This article presents in a unified way, the various optimization criteria used by researchers for optimal placement of piezoelectric sensors and actuators on a smart structure. The article discusses optimal placement of piezoelectric sensors and actuators based upon six criteria: (i) maximizing modal forces/moments applied by piezoelectric actuators, (ii) maximizing deflection of the host structure, (iii) minimizing control effort/maximizing energy dissipated, (iv) maximizing degree of controllability, (v) maximizing degree of observability, and (vi) minimizing spill-over effects. Optimal piezoelectric sensor and actuator locations on beam and plate structures for each criterion and modes of interest are presented in a tabular form. This technical review has two objectives: (i) practicing engineers can pick the most suitable philosophy for their end application and (ii) researchers can come to know about potential gaps in this area.

Optimization Criteria for Optimal Placement of Piezoelectric Sensors and Actuators on a Smart Structure: A Technical Review

Vibration control of civil structures using piezoceramic smart materials: A review

Active vibration control of smart piezoelectric beams: Comparison of classical and optimal feedback control strategies

In this paper, the placement of piezoelectric sensors and actuators has been studied. Genetic algorithms have been used to find efficient locations of piezoelectric sensors and actuators of a smart composite place. Locations of both sensors and actuators have been determined with consideration of controllability, observability and spillover prevention. The composite specimen with piezoelectric sensors and actuators has been prepared according to the optimization result. The experimental vibration control shows significant vibration reduction for the controlled modes with little effect on the residual modes. In addition, the closed loop system is observed to be robust with respect to system parameter variations.

http://iopscience.iop.org/article/10.1088/0964-1726/8/2/012/pdf

Optimal placement of piezoelectric sensors and actuators for vibration control of a composite plate using genetic algorithms

The recent advent of highly durable engineering materials and the advancement of latest structural design theories have made possible the fabrication of more efficient engineering structures. However, the safety and reliability of these structures remains the primary challenge and concern for engineers. Especially, for those structures which involve human traffic and huge investments such as the aerospace structures and bridges. Therefore, there is a compelling need to have high-quality online structural health monitoring (SHM) of such structures. The development of a real-time, in-service, and smart material-based SHM method has recently attracted the interest of a large number of academic and industrial researchers. In the recent past, piezoceramic (PZT) transducer has evolved as an efficient smart material, which is usually employed in electro mechanical impedance (EMI) and guided ultrasonic wave propagation techniques. In EMI technique, a PZT transducer interact with the host structure to result in un...

Application of Electromechanical Impedance Technique for Engineering Structures: Review and Future Issues:

In order to reduce the vibrational level of lightweight composite structures, active vibration control methods have been applied both numerically and experimentally. Using the classical laminated beam theory and Ritz method, an analytical model of the laminated composite beam with piezoelectric sensors and actuators has been developed. Smart composite beams and plates with surface-bonded piezoelectric sensors and actuators were manufactured and tested. It is found that the developed analytical model predicts the dynamic characteristics of smart composite plates very well. Utilizing a linear quadratic Gaussian (LQG) control algorithm as well as well known classical control methods, a feedback control system was designed and implemented. A personal computer (PC) was used as a controller with an analogue - digital conversion card. For a cantilevered beam the first and second bending modes are successfully controlled, and for cantilevered plates the simultaneous control of the bending and twisting modes gives a significant reduction in the vibration level. LQG has shown advantages in robustness to noise and control efficiency compared with classical control methods. In this study examples of control spillover are demonstrated via the instantaneous power spectrum of the sensor output.

https://iopscience.iop.org/article/10.1088/0964-1726/6/5/006/pdf

An experimental study of active vibration control of composite structures with a piezo-ceramic actuator and a piezo-film sensor

An adaptive controller, Adaptive Positive Position Feedback (APPF) is proposed for the multi-modal vibration control of frequency varying structures. Spillover phenomena and real-time system identification have been obviously difficult obstacles for the multi-modal adaptive vibration control. To overcome these problems, a fast and powerful algorithm is proposed to identify the frequencies of time-varying structures. Variable PPF controllers are adjusted with estimated natural frequencies at every time step. A composite plate with a bonded piezoelectric sensor and an actuator was prepared as an experimental model, and the natural frequencies of the model are changed by attaching masses. The experimental results show that natural frequencies are estimated quite accurately and that the vibration of controlled modes is significantly reduced. No significant performance reduction has been observed with respect to approximately 10% frequency changes of the corresponding modes. On the contrary, the performance of...

