Smart control is a fundamental component in the design of all autonomous systems. One example of an autonomous system is a smart structure that makes use of the strain and electrical couplings within piezoelectric materials together with smart control strategies to allow self-adaptation of the structure. This concept is being exploited in the aviation, maritime, automotive, and robotic sectors where for weight considerations, the use light flexible composite materials are favoured. These materials, however, inadvertently render the structure more sensitive to the low-frequency structural modes which threaten the system behaviour as well as its stability. The focus of this research programme revolves around the development of advanced active vibration cancellation techniques for structural stabilisation.
One aspect of our work is concerned with the development of advanced control strategies that can effectively identify and suppress vibration even when the structural and environmental properties of the system are constantly changing. Another aspect of the work is concerned with the development of smart structures which involves designing the sensing and actuation mechanisms as well as designing the embedded control architectures required to support the vibration suppression in real-time. All of the control schemes developed through this research programme have been implemented and validated on our laboratory-based physical prototype systems.
- Adaptive multi-mode control of dynamically-loaded structures
Instead of controlling an ideal fixed-structure system with “known” disturbance, the aim of this project was to develop control strategies for more realistic situations such as a dynamically loaded flexible structure exposed to an unknown variable multi-mode disturbance. The outcome of this work was the development of novel adaptive estimation and resonant control strategies that would allow automatic identification of the states of a structure and the characteristics of the disturbance, and consequent self-tuning of the controller. The same estimation and adaptive control strategies could be reused for non-vibration applications.
- Self-healing distributed MIMO vibration control networks for flexible structures:
Large flexible structures such as panels and shells have closely spaced and numerous low-frequency modes. Good system observability and controllability require many sensors and actuators, and thus MIMO control techniques, to ensure effective control and minimal coupling between modes. In this project, the application of distributed adaptive/nonlinear MIMO-based control strategies to minimise vibration due to broadband disturbances in large flexible structure is studied both analytically and experimentally. The control architecture is designed based on a system identification model that is estimated on-line. The objectives of the project are (i) to investigate suitable distributed-parameter MIMO control schemes, and (ii) to assess the effectiveness of such distributed MIMO control systems. The distributed controller has the advantages of scalability for application in large systems and fault-tolerance for gradual control degradation rather than sudden complete failure. This project builds on the techniques developed by the group across a cross-section of its projects.
- Dr. Sook Ying Ho, DSTO
- Dr. Alex Kristic, Spectre Ballistic Solutions Pty Ltd