&lt;title&gt;Modeling and robust control of smart structures&lt;/title&gt;

Tebbe, Chris D.; Schroeder, Tim G.; Butler, Ralph; Rao, V. Sree Hari; Koval, L. R.; Kern, Frank J.

doi:10.1117/12.148420

Cited by 6 publications

(5 citation statements)

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“…Equations (2), (4), and (5), which describe the heat transfer effects and the relation of temperature and Austenite ratio, are used directly in this bundle-wire dynamics. The relation between the inertia and load forces of the bundle wires and the stresses in the wires needs to be established and applied to Equation (13). In addition, the relation of the length change of the bundle SMA wires and the strain in the wires is also needed for Equation (13).…”

Section: Dynamics Of the Sma Bundle Actuatormentioning

confidence: 99%

“…The relation between the inertia and load forces of the bundle wires and the stresses in the wires needs to be established and applied to Equation (13). In addition, the relation of the length change of the bundle SMA wires and the strain in the wires is also needed for Equation (13). This dynamic model of the SMA bundle actuator is further linearized in order to be applied in the controller design.…”

Section: Dynamics Of the Sma Bundle Actuatormentioning

confidence: 99%

“…The system dynamics of the SMA bundle actuator in the linear load configuration can be derived from the stress/strain relation of Equation (13). The stress (σ) applied to the bundle wires is approximated as:…”

Section: Dynamics Of the Sma Bundle Actuatormentioning

confidence: 99%

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Analytical Dynamic Model and Experimental Robust and Optimal Control of Shape-Memory-Alloy Bundle Actuators

Lee

Mavroidis

2002

Dynamic Systems and Control

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In this paper, the analytical dynamic model derivation and the robust and optimal position control of Shape Memory Alloy (SMA) bundle actuators using the LQR and H2 techniques are presented. SMA bundle actuators, composed of multiple SMA wires placed in parallel, have been recently proposed as a means to considerably increase the lifting capabilities of SMA actuators. Robust and optimal linear controllers could provide the desired robustness in the performance of these non-linear and highly sensitive actuators combined with the simplicity of these control schemes. The novel contributions of the present research are: a) the derivation of a generic, linearized, time-invariant analytical system model for SMA Bundle actuators that is used in the design of the LQR and H2 based controllers; b) the development of a new improved estimator in discrete-time H2 optimal control design based on the Kalman Filter predictor form for use in the control of SMA bundle actuators; c) the experimental study of two control design methods using state-space models, LQR and H2 Optimal Design, in discrete-time domain, using an experimental SMA bundle actuator consisting of 48 Flexinol™ SMA wires and able to apply up to 100 lbs. (445 N). As demonstrated in the experiments, the designed controllers provide satisfactory results in accuracy, stability and speed.

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Section: Dynamics Of the Sma Bundle Actuatormentioning

confidence: 99%

Section: Dynamics Of the Sma Bundle Actuatormentioning

confidence: 99%

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Analytical Dynamic Model and Experimental Robust and Optimal Control of Shape-Memory-Alloy Bundle Actuators

Lee

Mavroidis

2002

Dynamic Systems and Control

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“…Grant and Hayward [20,21] applied variable structure/sliding mode control methods to perform position and force control tasks. Tebbe, Schroeder and Butler [22] studied state-space multivariable control in large flexible smart structures using either Eigenvalue pole placement or LQR methods.…”

Section: Introductionmentioning

confidence: 99%

B-Spline Based Adaptive Control of Shape Memory Alloy Actuated Robotic Systems

Eren

Mavroidis

Nikitczuk

2002

Dynamic Systems and Control

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In this paper we present a novel controller for Shape Memory Alloy (SMA) actuated robotic systems. The new controller, called BAC (B-spline based Adaptive Control), is based on a hybrid combination of gain scheduling, B-spline approximation, variable structure control and integral control. The proposed controller shows excellent positioning accuracy and speed throughout the full range of motion of a SMA actuated robotic system in large-scale applications. To demonstrate the validity of BAC, a novel anthropomorphic SMA Actuated forearm/wrist mechanism is utilized in real-time PC based control experiments. BAC is experimentally compared to PID and integral variable structure controllers and it is shown that its performance is superior.

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“…The LQGLTR controller is designed based on Equation (16) and (17). More details on the fundamental equations used for the LQGLTR controller design are contained in [8]- [11].…”

Section: Controller Designmentioning

confidence: 99%

Robust Control of Flexible Structures Using Multiple Shape Memory Alloy Actuators

Lashlee

Butler

Rao

et al.

Proceedings. The First IEEE Regional Conference on Aerospace Control Systems,

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The design and implementation of control strategies for large, flexible smart structures presents challenging problems. To demonstrate the capabilities of shape-memory-alloy actuators, we have designed and fabricated a three-mass test article with multiple shape-memory-alloy (NiTiNOL) actuators. The force and moment actuators were implemented on the structure to examine the effects of control structure interaction and to increase actuation force. These SMA actuators exhibit nonlinear effects due to deadband and saturation. The first step in the modeling process was the experimental determination of the transfer function matrix derived from frequency response data. A minimal state space representation was determined based on this transfer function matrix. Finally in order to reduce the order of the controller, a reduced order state space model was derived from the minimal state space representation. The simplified analytical models are compared with models developed by structural identification techniques based on vibration test data.From the reduced order model, a controller was designed to dampen vibrations in the test bed. To minimize the effects of uncertainties on the closed-loop system performance of smart structures, a LQGLTR control . methodology has been utilized. An initial standard LQGLTR controller was designed; however, this controller could not achieve the desired performance robustness due to saturation effects. Therefore, a modified LQGLTR design methodology was implemented to accommodate for the limited control force provided by the actuators. The closed-loop system response of the multiple input-multiple output (MIMO) test article with robustness verification has been experimentally obtained and presented in the paper. The modified LQGLTR controller demonstrated performance and stability robustness to both sensor noise and parameter variations.- IntroductionIn recent years there has been considerable interest in the design and implementation of active controllers for smart structures. The application of both piezo-electric and shape memory alloy materials as actuators and sensors in the active control of structures has been extensively reported in the literature. We have utilized the shape memory alloy (SMA), Ni'IiNOL, in the design and implementation of multivariable robust controllers. In addition to the design of multivariable robust controllers, this research examines the effects of control-structure interaction using SMA actuators on a flexible structures. To implement and evaluate the performance of various controllers, we have designed and fabricated a three-mass test article equipped with strain gauge sensors, force and moment SMA actuators, and signal processing circuits. The force and moment SMA actuators allow the application of increased control force and the investigation of control-structure interaction, In order to design active controllers for flexible structures, a mathematical representation of the system is needed. This system contains inherent nonlinearities resulting from bot...

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<title>Modeling and robust control of smart structures</title>

Cited by 6 publications

References 0 publications

Analytical Dynamic Model and Experimental Robust and Optimal Control of Shape-Memory-Alloy Bundle Actuators

Analytical Dynamic Model and Experimental Robust and Optimal Control of Shape-Memory-Alloy Bundle Actuators

B-Spline Based Adaptive Control of Shape Memory Alloy Actuated Robotic Systems

Robust Control of Flexible Structures Using Multiple Shape Memory Alloy Actuators

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