Active Suspension Damping Control for Wheel Position Misalignment
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Solution Overview
Problem
Existing damping control systems for vehicles face inaccuracies in controlling sprung vibrations due to misalignment of wheel positions and unsprung displacement-related values, particularly in high-frequency regions, leading to reduced controllability and accuracy in damping control.
Innovation Solution
A damping control apparatus that calculates a target control force using a combination of two unsprung displacement-related values: one based on motion state quantities and another based on pre-stored information, allowing for precise control by determining a predicted wheel passage position and applying a sum of control components to reduce sprung vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an unsprung displacement-related value based on motion state quantity is used for damping control, then measurement precision is improved, but position misalignment occurs in high frequency regions reducing controllability
Solution Approach 1:
The system dynamically switches between two different unsprung displacement-related values based on the frequency characteristics of the input signal. A switching section determines whether to use the motion state quantity-based value or the preview sensor-based value according to the frequency content, allowing the system to adapt its behavior to different operating conditions and maintain both precision and controllability.
2Reliability
If an unsprung displacement-related value acquired by preview sensor is used, then position alignment is maintained, but measurement precision is reduced
Solution Approach 1:
The system dynamically switches between two different unsprung displacement-related values based on the frequency characteristics of the input signal. A switching section determines whether to use the motion state quantity-based value or the preview sensor-based value according to the frequency content, allowing the system to adapt its behavior to different operating conditions and maintain both precision and controllability.
3Device complexity
If a single unsprung displacement-related value is used for control calculation, then device complexity is reduced, but damping control accuracy is insufficient
Solution Approach 1:
The system dynamically switches between two different unsprung displacement-related values based on the frequency characteristics of the input signal. A switching section determines whether to use the motion state quantity-based value or the preview sensor-based value according to the frequency content, allowing the system to adapt its behavior to different operating conditions and maintain both precision and controllability.
Solution Approach 2:
The system changes the parameter being used for control based on frequency conditions. By switching between different unsprung displacement-related values depending on the frequency content of the road surface input, the system optimizes control accuracy for different driving conditions without requiring a completely complex multi-sensor system.
Data Source
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AI summary
A damping control apparatus has a control unit that controls an active actuator that generates a control force to damp a sprung, and a storage device for storing a unsprung displacement acquired based on a vertical motion state quantity of a vehicle when the vehicle travels, and the control unit determines a predicted wheel passage position where a wheel is predicted to pass, calculates a time derivative value of an unsprung displacement at the predicted wheel passage position acquired by a preview sensor, calculates a target control force based on a sum of a first control component proportional to the time derivative value and a second control component proportional to an unsprung displacement at the predicted wheel passage position acquired from the storage device, and controls a control force generating device so that a control force when the wheel passes the predicted wheel passage position becomes the target control force.