Steering Assistance Device Speed-Dependent Control
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Solution Overview
Problem
Existing steering assistance systems fail to adjust the steering assistance amount based on the vehicle's travel state, particularly requiring excessive assistance at low speeds and inadequate guidance at high speeds.
Innovation Solution
A steering assistance device with a control unit that adjusts the steering assistance amount by increasing the motor's assistance when the vehicle's speed exceeds a predetermined threshold and reducing the oil pressure assistance, allowing for dynamic adjustment of steering assistance based on the vehicle's speed and steering angle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If steering assistance amount is increased for low-speed travel, then ease of steering operation is improved, but vehicle stability deteriorates due to excessive lightness at high speeds
Solution Approach 1:
The steering assistance device dynamically adjusts the assistance amount based on vehicle speed. At low speeds, the pump unit provides high assistance for easy maneuvering. At high speeds, the control unit reduces pump unit output and increases motor unit output to provide finer control and maintain stability, preventing excessive lightness while preserving low-speed ease of operation.
Solution Approach 2:
The system changes the steering assistance parameters according to vehicle speed conditions. The control unit modifies the assistance characteristics by adjusting the contribution ratios of the pump unit and motor unit based on speed thresholds, thereby adapting the steering feel and assistance level to match the operational requirements at different speeds.
2Measurement precision
If steering assistance is provided for high-speed travel, then vehicle position correction capability is improved, but steering becomes too light and loses guidance function at low speeds
Solution Approach 1:
The system dynamically switches between pump unit dominance at low speeds and motor unit dominance at high speeds. The control unit monitors vehicle speed and adjusts the assistance source accordingly, enabling precise position correction at high speeds while maintaining adequate guidance function at low speeds through pump unit assistance.
Solution Approach 2:
The control unit changes the assistance parameters by adjusting the ratio of pump unit to motor unit contribution based on speed. This parameter adjustment ensures that the steering system provides appropriate guidance characteristics for each speed regime, preventing loss of guidance function while enabling precise correction when needed.
3Device complexity
If a single assistance unit is used for all speed ranges, then device complexity is reduced, but adaptability to different travel states deteriorates
Solution Approach 1:
The steering assistance device is segmented into two independent assistance units: a pump unit for hydraulic assistance and a motor unit for electric assistance. The control unit selectively activates and adjusts each unit based on vehicle speed, enabling adaptability to different travel states while maintaining manageable system complexity through modular architecture.
Solution Approach 2:
The dual-unit system provides multi-functionality by enabling the pump unit to handle low-speed high-assistance requirements and the motor unit to handle high-speed precision requirements. This universal design allows a single steering assistance system to effectively serve multiple operational scenarios that a single unit could not adequately address.
Data Source
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AI summary
A steering assistance device 1 includes: a steering angle detection unit 71 that detects the steering angle of a vehicle V; a pump unit 60 that performs steering assistance of the vehicle V by using oil pressure; a motor 20 that performs steering assistance of the vehicle V by using electrical power; and a steering control unit 74 that causes the pump unit 60 to perform steering assistance with the steering assistance amount thereof reduced by a predetermined amount from the predetermined steering assistance amount, and causes the motor 20 to perform steering assistance, in a case where the pump unit 60 can perform steering assistance in a steering assistance amount predetermined for the detected steering angle.