Design, manufacturing, and application of coaxial magnetic gears on fin actuation systems

The necessity for innovative power transmission mechanisms that can satisfy the emerging demands across various domains, particularly in the aviation, space, and defense sectors, is escalating on a daily basis. In this context, as a power transmission element that can operate in oil-free and frictionless conditions, Magnetic Gears (MGs) have the potential to meet the needs arising in these areas. Research on this subject has gained momentum, especially in recent years. The scope of this thesis encompasses the design of coaxial MGs intended for utilisation in the power transmission mechanisms of Fin Actuation System (FAS). These designs have been formulated based on the findings of Electromagnetic Numerical Analysis (ENA), employing a two-dimensional (2D) and three-dimensional (3D) finite element modelling approach. The fabrication of designs that meet the performance criteria at the highest level has been undertaken, and the potential of MGs in terms of application has been demonstrated through experimental performance tests. In the development of MG designs that can provide the required transmission ratio and Volumetric Torque Density (VTD) values (5-5,5 and ~230 Nm/L) for the FAS application, the appropriate pole pair and number of segments were first determined by considering different combinations. In the following study, three distinct magnet array types, namely, Radial Array (RA), Halbach Array (HA), and Flux Concentration Halbach Array (FCHA), were considered. The objective was to determine the magnet array type with the highest potential to meet the desired performance targets. This was achieved by employing 2D and 3D ENA, with different geometrical parameters defined as variables. The ENA results demonstrated that the designs with the highest potential to meet the specified performance targets were FCHA MG. Furthermore, experimental results obtained from ENA have demonstrated that the performance of FCHA MG designs can be significantly enhanced by the selection of appropriate design and magnet level parameters. In the FCHA MG designs, two different MG versions using AISI 1018 and laminated electrical steel as Middle Rotor (MR) material were also considered, and the performances of these designs were compared in terms of VTD. The performances of the MG designs in the mechanical direction were revealed by the structural analyses performed. In order to demonstrate the experimental performance of the developed FCHA MG designs, the manufacturing and assembly of the components of the designs were carried out using different manufacturing approaches and specially developed auxiliary apparatus. The power transmission ratio, derived from the number of pole pairs and segments of the fabricated MGs, is obtained through experimental means using the test setup. The consistency of the findings with the numerical results is demonstrated. Experimental evidence has demonstrated that the power transmission ratios of the FCHA MG versions are within the range of 5,32-5,35, thereby validating the numerical analyses. Furthermore, an experimental investigation was conducted to compare the performance of the MG designs with that of the designed real-time loading system. Initially, the output torque values at which the two designs are pushed to their limits and enter the intrinsically safe state are obtained. Subsequently, the VTD values were measured experimentally for both designs. At this point, the VTD values were 221,66 Nm/L and 229,46 Nm/L for the first and second MG versions, respectively. Furthermore, experimental testing was conducted to obtain efficiency values for both designs, with variations in speed and torque loadings. In this context, efficiency values of up to 99,9% have been calculated at high output torque values. Subsequently, the developed MGs are integrated into a typical FAS mechanism, and their performance is investigated through experimental means. Subsequent to this, an analysis of the performance of the FAS designs with MG utilizing disparate MR versions was conducted using the real-time loading system. This analysis yielded experimental evidence that the targeted VTD value for the FAS was successfully achieved. As a result of the experimental tests performed with precision position encoders, magnetic torque spring constants were obtained. These findings were then compared with numerical results. The nonlinear behavior of the output position, when subjected to varying torque loads, has underscored the imperative for the development of control algorithms that are characterized by a distinct structural design. The results obtained within the scope of this thesis have revealed the advantages and disadvantages of MGs as a power transmission element with the potential to be used in FAS and similar applications, and the findings obtained in this context will guide the designers.