What is the motion principle of McNamham wheel?

The principle of McNamham's wheel movement is to rotate the two wheat wheels on the same side of the vehicle in opposite directions, so that the forces along the front and rear will be offset, while the lateral forces are just in the same direction. McNamun wheel is an omni-directional wheel, which can move in all directions, and is referred to as wheat wheel for short. It consists of a hub and rollers surrounding the hub, and the included angle between the roller axis of the wheat wheel and the hub axis is 45 degrees. There are many small wheels, that is, rollers, distributed obliquely on the rim of the hub, so the small wheels can slide sideways. Drum is a small drum without power. The generatrix of the small roller is very special. When the wheel rotates around the fixed shaft, the envelope surface of each small roller is cylindrical, so the wheel can roll forward continuously. The McNamun wheel is installed in the car and can move in all directions. It can move from front to back, from left to right and horizontally. It can completely translate and rotate 360 degrees in any direction, and it can flexibly move to its destination even in a small empty room. Installation method of McNamun wheel: x square: the moment generated by the rotation of the small wheel will pass through the same point, so the yaw axis cannot actively rotate or keep the angle of the yaw axis. X-rectangle: the rotation of the small wheel can produce the turning moment of the yaw axis, but the arm of the turning moment will be shorter. O-shaped square: four small wheels are located at the four vertices of the square and can be translated or rotated. Limited by the shape and size of the robot chassis, the feasibility of installation is limited. O-shaped right angle: the rotation of the small wheel can produce the rotating moment of the yaw shaft, and the arm of the rotating moment is longer, which is the most common installation method.