Vehicle Steering Control for External Force Cancellation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing driving support control systems for vehicles fail to accurately follow a target path due to external forces like crosswind, as the correlation between lateral lane position changes and external forces is not high, leading to potential vehicle drift.
Innovation Solution
A driving support control system that calculates steering angles based on the difference between target and actual lateral acceleration or yaw rate, using gain values to adjust for external forces, with guarding processes to prevent excessive steering and acceleration limiting to enhance controllability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a rate of change in lateral lane position is used for disturbance correction, then the control system can respond to lateral movements, but the external force acting on the vehicle cannot be accurately identified leading to path following errors
Solution Approach 1:
The control device calculates a difference value between the actual vehicle motion parameter (lateral acceleration or yaw rate) and the target value, then uses this feedback to calculate a second steering angle that cancels out external forces. This closed-loop feedback mechanism enables accurate identification and compensation of external disturbances, resolving the contradiction between measurement capability and path following reliability.
Solution Approach 2:
The patent replaces the mechanical/geometric approach of using lateral lane position changes with a dynamic parameter approach using lateral acceleration or yaw rate. This substitution allows the system to directly measure the vehicle's dynamic response to external forces, significantly improving the accuracy of external force detection and subsequent path following performance.
2Reliability
If steering angle is increased to cancel external force, then path following accuracy improves, but excessive steering may cause vehicle instability
Solution Approach 1:
The control device independently calculates two steering angles: a first steering angle for path following and a second steering angle for external force cancellation. By parameterizing the control into separate components, the system can precisely adjust the cancellation steering angle based on the magnitude of external forces without causing excessive steering, thus maintaining vehicle stability while improving path following accuracy.
Solution Approach 2:
The patent segments the steering control into two independent components: path following control and disturbance rejection control. This segmentation allows each component to be optimized independently, where the second steering angle for external force cancellation is calculated separately and added to the first steering angle, preventing excessive total steering input while maintaining both path accuracy and vehicle stability.
Data Source
AI summary
A driving support control system includes a steering device and a control device. The control device performs a target value calculating process of calculating a target value; a first steering angle calculating process of calculating, as a first steering angle, a steering angle for causing a vehicle motion parameter to coincide with the target value; an actual value calculating process of calculating an actual value of the vehicle motion parameter; a second steering angle calculating process of calculating, as a second steering angle, a steering angle for cancelling out an external force based on a difference value between the actual value and the target value; a target steering angle calculating process of calculating, as a target steering angle, a summed value of the first and second steering angles; and a control process of controlling the steering device so that the steering angle coincides with the target steering angle.