ResearchPaper
Space subsystems design: (navigation, control, structure and…)
Abbas Dideban; Alireza Ahangarani Farahani
Articles in Press, Accepted Manuscript, Available Online from 29 August 2022
Abstract
This paper presents a new control methodology based on Continuous Time Delay Petri Nets (CTDPN) tool for the attitude control of satellite simulator. The graphical and mathematical features of this tool help the expert designer to design an appropriate controller using graphical model easily, and then ...
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This paper presents a new control methodology based on Continuous Time Delay Petri Nets (CTDPN) tool for the attitude control of satellite simulator. The graphical and mathematical features of this tool help the expert designer to design an appropriate controller using graphical model easily, and then apply the necessary changes to the mathematical model. In this approach, the controller gains are derived from the states and some other variables. Thus, the system states and variables must be available. The new gain tuning algorithm consists of three stages. First, A simulation environment is made for mathematical modeling based on the CTDPN tool and controller design. Secondly, using optimal methods, the controller gains are calculated at any given time and the data are collected. Finally, using the database, a relationship between the set of variables and the gains are derived. Experimental results indicate the promising performance of the controller in comparison to the conventional controller applied to the satellite simulator platform. The results indicate that the designed controller is robust against variation of parameters, as the controller gains are tuned based on the system state and variables.
ResearchPaper
Space subsystems design: (navigation, control, structure and…)
Ali Kasiri; Farhad Fanisaberi; Vahid Joudakian
Articles in Press, Accepted Manuscript, Available Online from 25 January 2022
Abstract
Many studies have investigated the problem of external disturbance rejection and also increasing the attitude control system's robustness against the parametric uncertainties. Due to stochastic properties, noise effect minimization becomes an interesting and challenging problem in the field of spacecraft ...
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Many studies have investigated the problem of external disturbance rejection and also increasing the attitude control system's robustness against the parametric uncertainties. Due to stochastic properties, noise effect minimization becomes an interesting and challenging problem in the field of spacecraft attitude control that has been underestimated, while control actuators and attitude sensors themselves are important sources of noise generation., the main purpose of this paper is to (i)control the satellite’s attitude and (ii)minimize the variance of output, simultaneously. The Minimum Variance controller, which is considered the simplest type of model predictive controller, has a powerful capability for minimizing the effects of output noise. This feature makes it a suitable control scheme for space-based high-resolution photography missions. so,, we described the conventional Minimum Variance regulator method at first, then an Incremental version of the regulator has been presented to solve the tracking problem. Finally, the generalized minimum variance controller which can control both minimum-phase and non-minimum-phase systems is derived for a high pointing accuracy spacecraft. The simulation results show the efficiency of the proposed controller to restrain the noise effects in a high-resolution tri-stereo imaging mission.
ResearchPaper
Space subsystems design: (navigation, control, structure and…)
Valiollah Shahbahrami; Milad َAzimi; َAlireza Alikhani
Articles in Press, Accepted Manuscript, Available Online from 06 March 2022
Abstract
In this paper, a robust adaptive hybrid control approach based on a combination of super-twisting and non-singular terminal sliding mode control (STNSMC) approaches for vibration and attitude control of a flexible spacecraft with fully coupled dynamic is developed. The proposed adaptation law eliminates ...
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In this paper, a robust adaptive hybrid control approach based on a combination of super-twisting and non-singular terminal sliding mode control (STNSMC) approaches for vibration and attitude control of a flexible spacecraft with fully coupled dynamic is developed. The proposed adaptation law eliminates the need for bounds knowledge of external disturbances and uncertainties. Then an ST-based NSMC generates a continuous control signal to reject the Chattering phenomenon, the non-singular terminal switching control law with the ability to generate continuous control commands to eliminate the chattering phenomenon. Moreover, finite-time convergence is achieved, and the singularity problem has been avoided. The overall stability of the system has been demonstrated using the Lyapunov theory. One of the essential features of the proposed control algorithm is to prevent overestimation of control gains and faster convergence rates comparing to conventional ST and non-singular terminal SMC approaches. The simulations in the form of a comparative study for large-angle maneuver reveal the advantage of the proposed approach.
