POOL-SHOT PHYSICS DEMO ROBOT -AND OTHER POOL MACHINE LINKS

StormDog

New member
I found AzBilliards while investigating what diameter and radius cue tip I should get with the new pool cue I'm buying. I did some drawings and posted them here.

That made me remember a slightly interesting physics demo I helped some high school students build a few years back. It was part of what was called the "Carousel of Physics" that included 12 pie shaped sectors, each with four demos related to a principle of physics. My sector was on force and momentum. The pool-shot demo basically recycled a miniature cue ball and an object ball over and over and shot the object ball into a target which moved to various angles.

I hadn't thought about this for a long time. It was fun helping the kids. Another interesting project I helped with was to the left of the pool-shot. It was a little robot arm that lifted a cup onto a second flat robot arm that then moved away sideways so fast that the cup fell straight down into it's original position. It was meant to simulate pulling a tablecloth out from under wine glasses without knocking them over. I need to find a better video of that one.

Anyway, I look forward to reading through this site. I'd like to get better at pool, and I enjoy learning about pool physics and techniques.

Maybe this thread could be a source of pool related robot and machine links? -Not that this first one is THAT impressive, but it was from a high school.

Pool-Shot Physics Demo Robot:


Carousel of Physics: (partial tablecloth demo at 1:27)
 
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sbrownn

Registered
The shaft diameter at the ferrule determines your tip diameter and the radius is half of the diameter, so you are stating the same measurement "almost" twice. Are you interested in also finding out the circumference of the tip? I feel that tip diameter, shaft diameter and taper plus tip circumference are some of the most unique tuning traits a player can take on, when they are ready to do that. Overall cue balance and weight are others. I don't think you can do any of this by research and instead, you need to do it by feel and experimentation.
 

Cuebuddy

Mini cues
Silver Member
I found AzBilliards while investigating what diameter and radius cue tip I should get with the new pool cue I'm buying. I did some drawings and posted them here.

That made me remember a slightly interesting physics demo I helped some high school students build a few years back. It was part of what was called the "Carousel of Physics" that included 12 pie shaped sectors, each with four demos related to a principle of physics. My sector was on force and momentum. The pool-shot demo basically recycled a miniature cue ball and an object ball over and over and shot the object ball into a target which moved to various angles.

I hadn't thought about this for a long time. It was fun helping the kids. Another interesting project I helped with was to the left of the pool-shot. It was a little robot arm that lifted a cup onto a second flat robot arm that then moved away sideways so fast that the cup fell straight down into it's original position. It was meant to simulate pulling a tablecloth out from under wine glasses without knocking them over. I need to find a better video of that one.

Anyway, I look forward to reading through this site. I'd like to get better at pool, and I enjoy learning about pool physics and techniques.

Maybe this thread could be a source of pool related robot and machine links? -Not that this first one is THAT impressive, but it was from a high school.

Pool-Shot Physics Demo Robot:


Carousel of Physics: (partial tablecloth demo at 1:27)
Interesting videos, thanks for sharing and welcome to the forum.
 

StormDog

New member
The shaft diameter at the ferrule determines your tip diameter and the radius is half of the diameter, so you are stating the same measurement "almost" twice. Are you interested in also finding out the circumference of the tip? I feel that tip diameter, shaft diameter and taper plus tip circumference are some of the most unique tuning traits a player can take on, when they are ready to do that. Overall cue balance and weight are others. I don't think you can do any of this by research and instead, you need to do it by feel and experimentation.
Hello sbrownn,
That's funny. I didn't explain myself well. I meant tip cylindrical diameter (equal to ferrule diameter like you say), and tip spherical radius typically compared to a dime or a nickel. I drew some diagrams and did some graphical calculation. It's all described in this post. I'm happy to hear your thoughts over there.
 

StormDog

New member
How does the shooter work? What sorcery did you use to calibrate the mechanism?
It was pretty fun to make. Honestly the students mostly just watched me, but I think they got something out of it. Here are some pictures. I took effort to get rid of any play in the aiming and to make sure it homed itself accurately enough. Then it was a matter of packaging everything compactly and learning how to make things from laser cut plexiglass. There were I think three or four 3d printed parts. I was bummed the target audibly rattled as it moved. I should have seen that coming, but I don't usually work with stepper motors. Here are some pictures, thanks for asking.

middle area.jpg


cross section.jpg


feeder asm.jpg



Here is a model of the other one I mentioned. It used a cam and spring to move the horizontal arm and pull the spring, then when the cam got to the edge, the horizontal arm moved lightning fast clock-wise and the cup dropped straight down.
2025-02-03 19_00_59-SolidWorks 2013 x64 Edition - [_GJ_jenga.SLDASM].png
 
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sbrownn

Registered
Hello sbrownn,
That's funny. I didn't explain myself well. I meant tip cylindrical diameter (equal to ferrule diameter like you say), and tip spherical radius typically compared to a dime or a nickel. I drew some diagrams and did some graphical calculation. It's all described in this post. I'm happy to hear your thoughts over there.
Nothing funny in my reply, just trying to help. And it seems like you are inventing new geometrical non-proven terms with your posts...
 

