Transfer Function Of Actuator Research Articles

Experimental investigation of vibration attenuation on a cantilever beam using air-jet pulses with the particle swarm optimized quasi bang–bang controller

This study deals with the vibration reduction of a cantilever beam using air-jet thruster actuators controlled by the particle swarm optimized quasi bang–bang controller. In this study, the finite element model of a cantilever beam with the lumped mass of actuators is formed for the numerical simulations. Furthermore, the first-order plus dead time transfer function of the air-jet thruster actuator is found between the inlet pressure and the thrust. The quasi bang–bang control is proposed to suppress vibrations on the beam with impulsive air-jet pulses. The optimal location of the actuators and control parameters are determined with parametric study and particle swarm optimization, respectively. The performance of the control method is measured with the experiments of initial displacement, the presence of tip masses, and external disturbances. According to all results obtained in this study, it has been observed that the air-jet pulses successfully and rapidly attenuate vibration on the cantilever beam with the quasi bang–bang controller.

Structural-parametric model actuator of adaptive optics for composite telescope and astrophysics equipment

In this paper, we obtained the structural-parametric model, the matrix transfer function, the static and dynamic characteristics of the multilayer electromagnetoelastic actuator of adaptive optics. It was designed the structural diagram of the multilayer electromagnetoelastic actuator of adaptive optics for composite telescope and astrophysics equipment in contrast to electrical equivalent circuits of the piezotransducer and the vibration piezomotor.

Structural-parametric model of an electroelastic actuator for nanomechanics

Structural-parametric models, structural schemes are constructed and the transfer functions of electro-elastic actuators for nanomechanics are determined. The transfer functions of the piezoelectric actuator with the generalized piezoelectric effect are obtained. The changes in the elastic compliance and rigidity of the piezoactuator are determined taking into account the type of control. Keywords electro-elastic actuator, piezo actuator, structural-parametric model, transfer function, parametric structural scheme

Structural Schemes and Structural-Parametric Models of Electroelastic Actuators for Nanomechatronics Systems

The parametric structural schemes, structural-the parametric models and the transfer functions of the electroelastic actuators for the nanomechatronics systems are obtained. The transfer functions of the piezoactuator are determined under the generalized piezoelectric effect. The changes in the elastic compliance and the stiffness of the piezoactuator are found, taking into account the type of control. The decision wave equation and the structural-parametric models of the electroelastic actuators are obtained. Effects of the geometric and physical parameters of the electroelastic actuators and the external load on its static and dynamic characteristics are determined. The parameteric structural schemes for the electroelastic actuators for the nanomechatronics systems are obtained. The transfer functions are determined. For calculation of the automatic control systems for the nanometric movements with the electroelastic actuators are obtained the parametric structural schemes and the transfer functions of actuators. Static and dynamic characteristics of the electroelastic actuators are determined. The application of electroelastic actuators solves problems of the precise matching in microelectronics and nanotechnology, compensation of temperature and gravitational deformations, atmospheric turbulence by wave front correction. By solving the wave equation with allowance for the corresponding equations of the piezoelectric effect, the boundary conditions on loaded working surfaces of the electroelastic actuator, the strains along the coordinate axes, it is possible to construct the structural parametric model of the actuator. The transfer functions and the parametric structural schemes of the electroelastic actuator are obtained from the equations describing the corresponding structural parametric models and taking into account the opposed electromotive force of the electroelastic actuator for the nanomechatronics systems.

