# Design and Development of an Omnidirectional Three-Wheeled Industrial Mobile Robot Platform
## 5 Mechatronic Design
### Mechanical System
#### 5.1.3 Platform Structure  
The structural design of the omnidirectional platform focuses on achieving a robust, lightweight, and modular architecture, capable of supporting significant loads without \begin{table}
\begin{tabular}{c c c} \hline \hline
**Component** & **Parameter** & **Value** \\ \hline Belt & Designation & PHG 160-XL-037 \\  & Belt width (mm) & 9.525 \\  & Current service factor & 0.55 \\  & Belt power (kW) & 0.02 \\  & Belt mass (kgf) & 0.01 \\ \hline Driver Pulley & Designation & PHP 14-XL-37 RSB \\  & Reference diameter (mm) & 22.64 \\  & Number of teeth & 14 \\  & Pitch (in) & 0.2 \\ \hline Driven Pulley & Designation & PHP 56-XL-37.5 RTB \\  & Reference diameter (mm) & 90.55 \\  & Number of teeth & 56 \\  & Pitch (in) & 0.2 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Properties of transmission components. compromising stability or maneuverability. The structure is developed using standard aluminum T-slot profiles, selected for their high strength-to-weight ratio, modularity, and ease of assembly. The design process is divided into three main components:  
Lower Frame: Based on the design study presented in Section 3, the lower frame adopts a rigid triangular geometry that supports the 3A configuration, with dimensions optimized to accommodate both the transmission systems and the electronic components as shown in Figure 18.  
The structural framework of the lower base is built using steel Tee profiles, arranged from the geometric center outward toward each lateral centerline, effectively channeling operational loads and reactions directly through the main structural paths. Vertical Structure: The vertical supports connecting the lower frame to the upper platform are designed using a Warren truss configuration with verticals (option g, Figure 19). The classic Warren truss is characterized by equilateral triangles, where members are subjected to pure compression or tension, and where the diagonal elements have identical lengths. This geometry results in an efficient distribution of internal forces and provides an excellent weight-to-span ratio, particularly advantageous for short spans such as those encountered in the platform. The incorporation of vertical members further enhances the performance of the structure under non-uniform loading conditions. In the Warren truss with verticals, vertical elements handle shear forces more effectively, allowing diagonal members to maintain primarily axial loads (compression or tension). This reduces bending stresses and local deformations under dynamic operational conditions, such as acceleration, deceleration, and maneuvering with heavy loads. Additionally, using members of identical length simplifies manufacturing and assembly processes, reducing construction costs and ensuring consistency in mechanical behavior across all sections [30]. Upper Platform: To maximize the available area for payload accommodation, the upper platform is designed to approximate a circular geometry with a diameter of 1 m, despite the underlying triangular configuration of the main structure. This design choice provides a larger and more uniform surface, facilitating the placement and securing of bulky loads, and improving the overall usability of the platform for industrial material handling tasks. Structurally, the platform consists of a top-mounted non-slip steel plate, serving as the primary load-bearing surface where the cargo is placed. Underneath this plate, a reinforcing  
Figure 18: Distribution of the transmission system and electronic components. substructure of Tee profiles is arranged radially and orthogonally as shown in Figure 20, which depicts the underside view. The reinforcement is concentrated at the center, where the highest stresses due to load concentrations are expected, ensuring that the plate can maintain structural integrity under operational conditions. The modular profile-based construction allows easy adjustments and potential future expansions of the system, facilitating maintenance and reconfiguration for different industrial tasks.