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A co-design problem of privacy-preserving encoding and filtering is concerned in this paper. A remote legal user estimates states of a dynamic system by the received innovation messages. However, the communication channel is neither reliable nor secure. The messages may be missing during the transmission and have a risk of being intercepted by an eavesdropper. Therefore, in this work, an encoding scheme together with an MMSE estimation algorithm are designed for preserving information privacy and meanwhile guaranteeing estimation performance. We introduce a novel encoding approach using a weighted innovation with a public key to achieve privacy security as well as low computational expense. A filtering algorithm is designed under such an encoding mechanism. And the performance of the filter and the encoding method is analyzed. The feasibility of the encoding approach and the filtering algorithm is illustrated through numerical examples of an unstable system and a stable ballistic roll rate estimation system. • A novel encoding mechanism using a weighted innovation is proposed. • A state estimation algorithm is designed under the proposed encoding mechanism. • The performance of the filter and the encoding method is analyzed. [ABSTRACT FROM AUTHOR]

Highlights • Model of dual planar cranes carrying a distributed-mass beam is derived. • A new method is developed for estimating the natural frequency of dual planar cranes. • MEI input shaper is presented for limiting oscillations of dual cranes. • Experiments validate dynamic behaviour and the effectiveness of MEI shaper. Abstract Unwanted oscillations caused by the operator-commanded motions lower the capable operating speeds and degrade the safety of dual cranes moving distributed-mass payloads. Mounting numbers of works have been devoted to the dynamics and control of dual cranes. However, few studies have been dedicated to the accurate estimation of natural frequency, which is a critical factor for controlling the dual cranes. This paper develops a new method to predict the natural frequency of dual planar cranes with different cable lengths. Furthermore, a modified extra-insensitive (MEI) input shaper is proposed to suppress the oscillations of the payload swing and pitch in the dual cranes. The MEI shaper has good robustness to large changes in the frequency, and has good performance in the jerk limitation. Simulated and experimental investigations are performed on small-scale dual cranes transporting a slender beam to validate the system dynamic behavior and the effectiveness of the MEI shaper. [ABSTRACT FROM AUTHOR]

Abstract In order to study the nonlinear dynamic behaviors of Thermal Protection System (TPS) and the nonlinear dynamic strength of the strain-isolation-pad (SIP), a two degree-of-freedom nonlinear dynamic theoretical model was presented under the acoustic excitation and base excitation. The tile is simplified as a mass point, a linear spring and a damping element, and the SIP is simplified as a mass point, a nonlinear spring and a damping element. On this basis, the solving process of the nonlinear theoretical model and the iterative process of the equivalent linear stiffness coefficient of SIP were derived by the statistical linearization method. The dynamic responses analyzed by the nonlinear theoretical model and linear theoretical model are compared. The nonlinear stiffness of SIP shows obvious influence on behaviors of TPS and dynamic stress of SIP, and the equivalent linear stiffness of SIP is related to the types of excitations. Finally, the influences on above dynamic responses by the nonlinear stiffness level of SIP were studied. The equivalent linear stiffness coefficient of SIP, acceleration of TPS and dynamic stress of SIP decrease with the increase of the nonlinear level for the stiffness of SIP. Highlights • Nonlinear dynamic theoretical model is presented for TPS. • Nonlinear stiffness of SIP is considered. • Iterative process of equivalent linear stiffness coefficient of SIP is derived. • Effects on dynamic responses by nonlinear stiffness level of SIP are studied. [ABSTRACT FROM AUTHOR]