Adjustable Shock Absorber Control With Dead Zone Stroke Segmentation
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Solution Overview
Problem
Existing suspension control devices struggle to effectively suppress impact and noise during full extension and full compression of the piston rod, leading to reduced durability and service life.
Innovation Solution
A suspension control device equipped with a vehicle behavior calculation unit, a damping force adjustable shock absorber, and a controller that adjusts damping force based on vehicle behavior calculations. The device includes full extension and full compression suppression mechanisms, with a dead zone between these control regions where no suppression control is executed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If damping force is adjusted based on piston position and piston speed to suppress full extension and full compression, then impact and noise are reduced, but the control effectiveness is insufficient in certain stroke ranges
Solution Approach 1:
The patent applies different damping force control strategies to different stroke ranges. Specifically, it sets a dead zone in the middle stroke range where no full extension/full compression suppression control is executed, while applying suppression control only in the outer stroke ranges (beyond the dead zone). This local differentiation allows the system to effectively suppress impact and noise where needed while avoiding control interference in the middle range, thereby resolving the contradiction between reducing harmful factors and maintaining reliable control.
2Reliability
If damping force is continuously adjusted to suppress full extension and full compression, then durability is improved, but control interference occurs in the middle stroke range
Solution Approach 1:
The patent segments the piston stroke range into three distinct zones: a first stroke range beyond the dead zone on one side, a dead zone in the middle, and a second stroke range beyond the dead zone on the other side. Suppression control is applied only in the first and second stroke ranges, while the dead zone is excluded from suppression control. This segmentation simplifies the control logic by clearly defining when suppression should and should not be applied, reducing control interference while maintaining durability.
3Measurement precision
If the stroke from neutral position to full compression control start position is made longer than to full extension control start position, then control precision is improved, but asymmetry in the system increases
Solution Approach 1:
The patent deliberately introduces asymmetry in the stroke lengths from the neutral position to the full extension control start position and from the neutral position to the full compression control start position. The stroke to the full compression control start position is set longer than the stroke to the full extension control start position. This asymmetric design allows for more precise control by accounting for the different mechanical characteristics and load conditions during extension and compression strokes, thereby improving control precision while accepting the necessary asymmetry in stroke lengths.
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
The solution effectively reduces impact and noise during full extension and full compression, enhancing the durability and service life of the suspension system by optimizing damping force adjustments based on vehicle behavior.
Implementation Method 1
a damping force adjustable shock absorber capable of adjusting a damping force is provided between a vehicle body and each wheel
Implementation Method 2
a controller configured to adjust a damping force of the damping force adjustable shock absorber based on a calculation result of the vehicle behavior calculation unit
Data Source
AI summary
A controller executes full extension suppression control or full compression suppression control of adjusting a damping force to be large when a piston being displaced through sliding in an inner tube approaches a full extension position or a full compression position. Moreover, a stroke from a neutral position of the piston in the inner tube to a full compression control start position is set so as to be longer than a stroke from the neutral position of the piston to a full extension control start position. A portion between the full extension control start position to the full compression control start position is set to a dead zone in which none of the full extension suppression control and the full compression suppression control are executed.