STATIC SHAPE CONTROL

COMPOSITE AND SMART STRUCTURES GROUP (CSSG)
School of Aerospace, Mechanical and Mechatronic Engineering, Building J07 University of Sydney,
Sydney, NSW, Australia, 2006.
Tel: 61-2-9351 2338 Fax: 61-2-9351 4841
  1. Buildup Voltage Distribution BVD
  2. Perturbation Buildup Voltage Distribution PBVD
  3. Buildup Orientation Distribution BOD
  4. Publications associated with SSC

This page gives an overview of the work done at the CSSG on the Static Shape Control SSC of intelligent structures using piezoelectric actuators. Potential structural candidates for this application include:

The goal of SSC is to calculate the actuation parameters, such as electric voltages for piezoelectric actuators, given a specific desired shape. As this is a kind of inverse problem - one approach to solve this is to use heuristic search algorithms. Three iterative heuristic algorithms have been developed, see below. These algorithms have been developed specifically for this particular shape control application and hence they allow the user a more intuitive way to control the algorithms' parameters as oppose to other generic optimization algorithms. This enables the user to focus the analysis of the significance of the results in terms of structural / physical veiwpoint rather than on numerical issues. The shape control algorithms is applied over the mathematical - structural mixed model, also developed here, for the structural analysis.

Buildup Voltage Distribution BVD

Iteratively builds up voltages on actuators which has the greatest influence in affecting the structure's shape to conform to the desired shape. Has been shown to be faster than Simulated Annealing and Downhill Simplex search routines. Uses transverse displacements to measure the difference between desired and actual shape.

The two plots are 3D oblique view for two different patch voltage configurations. Each plot superimposes the actual shape on the desired bending shape.

Perturbation Buildup Voltage Distribution PBVD

Using the same concepts as BVD. However, using transverse displacements as the initial criterion then use slope or curvatures as the perturbing criteria. These are referred to as slope displacement shape control and curvature displacement shape control respectively.

Results in reduction in local unevenness / bumpiness caused by discrete actuators. Significant improvement in internal stresses compared to using pure displacement based shape control.

The animation below shows the reduction in internal stresses comparing the use of PBVD slope displacement shape control as oppose to using just displacement shape control. The structure is a cantilevered composite laminate with 20 piezoelectric patch actuators.

Buildup Orientation Distribution BOD

Similar concept to BVD but instead of calculating the best voltage configuration, BOD calculates the best actuator orientation for the actuators. More details soon ....

Publications associated with Shape Control

  1. C.Chee, L.Tong and G.P.Steven, "A Review on the Modelling of Piezoelectric Sensors and Actuators Incorporated in Intelligent Structures"; Journal of Intelligent Material Systems and Structures , Vol. 9, No. 1, (1998), pp 3-19.

  2. C.Chee, L.Tong and G.P.Steven, "A Mixed Model for Composite Plates with Piezoelectric Sensors and Actuators" Proceedings of the Second Australian Congress on Applied Mechanics (ACAM-99), Canberra, 10th - 12th, Feb., 1999.

  3. C.Chee, L.Tong and G.P.Steven, "A Mixed Model for Composite Beams with Piezoelectric Actuators and Sensors", Smart Materials and Structures Vol.8 (1999) pp 417-432

  4. C.Chee, L.Tong and G.P.Steven, "Shape Functions Generation using Macsyma", Communications in Numerical Methods in Engineering (accepted for publication).

  5. C.Chee, L.Tong and G.P.Steven, "A Mixed Model for Adaptive Composite Plates with Piezoelectric for Anisotropic Actuation", Computers and Structures Vol. 77, No. 3, Jun-2000, pp 253-268.

  6. C.Chee, L.Tong and G.P.Steven, "A Buildup Voltage Distribution (BVD) algorithm for shape control of smart plate structures", Computational Mechanics (awaiting publication).

  7. C.Chee, L.Tong and G.P.Steven, "Static Shape Control of Composite Plates Using a Slope-Displacement Based Algorithm", 41st AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference , Atlanta, Georgia, U.S.A., April 3rd - 7th, 2000

  8. C.Chee, L.Tong and G.P.Steven, "Static Shape Control of Composite Plates Using a Slope-Displacement Based Algorithm", AIAA Journal, (under review)

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