## 2 Tower Mechanical Structure Modeling  
The tilt sensor should be placed at the location where the displacement changes the most when the tower is deformed, and a finite element model of the tower must be constructed to achieve this purpose. First, the design modeler was used to modeling the mechanical structure of the tower, and the mechanical model was input to ANSYS Workbench platform for finite element analysis of the tower's mechanical structure. Through the finite element analysis results, the placement position of the tilt sensor was analyzed to achieve the best monitoring effect [16]. Taking the MZ2-27 cathead linear tower as an example, the main material of the tower adopts angle steel as the material, the main material is Q345 steel, and the oblique material is Q235 steel. These relevant material parameters were imported into the design modeler, and the bolts were used to attach the main material and the oblique material,  
Figure 3: (**a**) One-vs-one method of classifying hyperplanes; (**b**) one-vs-all method of classifying hyperplanes. which can eliminate part of the stress generated by the tower vibration and reduce the shaking amplitude of the tower. Therefore, the tower cannot be regarded as a truss structure but should be simulated and analyzed as a mixed steel frame and truss structure. The parameters related to the main material and diagonal material are shown in Table 1.  
Usually, the main material is regarded as a beam structure, which not only bears axial pressure and tension but also bends at a certain degree; the oblique material is regarded as a rod structure, which only bears axial strain and theoretically does not produce bending. Different from the classic ANSYS version, the Workbench platform set the line body as a beam element by default and eliminated the direct switch between beam element and rod element. Therefore, two solutions are proposed in this paper: one is to force the unit type of the oblique material to change to a Link180 unit through the command flow; the other is to use the beam unit instead of the rod unit and set the connection nodes on both sides of the beam unit to be hinged, releasing the rotation degrees of freedom in three directions to achieve accurate modeling. Because the oblique material of the tower generating a small bending moment is more realistic, and because the cross-sectional area of the line body must be recalculated if Method 1 is adopted, Method 2 was chosen for the mixed modeling of the truss and rigid frame. The MZ2-27 cat-head-type linear tower is an overhanging tower. The force characteristic of the overhanging tower is that both sides of the conductor are not broken, thus the load of an overhanging tower is mainly composed of the wind load and ice load. Wind load includes line wind load, tower wind load, and insulator string wind load, and ice load mainly refers to the ice load of the conductor and the ground wire. In the Workbench platform, the stress of the tower under each working condition was calculated, and the load under each working condition was calculated by taking the wind speed of 10m/s and the conductor and ground wire's icing thickness of 20 mm as an example [17]. Relevant calculation formulas for line wind load, tower wind load, and insulator string wind load are provided in the literature [18].