Effect of sensor and actuator errors on static shape control for large space structures

Haftka, Raphael T.; Adelman, Howard M.

doi:10.2514/3.9592

Cited by 17 publications

(4 citation statements)

References 13 publications

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“…14; this presents the worst case from among all the experimental data. 7. A sinusoidal curve defining the corresponding "ideal" sinusoidal shape is plotted in the Figure as well.…”

Section: Summary and Discussionmentioning

confidence: 99%

Closed-loop dynamic shape control of a flexible beam

Burke

Hubbard

1990

SPIE Proceedings

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ABSTRACFAn experimental implementation of a new distributed parameter shape control design methodology is presented. The technique is based upon the input/output representation of distributed parameter systems in a spatially-and temporallytransformed frequency space. The analysis is specialized to shape control through the introduction of generalized spatial transforms of the plant response which explicitly parameterize the shape control task. Experiments are summarized wherein a 4Oin pinned-pinned steel beams shape is controlled, in the presence of quasi-static and resonant disturbances, over a bandlimited set of four sinusoidal shape basis functions at a closed-loop temporal bandwidth of 2Hz, using distributed piezoelectric actuators. Temporal compensation is provided by digitally-implemented LQG/LTR compensators. A novel inner-loop damping formulation, based upon the second method of Lyapunov, is developed and implemented to damp the beam resonant response beyond the LQG/LTR control bandwidth. . INTRODUCFIONA principal issue in the design and operation of deformable mirrors or large space-based large antenna reflectors is the precise control of the system's shape to guarantee satisfactory While the need to control the structural shape is clear, the practical implementation of shape control strategies is a subject of current research6'7'8. The link between the loss of performance and deformation of the structure hs typically been based upon the RMS value of its surface distortion. In this vein, Weeks9 has presented an analytically accessible study of structural shape control, using an integral equation formulation. The analysis is restricted to the static, open-loop problem, using discrete point displacement sensors and force actuators. Spatial perfonnance is posed in terms of determining actuator sites to best achieve (in an RMS sense) a single shape. Schaechter10'11'12 has implemented an experiment utilizing Weeks' analysis to drive a flexible beam, suspended vertically in a gravity field, to two static shapes. The experiment was static, and quasi open-loop. Certainly, if a structural control system can achieve some specific shape, then it will be capable of rejecting this same shape. However, the performance of any open-loop approach will suffer from plant model errors, as well as the quasi-static and dynamic nature of the disturbance environment.Although a reduction in the RMS surface profile error has a significant effect on the system perfonnance, it does not necessarily improve performance parameters specific to the details of the distortion throughout the surface of the reflector.These issues have recently been addressed for space structural systems in a static, open-loop optimization approach5. A more general dynamic approach to structural shape control has recently been developed by Burke13'14. In this approach, which is a generalization of previous optical investigations15'16, a structure's surface profile y(x,t) is parameterized by an expansion in an orthogonal set of "eigenshapes" ((x)) defined ove...

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“…14; this presents the worst case from among all the experimental data. 7. A sinusoidal curve defining the corresponding "ideal" sinusoidal shape is plotted in the Figure as well.…”

Section: Summary and Discussionmentioning

confidence: 99%

Closed-loop dynamic shape control of a flexible beam

Burke

Hubbard

1990

SPIE Proceedings

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“…Haftka and Adelman [14] conducted shape adjustment experiments on space structures utilizing heat as the actuation mechanism. Additionally, they conducted a study to anticipate and evaluate the impact of actuator inaccuracy on the shape adjustment process for delicate space systems, with the applied temperature serving as the actuation method [103]. Furthermore, Giusti, Mróz [104] described a method for designing thermomechanical actuators.…”

Section: Thermal Effectmentioning

confidence: 99%

A Review: Structural Shape and Stress Control Techniques and their Applications

Manguri,

Saeed,

Jankowski

2024

Arch Computat Methods Eng

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This review article presents prior studies on controlling shape and stress in flexible structures. The study offers a comprehensive survey of literature concerning the adjustment and regulation of shape, stress, or both in structures and emphasizes such control’s importance. The control of systems is classified into three primary classes: nodal movement control, axial force control, and controlling the two classes concurrently. Each class is thoroughly assessed, showcasing diverse methods anticipated by various scholars. Furthermore, the paper discusses methods to reduce the number of devices (actuators) to adjust and optimize actuators’ placement to achieve optimal structural control, considering the cost implications of numerous actuators. Additionally, various actuators are presented in detail, their advantages and disadvantages are also discussed. Moreover, the applications of the presented techniques are reviewed in detail, the essential recommendations for future work are also suggested.

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“…Different types of actuators are implemented for shape and stress condoling of structures, for example, piezoceramic actuators are utilized to obtain the required shape of flexible structures [6] and composite structures [7,8]. Moreover, Haftka and Adelman [9] applied temperature to alter the length of some members of space structures. Furthermore, other types of actuators were embedded in members of structures, for example, lead active screw members [10] and mechanical actuators [11].…”

Section: Introductionmentioning

confidence: 99%

Using Minimum Actuators to Control Shape and Stress of a Double Layer Spherical Model Under Gravity and Lateral Loadings

Saeed¹,

Katebi²,

Manguri³

et al. 2022

Adv. Sci. Technol. Res. J.

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Spherical domes are picturesque structures built in developed countries to attract tourists. Due to horizontal and vertical overloading, the structures' attractive shapes may be disturbed, and some members' stress may exceed the elastic level. In this paper, the shape and stress of a deformed double-layer spherical numerical model due to simultaneous lateral and vertical loadings are controlled, meanwhile, the number of actuators to alter the length of active members is minimized. The nodal displacements of the outer shape of the numerical model of the double-layer spherical structure are nullified. In addition, the stress of the members of the structure was monitored to stay within the elastic level. Moreover, the number of used actuators was minimized. These objectives are done by subjecting controlling formulations to a function that finds the minimum of constrained nonlinear multivariable which is called fmincon. The defined function in MATLAB uses one of the optimization algorithms (sequential quadratic programming, interior point, trust-region reflective, and active set). The algorithms search for active members that have a significant influence in controlling the targeted joints and members. Furthermore, the algorithms exclude the inactive actuators in several loops. The results obtained from MATLAB program are validated by SAP2000 software.

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Effect of sensor and actuator errors on static shape control for large space structures

Cited by 17 publications

References 13 publications

Closed-loop dynamic shape control of a flexible beam

Closed-loop dynamic shape control of a flexible beam

A Review: Structural Shape and Stress Control Techniques and their Applications

Using Minimum Actuators to Control Shape and Stress of a Double Layer Spherical Model Under Gravity and Lateral Loadings

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