Anatoliy Kulik
National Aerospace University "KhAI"
Ukraine
Title: Control of operability of redundant electrical flywheel actuator units under the destabilizing influences
Biography
Biography: Anatoliy Kulik
Abstract
During the spaceflight, satellites are influenced by external perturbation actions of gravitational, magnetic, aerodynamic, electric, solar, and other forces and moments. To fend off these disturbances in order to maintain required orientation of the satellite, actuators are used, which create reactive moments for the conservation of angular momentum of the satellite. Electric-flywheels implemented as motor-flywheels are effectively used as actuators for satellites. These devices are combined to actuator units, which creates control vectors of reactive moments. The structure of three such actuators placed along the axes of the orthogonal coordinate system, allows fending off external disturbances. Units with redundant structure of flywheels actuators also allow parrying complex internal disturbances called as rejection. External and internal disturbances represent a lot of destabilizing influences. These actions violate the operation of electric flywheel actuator units. The units of actuators with redundant structure provide the ability to fend off a destabilizing effect. This problem is actually both in theory and in practice of satellite control. A new diagnosis-based control principle is used to solve this problem. By using that approach for operability control allows to provide a diagnosability and recoverability relative to a plurality of potential destabilizing effects of actuator unit during its designing. The new diagnostic models, which assign direct and indirect signs of destabilizing influences, were developed. The criteria of structural and signal diagnosability for these models were formed. The algorithms for diagnosing of a flywheels actuator unit with pyramidal structure were developed. The models and algorithms of operability recovery of such actuator units were formed. The breadboard model of electromechanical actuators with pyramidal structure in gimbals was made. The series of experimental research were carried, which confirmed the theoretical and practical applicability of proposed control approach of redundant electrical flywheels actuator unit operability.