Review of State of Art of Smart Structures and Integrated Systems

Review of magnetostrictive patch transducers and applications in ultrasonic nondestructive testing of waveguides.

In this article we present results for magnetostrictive composites containing between 10% and 50% Terfenol-D (Tb0.3Dy0.7Fe2) in a nonmetallic binder. The composite consists of aligned Terfenol-D particles representative of a [1-3] fiber composite. For this study we measure the modulus of elasticity and other pertinent magnetostrictive properties. The measured stiffness values fall between the upper and lower bounds predicted by a rule of mixtures approximation. The magnetostriction for the composites rival that of the monolithic at comparable magnetic field levels. A mechanically unloaded 20% volume fraction composite produces 900 ppm and a 30% volume fraction composite preloaded with 8 MPa produces 1000 ppm. Contrary to the belief that the greater the magnetostrictive particulate volume, the greater magnetostrictive properties—this study shows that there is an optimal balance of epoxy and magnetostrictive material that will maximize magnetostriction for a mechanically unloaded specimen. For the matrix ch...

Large magnetostrictive response of Terfenol-D resin composites (invited)

Magnetostrictive materials are routinely employed as actuator and sensor elements in a wide variety of noise and vibration control problems. In infrastructural applications, other technologies such as hydraulic actuation, piezoelectric materials and more recently, magnetorheological fluids, are being favored for actuation and sensing purposes. These technologies have reached a degree of technical maturity and in some cases, cost effectiveness, which justify their broad use in infrastructural applications. Advanced civil structures present new challenges in the areas of condition monitoring and repair, reliability, and high-authority actuation which motivate the need to explore new methods and materials recently developed in the areas of materials science and transducer design. This paper provides an overview of a class of materials that because of the large force, displacement, and energy conversion effciency that it can provide is being considered in a growing number of quasistatic and dynamic applications. Since magnetostriction involves a bidirectional energy exchange between magnetic and elastic states, magnetostrictive materials provide mechanisms both for actuation and sensing. This paper provides an overview of materials, methods and applications with the goal to inspire novel solutions based on magnetostrictive materials for the design and control of advanced infrastructural systems.

On magnetostrictive materials and their use in adaptive structures

Magneto-thermo-mechanical characterization of 1–3 type polymer-bonded Terfenol-D composites

Magnetostrictive particulate actuators (MPAs) that take advantage of easy embedability and remote excitation capability of magnetostrictive particles are proposed as new actuators for smart structure applications. A MPA is configured as a small rectangular polymeric beam with magnetostrictive particles dispersed uniformly. Based on the compatibility condition, a load line equation is developed that relates the free strain with the mechanical stress experienced by the magnetostrictive particles. The load line equation and the magnetoelastic property of the material are used to develop a macroscopic behavior model of a MPA. Characterization experiments are used to find the orientation factor and pre-stress. Experimental work shows that the static performance of MPAs for an applied magnetic field depends on the volume fraction, orientation field, mechanical preload, and the stiffness of the polymeric matrix. In general this actuator can be used where the structure needs to be excited with a large force and small strain over a wide frequency range. For example, embedded in a laminated composite, MPAs can be used as micropositioners, vibration dampers, platform stabilizers, and motors.

https://iopscience.iop.org/article/10.1088/0964-1726/6/4/002/pdf

Magnetostrictive particulate actuators: configuration, modeling and characterization

In this article, a desired compensation version of the output feedback controller (DOFCESO) without using velocity measurement signal is proposed for precise tracking control of the three‐axis electrical‐optical gyro‐stabilized platform in the presence of largely unknown matched and mismatched modeling uncertainties. The proposed controller takes into account not only the system parametric deviations as well as the unmeasurable signal and external disturbances. To further handle the unmeasurable signal and the external disturbances, the composite extended state observer and nonlinear disturbance observer are constructed simultaneously via integrating adaptive nonlinear feedback tracking control design. To address the uncertainties arising from parametric deviations and external disturbances, the parameter adaptation mechanism is incorporated into the composite observer design to estimates of both the unmeasurable signal and the mismatched disturbance in the adaptive backstepping design. The tracking differentiator design is introduced here to estimate the derivative of the virtual control, leading to a much simpler control structure and reduced implementation costs. Furthermore, the proposed controller guarantees final tracking accuracy in the presence of time‐invariant modeling uncertainties and preserves the performance results of both control methods while overcoming their practical performance limitations. Extensive comparative experimental results are obtained to verify the high‐performance nature of the proposed control strategy.

