scholarly journals Partial Frequency Assignment for Torsional Vibration Control of Complex Marine Propulsion Shafting Systems

2019 ◽  
Vol 10 (1) ◽  
pp. 147
Author(s):  
Meilong Chen ◽  
Huajiang Ouyang ◽  
Wanyou Li ◽  
Donghua Wang ◽  
Siyuan Liu
Keyword(s):  
Vibration Control ◽  
Natural Frequency ◽  
Torsional Vibration ◽  
Control Method ◽  
Excitation Frequency ◽  
Frequency Assignment ◽  
Effective Control ◽  
Partial Frequency ◽  
Structural Modifications ◽  
Ship Propulsion

With the large-scale and complexity of ship propulsion shafting, it is more difficult to analyze and control the torsional vibration of shafting. Therefore, an effective control method for the torsional vibration of shafting is of great significance in the field of ship engineering. The main strategy of torsional vibration control adopted in this paper is to keep the natural frequency of a shaft system away from the excitation frequency through structural modifications. In addition, because the basic parameters of much of the equipment in engineering applications cannot be changed, this restriction cannot be ignored when seeking solutions related to structural modifications. This paper studies the partial eigenvalue assignment for the torsional vibration control of complex ship propulsion shafting using the gradient flow method, which can shift a “dangerous” natural frequency to a safe value, while satisfying complex physical constraints. The models of a ship propulsion system and a diesel generator set are established to demonstrate several different desired modification schemes and constraint conditions in practice. In particular, close frequencies are shifted. The numerical simulation results demonstrate that it is effective and feasible to make a partial frequency assignment of torsional vibration, which provides a reliable approach for the control of torsional vibration for complex shaft systems in practical engineering.

scholarly journals Simulation Model and Method for Active Torsional Vibration Control of an HEV

2018 ◽  
Vol 9 (1) ◽  
pp. 34 ◽  
Author(s):  
Biqing Zhong ◽  
Bin Deng ◽  
Han Zhao
Keyword(s):  
Simulation Model ◽  
Vibration Control ◽  
Active Control ◽  
Torsional Vibration ◽  
Dynamic Models ◽  
Control Method ◽  
Vehicle Body ◽  
Bench Test ◽  
Torsional Angle ◽  
Hybrid Electric

Hybrid electric vehicles (HEV) might cause new noise vibration and harshness (NVH) problems, due to their complex powertrain systems. Therefore, in this paper, a new longitudinal dynamic simulation model of a series-parallel hybrid electric bus with an active torsional vibration control module is proposed. First, the schematic diagrams of the simulation model architecture and the active control strategy are given, and the dynamic models of the main components are introduced. Second, taking advantage of the characteristics of hybrid systems, a method of determining the key dynamic parameters by a bench test is proposed. Finally, in a typical bus-driving cycle for Chinese urban conditions, time domain and frequency domain processing methods are used to analyze vehicle body jerk, fluctuation of rotational speed, and torsional angle of the key components. The results show that the active control method can greatly improve the system’s torsional vibration performance when switching modes and at resonance.

scholarly journals Structural Modifications for Torsional Vibration Control of Shafting Systems Based on Torsional Receptances

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Zihao Liu ◽  
Wanyou Li ◽  
Huajiang Ouyang
Keyword(s):  
Vibration Control ◽  
Torsional Vibration ◽  
Structural Data ◽  
Element Model ◽  
Mode Shapes ◽  
Structural Modifications ◽  
Shaft System ◽  
Vibration Problems ◽  
Set Up ◽  
Levels Of Integration

Torsional vibration of shafts is a very important problem in engineering, in particular in ship engines and aeroengines. Due to their high levels of integration and complexity, it is hard to get their accurate structural data or accurate modal data. This lack of data is unhelpful to vibration control in the form of structural modifications. Besides, many parts in shaft systems are not allowed to be modified such as rotary inertia of a pump or an engine, which is designed for achieving certain functions. This paper presents a strategy for torsional vibration control of shaft systems in the form of structural modifications based on receptances, which does not need analytical or modal models of the systems under investigation. It only needs the torsional receptances of the system, which can be obtained by testing simple auxiliary structure attached to relevant locations of the shaft system and using the finite element model (FEM) of the simple structure. An optimization problem is constructed to determine the required structural modifications, based on the actual requirements of modal frequencies and mode shapes. A numerical experiment is set up and the influence of several system parameters is analysed. Several scenarios of constraints in practice are considered. The numerical simulation results demonstrate the effectiveness of this method and its feasibility in solving torsional vibration problems in practice.

