Rear Wheel Steering Control Priority Management
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Solution Overview
Problem
Existing vehicle steering control systems face challenges in optimizing vehicle behavior when multiple rear wheel steering controls interfere with each other, leading to unstable vehicle behavior and neglect of the driver's intention, as they prioritize one control over the others.
Innovation Solution
A vehicle steering control apparatus that sets and manages two target steering angles for the rear wheels independently - one based on the driver's intention and the other for automatic stabilization, allowing for continuous limitation of interference between them to prioritize stable vehicle behavior and reflect the driver's input effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the control of the rear wheel steering ratio in the normal region is always prioritized, then the driver's steering intention is reflected, but the vehicle behavior stability during automatic steering intervention deteriorates
Solution Approach 1:
The patent applies dynamics by making the priority between driver steering and automatic steering adjustable rather than fixed. The controlling device dynamically switches priority based on operational conditions - during normal steering the driver's intention is prioritized, but during automatic steering intervention the automatic control is prioritized. This dynamic adjustment resolves the contradiction by allowing the system to adapt to different operational states.
Solution Approach 2:
The patent changes the control parameter priority state based on operational conditions. When automatic steering intervention is detected, the system changes the priority parameter to favor automatic control; otherwise, it maintains driver steering priority. This parameter change approach allows the system to optimize vehicle behavior stability when needed while preserving driver intent under normal conditions.
2Stability of the object's composition
If the rear wheel steering ratio control is limited to avoid interference with behavior stabilization control, then vehicle behavior stability is improved, but the driver's steering intention is neglected
Solution Approach 1:
The system dynamically adjusts the degree of limitation on rear wheel steering ratio control based on whether automatic steering intervention is active. During normal operation, the driver's steering intention is fully reflected without limitation. During automatic steering intervention, the limitation is applied to prevent interference with stabilization control. This dynamic approach resolves the contradiction by applying limitation only when necessary.
Solution Approach 2:
The controlling device creates a copied or alternative control path for automatic steering intervention that operates independently from the driver's steering input. When automatic steering is active, the system uses the automatic control commands rather than the driver's steering ratio control, effectively copying the stabilization function while suppressing the conflicting driver input. This allows the driver's intention to be preserved in normal conditions while ensuring stability during automatic intervention.
3Extent of automation
If binary control form is used to prioritize automatic steering upon interference, then automatic steering priority is ensured, but the vehicle behavior is not always desirable in situations where driver steering should be prioritized
Solution Approach 1:
The patent replaces binary control with dynamic control that continuously assesses operational conditions. The system monitors whether automatic steering intervention is active and adjusts priority accordingly. This dynamic approach allows the system to be adaptive rather than rigid, optimizing vehicle behavior by selecting the appropriate priority mode (driver steering or automatic steering) based on real-time conditions rather than always prioritizing automatic steering.
Solution Approach 2:
The system changes the control priority parameter based on the operational state. When automatic steering intervention is detected, the priority parameter switches to favor automatic control; otherwise, it maintains driver steering priority. This parameter change mechanism provides versatility by allowing the system to adapt to different situations, ensuring automatic steering priority only when necessary while preserving driver control during normal operation.
Data Source
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AI summary
A vehicle steering control apparatus is provided with: a first setting device for setting a first target steering angle of rear wheels according to a steering wheel operation of a driver; a second setting device for setting a second target steering angle of the rear wheels which does not work with the steering wheel operation by the driver and which is associated with automatic steering; a controlling device for controlling a steering angle of the rear wheels on the basis of the set first and second target steering angles; and a limiting device for limiting an influence of the first target steering angle on the steering angle of the rear wheels in accordance with a driving condition of the vehicle if the set first and second target steering angles have a mutually anti-phase relation, the limiting device limiting an influence of the second target steering angle on the steering angle of the rear wheels in accordance with the driving condition of the vehicle in preference to the first target steering angle if the automatic steering associated with the setting of the second target steering angle suppresses a change in the vehicle state quantity produced in a process of controlling a state controlled variable which is different from the steering angle of the rear wheels.