ResearchPaper
safety in space
Mohammad Nadjafi; Hassan Naseh; Mehrdad Sedigh Koochaki
Articles in Press, Accepted Manuscript, Available Online from 05 February 2023
Abstract
The Monopropellant Hydrazine Propulsion system is one of the most widely used types of single-agent propulsion systems to control the position or correction of satellites in orbits. This system consists of combustion chamber subsystems (catalyst bed, catalyst, nozzle, and cap), fuel and fuel tank, high-pressure ...
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The Monopropellant Hydrazine Propulsion system is one of the most widely used types of single-agent propulsion systems to control the position or correction of satellites in orbits. This system consists of combustion chamber subsystems (catalyst bed, catalyst, nozzle, and cap), fuel and fuel tank, high-pressure tank, control valves, and interface pipes. In this paper, the MPHP system (as a case study) is described in detail, and then critical risks are identified by creating FMECA tables on the case study in the design phase. Based on the proposed FMCEA flowchart, potential failure modes are identified. In the next step, decisions and corrective actions are formulated regarding the inherent failures of the system. Finally, the necessary measures to reduce the risks will be taken according to the system's failure modes, and the reduction of the identified risks to an acceptable level is presented. The attained results show that the catalyst decomposition chamber, catalyst bed, inlet flow control valve, and propellant management facilities units have the highest risk index values (RPN), respectively. For this purpose, corrective measures have been suggested for each of these.
ResearchPaper
Space subsystems design: (navigation, control, structure and…)
Arash Abarghooei; Hassan Salarieh; Pedram Hosseiniakram
Articles in Press, Accepted Manuscript, Available Online from 05 February 2023
Abstract
Linear algorithms are the most widely used method for satellite attitude control using reaction wheels because of their simplicity and low computational cost. The first part of the paper introduces different attitude determination and control algorithms, and reviews resources that utilized optimal linear ...
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Linear algorithms are the most widely used method for satellite attitude control using reaction wheels because of their simplicity and low computational cost. The first part of the paper introduces different attitude determination and control algorithms, and reviews resources that utilized optimal linear and nonlinear control methods (such as LQR and SDRE). Next, dynamic equations for the control of the satellite using reaction wheels have been extracted, then the satellite controller has been designed by using optimal linear and nonlinear methods, which are robust against noise and disturbance, as an alternative for the PD controller. Finally, the designed control algorithms have been implemented for different satellite pointing scenarios, and by simulating these methods in MATLAB software, their performance has been studied and compared.
ResearchPaper
investigating space radiation
Pedram Hajipour; Leila mohammadi; Azam Eidi; Sara Shoorian; Nahid Eidi esfiani; Seyed Amir Hossein Feghhi
Articles in Press, Accepted Manuscript, Available Online from 12 March 2023
Abstract
One of the damaging factors for the proper functioning of telecommunication payloads are high energy ionizing particles in space, which the use of proper shield is a way to deal with it. In the design of protection, several factors, such as the type of part and the amount of weight acceptable for the ...
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One of the damaging factors for the proper functioning of telecommunication payloads are high energy ionizing particles in space, which the use of proper shield is a way to deal with it. In the design of protection, several factors, such as the type of part and the amount of weight acceptable for the payload.etc.must be taken into consideration. In recent years, in order to reduce the costs of construction and launch, the use of non-space components has been favored.Therefore, the use of shields with the suitable material in with radiation resistance, with respect to the weight budget considerations, will be one of the important challenges .In this paper, the aim is to investigate the methods of reducing the weight budget considering with respect to the radiation damage of ionizing dose. In this regard, a five-year technology development mission in the GEO orbit has been predicted, and the results of simulations and testing of aluminum and polyethylene shielding to check ionizing dose damage, according to the initial and reference weight budget, have been presented and compared. The analysis and evaluation of the test results using polyethylene protection shows a 17.21 percentage reduction between the two external and internal radiation meters.
ResearchPaper
GPS and navigation
reza ghasrizadeh; Amir Ali Nikkhah
Articles in Press, Accepted Manuscript, Available Online from 12 May 2023
Abstract
This paper presents a solution for detecting and recovery for the spoof error of GPS receiver signals, in order to increase the accuracy of the navigation system integrating inertial systems with GPS signals. integrated inertial navigation and GPS data has many advantages. However, due to the weakness ...
