A comparative study for collocated and non-collocated sensor/actuator placement in vibration control of a maneuvering flexible satellite

Author(s):  
Morteza Shahravi ◽  
Milad Azimi

This paper presents a study concerning the vibration control of smart flexible sub-structures of satellite during attitude maneuver. A comparison between the collocated and non-collocated piezoceramic patches acting as sensors and actuators is performed in order to investigate their effectiveness to suppress vibrations in flexible substructures. A rigid hub with two elastic appendages containing surface bounded piezoelectric patches is being considered as satellite model. Finite element method and Lagrangian formulation are used for derivation of system equations of motion. Stability proof of the overall closed-loop system is given via Lyapunov analysis. The numerical simulations verify the results of the study.

1997 ◽  
Vol 119 (3) ◽  
pp. 658-667 ◽  
Author(s):  
J. P. Hathout ◽  
A. El-Shafei

This paper describes the proportional integral (PI) control of hybrid squeeze film dampers (HSFDS) for active control of rotor vibrations. Recently it was shown that the automatically controlled HSFD based on feedback of rotor speed can be a very efficient device for active control of rotor vibration when passing through critical speeds. Although considerable effort has been put into the study of steady-state vibration control, there are few methods in the literature applicable to transient vibration control of rotor-bearing systems. Rotating machinery may experience dangerously high dynamic loading due to the sudden mass unbalance that could be associated with blade loss. Transient run-up and coast down through critical speeds when starting up or shutting down rotating machinery induces excessive bearing loads at criticals. In this paper, PI control is proposed as a regulator for the HSFD system to attenuate transient vibration for both sudden unbalance and transient runup through critical speeds. A complete mathematical model of this closed-loop system is simulated on a digital computer. Results show an overall enhanced behavior for the closed-loop rotor system. Gain scheduling of both the integral gain and the reference input is incorporated into the closed-loop system with the PI regulator and results in an enhanced behavior of the controlled system.


2011 ◽  
Vol 2-3 ◽  
pp. 33-38
Author(s):  
Shao Hua Li ◽  
Shao Pu Yang ◽  
Na Chen

A two degree of freedom (DOF) lateral dynamic model for a three-axe heavy vehicle is set up and the vehicle ordinary differential equations of motion are derived. The nonlinear lateral tire forces are obtained by Gim model with vertical loads, slip angles and cornering performances of front and rear tires being input parameters. A revised closed-loop single-point preview method is proposed to model the driver’s directional control performance. In this proposed method, the steering angle of front wheels is calculated in real time according to the track error between a certain point ahead of the vehicle and the required route. Then the steering angle is input into the vehicle model to gain the dynamic responses and position of the vehicle in next time step. Thus the driver-heavy-vehicle closed-loop system is built. The dynamic responses of the system are simulated on the condition of double lane change and the effects of system parameters on the path following behavior of the vehicle are researched. Then the advice on how to improve the vehicle directional control ability can be brought forward.


2020 ◽  
Vol 10 (6) ◽  
pp. 6549-6556
Author(s):  
K. G. Aktas ◽  
I. Esen

The aim of this study is to design a Linear Quadratic Regulator (LQR) controller for the active vibration control of a smart flexible cantilever beam. The mathematical model of the smart beam was created on the basis of the Euler-Bernoulli beam theory and the piezoelectric theory. State-space and finite element models used in the LQR controller design were developed. In the finite element model of the smart beam containing piezoelectric sensors and actuators, the beam was divided into ten finite elements. Each element had two nodes and two degrees of freedom were defined for each node, transverse displacement, and rotation. Two Piezoelectric ceramic lead Zirconate Titanate (PZT) patches were affixed to the upper and lower surfaces of the beam element as pairs of sensors and actuators. The location of the piezoelectric sensor and actuator pair changed and they were consecutively placed on the fixed part, the middle part, and the free end of the beam. In each case, the design of the LQR controller was made considering the first three dominant vibratory modes of the beam. The effect of the position of the sensor-actuator pair on the beam on the vibration damping capability of the controller was investigated. The best damping performance was found when the sensor-actuator pair was placed at the fixed end.


