Mohammad Reza Mortazavi; Ali Reza Alikhani
Volume 8, Issue 1 , April 2015, , Pages 27-41
Abstract
This paper presents a suitable technique for nonlinear control of a flexible spacecraft in proximity operations. To do proximity operations well, the pursuer spacecraft must place itself in a pre specified location relative to target and align its docking port to target’s docking port while keeping ...
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This paper presents a suitable technique for nonlinear control of a flexible spacecraft in proximity operations. To do proximity operations well, the pursuer spacecraft must place itself in a pre specified location relative to target and align its docking port to target’s docking port while keeping their attitude compatible. This procedure usually needs large, fast and accurate manoeuvres which can cause flexible structure vibrations. In addition, external disturbances, actuator saturation and model uncertainties increase difficulties of achieving such a goal. Consequently it is necessary to utilize an effective and nonlinear controller design approach to overcome these challenges. To perform considered scenario successfully, in this paper we use a method in nonlinear optimal control called State Dependent Riccati Equation (SDRE). Simple formulation and tuning as well as good performance and satisfactory robustness are some advantages of this approach in unified control of the spacecraft position, attitude and flexible motion during a proximity operation. 6DoF simulations show good performance of controller in presence of structure flexibility, parametric uncertainties, input uncertainty and saturation and external disturbance.