Torsional Vibration Control of a Hooke’s Joint Driven Flexible Shaft System

2014 ◽  
Author(s):  
Samuel F. Asokanthan ◽  
Xiao-Hui Wang ◽  
Seung-Hoon Baik
Keyword(s):  
Vibration Control ◽  
Torsional Vibration ◽  
Control Method ◽  
Controller Design ◽  
Velocity Ratio ◽  
Analytical Models ◽  
Time Varying ◽  
Varying Coefficients ◽  
Time Varying Coefficients ◽  
Hooke’S Joint

Torsional vibration control of a rotating mechanical system which incorporates a Hooke’s joint is investigated by pole assignment techniques. Linearized analytical models for the torsional system are established for the purposes of controller design. The resulting two-degree-of-freedom rotational system which contains time varying coefficients is parametrically excited due to an inherent non-linear velocity ratio across the Hooke’s joint. The controller is designed via full state feedback and observer based feedback in the transformed domain, using Lyapunov transformation. This transformation reduces the original time-varying system to a form suitable for controller design. A dual-system approach is employed to calculate the observer gain matrix for the time-varying system. Numerical simulation results show that the proposed control method is effective for suppressing torsional vibration of a Hooke’s joint driven system.

Reduction of Flow-Induced Vibration Using Parametric Excitation

2002 ◽  
Author(s):  
Tomotsugu Tanaka ◽  
Koetsu Takano ◽  
Hiroyuki Fujiwara ◽  
Osami Matsushita
Keyword(s):  
Parametric Excitation ◽  
Control Method ◽  
Excitation Frequency ◽  
Effective Control ◽  
Suspension Bridges ◽  
Control Procedure ◽  
Control Methods ◽  
Actual Structure ◽  
Excited Vibration ◽  
Experimental Apparatus

Vibration of structures, such as suspension bridges, skyscrapers and high rises, sometimes cause people to feel anxious. These vibrations are usually induced by the fluid flow, especially vortex shedding and they grow into self-excited vibrations, which are normally accompanied by the extremely large vibration amplitude. In order to solve these vibration problems, many researchers have reported the effectiveness of vibration control methods and most of the methods are very practical for the actual structure. These control methods usually consist of feedback control systems for the active control and some kinds of damper for the passive control. This paper deals with one control method, which is using the parametric excitation. The efficiencies of this method for the self-excited vibration have already been analytically examined by Tondl. However, it is not confirmed experimentally, and it is necessary to discuss the possibility of realization and application for the actual system. In this study, our experiment confirms the effectiveness of this control method. For this purpose, an experimental apparatus, which expressed a two degrees of freedom system and consisted of an electromagnetic actuator, a steel beam and two masses, were prepared. A digital signal processor was used for the realization of the parametric excitation control. During the experiments, we confirmed the effectiveness of the control procedure and accuracy of the theoretical results. In addition, the relationships between the ratio of the two masses and the ratio of the natural and the parametric excitation frequency, which are required for the effective control, were cleared. According to this study, the quenching of self-excited vibration by using the parametric excitation is realized within the very narrow band of frequency and the mass ratio should be small.

Suppression of Vibration by Using Antiresonance Point of a Dynamic Vibration Absorber

2007 ◽  
Author(s):  
Hidetoshi Okaguchi ◽  
Hiroshi Yabuno
Keyword(s):  
Real Time ◽  
Natural Frequency ◽  
Control Method ◽  
Excitation Frequency ◽  
Time Estimation ◽  
Dynamic Vibration Absorber ◽  
Main System ◽  
Wide Range ◽  
Dynamic Absorber ◽  
And Control

The conventional passive dynamic absorber reduces the amplitude of the main system when the natural frequency of the absorber corresponds to the excitation frequency. The dynamic absorber produces two resonance peak. In this paper, we propose a control method of the semi-active dynamic absorber to reduce the amplitude of the main system to zero over the wide range of excitation frequency. The proposed controller has the system of real time estimation of excitation frequency by applying adaptive filter. When the excitation frequency varies, the frequency is estimated by the controller in real time and control signal is generated according to the estimated frequency. As a result, the natural frequency of the absorber is changed in real time and the amplitude of the main system is kept to zero over the wide range of excitation frequency. The performance of the proposed control method is experimentally discussed.

scholarly journals A Variable Parameter Ambient Vibration Control Method Based on Quasi-Zero Stiffness in Robotic Drilling Systems