Структурные схемы электроупругого актюатора наномехатронных систем

The structural diagrams of an electroelastic actuator for nanomechatronic systems on the basis of the generalized piezoelectric effect and taking into account the counter EMF caused by the direct piezoelectric effect are defined. The structural-parametric models of electroelastic actuators for nanomechatronic systems under the conditions of transverse, longitudinal, shear, and generalized piezoelectric effects, and with control using the voltage or current feedback signals are obtained. The structural-parametric model and structural diagrams with feedbacks developed for the electroelastic actuators of nanomechatronic systems reflect the conversion of electrical energy into mechanical energy. The structural-parametric model and structural diagram of an electroelastic actuator are determined depending on the type of its control using the voltage or current feedback signal. The maximal forces and mechanical stresses developed by the piezo actuator of nanomechatronic systems under the conditions of transverse, longitudinal, shear, and generalized piezoelectric effects are determined. The piezo actuator’s elastic compliance and stiffness values under the conditions of transverse, longitudinal, shear, and generalized piezoelectric effects are determined depending on the type of control in a nanomechatronic system: using the voltage or current feedback signal. The transfer functions of piezo actuators under the conditions of transverse, longitudinal, shear, and generalized piezoelectric effects and with control using the voltage or current feedback signal are obtained.

Line of sight controller tuning using Bayesian optimisation: application to a double stage stabilisation platform

ABSTRACTThe inertial stabilisation of the line of sight of an imager fixed on a mobile carrier is considered in order to acquire good quality images despite the disturbances generated by the carrier. A double stage mechanical stabilisation architecture is proposed, where a second stabilisation stage, based on a piezoelectric actuator, is added to the usual structure. The piezoelectric actuator transfer function and hysteresis are characterised through experiments. In order to design the controllers of both stages, a high-level image quality criterion (the modulation transfer function (MTF)) is considered, together with design constraints on the main variables of interest. The criterion and the constraints are evaluated by realistic simulations based on some input and noise profiles measured on a real-life system. The MTF evaluation being time-consuming, a Bayesian optimisation method specially dedicated to expensive-to-evaluate functions is used to obtain the parameters of the controllers. The obtain experimental results are displayed and their performances discussed.

Structural-Parametric Models and Transfer Functions of Electromagnetoelastic Actuators Nano- and Microdisplacement for Mechatronic Systems

Structural-parametric models, parametric structural schematic diagrams and transfer functions of electromagnetoelastic actuators are determined. A generalized parametric structural schematic diagram of the electromagnetoelastic actuator is constructed. Effects of geometric and physical parameters of actuators and external load on its dynamic characteristics are determined. For calculations the mechatronic systems with piezoactuators for nano- and microdisplacement the parametric structural schematic diagrams and the transfer functions of piezoactuators are obtained.

Modelowanie i aproksymacja funkcji przenoszenia maszynek sterowych rakiety przeciwlotniczej

Modelowanie i aproksymacja funkcji przenoszenia maszynek sterowych rakiety przeciwlotniczej

Self-Sensing Control of Nafion-Based Ionic Polymer-Metal Composite (IPMC) Actuator in the Extremely Low Humidity Environment

This paper presents feedforward, feedback and two-degree-of-freedom control applied to an Ionic Polymer-Metal Composite (IPMC) actuator. It presents a high potential for development of miniature robots and biomedical devices and artificial muscles. We have reported in the last few years that dehydration treatment improves the electrical controllability of bending in Selemion CMV-based IPMCs. We tried to replicate this controllability in Nafion-based IPMC. We found that the displacement of a Nafion-based IPMC was proportional to the total charge imposed, just as in the Selemion-CMV case. This property is the basis of self-sensing controllers for Nafion-based IPMC bending behavior: we perform bending curvature experiments on Nafion-based IPMCs, obtaining the actuator's dynamics and transfer function. From these, we implemented self-sensing controllers using feedforward, feedback and two-degree-of-freedom techniques. All three controllers performed very well with the Nafion-based IPMC actuator.

Modeling and validation of magnetostrictive sound transducer including flat panel

This paper contains models of the magnetostrictive actuator and flat panel for the investigation of interaction between actuator and flat panel. (1) A transfer function of the magnetostrictive actuator between a displacement Ua and input current I: Ga(s)=Ua(s)/I(s)=nd/(1+c/co+sr/co+s2m/co), where n is number of coil turns, d is magnetostrictive constant, c is stiffness of prestress spring, co is open circuit stiffness, r is damping coefficient, and m is effective mass. (2) Transfer functions of a flat panel: Gf(s)=Uf(s)/Ua(s)=−A/(−B+C+D),A=m1k1s2/(m1s2+c1s+k),B=m2s2+(c1+c2)s+(k1+k2),C=(c1s+k1)2/(m1s2+c1s+k1),D=(c2s+k2)2/(m3s2+(c2+c3)s+k2+k3), where m, c, and k are parameters of the actuator and flat panel models, and parameters are determined experimentally. The final transfer function of actuator and flat panel is expressed by multiplying Ga(s) and Gf(s). Simulations are performed through commercial program under the conditions applying a white noise to the final transfer function. The simulated and experimental frequency responses are compared.