Author(s):  
J. P. Hathout ◽  
A. El-Shafei

This paper describes the proportional integral (PI) control of hybrid squeeze film dampers (HSFDs) for active control of vibrations of rotors. Recently it was shown that the automatically controlled HSFD based on feedback of rotor speed can be a very efficient device for active control of rotor vibration when passing through critical speeds. Although considerable effort has been put into the study of steady state vibration control, there are few methods in the literature applicable to transient vibration control of rotor-bearing systems. Rotating machinery may experience dangerously high dynamic loading due to the sudden mass unbalance that could be associated with blade loss. Transient run-up and coast down through critical speeds when starting up or shutting down rotating machinery induces excessive bearing loads at criticals. In this paper, PI control is proposed as a regulator for the HSFD system to attenuate transient vibration for both sudden unbalance and transient run-up through critical speeds. A complete mathematical model of this closed-loop system is simulated on a digital computer. Results show an overall enhanced behavior for the closed-loop rotor system. Gain scheduling of both the integral gain and the reference input is incorporated to the closed-loop system with the PI regulator and results in an enhanced behavior of the controlled system.


Author(s):  
H. S. Tzou

Abstract Conventional shell continua are passive, which do not possess any sensation and action/reaction capabilities. In this paper, distributed piezoelectric layers coupled with conventional elastic shell distributed systems are used as distributed “neurons” (sensors) and “muscles” (actuators) for structural monitoring and actuation of shells. New theories on distributed “neural” sensation and actuation of shells are developed based on a generic shell continuum coupled with piezoelectric neurons and muscles. Open and closed loop system dynamic equations are also derived. The system equations are further transferred to state equations. The derived theories can be directly simplified to a broad class of geometries, cylindrical shells, spherical shells, conical shels, zero-curvature shells (i.e., plates: rectangular, circular, etc.), beams, etc. Applications of the theories to a cylindrical shell using four system parameters, two Lame’s parameters and two radii of curvature, are demonstrated.


AIAA Journal ◽  
1998 ◽  
Vol 36 ◽  
pp. 1763-1765
Author(s):  
Young K. Kang ◽  
Hyun C. Park ◽  
Brij Agrawal

2015 ◽  
Vol 77 (17) ◽  
Author(s):  
Auwalu M. Abdullahi ◽  
Z. Mohamed ◽  
M. S. Zainal Abidin ◽  
R. Akmeliawati ◽  
Amiru A. Bature

This paper presents stability analysis and vibration control of a class of negative imaginary systems. A flexible manipulator that moves in a horizontal plane is considered and is modelled using the finite element method. The system with two poles at the origin is shown to possess negative imaginary properties. Subsequently, an integral resonant controller (IRC) which is a strictly negative imaginary controller is designed for the position and vibration control of the system. Using the IRC, the closed-loop system is observed to be internally stable and simuation results show that satisfactory hub angle response is achieved. Furthermore, vibration magnitudes at the resonance modes are suppressed by 48 dB.


Author(s):  
A. H. Daraji ◽  
J. M. Hale

This paper concerns optimal placement of discrete piezoelectric sensors and actuators for active vibration control, using a genetic algorithm based on minimization of linear quadratic index as an objective function. A new method is developed to get state space matrices for simple and complex structures with bonded sensors and actuators, using the ANSYS finite element package taking into account piezoelectric mass, stiffness and electromechanical coupling effects. The state space matrices for smart structures are highly important in active vibration control for the optimisation of sensor and actuator locations and investigation of open and closed loop system control response, both using simulation and experimentally. As an example, a flexible flat plate with bonded sensor/actuator pairs is represented in ANSYS using three dimensional SOLID45 elements for the passive structure and SOLID5 for the piezoelectric elements, from which the necessary state space matrices are obtained. To test the results, the plate is mounted as a cantilever and two sensor/actuator pairs are located at the optimal locations. These are used to attenuate the first six modes of vibration using active vibration reduction based on a classical and optimal linear quadratic control scheme. The plate is subject to forced vibration at the first, second and third natural frequencies and represented in ANSYS using a proportional derivative controller and compared with a Matlab model based on ANSYS state space matrices using linear quadratic control. It is shown that the ANSYS state space matrices describe the system efficiently and correctly.


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