StormDog

New member
Nothing funny in my reply, just trying to help. And it seems like you are inventing new geometrical non-proven terms with your posts...
"non-proven terms" -yes. I often use the wrong terms. I didn't mean your reply was funny. You reacted to exactly what I said. I thought it was funny that I made that error. Then I was imagining I could have done even worse, like choosing the diameter, radius, and circumference of my new stick -and that made me laugh. Thank you for your thoughts. This is my first cue with a pro taper and I really like it. I ended up buying a JFlower SMO shaft. The butt is too fancy for me, so I also bought a cheaper stick to swap out the butt. (I actually spent money to get something less fancy.) And I agree you can't calculate and research too much. That's why I was happy to find a mathematical difference in one aspect of the options I was considering. The distance from the edge where the tip contacts the ball does change depending on cue cylindrical diameter and spherical radius. I don't know how close to the edge makes a difference, but further from the edge seems better. I think and hope I'll be able to get used to whatever balance my stick is, or if I have to, then I bet I can adjust that.
 

straightline

CPG CBL
Silver Member
Ok. The two objects are stationary and the flag and shooter move independently. Microprocessor? What's the math?
 

StormDog

New member
Ok. The two objects are stationary and the flag and shooter move independently. Microprocessor? What's the math?
Yes. You can see the two elevators with stepper motors under them. The brown posts (in the cross section view) move down, then a ball rolls in, and then the brown posts move up to bring the cue ball and the object ball up to the table. You can see the solenoid pivots around the cue ball elevator so that the plunger always hits through the middle of the cue ball. The aiming is done with this yellow partial gear against a small purple gear driven by another stepper motor underneath. This purple gear and motor pivoted relative to the gray base plate and was locked down so it actually pushed against the yellow gear to remove any backlash there.
2025-02-03 19_47_34-POOL-SHOT PHYSICS DEMO ROBOT -AND OTHER POOL MACHINE LINKS _ AzBilliards F...png

If I remember right, I cut the gear tooth profile to run better with no backlash. You can see the blue flag like part that passes through the gray optical homing sensor. That blue flag like part interrupts the sensor for half the travel of the aiming yellow gear. You can see it only moves through a small angle.
The target moves around the object ball elevator driven by another stepper motor. The target doesn't have to move accurately compared to the target, but it has to move over a larger angle. There is another homing optical sensor for the target. There's also one for each of the elevators.
2025-02-03 19_55_19-2025-02-03 19_43_53-POOL-SHOT PHYSICS DEMO ROBOT -AND OTHER POOL MACHINE L...png

And yes I used a microprocessor. It was an Arduino programmed in a simple version of C. It received a few commands from the central carousel computer to home itself, and to run through it's routine.

As far as the mathematics go, I did not calculate a formula for what angle to shoot the cue ball. I did calculate how many stepper motor steps it take to move the cue solenoid and the target one degree. This is from the size (number of teeth) of the gears. After that I may have measured the physical angles after it homes itself to the optical homing sensors. Finally to calculate angles, I just used the my cad software. I drew a diagram like below, then set the target angle to what I wanted and then just read the cue ball angle and used that. I remember that none of the shots needed any adjustment and the machine never missed. -Just like me when I play pool :)
2025-02-03 20_08_07-SolidWorks 2013 x64 Edition - [Sketch1 of Part1 _].png


Sorry for such a long answer. It was a very fun project.
 

sbrownn

Registered
"non-proven terms" -yes. I often use the wrong terms. I didn't mean your reply was funny. You reacted to exactly what I said. I thought it was funny that I made that error. Then I was imagining I could have done even worse, like choosing the diameter, radius, and circumference of my new stick -and that made me laugh. Thank you for your thoughts. This is my first cue with a pro taper and I really like it. I ended up buying a JFlower SMO shaft. The butt is too fancy for me, so I also bought a cheaper stick to swap out the butt. (I actually spent money to get something less fancy.) And I agree you can't calculate and research too much. That's why I was happy to find a mathematical difference in one aspect of the options I was considering. The distance from the edge where the tip contacts the ball does change depending on cue cylindrical diameter and spherical radius. I don't know how close to the edge makes a difference, but further from the edge seems better. I think and hope I'll be able to get used to whatever balance my stick is, or if I have to, then I bet I can adjust that.
you are over thinking it, if you want to learn how to play pool well. just trying to help
 

