Nonlinear Quaternion Feedback Attitude Control of an under-actuated Satellite

On-orbit Failure of the reaction wheels is a well -known phenomenon that has already been disastrous for several space missions. In many cases, it’s impossible to use backup hardware as a redundancy. Thus, the problem of 3-axis attitude control of a nano-satellite with two orthogonal reaction wheels is addressed in this paper. In this regard, we first presented the nonlinear dynamics and kinematics equations of rigid satellite attitude motion. Then, a nonlinear controller based on kinematics quaternion representation parameters is presented. The controller has been developed under the perfect zero total angular momentum condition and uses the body angular rates as virtual input. In fact, we used dynamical coupling and nonlinearity effects to produce a desired body angular velocity trajectory which is able to control an under-actuated satellite s attitude. Finally, the desired angular velocity trajectory tracking provides the control torque. Simulation results show that the attitude is rapidly and accurately converges to the required nadir-pointing condition from any initial condition.

کلیدواژه ها:

Nanosatellite ، Nonlinear control ، Under-actuated satellite ، Attitude control ، Reaction wheel