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Secure guidance for missiles against cyber-attacks is an interesting topic of both theoretical and practical importance, but so far few results are available. In this paper, two multivariable secure guidance laws are proposed for precise strikes interceptors with cyber-attacks in guidance commands. Different engagement scenarios are studied in three-dimensional space. Against highly maneuvering targets, the proposed secure guidance law can guarantee some states related to the line-of-sight (LOS) angular rates to converge to zero within finite time, where the cyber-attacks are indirectly estimated and compensated with the aid of an attack observer. Moreover, against non-maneuvering targets with impact angle constraints, the proposed secure guidance law is designed based on the backstepping technique, where the cyber-attacks are directly estimated and compensated. Particularly, prescribed performance functions are introduced in the second guidance law to flexibly determine the convergence rates of the LOS angles. Numerical simulations are performed to illustrate the effectiveness of the proposed schemes. [ABSTRACT FROM AUTHOR]

In this paper, an observer-based fault-tolerant control scheme is proposed for the attitude stabilization of rigid spacecraft in the presence of actuator fault, configuration misalignment, input saturation and even external disturbances simultaneously. More specifically, an iterative learning observer is firstly developed to estimate the torque deviation and steer the estimation errors into some small residual sets. And also the detailed derivations of the observer are provided, along with a thorough analysis for the associated ultimate bounded stability and estimation error convergence property. Then, an integral-type sliding mode control law is designed to produce the three-axis virtual control signals with the desired performance for being distributed among the individual actuators. Under this, a robust control allocation algorithm is developed to map the virtual control demand onto individual actuator in an optimal manner, which takes into account the estimation uncertainties and ensures some fault-tolerant ability. The key feature of the proposed strategies is that the whole closed-loop fault tolerant control system can be guaranteed theoretically to be stable by the development of Lyapunov methodology. Numerical simulation results are presented to illustrate and highlight the fine performance benefits obtained using the proposed schemes. [ABSTRACT FROM AUTHOR]

This paper addresses the control problem of air-breathing hypersonic vehicles subject to input nonlinearities, aerodynamic uncertainties and flexible modes. An adaptive backstepping controller and a dynamic inverse controller are developed for the altitude subsystem and the velocity subsystem, respectively, where the former eliminates the problem of “explosion of terms” inherent in backstepping control. Moreover, a modified smooth inverse of the dead-zone is proposed to compensate for the dead-zone effects and reduce the computational burden. Based on this smooth inverse, an input nonlinear pre-compensator is designed to handle input saturation and dead-zone nonlinearities, which leads to a simpler control design for the altitude subsystem subject to these two input nonlinearities. It is proved that the proposed controllers can guarantee that all closed-loop signals are bounded and the tracking errors converge to an arbitrarily small residual set. Simulation results are carried out to demonstrate the effectiveness of the proposed control scheme. [ABSTRACT FROM AUTHOR]