straightline

CPG CBL
Silver Member
Yes. You can see the two elevators with stepper motors under them. The brown posts (in the cross section view) move down, then a ball rolls in, and then the brown posts move up to bring the cue ball and the object ball up to the table. You can see the solenoid pivots around the cue ball elevator so that the plunger always hits through the middle of the cue ball. The aiming is done with this yellow partial gear against a small purple gear driven by another stepper motor underneath. This purple gear and motor pivoted relative to the gray base plate and was locked down so it actually pushed against the yellow gear to remove any backlash there.
View attachment 805594
If I remember right, I cut the gear tooth profile to run better with no backlash. You can see the blue flag like part that passes through the gray optical homing sensor. That blue flag like part interrupts the sensor for half the travel of the aiming yellow gear. You can see it only moves through a small angle.
The target moves around the object ball elevator driven by another stepper motor. The target doesn't have to move accurately compared to the target, but it has to move over a larger angle. There is another homing optical sensor for the target. There's also one for each of the elevators.
View attachment 805608
And yes I used a microprocessor. It was an Arduino programmed in a simple version of C. It received a few commands from the central carousel computer to home itself, and to run through it's routine.

As far as the mathematics go, I did not calculate a formula for what angle to shoot the cue ball. I did calculate how many stepper motor steps it take to move the cue solenoid and the target one degree. This is from the size (number of teeth) of the gears. After that I may have measured the physical angles after it homes itself to the optical homing sensors. Finally to calculate angles, I just used the my cad software. I drew a diagram like below, then set the target angle to what I wanted and then just read the cue ball angle and used that. I remember that none of the shots needed any adjustment and the machine never missed. -Just like me when I play pool :)
View attachment 805609

Sorry for such a long answer. It was a very fun project.
No no, hanging on every word. If only real pool worked so well.:ROFLMAO:
 

Bob Jewett

AZB Osmium Member
Staff member
Gold Member
Silver Member
Previous pool robot threads:

Very precise stick actuator: https://forums.azbilliards.com/threads/wow-next-level-cue-robot.566778/

Cue testing with a robotic arm -- go about half way in:

Using a novel actuator with somewhat higher speed :devilish: :

A mobile robot with vision system:

Same robot, but video from designers:

Not your typical looking pool robot, but it has a vision system:

A general-purpose robot playing pool and very proud of itself: https://www.youtube.com/watch?v=nH08-JQwsZQ

A simple mechanical cue testing "robot": https://forums.azbilliards.com/threads/pool-cue-testing-robot.262820/

The Queen's University robot, Deep Green: https://www.youtube.com/watch?v=AENJxqR0g48

A student group playing pool with a general robot, "Pool Shark" : https://www.youtube.com/watch?v=HMx1xW2E4Gg
 

StormDog

New member
Thank you Bob. I'll check these out.
Wow. These were very interesting. Thank you for collecting them!

Here are some thoughts I had while watching
  • These showed a big range of sizes and the use of rotary versus linear joints. There were a couple of gantry robots over the whole table, all the way to the orange compact robot arm that was proud of itself. The first "stick actuator" machine was quite large for it's function.
  • It would be fun to program a machine to play pool. It was impressive what those college kids did in just five days. I didn't find the "fast phys' library they referred to, but I'll keep looking for it.
  • I liked the projections of predicted shot results onto the table.
  • On this post, @kling&allen shows a graph on throw and refers to a throw video. Do you know what video he's referring to? I'd like to see it.
 

garczar

AzB Silver Member
Silver Member
PEOPLE play pool not fkng machines. Time to leave mom's basement and go find a table. We already have one justnum. Brutal? Maybe but this stuff is not for real pool players.
 

kling&allen

AzB Gold Member
Gold Member
Wow. These were very interesting. Thank you for collecting them!

Here are some thoughts I had while watching
  • These showed a big range of sizes and the use of rotary versus linear joints. There were a couple of gantry robots over the whole table, all the way to the orange compact robot arm that was proud of itself. The first "stick actuator" machine was quite large for it's function.
  • It would be fun to program a machine to play pool. It was impressive what those college kids did in just five days. I didn't find the "fast phys' library they referred to, but I'll keep looking for it.
  • I liked the projections of predicted shot results onto the table.
  • On this post, @kling&allen shows a graph on throw and refers to a throw video. Do you know what video he's referring to? I'd like to see it.

I manually plotted that from data from the robot’s video. The data in the video wasn’t in a good format.

The robot dude has lots more good videos:

 

alphadog

AzB Silver Member
Silver Member
PEOPLE play pool not fkng machines. Time to leave mom's basement and go find a table. We already have one justnum. Brutal? Maybe but this stuff is not for real pool players.
Just because you can't understand something doesn't mean others won't understand it and appreciate it.
 
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