Steer-by-Wire Reaction Force Control for Driver Intent
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Solution Overview
Problem
In steer-by-wire vehicles, the reaction force control during driving assist operations can cause a feeling of strangeness in drivers due to the unexpected steering forces.
Innovation Solution
A vehicle control system that adjusts the system turn angle based on the driver's steering intention, reducing the difference between the driver's turn angle and the system turn angle, thereby minimizing the steering reaction force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If reaction force control is performed in conjunction with vehicle turning caused by driving assist control, then the vehicle turning performance is improved, but the driver experiences a feeling of strangeness due to unexpected steering forces
Solution Approach 1:
The patent applies dynamics by making the reaction force control adjustable based on driving conditions. The control system dynamically adapts the reaction force application according to whether the driver is performing manual steering or the system is performing automated turning, thereby resolving the contradiction between maintaining turning performance and avoiding driver discomfort
Solution Approach 2:
The patent changes the parameter of reaction force control by introducing a flag that switches between two control modes: one where reaction force is applied during automated turning, and another where it is not. This parameter change allows the system to maintain turning performance while eliminating the strange feeling when the driver intends to steer manually
2Stability of the object's composition
If the steering reaction force is applied during driving assist control, then the steering stability is improved, but the driver's steering intention may be compromised
Solution Approach 1:
The patent implements feedback by continuously monitoring the driver's steering operation through the steering angle sensor and comparing it with the target turn angle from driving assist control. Based on this feedback, the system determines whether to apply reaction force control, thereby maintaining steering stability when needed while respecting driver intention when manual steering is detected
Solution Approach 2:
The system dynamically adjusts the reaction force control based on real-time detection of driver steering intention. When the driver performs manual steering operations, the system switches to a mode where reaction force is not applied, preserving driver steering intention while maintaining stability through alternative control mechanisms
Data Source
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AI summary
A vehicle control system (10) for a steer-by-wire vehicle (1) executes: driving assist control that assists driving of the vehicle (1); and conjunction reaction force control that applies a steering reaction force component to a steering wheel (3) in conjunction with vehicle turning caused by the driving assist control. A driver turn angle (δx) is a target turn angle corresponding to a steering angle (θs) of the steering wheel (3), and a first system turn angle (δy1) is a target turn angle required by the driving assist control. In the conjunction reaction force control, a second system turn angle (δy2) is acquired by adjusting the first system turn angle (δy1) according to a driver's steering intention such that the difference between the system turn angle and the driver turn angle (δx) becomes smaller. Then, a steering reaction force component is applied in a direction of reducing a difference (d2) between the driver turn angle (δx) and the second system turn angle (δy2).