Damping Force Control Device for Ungrounded Wheel Conditions
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Solution Overview
Problem
Conventional damping force control devices for vehicles fail to generate sufficient damping force when wheels become ungrounded, leading to reduced ride comfortability and drivability on rough roads, as they assume all wheels are grounded and adjust damping coefficients accordingly.
Innovation Solution
A damping force control device with variable damping shock absorbers and a controller that adjusts damping coefficients based on the vertical vibration state quantities, setting the damping coefficient of grounded wheels to a higher value and ungrounded wheels to a lower value when a specific condition is met, ensuring sufficient damping force is generated even when wheels are ungrounded.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the damping coefficient is adjusted based on a predetermined control law assuming all wheels touch ground, then the control system operates normally under standard conditions, but sufficient damping force cannot be generated when at least one wheel becomes ungrounded
Solution Approach 1:
The control system dynamically switches between ordinary control mode (for normal grounded conditions) and specific control mode (for ungrounded conditions). The controller detects wheel ground status and adaptively adjusts damping coefficient settings based on the current operational state, ensuring reliable damping force generation regardless of wheel contact conditions.
Solution Approach 2:
The system changes the damping coefficient parameter based on detected wheel conditions. When an ungrounded wheel is detected, the controller modifies the damping coefficient for grounded wheels to a first specific value greater than the minimum, and sets the damping coefficient for ungrounded wheels to a second specific value, optimizing damping force generation for the specific operational condition.
2Stability of the object's composition
If the damping coefficient is set according to ordinary control law, then the system maintains standard operation, but the vibration of vehicle body cannot be sufficiently attenuated when wheels are ungrounded
Solution Approach 1:
The controller detects the ground contact status of each wheel and uses this feedback information to determine whether to apply ordinary control or specific control. This feedback mechanism enables the system to respond appropriately to ungrounded conditions, maintaining vehicle body stability by attenuating vibrations through adjusted damping coefficients.
3Reliability
If the damping coefficient is increased for grounded wheels when ungrounded condition is detected, then sufficient damping force is generated to attenuate vibration, but the system complexity increases due to additional control logic
Solution Approach 1:
The control system is segmented into distinct control modes (ordinary control and specific control) that are activated based on detected wheel conditions. This segmentation allows the system to implement complex adaptive behavior through structured, modular control logic that can be clearly defined and executed.
Data Source
AI summary
A damping force control device 10 comprises vary damping shock absorbers, a detector, and a controller. Each of the shock absorbers sets damping coefficient from a minimum value to a maximum value in order to adjust damping force. The detector detects vertical vibration state quantity relating to vibration of the sprung mass. The controller performs an ordinary control for setting the damping coefficient based on the vertical vibration state quantity and according to a predetermined control law suitable for an assumption that all of the wheels touch ground. The controller performs, when at least one of the wheels is an ungrounded wheel which does not touch the ground and each of the other wheels is a grounded wheel which touches the ground, a specific control for setting the damping coefficient of the shock absorber corresponding to the grounded wheel to a first specific value greater than the minimum value.