing a vehicle speed of the vehicle close to a second vehicle speed that is lower than the first vehicle speed, when the vehicle enters the roundabout; and a second control step of bringing the vehicle speed of the vehicle close to the first vehicle speed, after the vehicle enters the roundabout.