# Design and Development of an Omnidirectional Three-Wheeled Industrial Mobile Robot Platform
## 3 Global Platform Design  
The design basically consists of a vehicle with a body in the shape of an equilateral triangle as depicted in Figure 3. An omnidirectional wheel set is placed on each side. A motor in conjunction with a reducer will provide the necessary torque to each wheel. The design of each omnidirectional wheel set proposed in this paper is inspired by configurations reported in the state of the art (see Section 2.2) and enhances their performance by assembling two omniwheels in tandem. Each wheel features rollers spaced at 90\({}^{\circ}\) intervals, and the two wheels are mounted with a 45\({}^{\circ}\) angular offset as illustrated in Figure 4. This offset ensures staggered roller contact with the ground, distributing the load more evenly and smoothing the motion. The double-row design primarily aims to mitigate vibrations caused by the intermittent contact of the rollers during movement. By overlapping the ground contact points, the transition between rollers becomes smoother, which reduces abrupt variations in contact forces. This significantly diminishes vertical oscillations transmitted to the robot's structure and improves the overall stability of the platform. Furthermore, the increased continuity of contact improves traction and reduces lateral slip, especially during combined translational and rotational motions. This characteristic is crucial for industrial applications that demand high precision and stable load transportation. Supporting this approach, [PERSON] et al. proposed in 2023 [7] that, compared to Mecanum wheels, omnidirectional wheels generally exhibit lower vibration levels due to a more stable ground contact behavior. Additionally, [PERSON] and [PERSON] [22] analyzed various omnidirectional wheel designs, including double-row configurations, concluding that such designs improve stability and reduce vibratory phenomena in mobile robots. Figure 3: Omnidirectional robot CAD design. Figure 2: The structure of the omniwheel [21]. The effectiveness of the proposed dual-wheel design with 45\({}^{\circ}\) offset has been experimentally validated in our platform, demonstrating enhanced stability, improved traction, and reduced vibrations during operations on cemented surfaces with controlled friction, ultimately ensuring safer and more efficient handling of heavy loads in industrial environments. The three motors are controlled by microcontrollers and power drivers. Power supply is provided by hard-wired sources connected to a 110/220 VAC electrical outlet. As this is a cargo vehicle, all elements, such as wheels, axles, structure, and constituent parts, are designed under these considerations. The control of the platform is based on an algorithm (see Section 6.1), where it will be assigned trajectories to follow, analogous to pose-to-pose (PTP) and continuous path (CP) control [23]. The omnidirectional robot platform has three wheels positioned at 120\({}^{\circ}\), where each of the wheels has the ability to rotate in both directions as seen in Figure 5.  
This bidirectional rotation is achieved through the use of stepper motors directly coupled to each wheel via a pulley-and-belt transmission system. The motors are controlled independently, allowing the precise command of angular velocity and direction for each wheel. The combination of bidirectional wheel rotation with the symmetric 120\({}^{\circ}\) wheel arrangement enables the robot to perform simultaneous translational and rotational movements in any direction, maintaining a smooth and continuous trajectory even in confined industrial environments. This configuration results in greater maneuverability for avoiding obstacles or performing lateral positioning, the seamless execution of trajectories in crowded spaces without the need for global reorientation, and improved time efficiency and accuracy when docking at fixed stations or following production lines. Figure 4: Universal/omniwheels, assembly of two wheels with rollers distributed at 90\({}^{\circ}\) intervals, with a 45\({}^{\circ}\) angular offset between the wheels.