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In this paper, the guidance law designing problem in the presence of the control loop dynamics using sliding mode control has been studied. For this purpose in the design process, stable control loop dynamic considered that usually not considered by the designers. In practice there is a lag for control loop that may lead to instability in the guidance loop. In this paper the control loop dynamic that is stabilized with an autopilot, approximated as first order lag and then is considered with kinematic equation of motion in designing procedure. To solve the problem because of the nonlinearity in equations and target maneuvers as uncertainty, the sliding mode control scheme is used. So just having the bounds of the uncertainty we can design guidance law and the measure or estimate of uncertainty is not required. The sliding variable is defined with respect to parallel navigation idea using relative lateral velocity between the interceptor and the target. Then a controller is designed for reaching the sliding variable to sliding surface. Therefore the line of sight rate will be zero and collision is inevitable. Also for removing chattering, the continues approximation method is used.

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In this paper, a new combination of fractional order calculus and finite time sliding mode control, used to design an aircraft autopilot. This combination aims to reduce the chattering phenomena and have a smoother control signal than conventional sliding mode. Fractional order control uses fractional integrator and derivative to improved integer order control methods. The sliding surface and sliding mode control law is proposed to reduce the chattering phenomena and also, closed-loop stability is guaranteed too. Using this algorithm, a robust autopilot against aerodynamic coefficients uncertainty is designed for an aircraft and proposed control law is utilized to stabilize the close loop system by Lyapunov stability theorem. The proposed autopilot is applied to the aircraft model and simulation results illustrate the reduction of chattering phenomena.

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Thrust vector control is a special method to change the attitude and position of flying objects, which can only be applied in some missions. These systems require feedback control and lead to better maneuverability. In this paper, a finite time adaptive sliding model controller is presented for controlling the thrust vector of a flying object. The first-order sliding model method requires information about the upper bound of system uncertainties and also this method causes chattering in the control signal. The standard adaptive sliding model method has solved the problem of the need for the uncertainty bound and also reduces the chattering range. But this method does not guarantee finite time stability. In this article, the finite time type of adaptive sliding model is used to control the thrust vector. This method guarantees finite time stability without the need for upper bound information of system uncertainties, and in it, the convergence time of the tracking error and estimation depending on the initial conditions can be calculated. The performance of the proposed thrust vector control system has been investigated by computer simulation and its efficiency is shown in comparison with other methods.