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This paper presents a solution for detecting and recovery for the spoof error of GPS receiver signals, in order to increase the accuracy of the navigation system integrating inertial systems with GPS signals. integrated inertial navigation and GPS data has many advantages. However, due to the weakness of satellite signals against jamming and spoof attacks of providing analytical solutions, they have a special place in improving Kalman filter estimation compared to hardware solutions. In this paper, a new method for loosely coupled of INS/GPS is presented, in which the steady state of Kalman gain parameters is used during deception detection and recovery. With the gain parameters of the Kalman filter tending to constant values, with the aim of correcting and predicting the error of state variables, it can be used to detection GPS spoofed data. It can be detected by spoof in the GPS receiver signal when couple with inertial waves through the amount of Kalman gain fluctuations. In the case of closed loop, the Kalman gain matrix denominators tend to a constant value, and in case of deception, this function is associated with many fluctuations. By using dynamic weighting, the effect of errors caused by these attacks is recovered.
Technical Note
space sciences and exploration
Fateme Mousavi
Articles in Press, Accepted Manuscript, Available Online from 21 May 2023
Abstract
Seed aging is a process that can lead to a complete loss of seed viability. This process occurs when seeds are exposed to long-term storage or controlled deterioration treatments such as excessive dryness, lack of oxygen, and temperature fluctuations on Earth or in outer space. Proteomic changes can ...
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Seed aging is a process that can lead to a complete loss of seed viability. This process occurs when seeds are exposed to long-term storage or controlled deterioration treatments such as excessive dryness, lack of oxygen, and temperature fluctuations on Earth or in outer space. Proteomic changes can occur in the dry state of seeds. Extreme temperature fluctuations in outer space, especially on the moon and Mars, are one of the most important challenges for space scientists to transfer plant seeds and grow them in outer space outside the atmosphere. The present study studied the effects of simulated space temperature fluctuations on the quantitative and qualitative content of dry tomato seed proteins. The results showed 13 protein bands in the molecular weight range of 8.89 to 91.82 kilodaltons. A double or more significant decrease in the intensity of protein bands with high molecular weight was also observed in the treated group compared to the control. Finally, the two-dimensional electrophoresis technique followed by mass spectrometry is suggested for better resolution of tomato seed proteins and their better separation, as well as identification of unknown protein bands in future studies.
ResearchPaper
communications
Peyman Mohammadi; Mehdi Alemi Rostami
Articles in Press, Accepted Manuscript, Available Online from 19 June 2023
Abstract
One of the most important issues related to the power supply of TWTA lamps in satellites is to have low ripple, high efficiency, high reliability and optimal volume and weight,. In this article, the efficiency and reliability of high voltage DC/DC electronic-power converter is optimized for use in satellite ...
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One of the most important issues related to the power supply of TWTA lamps in satellites is to have low ripple, high efficiency, high reliability and optimal volume and weight,. In this article, the efficiency and reliability of high voltage DC/DC electronic-power converter is optimized for use in satellite and TWTA lamps. The goal of optimization using multi-objective genetic algorithm (NSGA-II) in this article is to minimize the objective function, which includes efficiency and reliability. Markov model is used to evaluate reliability, in which short-circuit and open-circuit errors are considered for circuit switches and diodes, and short-circuit errors are considered for passive circuit elements. for optimization, first, the input variables of the algorithm are determined as the input of the objective function, so that with the help of sensitivity analysis, the parameters that have low sensitivity and their changes do not have a major impact on the objective function are eliminated. parameters of NSGA-II algorithm, including the number of iterations, the number of populations, and the probability have been determined for the accurate calculation of circuit variables. the results section this method, in addition to maintaining high efficiency, with the optimal selection of elements, high reliability can be achieved .
ResearchPaper
space sciences and exploration
Iman Shafieenejad
Articles in Press, Accepted Manuscript, Available Online from 25 July 2023
Abstract
The aim of this research is to optimize the trajectory of a low-trust spacecraft carrying biological cargo. Reducing the radiation stresses of the Van Allen belt is the optimal criterion of the optimal control problem of the orbital transfer from the low orbits to the high orbits. Since the minimum radiation ...
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The aim of this research is to optimize the trajectory of a low-trust spacecraft carrying biological cargo. Reducing the radiation stresses of the Van Allen belt is the optimal criterion of the optimal control problem of the orbital transfer from the low orbits to the high orbits. Since the minimum radiation stress criterion introduced in this article is not among the conventional optimality criteria, solving the above optimal control problem will be complicated and the honey bee optimization method has been used. The optimization of the path in this article is done by rewriting the motion equations based on the control variable and solving the new motion equations with the help of bee optimization. The main advantage of the method used in this problem is the use of optimal control theory and population-based optimization methods with a global approach. In the presented new method, the optimal control problem is simplified by redefining the differential equation system, and the results show the accuracy and ease of solution. Results of the optimal criterion of the minimum time and the minimum radiation stresses presented in this article, the criterion of the minimum radiation causes an increase of 8.89% in the transfer time.
