Phase Portrait Analysis of Small Satellites: With and Without Torque

Abstract

The qualitative behavior analysis of attitude dynamics of small satellite, especially nanosatellite, with lesser weight and smaller size is presented in this paper. Nanosatellites are high dimensional, nonlinear small satellite systems sensitive toward external disturbances and internal variations. The objective of the work is to ascertain the variation in angular velocity when the dynamical system is affected with and without torque. At first, the satellite behavior is inspected with Euler’s equation of motion: torque-free motion of an axisymmetric satellite body and for the generalized torque-free motion. Next, the behavior is examined for the attitude control of satellite in space with torque. Any change in the initial condition is reflected along with the changes in the angular velocity at the respective axis. It is validated with the simulation result of the mentioned categories: time series, two-dimensional and three-dimensional phase portraits of torque-free and torque-imposed motions.