Composite‐observer‐based adaptive robust control of electrical‐optical gyro‐stabilized platform with largely unknown modeling uncertainties and partial state feedback

In this paper, an error-driven adaptive robust feedback control with an extended sliding mode disturbance observer (ARCESO) has been developed for uncertain nonlinear systems with parametric uncertainties and uncertain nonlinearities. To address the uncertainties arising from parametric deviations and external disturbances, the parameter adaptation mechanism is incorporated into the extended sliding mode disturbance observer (ESMDO) design to estimates of both the unmeasurable signal and uncertain nonlinearities, which has better transient behavior of the estimations. An improved error-driven nonlinear functions are constructed with feedback gain self-regulates to avoid the high gain chattering of the closed loop system. The salient feature is that control performance, parametric deviations and uncertain nonlinearities as well as output feedback difficulties can be comprehensively handled with acceptable control performance. The motion control of a motor-driven robot manipulator is investigated as an application example and comparative simulation results are obtained to verify the benefits and effectiveness of the proposed control strategy.

Extended Sliding Mode Disturbance Observer-Based Error-Driven adaptive robust feedback Control of Uncertain Nonlinear Systems: theory and application

Extended-state-observer-based Error-driven Adaptive Nonlinear Feedback Control of Electrical-optical Gyro-stabilized Platform via Modified Dynamic Surface Control with Error Constraint

It is still an open and challenging issue to the typical position control problems of the three-axis electrical-optical gyro-stabilized platform systems (TEOGSP), due to inherent characteristics, for example, measurement noise, input saturation, parametric uncertainties, largely unknown load disturbance. To solve this problem, a saturated adaptive robust feedback controller using an adaptive cascaded extended state observer (SAFCESO) is proposed for compromising between the measurement noise effect and the sensitivity to disturbances. Firstly, the matched and mismatched disturbances existing in the TEOGSP system are estimated and rejected by the cascaded adaptive extended state observers (CESO). Secondly, the parametric uncertainties are evaluated by the adaptive control, and the match disturbances are attenuated by the robust control. Moreover, the adaptive robust control law does not require the velocity measurement signal and internal dynamics information of the system, which is practical to implement. Hence, all various uncertainties could be mainly compensated. Then, the improved auxiliary systems governed by smooth switching functions are developed and incorporated into the control design to compensate for the effect of the input saturation. Finally, the command filters are introduced to limit the magnitude of the virtual control and to calculate the derivative of the virtual control, respectively. The extensive comparative experimental results in the TEOGSP systems showed that the proposed SAFCESO method had superiorities in terms of high-precision tracking accuracy, robustness, and noise reduction. 

https://onlinelibrary.wiley.com/doi/pdfdirect/10.1049/cth2.12458

Saturated adaptive feedback control of electrical‐optical gyro‐stabilized platform based on cascaded adaptive extended state observer with complex disturbances

Yuefei Wu

Papers

Magnetostrictive particulate actuators: configuration, modeling and characterization

Composite‐observer‐based adaptive robust control of electrical‐optical gyro‐stabilized platform with largely unknown modeling uncertainties and partial state feedback

Extended Sliding Mode Disturbance Observer-Based Error-Driven adaptive robust feedback Control of Uncertain Nonlinear Systems: theory and application

Extended-state-observer-based Error-driven Adaptive Nonlinear Feedback Control of Electrical-optical Gyro-stabilized Platform via Modified Dynamic Surface Control with Error Constraint

Saturated adaptive feedback control of electrical‐optical gyro‐stabilized platform based on cascaded adaptive extended state observer with complex disturbances