ResearchPaper
Alireza Ahangarani Farahani; Amirhossain Adami; Hamed Arefkhani
Articles in Press, Accepted Manuscript, Available Online from 26 July 2023
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.
ResearchPaper
Space subsystems design: (navigation, control, structure and…)
Mohammad Haji Jafari; Afshin ValiMohammad; Mahsa Mahdavi
Articles in Press, Accepted Manuscript, Available Online from 05 August 2023
Abstract
In this research, the dynamic response of a U-12 CubeSat (20x20x30 cm) is investigated for three configurations during the launch conditions. Despite the existence of a successful design for this satellite, adding a mount to install on a standard adapter, the structural design of the satellite has been ...
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In this research, the dynamic response of a U-12 CubeSat (20x20x30 cm) is investigated for three configurations during the launch conditions. Despite the existence of a successful design for this satellite, adding a mount to install on a standard adapter, the structural design of the satellite has been modified for modal computability with the launcher., which is based on 3 general approaches: to apply geometric changes to the structure, changing the extent of the points to improve the limitations of connecting to the launcher, and rearranging the internal system components regarding the standards and principles of compatibility and proximity. Therefore, more than the addition of the adapter mount and a few changes in the separating plates, a spire has been added to the structure, which has caused a change in the internal arrangement, including the halving of the fuel tank (by reducing the capacity of 595 cubic centimeters). Despite the increase of 370 grams of total mass, the natural frequencies of the system have been increased enough without the need for redesign and there will be no frequency interference with the frequency spectrum of the launcher.
ResearchPaper
GPS and navigation
Alireza toloui; Mona Zahednamazi
Articles in Press, Accepted Manuscript, Available Online from 07 August 2023
Abstract
One of the attitude sensors for the spacecraft is the star sensor. The attitude calculation by the star sensor includes several steps: image processing, star identification, database search, and implementation of the attitude determination algorithm. This paper presents analysis and improvements on the ...
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One of the attitude sensors for the spacecraft is the star sensor. The attitude calculation by the star sensor includes several steps: image processing, star identification, database search, and implementation of the attitude determination algorithm. This paper presents analysis and improvements on the star identification algorithm based on singular value decomposition. To improve the identification results, modifications have been made to the algorithm. Also, analysis and simulation are presented to investigate the effect of field of view dimensions and the number of stars used on the identification results, and the rate of duplicate sets in the database. In addition, identification has been considered a two-step process based on singular values and vectors. The results show the superiority of the improved algorithm in increasing the identification rate and reducing the rate of duplicate sets in the database. The identification rate of the improved algorithm in 〖10〗^°×〖10〗^° and 〖12〗^°×〖12〗^° fields of view dimension is always more the %97. The simulations were performed based on the Hipparcos star catalog for stars brighter than magnitude 6.5 and using MATLAB software.
ResearchPaper
GPS and navigation
Seyed Ali Zahiripour
Articles in Press, Accepted Manuscript, Available Online from 29 August 2023
Abstract
In this article, a method for increasing the accuracy of the initial alignment process of inertial navigation systems with a stable platform is presented through state feedback control in flight mode. In the presented method, the state feedback controller is designed by using the stable plate deviation ...
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In this article, a method for increasing the accuracy of the initial alignment process of inertial navigation systems with a stable platform is presented through state feedback control in flight mode. In the presented method, the state feedback controller is designed by using the stable plate deviation angles and the sensor error which is extracted with the help of Kalman filter. To do this, while checking the observability of the system, by adding suitable flight maneuvers and expressing the equations of propagation of navigation error, in the form of a fixed piece system with time, it is possible to estimate the angles and errors of the sensors in the align phase. The groundwork is provided for the design of state feedback. Then, taking into account the stable platform motion equations and using the principle of separation of observer and controller design, a state feedback controller is designed. In the end, the simulation results of the proposed method show an increase in the accuracy of the alignment process and, consequently, an increase in the accuracy of the navigation, compared to the conventional output feedback method.
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