Multi-modal vibration control using Adaptive Positive Position Feedback

In this paper, the anthropomorphic robot hand is newly proposed by adopting dual-mode twisting actuation and EM joint locking mechanism. The proposed robot hand consists of five finger modules. Each finger has four links and three joints, and Joint 2 and 3 are coupled by the four-bar linkage mechanism. The dual-mode twisting actuation allows that the robot finger can move fast (up to 356.7 deg/sec) in Mode I and generate a large grasping force(up to 36.5 N) in Mode II. In addition, the workspace of the robot finger module is enlarged by EM joint locking mechanism depending on the locking states. In order to verify the effectiveness of the mechanisms adopted in the robot hand, we theoretically and numerically analyze the performances of the robot finger module such as bending speed, fingertip force, and workspace. Finally, through the developed robot hand, we perform the grasping test for various objects and the grasping performance is experimentally demonstrated.

Development of anthropomorphic robot hand with dual-mode twisting actuation and electromagnetic joint locking mechanism

In this paper, we propose the asymmetric S-curve motion profile that enables easy manipulation of jerks during the arrival time in order to effectively reduce the residual vibration. To derive the complete closed form solution to the asymmetric S-curve, a design parameter the so-called jerk ratio is introduced to scale down the jerks during the deceleration period so that the velocity profile is in an asymmetric S-curve. Thanks to the jerk ratio, the motion parameters are remarkably simplified in analytic forms for short, medium and long distances. The effectiveness of the proposed approach is validated by experiments with the AC motor control system. As the jerk ratio increases, the residual vibration decreases, but, the motion profile is lengthened as expected by simulations.

A Complete Solution to Asymmetric S-curve Motion Profile

In this paper, various methods for the real-time estimation of multi-modal frequencies are realized in real time and compared through numerical and experimental tests. These parameter-based frequency estimation methods can be applied to various engineering fields such as communications, radar and adaptive vibration and noise control. Well-known frequency estimation methods are introduced and explained. The Bairstow method is introduced to find the roots of a characteristic equation for estimations of multi-modal frequencies, and the computational efficiency of the Bairstow method is shown quantitatively. For a simple numerical test, we consider two sinusoids of the same amplitudes mixed with various amounts of white noise. The test results show that the auto regressive (AR) and auto regressive and moving average (ARMA) methods are unsuitable in noisy environments. The other methods apart from the AR method have fast tracking capability. From the point of view of computational efficiency, the results reveal that the ARMA method is inefficient, while the cascade notch filter method is very effective. The linearized adaptive notch filter and recursive maximum likelihood methods have average performances. Experimental tests are devised to confirm the feasibility of real-time computations and to impose the severe conditions of drastically different amplitudes and of considerable changes of natural frequencies. We have performed experiments to extract the natural frequencies from the vibration signal of wing-like composite plates in real time. The natural frequencies of the specimen are changed by added masses. Especially, the AR method exhibits a remarkable performance in spite of the severe conditions. This study will be helpful to anyone who needs a frequency estimation algorithm for real-time applications.

/pdf/real-time-estimations-of-multi-modal-frequencies-for-smart-4av11lp4o3.pdf

Keun-Ho Rew

Papers

An experimental study of active vibration control of composite structures with a piezo-ceramic actuator and a piezo-film sensor

Multi-modal vibration control using Adaptive Positive Position Feedback

Development of anthropomorphic robot hand with dual-mode twisting actuation and electromagnetic joint locking mechanism

A Complete Solution to Asymmetric S-curve Motion Profile

Real-time estimations of multi-modal frequencies for smart structures