Steered Wheel Phase-Delayed Control for Smoother Steering Response
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Solution Overview
Problem
The rapid response of vehicle behavior to steering operation causes a feeling of uneasiness for the driver due to the difference between the actual and target turning angles in existing turning devices.
Innovation Solution
A turning method that delays the phase of the turning force command value based on the difference between the actual and target turning angles to synchronize the steered wheel, using a steer-by-wire system with a controller to adjust the turning force command value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If turning force is generated based on the difference between actual turning angle and target turning angle, then the turning control responsiveness is improved, but the driver experiences a feeling of uneasiness due to excessively fast vehicle behavior response
Solution Approach 1:
The patent applies preliminary action by calculating and storing the integral value of the target turning angle in advance. This integral value represents the accumulated turning demand over time, which is then used to generate the turning force command value. By incorporating this pre-calculated integral term, the system achieves smooth turning response without excessive abruptness, resolving the contradiction between responsiveness and driver comfort.
Solution Approach 2:
The patent changes the parameter of turning force command value by introducing a new calculation method that combines the difference between actual and target turning angles with the integral value of the target turning angle. This parameter transformation allows the system to maintain fast response while avoiding the harmful effect of overly aggressive turning behavior that causes driver uneasiness.
2Measurement precision
If the turning angle is adjusted rapidly to match the target turning angle, then the tracking precision is improved, but the vehicle behavior becomes too responsive causing driver discomfort
Solution Approach 1:
The patent implements feedback by continuously calculating the difference between the actual turning angle and the target turning angle, and using this difference along with the integral value of the target turning angle to generate the turning force command value. This feedback mechanism ensures accurate tracking of the target turning angle while the integral term provides smoothing that maintains driver comfort during normal operation.
Data Source
AI summary
A turning method for turning a steered wheel of a vehicle includes detecting a steering angle of a steering wheel; detecting an actual turning angle. The actual turning angle is an actual turning angle of the steered wheel. The method includes calculating a target turning angle of the steered wheel according to the detected steering angle. The method includes calculating a turning force command value to cause the actual turning angle to coincide with the target turning angle, based on a difference between the actual turning angle and the target turning angle. The method includes delaying a phase of the turning force command value with respect to the detected steering angle; and generating turning force to turn the steered wheel in accordance with the turning force command value having a phase delayed.