Thank you for this video! Really good explanation on what the Pongbot can and cannot do!
I think that when a player (not the robot) increases speed there is less dwell on the ball, which means less spin and vice-versa: when you increase spin, you increase dwell time and the speed suffers. In that sense your power either goes into spin or speed, or a combination but the amount of power put into the shot stays the same - if that makes sense. Did you watch through the video to see my spin and speed. As a non pro, club level player, that will give you a good idea for non pro spin and speed.Great video, I was wondering what average speed and spin non pros would have.
An issue with this robot I've found(in addition to overshooting the table, gotta find a mobile meassurable solution for that), is that when you increase the speed then the spin will reduce. So while what you say is true it can produce similar speed as clublevel player, when it does, the spin is nowhere near the same as a clublevel player. And when the spin is somewhat near a club level player, then the speed is not. Maybe you covered this and I missed it. My feeling is it's very noticeable the ball quality is low compared to real people.
In my opinion I think this robots main purpose for me is footwork training. It sure beats having no partner to train with though.
That's generally not the case. While the perceived spin often decreases with increased speed, the actual spin usually increases even for amateurs.
Yes I saw your spin and speed, as I mentioned it was something I found very valuable.
github.com
| Speed | Max Spin | rps | km/h |
|---|---|---|---|
| 0 | 2 | -- | -- |
| 0.5 | 3 | -- | -- |
| 1 | 4 | -- | -- |
| 1.5 | 5 | 28 | 13 |
| 2 | 6 | 36 | 17 |
| 2.5 | 7 | 43 | 19 |
| 3 | 8 | 52 | 20 |
| 3.5 | 9 | 56 | 23 |
| 4 | 10 | 61 | 24 |
| 4.5 | 10 | 66 | 25 |
| 5 | 9 | 59 | 29 |
| 5.5 | 8 | 53 | 29 |
| 6 | 8 | 53 | 33 |
| 6.5 | 7 | 46 | 34 |
| 7 | 6 | 42 | 36 |
| 7.5 | 5 | 33 | 39 |
| 8 | 4 | 28 | 40 |
| 8.5 | 3 | 21 | 42 |
| 9 | 2 | 16 | 46 |
| 9.5 | 1 | 13 | 47 |
| 10 | 0 | 0 | 48 |
I wasn't using a single set of settings to get max speed and spin. I was using two different settings: one for max spin and another for max speed. This was just to see what the maximum I could get from the robot for both were. It makes sense that, as there is a max power output from the machine that you can't get max spin and speed at the same time from it. It's a conservation of energy thing. Interesting table by the way and I would say it is consistent with my results. Max speed in your table 48km/h, I got it up to 49km/h. Max spin in the table 66 rotations / sec, I got 64 consistently. I would add that for max speed, there is still a small amount of spin though. You can clearly see this at approx 2:30 into the video when the setting is on mx speed and a half coloured ball flies out and has about 3 full rotations across the distance of the table. It's not much spin, but it's not zero.Yes I saw your spin and speed, as I mentioned it was something I found very valuable.
The point im trying to "discuss/raise" to increase my understanding of your video and merge with my current understanding, is that the "Pongbot nova S pro" according to historically meassured data here on TTD have a relationship between speed and spin because of how it is built(rotation of the two wheels that send the balls out), which mean you can not have both max speed and max spin at the same time. At some point if you increase speed, then the spin will decrease and vice versa. Maximum spin is achieved at speed 4.5 and spin 10. While maximum speed is achieved at speed 10 and spin 0. Better explained by post #242 page 13 in the pongbot nova s pro thread, which give the formula for the correlation:
I use the "olanga app" for my pongbot, and based on reported data from mentioned "pongbot thread" a speed of 40+ km/h is reached first when the robot is on speed 8. But at speed 8 the robot is limited to 28 rps. So based on that I made the assumption(maybe wrongly) you meassured speed and rps separately with different pongbot settings, to claim it was comparable to your own meassured speed and spin that you generated as a benchmark for a club level player .
Based on datatable below the relation should be as follow:
General information
Contribute to olanga/nova development by creating an account on GitHub.The table above is for underspin, but since the robot just have two wheels that inverted I guess there shouldn't be to big a difference. If there is a big difference it would be interesting to know a table for topspin relationship in addition to the above table, since it seem your result seem to differ from current available data and I want to figure out how and why.
Speed Max Spin rps km/h 0 2 -- -- 0.5 3 -- -- 1 4 -- -- 1.5 5 28 13 2 6 36 17 2.5 7 43 19 3 8 52 20 3.5 9 56 23 4 10 61 24 4.5 10 66 25 5 9 59 29 5.5 8 53 29 6 8 53 33 6.5 7 46 34 7 6 42 36 7.5 5 33 39 8 4 28 40 8.5 3 21 42 9 2 16 46 9.5 1 13 47 10 0 0 48
What speed and spin settings where you using to achieve both 40km/h+ and 50-64 rps at the same time from your robot?
Thank you for the clarification, then it was as I thought.
