This paper presents the design and experiment results of active position control of a shape memory alloy (SMA) wires actuated composite beam. The composite beam is honeycomb structured with shape memory alloy wires em...
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This paper presents the design and experiment results of active position control of a shape memory alloy (SMA) wires actuated composite beam. The composite beam is honeycomb structured with shape memory alloy wires embedded in one of its phase sheet for active actuation. The potential applications of this experiment include thermo-distortion compensation for precession space structure, stern shape control for submarines, and flap shape control for aeronautical applications. Shape memory alloy wires are chosen as actuating elements due to their high recovery stress (maybe >700 MPa) and tolerance to high strain (up to 8%). However, shape memory alloy wires are inherently nonlinear and pose a challenge for control design. A robust controller is designed and implemented to active control the tip position of the composite beam. The experiment setup consists of the composite beam with embedded SMA wires, a programmable current/voltage amplifier to actuate the SMA wires, an infrared laser range sensor to detect the beam tip displacement, and a real-time data acquisition and control system. Experiments demonstrated the effectiveness of the robust control.
Adaptive structures optimal design problems and solution methods are presented and discussed for the cases of shape control and active damping. A general method to solve simultaneously optimal placement and control pr...
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ISBN:
(纸本)0819431419
Adaptive structures optimal design problems and solution methods are presented and discussed for the cases of shape control and active damping. A general method to solve simultaneously optimal placement and control problems for active damping applications is outlined. This method is based on a finite element structural model and on the calculation of the closed-loop system poles. Numerical results are given to illustrate this method for the case of a beam with collocated PZT sensor/actuator pair and a direct velocity feedback controller.
Among the numerous studies published in the field of shape memory alloys (SMA), an important part is devoted to the thermomechanical properties of these materials. Few studies have been done in order to develop contro...
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ISBN:
(纸本)0819431419
Among the numerous studies published in the field of shape memory alloys (SMA), an important part is devoted to the thermomechanical properties of these materials. Few studies have been done in order to develop control laws of SMA actuators for temperature, position and force control with guaranteed stability and performances. The reason is that these materials have an highly non linear dynamic behavior (including hysteresis) because of the physical principle of motions which is a solid-solid phase transition (between an austenitic and a martensitic phase). It is then difficult to guaranty stable control and to predict the dynamic behavior in closed-loop (trajectory and effort). For this purpose, this paper is focused on control of such actuators. To obtain a control law for the closed-loop motion or force control, we use a non linear dynamic model performed in a previous work. With this dynamic model, we use non linear control techniques based on the Lie algebra to obtain the control laws for the position or the force closed-loop. Experimentation show that the proposed method is very useful for the control of SMA actuators.
A one-dimensional model for shape memory alloys is presented that permits the simulation of actuatoric behavior. It is an improved version of the Muller-Achenbach single crystal model and calculates the length change ...
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ISBN:
(纸本)0819431419
A one-dimensional model for shape memory alloys is presented that permits the simulation of actuatoric behavior. It is an improved version of the Muller-Achenbach single crystal model and calculates the length change as a response to electric heating. Based on this model, a polycrystalline version is developed, which is shown to be in excellent agreement with experimental results. Finally, as an illustrative application,a real-time control is calculated for an adaptive beam using SMA actuators.
Modeling of piezoelectric smartstructures including absorbing material was studied for cabin noise problems, The finite element method which uses a combination of three dimensional piezoelectric, flat shell and trans...
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ISBN:
(纸本)0819431419
Modeling of piezoelectric smartstructures including absorbing material was studied for cabin noise problems, The finite element method which uses a combination of three dimensional piezoelectric, flat shell and transition finite elements is adopted to model the piezoelectric active structure. The acoustic pressure in the cubic shaped cavity is represented in terms of modes of the cavity and the absorbing material is modeled using surface acoustic impedance. Finally, the effect of the cavity pressure is introduced in the finite element equations. The simulation result of sound pressure in the cavity is compared with an experiment and they show a good agreement. The cavity pressure is reduced in a wide frequency range except the resonance frequencies of the plate by applying absorbing material. It can be concluded that the piezoelectric smartstructures with absorbing materials can be a creative technology for cabin noise problems.
This paper presents a hybrid actuator scheme to actively control the end-point position of a two-link flexible manipulator. A highly nonlinear system model including inertial effects is established using Lagrange'...
