Vehicle Steering Assistance Dynamic Transmission Ratio Adjustment
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Solution Overview
Problem
During automatic steering in vehicles, the differential transmission ratio between the steering input device and the turning device causes discomfort for drivers when they intervene with manual steering, as the existing systems do not adequately account for coordinated operations between automatic and manual steering modes.
Innovation Solution
A steering assistance apparatus and method that dynamically change the transmission ratio from the automatic steering mode to a manual steering mode when driver input is detected, prioritizing manual steering over automatic steering to reduce discomfort by adjusting the ratio to a value less than that of the automatic steering mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the transmission ratio during automatic steering is set greater than during manual steering, then the automatic steering performance is improved, but driver comfort deteriorates when steering intervention is performed
Solution Approach 1:
The transmission ratio is made dynamically adjustable based on the steering mode. The controller switches between a first transmission ratio (α1) during manual steering and a second transmission ratio (α2) during automatic steering, where α1 < α2. This dynamic adjustment resolves the contradiction by optimizing the transmission ratio for each specific operating mode, thereby improving automatic steering performance while maintaining driver comfort during manual intervention.
Solution Approach 2:
The patent changes the transmission ratio parameter according to the steering mode. When automatic steering is active, a larger transmission ratio (α2) is used to enhance automation performance. When manual steering intervention is detected, the system switches to a smaller transmission ratio (α1) to ensure driver comfort. This parameter change strategy allows the system to achieve high automatic steering performance without compromising driver comfort during interventions.
2Ease of operation
If the transmission ratio is changed when switching between automatic and manual steering modes, then steering comfort is improved, but system complexity increases
Solution Approach 1:
The controller continuously monitors the steering mode and detects when manual steering intervention occurs. Based on this feedback, the system automatically adjusts the transmission ratio between α1 and α2. This feedback mechanism enables smooth transitions between modes while maintaining steering comfort, without requiring complex mechanical reconfiguration systems.
Solution Approach 2:
The transmission ratio adjustment mechanism serves multiple functions: it improves steering comfort during mode transitions, maintains optimal performance in both manual and automatic modes, and enables smooth coordination between different steering modes. This multi-functionality reduces the need for separate systems for each function, thereby limiting the increase in overall system complexity.
3Ease of operation
If manual steering mode is prioritized over automatic steering mode during driver input, then driver comfort is improved, but automation level decreases
Solution Approach 1:
The system dynamically adjusts the transmission ratio based on the priority of steering modes. When manual steering is prioritized (driver input detected), the system uses transmission ratio α1. When automatic steering is prioritized (no driver input), the system uses transmission ratio α2. This dynamic adjustment allows the system to maintain high automation levels during normal operation while ensuring driver comfort during manual interventions.
Solution Approach 2:
The system prepares different transmission ratio settings (α1 for manual priority, α2 for automatic priority) in advance. When driver input is detected, the system has already configured the appropriate transmission ratio to ensure smooth transition and driver comfort. This preliminary preparation avoids last-minute adjustments that could compromise either comfort or automation performance.
Data Source
AI summary
In a steering assistance apparatus mounted in a vehicle, a steering input device and a turning device differentiate at a transmission ratio that is a ratio of an amount of change in the turning angle to an amount of change in the steering angle. A turning device actuator actuates the turning device. A controller executes an automatic steering mode, in which the controller determines the turning angle based on at least one of a travel condition and travel path information of the vehicle and controls the turning device actuator so as to achieve the determined turning angle. If detecting an input variation from the steering input device during execution of the automatic steering mode, the controller changes the transmission ratio to a value less than the transmission ratio in the automatic steering mode and prioritizes a manual steering mode over the automatic steering mode.