For real time monitoring of the wing state, in this paper, the inverse Finite Element Method (iFEM) is applied, which describes the displacement field of beam according to the Timoshenko theory, to sense the wing frame deformation. In order to maintain the accuracy and stability of frame deformation sensing with iFEM, an optimal placement model of strain sensors based on eigenvalue analysis is constructed. Through the model solution with the Particle Swarm Optimization (PSO) algorithm, two different optimal placement schemes of sensors are obtained. Finally, a simulation is performed on a simple cantilever beam and a static load experiment is conducted on an aluminum alloy wing frame. The results demonstrate that the iFEM is able to accurately sense the deformation of the wing frame, when the two optimal placement schemes of sensors are used.

A cable-driven parallel manipulator is an economic way to achieve manipulation over large workspace. However, unavoidable vibration in long cables can dramatically degenerate the positioning performance of manipulators. In this paper, dynamic models of large cable-driven parallel manipulators (CDPMs) are addressed where each cable is considered with distributed mass and can change in length during operation. The dynamic equation of a cable deployed or retrieved is derived using Hamilton's principle. The dynamic model of the system is characterized by partial differential equations with algebraic constraints. By properly selecting the independent unknowns, we solve the model using assumed-mode method.