Self-Diagnosis and Self-Repair of an Active Tensegrity Structure

Abstract

This paper addresses the study of tensegrity active control in case of unknown events, such as applied loading or damage. It describes methodologies for self diagnosis and self repair. Response due to unknown events is measured and analyzed in order to support self diagnosis. Since tensegrities are self-stressed and flexible structures, they exhibit geometrical non-linear behavior. Applied loading and damage thus induce changes in structural response to perturbations. This property is also used to support self diagnosis. Self-diagnosis solutions result in sets of good candidate description of the unknown event. Candidate descriptions exhibit responses to unknown events and perturbations that are close to the response measured on the real structure. These solutions are successfully employed within the framework of shape control and self repair. Self-repair abilities are demonstrated through increasing stiffness and decreasing stresses with respect to the damaged state by modifying the self-stress state of the structure. Validity of the results is demonstrated experimentally on a full-scale active tensegrity structure. The proposed methodologies are attractive for tensegrity active control in situations of unknown events.

Inherent Properties of Smart Tensegrity Structures

“…Moreover, tensegrities have some unique features that result from the infinitesimal mechanisms, which are stabilized by self-stress forces. It is possible to control their static and dynamic properties by adjusting the pre-stressing forces [15][16][17][18][19][20].…”

Active structures integrated with wireless sensor and actuator networks: a bio-inspired control framework

“…Adaptability to loads can sometimes be limited. In those model-based stochastic search procedures for the numerical FEM calculation, the load conditions have to be known or prescribed to the computer or the human controllers (the users) (Shea et al, 2002;Fest et al, 2003;, or at least the load has to be partially defined so that the load identification work can be done first (Adam and Smith, 2007a;. In situations where the only piece of information is the structural deformation (from totally unknown loads), the control task will be difficult.…”

“…Thus, AS are capable of self-diagnosis, self-repair, and learning. Adam and Smith (2007a;2007b; used a multi-objective approach for AS control to satisfy serviceability and additional robustness objectives. They proposed a control framework involving multi-objective search, reinforcementlearning, and self-diagnosis.…”

Mechanism-Based Approach for the Deployment of a Tensegrity-Ring Module

“…A single damaged member does not necessarily lead to structural collapse. Computational approaches that support self-diagnosis and self-repair have also been developed (Adam and Smith 2007b). Furthermore, dynamic behavior and vibration control of the five-module active tensegrity structure were studied in order to shift the natural frequencies away from excitation .…”