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Design and control of high precision 3D pickup actuators for near field recording system

In the NFR system, since the gap between SIL and disc is under 100 nm, the precise control of actuator is required. For the stable gap control, performance of actuator should be improved. When the mass center and centroid of actuator is not coincide with each other, coupling between linear and rotational motion appears and in near field recording system, it affects directly readout performance. Therefore, by constructing general mathematical model of actuator which can reflect coupling motion, quantity of coupling was analyzed. Moreover, by sensitivity analysis, critical variables which affect coupling motion were selected and by applying optimal value to the system, coupling effect was decreased effectively. By measuring transfer function of actuator, analytic approach was verified.

Adaptive disturbance rejection in an optical trap

This article presents a method for characterizing the system dynamics of a trapped particle in real-time and designing a controller to minimize disturbances to the particle's position. Specifically, adaptive system identification is used to determine the trap characteristics and the actuator transfer function describing the mirror voltage to trap position path. Using an internal model control scheme combined with a filtered-x least-mean-square algorithm, adaptive control was used to create a controller that minimizes a frequency weighted mean-squared-error. The dynamics associated with multiple particle sizes and materials were experimentally determined under different power levels, each case resulting in different system dynamics and demonstrating positive control results. The adaptive system identification and the controller presented automate the process of system identification and control design, enabling the automation of optical trap controller design.

Integrated servo/mechanical design of HDD actuators and bandwidth estimation

An optimal design technique of both the actuator dynamics and the servo controller is presented. The actuator dynamics are characterized by the time delay created by the unstables zeros of the actuator transfer function. The achievable bandwidth is a simple function of the time delay and the sampling frequency. The feedback controller, including the notch filter, is designed simultaneously. The performance with dynamics variations can also be evaluated by the time delay. It is shown that the variations of the high-frequency modes play an important role in the bandwidth improvement of the dual-stage system.

A design method of a multi-rate servo controller using H/sub ∞/

A method of designing a multi-rate servo controller for a HDD that operates at a higher sampling frequency than that of the position error signal (PES) is proposed. Multi-rate sampling has an advantage for increasing the track density of a HDD without increasing the overhead of the servo information on the disk. A plant model for a design with a higher sampling rate is obtained by adding a zero-interpolator at the output of the position error signal. The controller is calculated by the H/spl infin/ method to suppress the noise at the PES sampling frequency that is created by the use of multi-rate sampling. The servo bandwidth and margins of the method are studied for 2.5" and 3.5" HDDs, and for an HDD with a dual-stage actuator. The multi-rate sampling is especially effective for the dual-stage actuator because the MEMS actuator's transfer function is very clean.

Electromechanical Modeling of Hybrid Piezohydraulic Actuator System for Active Vibration Control

Electromechanical modeling of a hybrid piezohydraulic actuator system for active vibration control was developed. The transfer function of piezoelectric actuator was derived from the electromechanical potential energy law. This transfer function represents the dynamic relationship between input electric voltage and piezoelectric actuator displacement. The hydraulic actuator was characterized by impedance matching in which its transfer functions were experimentally determined. The transfer functions were transformed into a state-space representation, which is easily assembled into an active vibration control (AVC) closed-loop simulation. Good correlation of simulation and test was achieved for the hybrid system. A closed-loop dynamic simulation for imbalance response with/without AVC of a spinning rotor test rig at NASA Lewis was performed and showed excellent agreement with test results. The simulation couples the piezoelectric, hydraulic, and structural (rotor) components.