0 °: after the wave generator is installed in the flexible wheel, it forces the profile of the flexible wheel to change from the original circular shape to an elliptical shape. The teeth near the two ends of the long axis are fully engaged with the teeth of the rigid wheel, while the teeth near the two ends of the short axis are completely detached from the rigid wheel;

90 °: the rigid wheel is fixed, and the wave generator rotates in a clockwise direction. The flexible wheel generates elastic deformation, and the gear positions that mesh with the rigid wheel move in a counterclockwise direction

180 °: after the wave generator rotates 180 degrees clockwise, the flexible wheel only rotates one tooth counterclockwise

360 °: after the wave generator rotates 360 degrees (one revolution), the flexible wheel rotates counterclockwise by 2 teeth