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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 recent years, simultaneous localization and mapping (SLAM) has become a very challenging matter as a basic problem in the mobile robots navigation. This paper describes a new efficient inertial SLAM algorithm for a UAV or an airborne. This inertialSLAM could be properly applied to two different kinds of sensors: (i)Range/Bearing sensorsand (ii)Bearing-only sensors and so it does not need to any other external positioning systems like as GPS or any preprovided data. In this study, acomprehensive system has been presented which not only enhances the three-dimensional SLAM accuracy and performance, but overcomes the two fundamental problems that have less been noticed in previous researchesA) To consider all the degrees of freedom for the UAV that lets the UAV height changesbe usedin addition to two x and y directions. B) It does not experience any limit for the symbols status which means that the system is able to observe all the symbolsin different heights based on inertia sensors. Finally, the accuracy of proposed algorithm has been approved due to the simulation results using the actual aircraft flight data.

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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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Electromagnetic suspension technology has been developed in recent years due to advantages such as no contact and reduced friction. Of course, ensuring efficiency in these systems requires precise control of the position of the suspended object. Therefore, electromagnetic suspension is considered as a process by control engineers. The dynamics of electromagnetic suspension systems is nonlinear and also include model and parametric uncertainties such as the weight of the suspended object. In this paper, a finite time nonlinear hybrid method is used to stabilize the electromagnetic suspension system. Proof of finite time stability of the proposed method is performed using Lyapunov theory and a relation for calculating the convergence time depends on the controller gains is presented. To ensure the finite time convergence of the system state and output variables, the backstepping algorithm is used and in each step, the finite-time convergence theory is used. The controller designed in this paper is compared with the backsteping method and the superiority of the proposed method in various simulations is shown.

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In this paper, a control input based on terminal sliding mode control is provided for a mobile robot with four Mecanum wheels to move in a predetermined path and convergence into the path in a fixed-time. First, according to the robot structure, a dynamic model of the robot is presented. The dynamic model follows a nonlinear second-order equation. Based on terminal sliding mode control, a nonlinear sliding surface which is a function of position error vector is defined and then the control input is designed based on this sliding surface. Using the Lyapunov theorem, it has been proven that, using this control input, the robot converges to the predetermined path at a fixed time. The convergence time is a function of the constants defined in the control input. Finally, the simulation is presented based on the control input and the results are shown.

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The same size of the helix steps in a traveling wave tube has a direct relationship with the efficiency of the system. In this article, the goal is to build a device that measures helix steps automatically and with proper accuracy by using image processing. For this purpose, the proposed algorithm was presented along with innovations in the fields of noise removal and threshold determination for the automatic measurement of helix steps, and the prototype of the device was made. This device has the ability to work in two modes of manual and automatic measurement, and it has no domestic equivalent, and it is much cheaper in terms of cost and use in measuring helix steps than the sample made abroad. In automatic mode, this device is able to measure all helix steps at once. In the case of a similar sample made abroad the steps must be measured manually and separately. The selection of the beginning and end points of steps in this device is done adaptively, which increases the speed of measurement and increases the repeatability in measuring steps. In the sample made abroad, the selection of the start and end points of the steps is done by the user, which reduces the repeatability of the measurement. The obtained results show that the measurement accuracy of the manufactured device is acceptable compared to the sample made abroad.
 

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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.