Mecanum wheels (universal wheels) consist of a series of polyurethane (PU) covered rollers that are attached at an angle to the circumference of the wheel frame. When the Mecanum wheel rotates, the input force is only generated in the direction of the wheel, so by commanding the wheels to rotate in various combinations of directions, the vehicle can move in different motion modes. This kinematic characteristic makes the Mecanum wheel an ideal choice for AGV/AMR The mainstream of AMR. But even though the roller's shape is designed so that the circumference of the mecanum wheel forms a perfect circle, regular vibrations are often seen when the mecanum wheel rolls on the ground. We investigated the phenomenon and proposed a solution to the problem.

Structural analysis confirmed that the irregular polyurethane stiffness around the Mecanum wheel could cause vibrations. We changed the geometry of the metal core and polyurethane layers to achieve uniform stiffness. After a series of 3D finite element analyses, the final design was completed.

The 6-inch to 14-inch Mecanum wheels are the most widely used and representative ones. They are composed of eight rollers with a roller installation angle of 45 degrees. From the side of the Mecanum wheel, each roller is The arc of the rollers will be connected to form an arc, but in fact there will be a height difference between the rollers when they alternate.

Research results show that the height difference comes from the deformation of the roller. Therefore, our research goal is to change the geometric design of the Mecanum wheel so that the deformation of each angle during operation can be unified, so that the Mecanum wheel will not cause vibration due to the height difference during operation. We used finite element analysis to analyze the roller angle, polyurethane deformation, and overall bending deformation.

Our research found that the compression deformation of the roller is highly correlated with the thickness of the polyurethane. The thinner the polyurethane is, the higher the compression deformation is, and the thicker the polyurethane is, the lower the compression deformation is. Therefore, we adjusted the thickness of the polyurethane of the roller, keeping the outer curvature of the roller unchanged, and changed the amount of compression when the roller was subjected to force by modifying the iron core in the middle. This method can make the compression of the roller uniform in the continuous operation of the Mecanum wheel, and analyze the overlapping part of the roller to simulate the actual operation. The thickness adjustment of the side wall of the roller needs to be linked with the thickness in the middle. To process them separately, continuous analysis needs to be performed through modeling in the software to find the best solution.

The conclusions are summarized as follows:
The vibration source of the Mecanum wheel (universal wheel) comes from the compression deformation of the Mecanum wheel roller. Under the same force, there are different compression amounts, and there will be regular and high-frequency vibrations under continuous operation. By adjusting the thickness using the properties of polyurethane, the Mecanum wheel roller can withstand a weight of more than 200 kg at all angles, and the compression amount can be consistent, successfully reducing the vibration of the Mecanum wheel.