Suboptimal Robust Tube Based MPC: Satellite Attitude Control Application

Abstract

In this paper, a satellite attitude control system with the reaction wheels based on suboptimal robust tube based model predictive control is designed. The satellite receives many external bounded disturbances in space. Due to the fact that disturbances have a specific range, it is possible to satellite attitude control by using a robust predictive controller based on a tube. But since the satellite has a system with complex dynamics, the challenge of increasing the volume of calculations arises when calculating the minimal Robust Positive Invariant set. The challenge of increasing the volume of calculations of this set (tube) in complex systems such as satellites is caused by the large number of state variables of the system. The large number of system state variables causes an exponential increase in the volume of calculations due to the formation of multiple Minkowski sums in the tube calculation. In order to solve this challenge, a new solution of robust predictive controller based on suboptimal tube has been presented. This solution reduces the volume of tube calculations. Simulation has been done for the accuracy of the design of the predictive controller based on the suboptimal tube to attitude control of satellite.

Keywords

• tube based model predictive control
• approximate minimal robust positive invariant set
• satellite attitude control system
• reaction wheels
• bounded disturbance