Spherical Air Bearing Attitude Control Simulator for Nanosatellites

Author(s):  
Tyler Ustrzycki ◽  
Regina Lee ◽  
Hugh Chesser
Keyword(s):  
Author(s):  
J. Prado ◽  
G. Bisiacchi ◽  
L. Reyes ◽  
E. Vicente ◽  
F. Contreras ◽  
...  

A frictionless environment simulation platform, utilized for accomplishing three-axis attitude control tests in small satellites, is introduced. It is employed to develop, improve, and carry out objective tests of sensors, actuators, and algorithms in the experimental framework. Different sensors (i.e. sun, earth, magnetometer, and an inertial measurement unit) are utilized to assess three-axis deviations. A set of three inertial wheels is used as primary actuators for attitude control, together with three mutually perpendicular magnetic coils intended for desaturation purposes, and as a backup control system. Accurate balancing, through the platform’s center of mass relocation into the geometrical center of the spherical air-bearing, significatively reduces gravitational torques, generating a virtually torque-free environment. A very practical balancing procedure was developed for equilibrating the table in the local horizontal plane, with a reduced final residual torque. A wireless monitoring system was developed for on-line and post-processing analysis; attitude data are displayed and stored, allowing properly evaluate the sensors, actuators, and algorithms. A specifically designed onboard computer and a set of microcontrollers are used to carry out attitude determination and control tasks in a distributed control scheme. The main components and subsystems of the simulation platform are described in detail.


Author(s):  
Harry Septanto ◽  
Farohaji Kurniawan ◽  
Bambang Setiadi ◽  
Edi Kurniawan ◽  
Djoko Suprijanto

Author(s):  
Mahdi Saidimanesh ◽  
Azin Shahiri ◽  
Ali Nikparto

It is important to test the attitude control systems on satellites before they are launched in space. Traditionally this has been done by dropping the satellite, and firing the thrusters before the satellite makes a soft landing in a net. This method only allows a few seconds of testing and does not lend itself to the measurement of pointing accuracy. A better method is to mount the satellite on a spherical air bearing. In this paper behavior of a semi spherical air bearing is studied and analyzed in various conditions. These bearings are used in different applications such as simulation of approximately frictionless condition which is the satellite’s situation in space. In this analysis FLUENT 6.3.26 is used to simulate the air bearing’s behavior. Simulation process is divided into 5 sections. These sections are accordingly 2dimensional with static boundary condition, 3dimensional and static, 2dimensional and dynamic and 3dimensional and dynamic boundary conditions. At last bearing’s function was optimized by changing some adjustable parameters which are important in controlling the bearings behavior such as air entering nozzles diameter and their number and location. Importance of this study is to simulate the behavior of the bearing in dynamic boundary condition using dynamic mesh. Eventually results of the simulation are compared to the actual test results and bearing behavior is analyzed. Finally best arrangement for achieving maximum normal load is studied.


2020 ◽  
Vol 12 (4) ◽  
pp. 474-481
Author(s):  
M. Yu. Ovchinnikov ◽  
D. S. Roldugin ◽  
R. A. Borges ◽  
C. Cappelletti ◽  
S. Battistini

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