Space subsystems design: (navigation, control, structure and…)
Mahsa Javaheripour; Ahmad Reza Vali; Vahid Behnam Gol; Firouz Allahverdizadeh
Volume 15, Issue 3 , September 2022, , Pages 67-78
Abstract
Proportional navigation is one of the most widely used methods in guiding flying objects. This method requires the rotation rate of the line between the interceptor and the target to calculate the guidance command. For a variety of reasons, including cost savings, simple sensors are used to measure tracking ...
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Proportional navigation is one of the most widely used methods in guiding flying objects. This method requires the rotation rate of the line between the interceptor and the target to calculate the guidance command. For a variety of reasons, including cost savings, simple sensors are used to measure tracking information, including line of sight angle. Therefore, some non-measurable information such as the angular velocity of the line of sight must be estimated using mathematical equations. Due to the noise and other problems, the use of derivatives is not desirable in this situation. Therefore, in this paper, an extended nonlinear observer is used to estimate the angular velocity of the line. Due to the nonlinear dynamics of the intercepting of flying objects, a nonlinear type of observer has been selected. By performing a computer simulation, the correct operation of the proposed observer is shown.
Vahid Behnamgol; Ahmadreza Vali; ali mohammadi
Volume 11, Issue 2 , September 2018, , Pages 1-10
Abstract
Nonsingular terminal sliding mode (NTSM) guidance for intercepting the desired line of sight (LOS) angle in terminal phase is proposed in this paper. In order to satisfy the predefined LOS angle and to intercep into target, a nonsingular terminal sliding variable is introduced. In reaching phase, in ...
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Nonsingular terminal sliding mode (NTSM) guidance for intercepting the desired line of sight (LOS) angle in terminal phase is proposed in this paper. In order to satisfy the predefined LOS angle and to intercep into target, a nonsingular terminal sliding variable is introduced. In reaching phase, in the presence of uncertainties such as target maneuvers, robust NTSM guidance law is designed in order forzeroing the sliding variable in finite reaching time. Then, in sliding phase, due to introducing nonsingular terminal sliding variable, finite time stability of line of sight angle and line of sight angular rate is granteed without singularity in commanded acceleration as control signal Numerical simulations are presented to illustrate the potential of the proposed guidance law.
Vahid Behnamgol; Ahmadreza Vali; ali mohammadi; َAshknaz Oraee
Volume 11, Issue 2 , September 2018, , Pages 33-39
Abstract
A new adaptive smooth second-order sliding mode control is proposed for uncertain nonlinear systems in this paper. The finite time stability is proved using a Lyapunov technic. The proposed controller consists of an adaptive term equal to the uncertainty in finite time. This algorithm is used to design ...
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A new adaptive smooth second-order sliding mode control is proposed for uncertain nonlinear systems in this paper. The finite time stability is proved using a Lyapunov technic. The proposed controller consists of an adaptive term equal to the uncertainty in finite time. This algorithm is used to design terminal guidance law for homing interceptors to intercept maneuvering targets. The guidance law generates smooth acceleration commands and the control signal is able to stabilize relative lateral velocity in a desired time. Finally, the proposed guidance law is compared with the second-order sliding mode guidance law from carried out simulations.
Vahid Behnamgol; Ahmad Reza Vali; Ali Mohammadi
Volume 8, Issue 4 , January 2016, , Pages 9-17
Abstract
In this paper, a new procedure for designing the guidance law considering the control loop dynamics is proposed. The nonlinear guidance loop entailing a first order lag as the control loop dynamics is formulated. A new finite time and smooth backstepping sliding mode control scheme is used to guarantee ...
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In this paper, a new procedure for designing the guidance law considering the control loop dynamics is proposed. The nonlinear guidance loop entailing a first order lag as the control loop dynamics is formulated. A new finite time and smooth backstepping sliding mode control scheme is used to guarantee the finite time convergence of relative lateral velocity. Also in the proposed algorithm the chattering is removed and a smooth control signal is produced. Moreover, the target maneuver is considered as an unmatched uncertainty. Then a robust guidance law is designed without requiring the precise measurement or estimation of target acceleration. Simulation results show that the proposed algorithm has better performance as compared to the proportional navigation, augmented PN and the other sliding mode guidance law.
