Damping Force Control Device Using Segmented Processing Periods
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Solution Overview
Problem
Conventional damping-force adjustable damper systems face challenges in achieving precise control of damping forces due to limitations in processing power, leading to inadequate suppression of vehicle vibrations, especially when encountering successive bumps, and result in increased costs with high-performance CPUs required for faster processing.
Innovation Solution
A control device for damping-force adjustable dampers that includes a target damping force setting unit, stroke position detecting unit, stroke speed calculating unit, and processing-period setting unit, which sets individual processing periods based on resonant frequencies to optimize processing power and reduce CPU load, allowing for more precise control without increasing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the processing period of the CPU is reduced to improve response speed, then the damping force control precision is improved, but the CPU cost increases
Solution Approach 1:
The patent segments the processing period into multiple intervals: a first processing period for calculating stroke speed and a second processing period (longer than the first) for calculating target damping force. This segmentation allows the system to use a longer overall processing period while maintaining precise stroke speed control, thereby reducing CPU performance requirements and cost without sacrificing damping force control precision.
2Productivity
If the processing period is reduced to cope with high-frequency stroke speed changes, then the vibration suppression capability is improved, but the CPU process power requirement increases
Solution Approach 1:
The patent divides the control process into two segmented stages with different processing periods: rapid stroke speed calculation at a first processing period and target damping force calculation at a second, longer processing period. This allows the system to capture high-frequency stroke speed changes effectively while using a longer overall cycle for less computationally intensive damping force calculations, thereby reducing total CPU process power requirements.
Solution Approach 2:
The patent implements dynamic processing period adjustment where the processing period is adapted based on stroke speed magnitude. When stroke speed is high, a shorter first processing period is used to capture rapid changes; when stroke speed is low, a longer period can be used. This dynamic adjustment optimizes vibration suppression capability while minimizing CPU process power consumption.
3Speed
If the CPU processes all calculations at a short period to improve response to successive bumps, then the damping force adjustment speed is improved, but the system cost increases
Solution Approach 1:
The patent segments the damping control process into two distinct processing stages with different time scales: rapid stroke speed measurement at a first processing period and target damping force determination at a second, longer processing period. This segmentation enables the system to achieve fast damping force adjustment when needed while allowing less time-critical calculations to use longer periods, thereby reducing overall system cost without compromising adjustment speed.
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 enables more precise damping-force control, effectively attenuating vibrations and improving ride quality without the need for expensive high-performance CPUs, by optimizing processing periods and reducing the impact of quantized noises, thus enhancing the system's ability to handle high-frequency components in stroke speed.
Implementation Method 1
The damping-force adjustable dampers have a Magneto-Rheological Fluid (MRF) which generates damping force, change the viscosity in accordance with a magnetic field
Implementation Method 2
As a current is allowed to flow through the coil, the damping-force adjustable damper causes a magnetic field to act on the MRFs flowing through the fluid path of the piston
Data Source
AI summary
A damping-force-adjustable-damper control device includes a target damping force setting unit which sets target damping force, a stroke position detecting unit which detects a stroke position of the damping-force adjustable damper, a stroke speed calculating unit which calculates a stroke speed, and a target output calculating unit which calculates a target output value to be output to the damping-force adjustable damper in accordance with an obtained target damping force and an obtained stroke speed. The control device also includes a processing-period setting unit which sets the processing periods of the stroke speed calculating unit and the target output calculating unit in accordance with a resonant frequency of unsprung mass, and which sets the processing period of the target damping force setting unit to be longer than the processing periods of the stroke speed calculating unit and the target output calculating unit in accordance with a resonant frequency of sprung mass.