Follow-Up Steering Control With Adaptive Trajectory Approximation
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Solution Overview
Problem
In follow-up steering control, short inter-vehicle distances lead to detection errors in the lateral position of the preceding vehicle, while long distances result in inaccurate movement trajectory calculations due to accumulated yaw rate errors, causing fluctuations in the instruction steering angle.
Innovation Solution
A vehicle control system that switches between trajectory follow-up and yaw angle follow-up methods based on inter-vehicle distance, road curvature, and vehicle speed, using second-order and first-order function approximations to calculate control parameters for the steering actuator, thereby stabilizing the steering instruction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the inter-vehicle distance is short, then the camera can capture more of the preceding vehicle, but the entire preceding vehicle cannot be taken by the camera causing detection error in lateral position
Solution Approach 1:
The system dynamically changes the order of approximation based on inter-vehicle distance parameter. When distance is short, it uses second-order approximation; when distance is long, it uses first-order approximation. This parameter-based switching resolves the contradiction by adapting the calculation method to the current distance condition.
2Measurement precision
If the inter-vehicle distance is long, then the camera can capture the entire preceding vehicle, but error in yaw rate detection value is accumulated making movement trajectory calculation inaccurate
Solution Approach 1:
The system changes the approximation order parameter based on inter-vehicle distance. For long distances, it switches to first-order approximation to avoid accumulating yaw rate errors over multiple integration steps, thereby maintaining trajectory calculation accuracy despite the longer distance.
3Reliability
If second-order function approximation is used for trajectory follow-up, then movement trajectory can be calculated, but instruction steering angle fluctuates due to detection errors and accumulated yaw rate errors
Solution Approach 1:
The system dynamically switches between first-order and second-order approximation methods based on real-time conditions (inter-vehicle distance, road curvature, vehicle speed). This dynamic adaptation ensures reliable and stable steering control by selecting the appropriate calculation precision for each situation, preventing fluctuations in instruction steering angle.
Solution Approach 2:
The approximation order parameter is changed based on detection error magnitude and accumulated yaw rate error. When errors are small, second-order approximation provides sufficient accuracy; when errors accumulate, the system switches to first-order approximation to maintain stability and reduce fluctuations in control parameters.
Data Source
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AI summary
The present invention provides a vehicle control device configured to obtain a distribution between first-order follow-up control and second-order follow-up control based on information on a road curvature of a road on which a preceding vehicle traveling forward of a vehicle has traveled and information on a relative position between the vehicle and the preceding vehicle, the first-order follow-up control causing the vehicle to follow the preceding vehicle through use of a first-order trajectory, the second-order follow-up control causing the vehicle to follow the preceding vehicle through use of a second-order trajectory, and to output an instruction relating to steering of the vehicle for achieving the obtained first-order follow-up control and second-order follow-up control to a steering actuator unit relating to the steering of the vehicle.