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I have simulations of TT ball trajectories. I started the simulation over 10 years ago. I haven't done much with they lately but since I am now retired, I have more time to do simulations. Years ago, I showed a simulation of a TT ball being hit from about net height or a little lower at about 40m/s and at a upwards angle of 10 degrees so the ball would go over the net and drop. I just plotted the path of the ball. It was interesting. I could change the speed, spins and angles to see the resulting trajectory. After doing this I found it amazing we are able to train our NN ( neural nets and muscles ) to do this at all. What I didn't do it plot the downwards force due to gravity which is constant, the downwards force due to the Magnus effect, the rotational kinetic energy and the translational kinetic energy. I think that might be interesting. OK, I am a nerd but if you never ask the question, you never will get the answer.
What would be even more interesting is the right ratio of spin to speed you should have on the ball to land on the table from a given set of conditions.
TT players have two "friends". One is gravity. This makes the ball drop on to the table instead of floating off the end. The other is the Magnus effect the is the result of putting spin on the ball. Top spin adds an additional downwards force to the ball that allows one to hit the ball faster and still land the ball on the table. The Magnus effect is the cross product of the spin and speed. To make this simple, assume the axis of rotation is perpendicular to the direction of travel so the Magnus force is simply proportional to the spin x speed. Increasing spin always helps increase the Magnus effect. So does increasing speed but if the speed is too great then the ball will not have enough time to accelerate downwards before going of the end of the table. There is an optimal spin to speed ratio. The reason why I ask this question is that too many of my loops have plenty of spin but it seems that the don't drop fast enough to land on the table.
Slow spinny loops that are cause by brushing will have a lower speed and therefore a lower downwards force due to the Magnus effect. This is not a disaster because the lower speed gives gravity more time to accelerate the ball downwards. The problem is that the speed of the ball is low. However, the high spin will give lower skilled opponent troubles returning the ball even if they get to it and are able to hit the ball.
I think I will do a few simulations to find the answers. I wonder if anyone cares. It is the forces, actually, impulses we apply to the ball that make it go. All this crap about this rubber or that rubber or boosting is secondary if you don't know what you are really trying to achieve.
Ok, here is a question for you all. What do think think the engineers the program the Omron robot are thinking about?
What would be even more interesting is the right ratio of spin to speed you should have on the ball to land on the table from a given set of conditions.
TT players have two "friends". One is gravity. This makes the ball drop on to the table instead of floating off the end. The other is the Magnus effect the is the result of putting spin on the ball. Top spin adds an additional downwards force to the ball that allows one to hit the ball faster and still land the ball on the table. The Magnus effect is the cross product of the spin and speed. To make this simple, assume the axis of rotation is perpendicular to the direction of travel so the Magnus force is simply proportional to the spin x speed. Increasing spin always helps increase the Magnus effect. So does increasing speed but if the speed is too great then the ball will not have enough time to accelerate downwards before going of the end of the table. There is an optimal spin to speed ratio. The reason why I ask this question is that too many of my loops have plenty of spin but it seems that the don't drop fast enough to land on the table.
Slow spinny loops that are cause by brushing will have a lower speed and therefore a lower downwards force due to the Magnus effect. This is not a disaster because the lower speed gives gravity more time to accelerate the ball downwards. The problem is that the speed of the ball is low. However, the high spin will give lower skilled opponent troubles returning the ball even if they get to it and are able to hit the ball.
I think I will do a few simulations to find the answers. I wonder if anyone cares. It is the forces, actually, impulses we apply to the ball that make it go. All this crap about this rubber or that rubber or boosting is secondary if you don't know what you are really trying to achieve.
Ok, here is a question for you all. What do think think the engineers the program the Omron robot are thinking about?