GPS and navigation GPS)، GLONASS، GALILEO
Mohammad Hosein Shafiei; meisam jowkar; Behrooz Safarinejad
Volume 13, Issue 3 , September 2020, , Pages 69-77
Abstract
In this paper a new structure for the inertia measurement unit is presented; the proposed structure consists of three rotary discs around the three main axes in the body, and an accelerometer is mounted on each disc. It is shown in this paper that the proposed structure reduces the effect of disturbing ...
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In this paper a new structure for the inertia measurement unit is presented; the proposed structure consists of three rotary discs around the three main axes in the body, and an accelerometer is mounted on each disc. It is shown in this paper that the proposed structure reduces the effect of disturbing accelerometer parameters, such as constant and variable bias, as well as noise depletion. Due to the proposed rotational structure, it is necessary to continuously sample the accelerometers. In order to use the sampled data, calculations should be performed in discrete mode. In this paper, a method for combining this information is presented. By examining the proposed equations, the successful performance of this method is shown in the reduction of the effect of three constant bias parameters and the bias of the accelerometer and the measured noise. As well as the efficiency of the proposed method for measuring the acceleration of the device using Numerical representation is shown.
Mohammad Hosein Shafiei; negin vazirpour
Volume 12, Issue 3 , September 2019, , Pages 55-61
Abstract
In this paper, the approach of discrete-time partial stabilization is employed to design a robust three-dimensional guidance law against maneuvering targets. In the partial stabilization method, the considered system is divided into two sub-systems which achieving to asymptotic stability is desirable ...
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In this paper, the approach of discrete-time partial stabilization is employed to design a robust three-dimensional guidance law against maneuvering targets. In the partial stabilization method, the considered system is divided into two sub-systems which achieving to asymptotic stability is desirable only for the first one. One of the advantages of this paper is to design a discrete-time guidance law even with limitations and difficulties in discrete-time Lyapunov theorem. The Lyapunov function has been chosen based on the physics of the guidance problem (making the rate of line of sight (LOS) rotation close to zero). In this paper, it is shown that there is no possibility for asymptotic stabilization of the guidance problem in the case of maneuvering targets. Thus, it has been sufficed to limit the rotation rate of LOS to a small value which will guarantee the missile hit to the target in a short time. Simulations results show the appropriate performance of the proposed guidance law.
Hamed Chenarani; Tahereh Binazadeh; Mohammad Hosein Shafiei
Volume 11, Issue 2 , September 2018, , Pages 41-46
Abstract
This paper considers the problem of asymptotic stabilizing of velocity and body rates of a spacecraft in the presence of uncertainties and external disturbances. One of the important methods in controller design for nonlinear systems; is designing based on the passivity concept. This concept which provides ...
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This paper considers the problem of asymptotic stabilizing of velocity and body rates of a spacecraft in the presence of uncertainties and external disturbances. One of the important methods in controller design for nonlinear systems; is designing based on the passivity concept. This concept which provides a useful tool for analysis of nonlinear systems has been also used for asymptotic stabilizing of nonlinear dynamical systems especially mechanical systems. The passivity-based control law is a static output feedback and has valuable features. Because of existence of uncertainties and external disturbances in the state-space of equations of physical systems; first the robust version of passivity-based control method, which is recently developed in literature, is given and the control law for nonlinear uncertain systems with affine structure is presented. Then, this approach is used in controller design for a spacecraft. Since, this paper considers only the stabilization of velocity and body rates, therefore the reduced-order model is extracted from the state-space equation of a spacecraft with six degree of freedom and then the robust control law is designed. Computer simulations show the efficiency of the proposed controller in robust asymptotic stabilizing of the velocity and body rate vectors of the spacecraft in the presence of uncertainties and external disturbances.
Tahere Binazadeh; Mohammad Hossein Shafiei; Elham Bazregarzadeh
Volume 8, Issue 1 , April 2015, , Pages 1-7
Abstract
This paper presents a novel approach in design of missile guidance law against highly maneuvering targets. This approach is based on the principles of partial stability and finite-time stability (finite-time partial stability). Also, it is shown that the designed guidance law is in conformity with a ...
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This paper presents a novel approach in design of missile guidance law against highly maneuvering targets. This approach is based on the principles of partial stability and finite-time stability (finite-time partial stability). Also, it is shown that the designed guidance law is in conformity with a real guidance scenario that leads to collision. In the design procedure the acceleration vector of the target is assumed as an external bounded disturbance and only this bound is required in the design of the guidance law. Therefore, the maneuver of the target is not restricted to any known and predetermined structure and measurement or estimation of the target acceleration vector during the maneuver is not necessary. The performance of the proposed guidance law is shown through analysis and computer simulations.
