Space subsystems design: (navigation, control, structure and…)
Alireza Ahangarani Farahani; Amirhossain Adami; Hamed Arefkhani
Volume 16, Issue 3 , September 2023, , Pages 79-89
Abstract
In this article, a new approach has been presented in the design of a satellite's status controller using reaction wheels. First, a non-linear controller whose gains depend on the state variables at any moment is proposed. In the first step, the process of extracting control coefficients using the GA ...
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In this article, a new approach has been presented in the design of a satellite's status controller using reaction wheels. First, a non-linear controller whose gains depend on the state variables at any moment is proposed. In the first step, the process of extracting control coefficients using the GA optimizer is described. Then, using the results of a number of tests, sufficient data for meta-modeling of the system is extracted and the relevant control gain functions are optimized using the data bank. The input of the mentioned function is the system states and its output is the control coefficients. Finally, a simulator platform was used to determine and control the position of the satellite based on the air bearing to evaluate the proposed approach. Laboratory test results show that the performance of the proposed method is up to 30% better than the classical PID controller with fixed coefficients.
Space subsystems design: (navigation, control, structure and…)
M. Navabi; M. Salehi
Volume 16, Issue 2 , June 2023, , Pages 63-77
Abstract
In a flying system, attitude control is one of the essential subsystems. In this subsystem, estimating the current state is very important to control the state, which is achieved by considering the attitude sensors. Comprehensive research is being done today to reduce the cost of Attitude sensors in ...
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In a flying system, attitude control is one of the essential subsystems. In this subsystem, estimating the current state is very important to control the state, which is achieved by considering the attitude sensors. Comprehensive research is being done today to reduce the cost of Attitude sensors in applications such as drones, satellite simulation platforms, etc. For this purpose, sensors based on Micro-electromechanical Systems have received much attention due to their small size and low energy consumption. This model of sensors, despite its many advantages, has various noises and disturbances that require the application of fusion and estimation algorithms to obtain an acceptable output. In this research, to determine the attitude of the test platform, data fusion algorithms including complementary filter, Kalman filter, and Extended Kalman filter are implemented on a low-cost sensor. The mentioned estimation methods were implemented on the test platform and by determining the effective parameters in the estimation algorithms, the desired accuracy was obtained. The module obtained in these experiments is comparable to more expensive sensors.
Remote sensing
Javad Haghshenas; Reza Sharifi Hafshejani
Volume 16, Issue 1 , March 2023, , Pages 1-9
Abstract
In this paper, a step-by-step laboratory procedure for performing a satellite's payload’s alignment measurement is presented. Four highly accurate theodolites are used along with two or more alignment corner cube to accurately extract the final attitude. Theodolites are arranged around the satellite ...
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In this paper, a step-by-step laboratory procedure for performing a satellite's payload’s alignment measurement is presented. Four highly accurate theodolites are used along with two or more alignment corner cube to accurately extract the final attitude. Theodolites are arranged around the satellite in such a way that they have a clear direct view of the alignment cubes mounted on the payload and the satellite. Two theodolites should point to the payload’s alignment cube and the other two theodolites must point to the satellite’s alignment cube. Each theodolite must see at least one other theodolite, directly. Finally, by forming the coordinates systems of the payload and satellite in the theodolites coordinate system along with using the coordinate transfer matrices, the payload alignment correction matrix will be extracted in detail. The total method accuracy is within the order of few arcseconds.
Space systems design (spacecraft, satellites, space stations and their equipment)
َAlireza Alikhani; Mohammad Reza Salimi
Volume 15, English Special Issue , May 2022, , Pages 55-64
Abstract
The cold gas thruster is one of the significant components of a satellite and its application possesses a marked impact on the entire system performance. The nonlinear function and order of magnitude, lead to increasing the importance of thruster function. Therefore, pre-mission performance assessment ...
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The cold gas thruster is one of the significant components of a satellite and its application possesses a marked impact on the entire system performance. The nonlinear function and order of magnitude, lead to increasing the importance of thruster function. Therefore, pre-mission performance assessment has a considerable effect on the risk reduction of space missions. In this article, an uncomplicated and efficient pendulum scheme for development and implementation of a Thruster Test Stand (TTS), to measure the thrust produced at the end of the nozzle is proposed. The TTS is capable of measuring thrust levels in the range of 0.1Newtons to 3N with operating frequencies up to 50 Hz which is used by various satellite ranges. The experimental results demonstrate that although the designed device is less sophisticated than other test devices, it is capable of measuring the produced thrust very precisely and with less than 15mN.