Active Control of Flexible Structures Based on Fuzzy Logic

Composites Part B: Engineering, 1999

The temperature effects on frequency, loss factor and control of a flexible beam with a constrained viscoelastic layer and shape memory alloy layer(SMA) are discussed. It is shown that the temperature in the SMA (actuation) layer is very important in the determination of frequency and loss factor of such a structure. The effects of damping layer shear modulus and damping layer height as affected by the temperature are also discussed. As temperature plays such an important role, it is, therefore, imperative to evaluate temperature effects on the control of the system as well. Results with and without active control are discussed.

2005

An adaptive truss structure with self-learning active vibration control system is developed. A fuzzy-neural network (FNN) controller with adaptive membership functions is presented. The experimental setup of a two-bay truss structure with active members is constructed, and the FNN controller is applied to vibration suppression of the truss. The controller first senses the output of the accelerometer as an error to activate the adaptation of the weights of the controller, and then a control command signal is calculated based on the FNN inference mechanism to drive the active members. This paper describes active vibration control experiments of the truss structure using fuzzy neural network.

IEEE Transactions on Instrumentation and Measurement, 2005

2011

This paper investigates the feasibility of using active force control (AFC) method for the problem of active vibration control (AVC) of a flexible thin plate structure through simulation. The plate system was first modeled and simulated using Finite Difference (FD) method. Then, the validity of the obtained computational model was investigated through comparative studies between the plate natural frequencies predicted by the model and the exact values of resonance modes found in literature. The AFC algorithm was then embedded within the FD simulation platform to study the performance of the control scheme. An appropriate value of the mass gain in the AFC algorithm was estimated to be 14 kg through crude approximation technique which was later shown to be close to the real mass of the plate system. Different types of disturbances were applied to excite the plate system at different excitation points so that the robustness of the proposed control algorithm can be evaluated in terms of its performance in reducing the vibration at observation point. Results of the study clearly demonstrated the effectiveness of the proposed control strategy to attenuate the unwanted vibrations of the flexible thin plate system.

Proceedings of IEEE International Conference on Control and Applications CCA-94, 1994

This paper designs a fuzzy logic controller to suppress the vibrations of a large space antenna-like ground experimental structure located at the JPL/AF-PL Large Spacecraft Control Laboratory. This fuzzy logic controller provides a simple, yet robust, means to the vibration control of a highly uncertain structural system.

2002

The recent years have seen the innovative system integration of a great many actuator technologies, such as point force actuators for space vehicle applications and the use of single fire actuators; such as pyrocharges to guide a free falling bomb to it's target. The inherent limitations of these developments, such as nonlinear behavior under extreme environments and/or prolonged/repeated usage leading to a relaxation time component between firing of actuators and inherent system power limitations, have resulted in greater need for sophisticated control algorithms that allow for optimal switching between various actuators in any given embedded configuration so as to achieve the best possible performance of the system. The objective of this investigation is to offer a proof of concept experimental verification of a real time control algorithm, which switches between online piezoelectric actuators, employed for vibration control in an aluminum beam with fixed boundary conditions. In this investigation at a given interval of time, only one actuator is activated and the rest are kept dormant. The reason is to demonstrate the better vibration alleviation characteristics realized in switching between actuators depending on the state of the system, over the use of a single actuator that is always in fire mode. This effect is particularly pronounced in controlling systems affected by spatiotemporal disturbances. The algorithm can be easily adapted for various design configurations or system requirements. The optimality of switching is with respect to the minimal cost of an LQR performance index that corresponds to each actuator. Computer simulations with repeatable disturbance profiles, revealed that this algorithm offered better performance over the non-switched case. Performance measures employed were ii the time varying total energy norm of the dynamic system and position traces at any particular location on the beam. This algorithm was incorporated on a dSPACE rapid prototyping platform along with suitable hardware. Experimental and simulation results are discussed.

Modeling, Simulation and …

This paper presents the development of dynamic model of flexible beam structure using finite difference method. The simulated model is validated by comparing the resonance modes with the theoretical values. Simple proportional (P) control scheme is used as active vibration control (AVC) algorithm for the system. Simulation study of the control system is done by gradually increasing the proportional gain until it reaches the optimum value. The effectiveness of this control scheme is observed based on its capability to suppress unwanted vibration of the beam. The attenuation of the beam is validated through time and frequency responses. The effect of proportional gain on the dynamic behavior of the actuator is also reported. Simulation is done using LabVIEW graphical programming environment. Results of the study clearly reveal the effectiveness of proportional control scheme in reducing the vibration of the beam.

2008

In this paper the vibration suppression of a flexible structure using fuzzy controller with bonded piezoelements is investigated. A flexible beam with PZT piezoceramics as sensor and actuators is fabricated at the Advanced Dynamic and Control Systems lab (ADCSL). A dynamic model of the smart structure is derived from an experimental system ID. On the other hand using finite element method (FEM), a theoretical model of the structure is obtained which is in good agreement with the experimental model. A fuzzy control system is then designed and implemented for vibration suppression of the smart beam subjected to the impulse excitation and resonance disturbances. Results show the effectiveness of the fuzzy controller and its advantage over conventional controllers.

Nonlinear Dynamics, 1996

Active control of structures against environmental loads, such as earthquakes and wind, has received much attention in the last decade. Much of this research has involved development of control algorithms based on the assumption of exact knowledge of the system parameters, a condition that does not always exist in real-life applications. In addition, most of this research effort has focused upon linear control. Few active control strategies can effectively handle control of nonlinear behavior.

Modeling, Signal Processing, and Control for Smart Structures 2008, 2008

In this paper the vibration suppression of a flexible structure using fuzzy controller with bonded piezoelements is investigated. A flexible beam with PZT piezoceramics as sensor and actuators is fabricated at the Advanced Dynamic and Control Systems lab (ADCSL). A dynamic model of the smart structure is derived from an experimental system ID. On the other hand using finite element method (FEM), a theoretical model of the structure is obtained which is in good agreement with the experimental model. A fuzzy control system is then designed and implemented for vibration suppression of the smart beam subjected to the impulse excitation and resonance disturbances. Results show the effectiveness of the fuzzy controller and its advantage over conventional controllers.