• Journal of Institute of Control, Robotics and Systems
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• v.21 no.11
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• pp.1027-1033
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• 2015

For the attitude control of spacecraft, two variable-speed control moment gyros are proposed as main actuators in the article. Since a variable-speed control moment gyro (VSCMG) makes two control torques (gyroscopic torque and reaction torque), two VSCMGs are sufficient for controlling 3-axes attitude. Additionally, there are no singular conditions for two non-parallel VSCMGs. Since gyroscopic torque is usually much greater than reaction torque, the control performances of approximately 3 axes may not be the same. However, several missions can be accomplished by controlling two axes. For such missions, a selective axes control method is proposed. The method selects two axes for a certain task and controls the attitude of the selected axes. For the remaining axis, angular speed is controlled for stabilization. A hardware-in-the-loop simulation has been used to test VSCMG modules and to verify the proposed method. Two VSCMGs can be alternative actuators for small satellites.

• Journal of Aerospace System Engineering
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• v.12 no.1
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• pp.17-26
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• 2018

The interaction model between variable-speed control moment gyros and a satellite has been studied based on the multi-body dynamics. Using the interaction model, we could obtain data for the design of VCMG motors and the strength design of structure. The interaction effects of flexible modules such as solar panels were included. Flexible modes are excited by the satellite's maneuver, and these modes cause perturbations in the satellite attitude. We developed a simulation program by Modelica and verified the proposed model.