## 2 Methodology
### Design of the X, Y and Z-Axis Arm System  
Due to the complicated solution associated with the series connection of the individual elements of the four arms located on the device. It was necessary to pay increased attention to the so-called \"Trolleys\" moving along a guide bar and a linear guide. They are based on a solid trolley in which all the necessary components are stored. In the case of carriages in the X and Y axes, these components include bearings of type 608 2Z (1), which are used to support the 1 st stage arm (Figure 22). They also participate in its rotational motion. The construction has two components, which required increased attention in terms of their relative position and coaxial. These components, i.e., the linear ball bearing (4) and the guide nut (2), are fastened to the carriage body through screw connections (5 and 3). In the case of a linear bearing, the screw connection is realised on the housing (8) in which the bearing is located. Figure 22 shows the \"trolley\" of the Z and Z'- axes. Its design was modified due to the need to reduce the weight of the whole mechanism. The difference is also anchoring on the linear guide realized through M3 screws (5). The change in the type of line was necessary due to the increase required in the system's stability and rigidity in the Z-axis, which supports the effector's entire weight. Figure 21: Drive, transformation mechanism and device guidance in Z-axis. Figure 22: (**a**) Design of the truck in the X and Y axes; (**b**) The “trolley” of the Z and Z’-axes. The arm of the first stage of the proposed construction consists of a ridge hinge (1), fixed to the carriage through a screw and a nut M8 and six corresponding washers (Figure 23a). The arm further consists of a 20 \(\times\) 20 mm aluminium profile (6), screws (7), washers (8) and \"T\" shaped nuts ensuring the position and stability of both end elements. The arm's opposite side is formed by a hinge (10) with bearings that allow arm 2. The second component of the arm in the X and Y axes is the second stage arm (Figure 23b). This arm provides the connection of the first arm to the effector. The method of interconnection and transformation of motion is the same as in the previous step. It means that the component has a comb hinge, this time rotated by 90\({}^{\circ}\) (2), and an aluminium profile with a 20 \(\times\) 20 mm diameter, which is connected to the effector holder (7). It is attached to the aluminium frame through screw connections consisting of a screw (7), a washer (8) and a \"T\" shaped nut. The different shape of the end component is adapted so that it does not collide with the effector through which M8 threaded screws connect it during the movement of the arms in the X and Y- axes. The correct position of the screw connection and the bearings' trouble-free movement is ensured through washers (9). As for the connecting element, trolley in Z and Z\({}^{\prime}\) axes, its design is smaller and more compact, as shown in Figure 23c. It is a more compact design due to the heavier weight of the linear guide housing, which the drive must handle during the device's operation. The components of these structural elements are similar. Here is a ball bearing, which was replaced by a linear guide house. The trolley is attached to it through M3 screws (4). Other elements of this construction are bearings type 608 2Z, which are used to fasten the arm's first stage using a screw and nut with an M8 thread. The last element is the guide nut (3), which ensures, as with other components, the transformation of the rotational movement of the guide screw into a sliding movement of the house along with the linear guide. The lead nut is attached to the component with M4 screws (5). The arm's second stage in the Z and Z\({}^{\prime}\) axes is substantially identical to the X and Y-axes arm. The only difference is the different orientation of the swivel joint connecting the arm to the effector.