Vehicle Control Device Damping Force Saturation Adjustment

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Solution Overview

Problem

Existing vehicle control systems fail to sufficiently stabilize vehicle attitude across various stroke speed ranges due to limitations in damping force control, particularly with damping force variable shock absorbers.

Innovation Solution

The system adjusts the saturation degree of the damping force variable region based on stroke speed, narrowing it for low speeds to limit unnecessary damping force control and widening it for high speeds to ensure effective damping force control, thereby stabilizing vehicle attitude regardless of stroke speed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the damping force variable region is set wide for all stroke speeds, then the damping force control can be executed for low stroke speeds, but unnecessary damping force control occurs causing instability

Engineering Contradiction:
Improvedamping force control rangeVSAvoidvehicle attitude stability
Core Design Contradiction:
Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The saturation degree of the damping force variable region is dynamically adjusted based on stroke speed. When stroke speed is high, the saturation degree is set high to allow wide damping force control range. When stroke speed is low, the saturation degree is set low to limit the damping force control range and prevent unnecessary control. This dynamic adjustment resolves the contradiction by adapting the control range to actual operating conditions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of saturation degree according to stroke speed conditions. By varying this parameter, the damping force variable region's effective range is adjusted: expanded for high-speed strokes to ensure effective control, and contracted for low-speed strokes to avoid unnecessary control actions that would destabilize vehicle attitude.

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If the damping force variable region is set narrow for low stroke speeds, then unnecessary damping force control is suppressed, but effective damping control is limited

Engineering Contradiction:
Improvevehicle attitude stabilityVSAvoiddamping force control range
Core Design Contradiction:
Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The system dynamically adjusts the saturation degree based on real-time stroke speed detection. This allows the damping force variable region to be narrow when needed (low speeds) and wide when needed (high speeds), resolving the contradiction between stability and adaptability across different operating conditions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

By changing the saturation degree parameter according to stroke speed, the patent enables the damping force variable region to adapt its range. At low stroke speeds, the reduced saturation degree naturally limits the control range, preventing unnecessary control while maintaining stability. At high stroke speeds, the increased saturation degree expands the range to ensure effective damping control.

Inventive Principle:
Principle #35Parameter changes

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 effectively stabilizes vehicle attitude by optimizing damping force control across different stroke speed ranges, enhancing ride comfort and reducing high-frequency vibration issues.

Implementation Method 1

a damping force variable shock absorber that performs a damping force control to suppress sprung behavior

Methodology Applied
Scientific EffectDamping: Damping

Data Source

PatentEP2829424B1Vehicle control device and vehicle control method
Publication Date: 2018.05.23 NISSAN MOTOR CO LTD
  • EP2829424B1 patent drawingFigure 1
  • EP2829424B1 patent drawingFigure 2
  • EP2829424B1 patent drawingFigure 3~4

AI summary

In the present invention, a power source attitude control is performed to suppress changes in the sprung mass behavior of a vehicle, and damping force control for damping force variable shock absorbers is performed to suppress changes in the sprung mass behavior. When the stroke speed is low, the saturation degree of the damping force variable shock absorbers is set smaller than the saturation degree when the stroke speed is high.