Vehicle Control Device Damping Force Distribution During Turning
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Solution Overview
Problem
Existing vehicle control systems face challenges in maintaining a stable vehicle body orientation and reducing unnatural ride sensations during turning, particularly due to reduced sense of ground contact in the unsprung mass when shock absorber damping force is controlled based on sprung mass orientation.
Innovation Solution
A vehicle control device that calculates a damping force control amount based on the greater of unsprung vibration damping control and sprung vibration damping control amounts, prioritizing unsprung vibration damping to minimize rattling and maintain stable vehicle body orientation, while ensuring a suitable damping force distribution factor during turning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If shock absorber damping force is controlled based on sprung mass orientation control amount, then vehicle body orientation is stabilized, but sense of ground contact in the unsprung mass is reduced in resonant frequency region
Solution Approach 1:
The patent segments the damping force control into two independent control amounts: sprung mass vibration damping control amount and unsprung vibration damping control amount. This allows separate optimization of vehicle body orientation stability and unsprung mass ground contact sensation without mutual interference, resolving the technical contradiction by addressing each mass independently.
Solution Approach 2:
The patent changes the control parameter from a single damping force based on sprung mass orientation to a composite damping force that incorporates both sprung mass vibration damping control amount and unsprung vibration damping control amount. This parameter change enables simultaneous improvement of vehicle body orientation stability and unsprung mass ground contact sensation.
2Stability of the object's composition
If damping force control is based on sprung mass orientation control amount, then vehicle body orientation is stabilized, but unnatural ride sensation occurs during turning
Solution Approach 1:
The patent segments the damping force control into sprung mass vibration damping control amount and unsprung vibration damping control amount, allowing separate optimization of vehicle body orientation stability and ride sensation. This segmentation enables the system to address unnatural ride sensation during turning while maintaining vehicle body orientation stability.
Solution Approach 2:
The patent changes the control parameter to include both sprung mass vibration damping control amount and unsprung vibration damping control amount, with priority given to unsprung vibration damping control during turning. This parameter change eliminates unnatural ride sensation while preserving vehicle body orientation stability.
3Stability of the object's composition
If damping force control prioritizes sprung mass orientation control, then vehicle body orientation is stabilized, but rattling in the unsprung mass increases
Solution Approach 1:
The patent segments the damping force control into two independent control amounts: sprung mass vibration damping control amount and unsprung vibration damping control amount. This segmentation allows the system to suppress rattling in the unsprung mass through dedicated unsprung vibration damping control while maintaining vehicle body orientation stability through sprung mass control.
Solution Approach 2:
The patent changes the control parameter to incorporate both sprung mass vibration damping control amount and unsprung vibration damping control amount, with priority given to unsprung vibration damping control. This parameter change effectively suppresses rattling in the unsprung mass while maintaining vehicle body orientation stability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances the sense of ground contact and maintains stable vehicle body orientation by prioritizing unsprung vibration damping, effectively reducing unnatural ride sensations and improving vehicle stability during turning.
Implementation Method 1
a damping force control amount, such that a damping force distribution factor for each of the wheels corresponding to a target orientation is maintained, is calculated on the basis of an unsprung vibration damping control amount
Implementation Method 2
damping force control is performed based on whichever of the calculated damping force control amount and the sprung vibration damping control amount is greater
Data Source
AI summary
A vehicle control device includes a variable-damping-force shock absorber, a sprung vibration damping control device, an unsprung vibration damping control device, a driving state-determining device, a damping force distribution factor-calculating device, and a damping force control device that, when the driving state-determining device determines that the vehicle is traveling in a straight line, controls the damping force of the variable-damping-force shock absorber on the basis of a greater of an unsprung vibration damping control amount and a sprung vibration damping control amount, and that, when the driving state-determining device determines that the vehicle is turning, calculates the damping force control amount on the basis of an unsprung vibration damping control amount so as to maintain the damping force distribution factor, and controls the damping force of the variable-damping-force shock absorber on the basis of a greater of a calculated damping force control amount and the sprung vibration damping control amount.