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This paper presents a hybrid actuator scheme to actively control the end-point position of a two-link flexible manipulator. A highly nonlinear system model including inertial effects is established using Lagrange's equation associated with assumed mode method. control scheme consists of four different actuators; two servo-motors at the hubs and two piezoceramics bonded to the surfaces of the flexible links. Two sliding hyperplanes which have time varying parameters are designed for two servo-motors. The surface gradients of the hyperplanes are determined by pole assignment technique to guarantee the stability on the hyperplanes themselves. The sliding mode controllers corresponding to the hyperplanes are then synthesized on the basis of sliding mode conditions. During the motion, undesirable oscillations caused by the torques based on the rigid link dynamics are actively suppressed by applying feedback control voltages to the piezoceramic actuators. Consequently, desired tip motion is achieved. In order to demonstrate the effectiveness of the proposed methodology experiments are performed for the regulating and tracking control problem.
In this paper, the finite-element/boundary-element program CAPA(1) is presented, which has been developed by the authors during the last decade. With this software environment we are able to model quite different type...
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ISBN:
(纸本)0819431419
In this paper, the finite-element/boundary-element program CAPA(1) is presented, which has been developed by the authors during the last decade. With this software environment we are able to model quite different types of transducers which mostly ask for the numerical solution of a multifield problem, such as coupled electric-mechanical fields or magnetic-mechanical fields. Practical applications in the area of smartstructures will demonstrate the applicability of the developed software.
Vibration damping through phase transformation is one major area of application of shape memory alloys in smart systems and structures. The authors of this study have shown in earlier publications, how damping of vibr...
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Vibration damping through phase transformation is one major area of application of shape memory alloys in smart systems and structures. The authors of this study have shown in earlier publications, how damping of vibrating rods can be accomplished. Phase transformation due to heating/cooling is the tool for vibration damping in the past and present work. Here, an elastic, polycrystalline rod is considered, which is initially at rest, and from the time t = 0 on dynamically loaded. The loading function (pressure in the dependence on time) is in the simplest cases rectangular or bell-shaped. Special cases exist, which are equivalent to the release waves discussed in earlier papers. Heating/cooling is performed at the fixed end of the - after the impact - freely vibrating rod. This causes phase transformation on some parts of the rod according to the stress-temperature diagram. Thus, the governing equations are the heat conduction equation, the stress wave equation, the kinetic law to describe the phase transformation, and finally the constitutive law as well as a condition to ensure maximal damping. An integral equation algorithm is adapted to the impact problem for the numerical simulation. Results are provided for different, impact types and heating/cooling histories. These show the decrease of the energy divided by the impact energy depending on time.
A dynamic control model of suppressing external disturbance to beam-plates with piezoelectric sensors and activators is developed by means of the scaling function transform of the Daubechies wavelet theory. By virtue ...
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A dynamic control model of suppressing external disturbance to beam-plates with piezoelectric sensors and activators is developed by means of the scaling function transform of the Daubechies wavelet theory. By virtue of this new mathematical tool, an explicit formulation of identification of deflection configuration is expressed in terms of electric charge/current signals measured from piezoelectric sensors. After a control law of negative feedback of the identified deflection and velocity signals is employed, the wavelet Galerkin method or wavelet weighted residual method is used to determine a distribution of control voltage applied on the piezoelectric actuators. Due to that the scaling function transform is like a low-pass filter which can automatically filter out high-order signals of vibration or disturbance from the measurement and the controller employed here, this model does not lead to those undesired phenomena of control instability which is often appeared in a control system and caused by the spilling over of high-order signals from measurement and controller if no special technique is taken in the control system. Finally, a numerical simulation is carried out to show the efficiency and ability of the control programme proposed in this paper. It is found that this control model is more efficient than a control program of convention to the example.
In this paper we state the homogenized model of a periodic electro-piezo-mechanical thin shells. The electrical network is including resistive devices, tension sources, current sources and voltage to voltage amplifier...
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In this paper we state the homogenized model of a periodic electro-piezo-mechanical thin shells. The electrical network is including resistive devices, tension sources, current sources and voltage to voltage amplifiers. It is distributed evenly on the surface of the shell. The model derivation is based on a two-scale convergence which is based on the two-scale transform introduced by T. Arbogast, J. Douglas and U. Hornung. The present work is based on some results of two-scale convergence of gradients which leads to the same results than the usual two-scale convergence introduced by G. Allaire. We apply these results and those introduced in the framework of M. Lenczner and G. Senouci-Bereksi for the electrical network, to derive the two-dimensional electro-piezo-mechanical thin shell model applying Reisner-Mindlin kinematic.
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