Preview Damping Control Using Unsprung Displacement Data
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Solution Overview
Problem
The damping performance of existing preview damping control systems for vehicles is lower when using a target control force calculated based on road surface displacement, compared to using an unsprung condition amount indicating vertical displacement of the unsprung portion.
Innovation Solution
A vehicle damping control device that acquires an unsprung condition amount at a predicted passing position using preview reference data, and executes preview damping control by generating a control force that matches a target control force calculated based on this unsprung condition amount.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If preview damping control is performed based on road surface displacement, then the control system can be simpler, but the damping performance is lower
Solution Approach 1:
The system performs preliminary measurement of unsprung portion displacement using sensors before the wheel reaches the predicted passing position. This advance measurement allows the control system to prepare the optimal damping force in advance, improving damping performance while avoiding the need for complex real-time calculation systems.
Solution Approach 2:
The invention uses unsprung portion displacement as an intermediary parameter to represent road surface conditions. Instead of directly measuring road surface displacement, the system measures the displacement of the unsprung portion which indirectly reflects the road surface profile, simplifying the measurement system while improving control accuracy.
2Measurement precision
If road surface displacement is used for control, then measurement may be simpler, but deviations in calculation increase
Solution Approach 1:
The system uses unsprung portion displacement as an intermediary measurement that directly reflects actual road surface interaction. This intermediary measurement avoids the cumulative calculation errors and deviations associated with integrating acceleration data to obtain road surface displacement, providing more precise and reliable measurement information.
Solution Approach 2:
The system continuously monitors unsprung portion displacement and uses this feedback to adjust damping control in real-time. This closed-loop feedback mechanism ensures that the control system responds to actual measured conditions rather than calculated estimates, reducing information loss and improving measurement precision.
3Reliability
If unsprung condition amount is used, then damping performance improves, but more sophisticated sensors and processing are needed
Solution Approach 1:
The system measures unsprung portion displacement using standard vibration sensors mounted on the unsprung mass. This intermediary measurement approach converts the difficult task of directly measuring road surface profile into a simpler measurement of unsprung portion vibration, reducing measurement difficulty while maintaining high damping performance.
Solution Approach 2:
The invention replaces complex mechanical road surface profiling systems with electronic vibration sensors that measure unsprung portion displacement. This substitution uses electrical signal processing instead of mechanical measurement, reducing the difficulty of detection and measurement while improving reliability.
Data Source
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AI summary
A damping control device (20) is configured to acquire, as a preview condition amount, an unsprung condition amount at a predicted passing position where a wheel (11) of a vehicle (10) is predicted to pass, based on preview reference data (45) being sets of data in which unsprung condition amounts and pieces of positional information of the wheel (11) are linked to each other. The unsprung condition amounts indicate a displacement condition of an unsprung portion (50) displaced in a vertical direction due to a displacement of a road surface (55) acquired when the vehicle (10) has traveled on the road surface (55). The damping control device (20) is configured to execute, at a timing when the wheel (11) passes through the predicted passing position, preview damping control to cause control force to agree with a target control force.