Thank you very much for this video. I watched it several times. It, as we say, “dots all the i”. My analysis: standing on the side of the table, you turn on the robot. You can hear the motors running. You get up in the playing area, during this time the motors picked up speed. The first topspin has a strong rotation and, bouncing off the racket, flies out of the frame. All subsequent topspins have a weaker rotation and fall into the robot's grid (the motors do not have time to pick up speed). If you reduce the speed of the balls, for example to 30 balls per minute, then all the topspins will be more like the first topspin (the motors may have time to pick up speed, but this needs to be checked). It turns out that the force of rotation depends on the frequency of ball departures, balls that differ greatly in rotation cannot be combined into a series. For example, 1 ball is a short serve with strong bottom spin (top motors spin backwards, bottom motors spin forward). We set up the robot for this feed, everything is fine. Set up 2 ball (separate from 1). 2 ball is a slow topspin, but with strong spin. This is a typical game situation, I accept the cutoff serve, it flies a little over the edge of the table, the partner makes a topspin. For 2 balls, the top motors rotate forward, the bottom motor rotates backwards. Set up 2 ball, everything is fine. Then we combine these balls into a series, and everything is bad here. 2 the ball will be completely different, and not the one that was set up (the motors need to have time to change the rotation to the opposite). With a change in the speed of the balls from 30 to 120 per minute, there will be a different force of rotation and the speed of the ball.