Machines ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 67
Author(s):  
Laixi Zhang ◽  
Chenming Zhao ◽  
Feng Qian ◽  
Jaspreet Singh Dhupia ◽  
Mingliang Wu
Keyword(s):  
Vibration Control ◽  
Vibration Isolation ◽  
Control Method ◽  
Control Strategies ◽  
Equations Of Motion ◽  
Variable Parameter ◽  
Harmonic Balance Method ◽  
Variable Stiffness ◽  
Ambient Vibration ◽  
Robotic Drilling

Vibrations in the aircraft assembly building will affect the precision of the robotic drilling system. A variable stiffness and damping semiactive vibration control mechanism with quasi-zero stiffness characteristics is developed. The quasi-zero stiffness of the mechanism is realized by the parallel connection of four vertically arranged bearing springs and two symmetrical horizontally arranged negative stiffness elements. Firstly, the quasi-zero stiffness parameters of the mechanism at the static equilibrium position are obtained through analysis. Secondly, the harmonic balance method is used to deal with the differential equations of motion. The effects of every parameter on the displacement transmissibility are analyzed, and the variable parameter control strategies are proposed. Finally, the system responses of the passive and semiactive vibration isolation mechanisms to the segmental variable frequency excitations are compared through virtual prototype experiments. The results show that the frequency range of vibration isolation is widened, and the stability of the vibration control system is effectively improved without resonance through the semiactive vibration control method. It is of innovative significance for ambient vibration control in robotic drilling systems.

scholarly journals A New Model Predictive Control Method for Eliminating Hydraulic Oscillation and Dynamic Hydraulic Imbalance in a Complex Chilled Water System

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3608
Author(s):  
Yang Yuan ◽  
Neng Zhu ◽  
Haizhu Zhou ◽  
Hai Wang
Keyword(s):  
Model Predictive Control ◽  
Predictive Control ◽  
Control Method ◽  
Water System ◽  
Energy Performance ◽  
Effective Control ◽  
New Model ◽  
Chilled Water ◽  
Chilled Water System ◽  
Hydraulic Oscillation

To enhance the energy performance of a central air-conditioning system, an effective control method for the chilled water system is always essential. However, it is a real challenge to distribute exact cooling energy to multiple terminal units in different floors via a complex chilled water network. To mitigate hydraulic imbalance in a complex chilled water system, many throttle valves and variable-speed pumps are installed, which are usually regulated by PID-based controllers. Due to the severe hydraulic coupling among the valves and pumps, the hydraulic oscillation phenomena often occur while using those feedback-based controllers. Based on a data-calibrated water distribution model which can accurately predict the hydraulic behaviors of a chilled water system, a new Model Predictive Control (MPC) method is proposed in this study. The proposed method is validated by a real-life chilled water system in a 22-floor hotel. By the proposed method, the valves and pumps can be regulated safely without any hydraulic oscillations. Simultaneously, the hydraulic imbalance among different floors is also eliminated, which can save 23.3% electricity consumption of the pumps.

Modeling of nonlinear torsional vibration of the automotive powertrain

2016 ◽  
Vol 24 (9) ◽  
pp. 1774-1786 ◽  
Author(s):  
Sérgio J Idehara ◽  
Fernando L Flach ◽  
Douglas Lemes
Keyword(s):  
Natural Frequency ◽  
Torsional Vibration ◽  
Degrees Of Freedom ◽  
Front Wheel ◽  
Torsional Stiffness ◽  
Bench Test ◽  
Passenger Car ◽  
Engine Torque ◽  
Friction Moment ◽  
Wheel Drive

A vibration model of the powertrain can be used to predict its dynamic behavior when excited by fluctuations in the engine torque and speed. The torsional vibration resulting from torque and speed fluctuations increases the rattle noise in the gearbox and it should be controlled or minimized in order to gain acceptance by clients and manufactures. The fact that the proprieties of the torsional damper integrated into the clutch disc alter the dynamic characteristic of the system is important in the automotive industry for design purposes. In this study, bench test results for the characteristics of a torsional damper for a clutch system (torsional stiffness and friction moment) and powertrain torsional vibration measurements taken in a passenger car were used to verify and calibrate the model. The adjusted model estimates the driveline natural frequency and the time response vibration. The analysis uses order tracking signal processing to isolate the response from the engine excitation (second-order). It is shown that a decrease in the stiffness of the clutch disc torsional damper lowers the natural frequency and an increase in the friction moment reduces the peak amplitude of the gearbox torsional vibration. The formulation and model adjustment showed that a nonlinear model with three degrees of freedom can represent satisfactorily the powertrain dynamics of a front-wheel drive passenger car.

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