scholarly journals Modeling and Control of a Six Degrees of Freedom Maglev Vibration Isolation System

Sensors ◽  
2019 ◽  
Vol 19 (16) ◽  
pp. 3608 ◽  
Author(s):  
Qianqian Wu ◽  
Ning Cui ◽  
Sifang Zhao ◽  
Hongbo Zhang ◽  
Bilong Liu

The environment in space provides favorable conditions for space missions. However, low frequency vibration poses a great challenge to high sensitivity equipment, resulting in performance degradation of sensitive systems. Due to the ever-increasing requirements to protect sensitive payloads, there is a pressing need for micro-vibration suppression. This paper deals with the modeling and control of a maglev vibration isolation system. A high-precision nonlinear dynamic model with six degrees of freedom was derived, which contains the mathematical model of Lorentz actuators and umbilical cables. Regarding the system performance, a double closed-loop control strategy was proposed, and a sliding mode control algorithm was adopted to improve the vibration isolation performance. A simulation program of the system was developed in a MATLAB environment. A vibration isolation performance in the frequency range of 0.01–100 Hz and a tracking performance below 0.01 Hz were obtained. In order to verify the nonlinear dynamic model and the isolation performance, a principle prototype of the maglev isolation system equipped with accelerometers and position sensors was developed for the experiments. By comparing the simulation results and the experiment results, the nonlinear dynamic model of the maglev vibration isolation system was verified and the control strategy of the system was proved to be highly effective.

Author(s):  
Keisuke Sudo ◽  
Toru Watanabe ◽  
Kazuto Seto

This paper deals with the control system design for active isolation table[1][2][3]. It aims at controlling vibration of the installed object and isolation table. An experimental isolation table with flexible loaded object is built. Control simulations are carried out by using feedback controller designed according to LQ optimal control theory.


Drones ◽  
2020 ◽  
Vol 4 (4) ◽  
pp. 71
Author(s):  
Luz M. Sanchez-Rivera ◽  
Rogelio Lozano ◽  
Alfredo Arias-Montano

Hybrid Unmanned Aerial Vehicles (H-UAVs) are currently a very interesting field of research in the modern scientific community due to their ability to perform Vertical Take-Off and Landing (VTOL) and Conventional Take-Off and Landing (CTOL). This paper focuses on the Dual Tilt-wing UAV, a vehicle capable of performing both flight modes (VTOL and CTOL). The UAV complete dynamic model is obtained using the Newton–Euler formulation, which includes aerodynamic effects, as the drag and lift forces of the wings, which are a function of airstream generated by the rotors, the cruise speed, tilt-wing angle and angle of attack. The airstream velocity generated by the rotors is studied in a test bench. The projected area on the UAV wing that is affected by the airstream generated by the rotors is specified and 3D aerodynamic analysis is performed for this region. In addition, aerodynamic coefficients of the UAV in VTOL mode are calculated by using Computational Fluid Dynamics method (CFD) and are embedded into the nonlinear dynamic model. To validate the complete dynamic model, PD controllers are adopted for altitude and attitude control of the vehicle in VTOL mode, the controllers are simulated and implemented in the vehicle for indoor and outdoor flight experiments.


2017 ◽  
Vol 865 ◽  
pp. 480-485
Author(s):  
Jian Liang Li ◽  
Xiao Xi Liu ◽  
Shu Qing Li ◽  
Zhi Fei Tao ◽  
Lei Ma

The research mainly focuses on the performance of the controllable hypocenter in the low frequency band. The hybrid vibration isolation method based on the disturbance observer PID control algorithm is used to improve the excitation signal quality. Based on the analysis of the structure and working principle of vibration isolator, the physical model and mathematical model are established, and the simulation test of ZK-5VIC virtual test vibration and control system is carried out. The experimental platform of hybrid vibration isolation system with low frequency interference is set up. The experiment of excitation and acquisition of low frequency signal is carried out, which provides the theoretical basis and guarantee for the vibration isolation technology in the low frequency range below 3Hz.


2011 ◽  
Vol 383-390 ◽  
pp. 130-135 ◽  
Author(s):  
Fu Mao Wang ◽  
Chang Guo Wang ◽  
Lan Lan Guo ◽  
Bang Chun Wen ◽  
Yong Li

In this paper, based on the theory of double layered vibration isolation, the finite element dynamic model of floating raft vibration isolation system has been established for the project of vibration and noise control in a heat exchange station. The dynamic model of single pump is simplified an elastic cylinder based on the principle of equivalent parameters, and the elastic raft frame is used of steel structure. The dynamic characteristics of the system is analyzed by used of ANSYS with SOLID45 unit and COMBIN14 spring-damper unit, which provide an important basis for the engineering design of floating raft isolation system with pumping units.


Author(s):  
Liao Dao-Xun ◽  
Lu Yong-Zhong ◽  
Huang Xiao-Cheng

Abstract The multilayer vibration isolation system has been widely applied to isolate vibration in dynamic devices of ships, high-speed vehicles forging hammer and precise instruments. The paper is based on the coordinate transformation of space general motion for mass blocks (rigid bodies) and Lagrangian equation of multilayer vibration isolation system. It gives a strict mathematical derivation on the differential equation of the motion for the system with six degrees of freedom of relative motion between mass blocks (including base). The equations are different from the same kind of equations in the reference literatures. It can be used in the floating raft of ships in order to isolates vibration and decrease noise, also used in design calculation of the multilayer vibration isolation for dynamic machines and precise instruments on the dry land.


Author(s):  
A. Narimani ◽  
M. F. Golnaraghi

Semi-active isolators offer significant improvement in performance over passive isolators. These systems benefit from the advantages of active systems with the reliability of the passive systems. In this work we study a vibration isolation system with a magnetorheological (MR) damper. The experimental investigation of the mechanical properties of a commercially available linear MR damper (RD-1005-3) was conducted next. The mathematical Bouc-Wen model was adopted to predict the performance of MR damper. In addition, a modified Bingham model has been developed to characterize the damper behavior more accurately and efficiently. The measured hysteresis characteristics of field-dependent damping forces are compared with the simulation results from the described mathematical models. The accuracy of a damping-force controller using the proposed method is also demonstrated experimentally. Finally, a scaled quarter car model is set up to study the performance of the control strategy. The experimental results show that with the semi-active control the vibration of the quarter car model is well controlled.


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