نوع مقاله : مقاله پژوهشی
نویسندگان
1 دانشکده هوافضا - دانشگاه صنعتی شریف
2 دانشکده مهندسی هوافضا - دانشگاه صنعتی شریف
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
One of the important problems in controlling mechanical systems is the structural interactions. Obviously, all of the bodies have elastic behavior and rigidity is assumed for reducing the modeling complexity which is not applicable for many situations. For example, gravity gradient booms and solar panels used in satellites have considerable large deflections relative to their basements. These such systems are recognized as Coupled Rigid-Flexible structures. In these cases it is possible to consider the more flexible part of the structure as the elastic one and the other as the rigid part. With the development of fractional order calculus and more accurately modeling of physical phenomena, the problem of controlling these systems, by considering the uncertainties in the system, will become necessary and inevitable. In this thesis, the fractional order transfer function model of a satellite with Coupled rigid-flexible structures is used as the reference work of the research. To control this dynamical system, sliding mode control method, which is one of the robust control methods, has been used. It is clear that it is not possible to directly design a sliding mode controller for a transfer function. For this reason, a fractional order pseudo-state space model is first obtained from the fractional order transfer function model. Then a controller is designed for it. On the other hand, considering the dynamics of the system is used in the design process of sliding mode controller and proving its stability. Since the state space model is fractional, it is clear that the integer order sliding surface cannot be used. Therefore, the fractional sliding surface has been used for this purpose. The results show that in the presence of considerable uncertainties in each of the four parameters of the dynamical system, and considering the effects of sensor noise and the saturation element for the control signal, this controller can overcome it and follow the reference signal.
کلیدواژهها [English]
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