Vehicle Suspension Damping Control via Frequency Segmentation
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Solution Overview
Problem
Conventional suspension apparatuses for vehicles face challenges in controlling damping force across a wide frequency range, including both low and high frequencies, without the need for expensive and highly responsive controllers and actuators, which often results in compromised ride comfort and steering stability.
Innovation Solution
A suspension apparatus with a shock absorber and controller that includes a frequency response unit to reduce damping force during high-frequency vibrations, allowing the controller to adjust damping force only for low-frequency movements and maintaining a lower damping force adjustment level for higher frequencies, thereby simplifying the system and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a highly responsive controller and actuator are used to control damping force for high-frequency vibrations, then ride comfort and steering stability are improved, but system cost increases significantly
Solution Approach 1:
The patent divides the vibration control into two frequency segments: low-frequency vibrations are controlled by the actuator-adjustable damping force, while high-frequency vibrations are handled by the frequency response unit with reduced damping force. This segmentation allows each component to operate within its optimal frequency range, eliminating the need for an expensive highly responsive controller and actuator that would be required to handle all frequencies.
Solution Approach 2:
The patent applies different damping force characteristics to different frequency regions. The frequency response unit is specifically designed to reduce damping force for high-frequency vibrations, while the actuator maintains appropriate damping force for low-frequency vibrations. This local differentiation of damping characteristics allows effective vibration control without requiring high responsiveness across the entire frequency spectrum.
2Reliability
If damping force is controlled for high-frequency vibrations, then ride quality improves, but responsiveness requirements increase system cost
Solution Approach 1:
The patent implements dynamic damping force adjustment based on vibration frequency. The frequency response unit dynamically reduces damping force when high-frequency vibrations are detected, while the actuator dynamically adjusts damping force for low-frequency vibrations. This dynamic adaptation allows the system to maintain ride quality without requiring the controller to respond at high speeds across all frequency ranges.
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 configuration enables effective damping force control across a wide frequency range, improving ride quality and maintaining stability without the need for expensive components, while reducing the number of sensors and system complexity.
Implementation Method 1
a shock absorber disposed between a vehicle body side and a wheel side of a vehicle and capable of adjusting a damping force
Data Source
AI summary
Shock absorbers of left and right front wheel suspensions and shock absorbers of left and right rear wheel suspensions each are constituted by a damping force adjustable hydraulic shock absorber provided with a frequency response unit. An actuator of a damping force variable mechanism provided to the shock absorber is driven and controlled by a controller. The controller variably adjusts the damping force between the soft side and the hard side by the damping force variable mechanism according to a vertical vibration when a vehicle body vertically vibrates at a low frequency. The controller does not adjust the damping force when the vehicle body vibrates at a higher frequency than the low frequency.