Noise and Vibration Reduction on the Single Axis Adaptive Damping Controls

Author(s):  
Juchirl Park ◽  
John A. Peterson

Reducing or eliminating seat noise and vibration are the main objectives of a semi-active damping system implemented in a commercial vehicle seat. The system must be developed such that control forces minimize seat motion. Abrupt motion with semi-active damping systems is typically called ‘dynamic jerk.’ Semi-active damping in a seat application places the control forces close to the seat occupant so there is less ‘filtering’ to protect the human from feeling dynamic jerk. Whereas in an automotive suspension there might be more tolerance for dynamic jerk because the comparatively heavy vehicle body acts to filter some of the dynamic jerk and the interaction of the tire and road input may also mask it. In this research, dynamic jerk has been addressed and studied for the advanced SEAT application. The seat has been tested with varying sine inputs at specific amplitudes. The response of the semi-active damping seat system has been analyzed to characterize dynamic jerk and a control algorithm has been developed to minimize this undesirable response. The conclusion is that dynamic jerk is dependent on the damper’s physical properties as well as the system’s sensors. A Design of Experiments statistical study was carried out to determine what are the most influencing factors. Limiting the range of damping force reduces the control authority; however, allowing full damping force may trigger dynamic jerk. Identifying the dynamic jerk plays an important role in order to have the indication of the properly tuned system. In this research, the identification strategy of the dynamic jerk is studied and developed.

Author(s):  
Akira Fukukita ◽  
Tomoo Saito ◽  
Keiji Shiba

We study the control effect for a 20-story benchmark building and apply passive or semi-active control devices to the building. First, the viscous damping wall is selected as a passive control device which consists of two outer plates and one inner plate, facing each other with a small gap filled with viscous fluid. The damping force depends on the interstory velocity, temperature and the shearing area. Next, the variable oil damper is selected as a semi-active control device which can produce the control forces by little electrical power. We propose a damper model in which the damping coefficient changes according to both the response of the damper and control forces based on an LQG feedback and feedforward control theory. It is demonstrated from the results of a series of simulations that the both passive device and semi-active device can effectively reduce the response of the structure in various earthquake motions.


Author(s):  
Mehran Asdigha ◽  
Robert Greif

Abstract Independent Modal Space Control (IMSC) is an established technique in active suppression of vibrations, in which the control law is developed exclusively in the modal space, allowing for independent design of the modal control forces. These forces can be transformed to the physical domain through modal transformation. The resulting controller is fixed-gain, with the active damping introduced to the system determined independently for each mode and is a function of the velocity for the under-damped case. In this work we propose to modify IMSC using fuzzy reasoning. The result is a new non-linear control law, embedding fuzzy reasoning and an implicit fuzzy rule-base that transforms the traditional algorithm from a fixed-gain to a variable-gain controller. The algorithm uses information about the displacement profile across the sensed locations to distribute the active damping rationally among the modal controllers. This new algorithm complements the “local” view of the traditional algorithm in the modal space, with a “global” view of the displacements in the physical space. The results show significant improvement in the settling time as the performance criterion.


Author(s):  
Austin Downey ◽  
MohammadKazem Sadoughi ◽  
Liang Cao ◽  
Simon Laflamme ◽  
Chao Hu

Structural control systems, including passive, semi-active and active damping systems, are used to increase structural resilience to multi-hazard excitations. While semi-active and active damping systems have been investigated for the mitigation of multi-hazard excitations, their requirement for real-time controllers and power availability limit their usefulness. This work proposes the use of a newly developed passive variable friction device for the mitigation of multi-hazard events. This passive variable friction device, when installed in a structure, is capable of mitigating different hazards from wind and ground motions. In wind events, the device ensures serviceability, while during earthquake events, the device reduces the building’s inter-story drift to maintain strength-based motion requirements. Results show that the passive variable friction device performs better than a traditional friction damper during a seismic event while not compromising any performance during wind events.


Akustika ◽  
2019 ◽  
Vol 32 ◽  
pp. 247-250 ◽  
Author(s):  
Andrey Vasilyev ◽  
Vladimir Sannikov ◽  
Natalia Tyurina

Industrial noise and vibration leads to the workers disease, fatigue breakdown of pipeline and apparatus junction, decreasing of machine operating characteristics etc. According to statistics, amblyacousia and vibration illness takes the first places among all the other professional diseases. Investigations of noise and vibration levels at the operator's positions of "Volgoelectromontazh-1" Joint Stock Company of Russian Federation were done. Measurements were carried out according to existing methods and standards. In total 27 operator's positions were investigated in the main building and in the shop of consumer goods. The results of measurements showed, that for some positions (pendulum saw, cutting-off lathe, presses etc.) there were significant excesses of the sanitary standards of noise levels. Complex of measures of noise reduction was developed, including technical decisions and organizing measures. Results of measures implementation shows good efficiency of noise and vibration reduction.


2001 ◽  
Vol 110 (5) ◽  
pp. 2653-2653
Author(s):  
Conor D. Johnson ◽  
Roger M. Glaese ◽  
Paul C. Janzen

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