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dr_dave
05-22-2007, 04:23 PM
FYI, I had several student groups in one of my design courses create prototypes for automated cue-stick squirt testers. The students came up with some interesting ideas. I posted video demonstrations on YouTube (http://www.youtube.com/view_play_list?p=3093FA00CF449A6C) for you guys to check out. The focus of the project (for a "mechatronics" course) was on the electronics and programming, but the students came up with some interesting ideas for how to move the cue stick and for how to automatically measure the amount of squirt. I hope to work with a student group next year to design and build a much better (and usable) system that will utilize some of the ideas from the prototypes.

Please let me know if you guys have any feedback, recommendations, or advice.

Happy viewing,
Dave

cushioncrawler
05-22-2007, 05:30 PM
<blockquote><font class="small">Quote dr_dave:</font><hr> FYI, I had several student groups in one of my design courses create prototypes for automated cue-stick squirt testers. The students came up with some interesting ideas. I posted video demonstrations on YouTube (http://www.youtube.com/view_play_list?p=3093FA00CF449A6C) for you guys to check out. The focus of the project (for a "mechatronics" course) was on the electronics and programming, but the students came up with some interesting ideas for how to move the cue stick and for how to automatically measure the amount of squirt. I hope to work with a student group next year to design and build a much better (and usable) system that will utilize some of the ideas from the prototypes. Please let me know if you guys have any feedback, recommendations, or advice. Happy viewing, Dave<hr /></blockquote>Great stuff. I would like to see a test(s) of "pure squirt" ie where there iz no table reaction etc. A bit like what i did in the garage last year -- with the qball hanging on a cotton pendulum.

Ultimately, looking at a really usefull test for the pool industry (further to the existing robots and such tests allready out there), it would be good to have a gadget that could compare different cues etc. Once again, a pure-squirt test might be best for comparisons.

One problem is that the condition of the tip, goodness of the chalking, softness of the "grip" on the cue, speed, etc etc might all ultimately need to be factored in or out somehow. Theze comments are aimed at maximizing the helpfullness to the billiards industry, i think, which of course is (must be) secondary, and iz a big-ask anyhow.

A gadget involving a pendulum might be simpler and more consistent (not the main aim here of course). In fact, i woz thinking along the lines of holding (hanging) the cue stationary, and having the ball swing into the cue. Just a thort. madMac.

pigbrain
05-22-2007, 06:55 PM
it's fantastic. but i think the machine is a little thin, shaking after impact. won't that affect the results?
or it's just need low stiffness to simulate the cue-hand actions?

wolfdancer
05-22-2007, 07:12 PM
Mac, you're off your meds again???

cushioncrawler
05-22-2007, 08:27 PM
<blockquote><font class="small">Quote wolfdancer:</font><hr> Mac, you're off your meds again???<hr /></blockquote>Woolfy -- Me, myself, and others of like mind (some of whom have been allowed out to mix in the general community), are saddened to see that Pendulatronics has been usurped by "sexy" lasers and accelerometers and strainometers. I would back me and my cotton pendulometer against any (other) robot. madMac.

wolfdancer
05-22-2007, 09:21 PM
LOL !!!
How's things going down in the prison colony? Getting ready for winter?

cushioncrawler
05-22-2007, 09:32 PM
<blockquote><font class="small">Quote wolfdancer:</font><hr> LOL !!! How's things going down in the prison colony? Getting ready for winter?<hr /></blockquote>It has been raining allmost every day. The big log walls of the new house are going green, i will havta use some ExitMould i think. I am messing around at the house-site on the hill every day, and sneaking down to my brother's joint to check my emails (i am having lunch there now). Last Monday a dirty big crane-truck put up a big glulam beam, 10.5m long, that runs throo my new billiard room, where i will have my old billiard table (made in about 1870). I will rezume my tests n experiments in about September i reckon. I shood put some photos of the billiard room n table on the forum. MacArk.

"And the rain fell, and the floods came, and the winds blew, and they beat upon that house, and it fell not, for it was founded on a rock".

dr_dave
05-23-2007, 07:39 AM
<blockquote><font class="small">Quote cushioncrawler:</font><hr> <blockquote><font class="small">Quote dr_dave:</font><hr> FYI, I had several student groups in one of my design courses create prototypes for automated cue-stick squirt testers. The students came up with some interesting ideas. I posted video demonstrations on YouTube (http://www.youtube.com/view_play_list?p=3093FA00CF449A6C) for you guys to check out. The focus of the project (for a "mechatronics" course) was on the electronics and programming, but the students came up with some interesting ideas for how to move the cue stick and for how to automatically measure the amount of squirt. I hope to work with a student group next year to design and build a much better (and usable) system that will utilize some of the ideas from the prototypes. Please let me know if you guys have any feedback, recommendations, or advice. Happy viewing, Dave<hr /></blockquote>Great stuff. I would like to see a test(s) of "pure squirt" ie where there iz no table reaction etc.<hr /></blockquote>By "table reaction," what exactly do you mean? Are you referring to swerve? With the prototypes, the cue stick is perfectly horizontal to eliminate swerve as a factor. Also, the double IR beam squirt sensors (see the "motorized" prototype) take readings just after the cue ball leaves the tip, so even if there were swerve (and there shouldn't be any), the squirt results would not be affected much. Now, if you are referring to cloth effects during impact, I think the effect on the squirt angle would be negligible. Even if there were an effect here, I would want to include it since it would be part of the squirt "equation."

<blockquote><font class="small">Quote cushioncrawler:</font><hr>A bit like what i did in the garage last year -- with the qball hanging on a cotton pendulum.<hr /></blockquote>I'll have to try the pendulum trick one day. How do you quickly and accurate set up for each shot with the pendulum? Also, how do you get accurate readings for tip offset and squirt angle?

<blockquote><font class="small">Quote cushioncrawler:</font><hr>Ultimately, looking at a really usefull test for the pool industry (further to the existing robots and such tests allready out there), it would be good to have a gadget that could compare different cues etc. Once again, a pure-squirt test might be best for comparisons.<hr /></blockquote>If by "pure squirt" you mean "independent of throw and swerve," then I agree (see my comments above).

<blockquote><font class="small">Quote cushioncrawler:</font><hr>One problem is that the condition of the tip, goodness of the chalking, softness of the "grip" on the cue, speed, etc etc might all ultimately need to be factored in or out somehow.<hr /></blockquote>Agreed.

<blockquote><font class="small">Quote cushioncrawler:</font><hr>Theze comments are aimed at maximizing the helpfullness to the billiards industry, i think, which of course is (must be) secondary, and iz a big-ask anyhow.<hr /></blockquote>I don't know what you mean by this. To me, the whole point is to be able to characterize and compare different cue sticks.

<blockquote><font class="small">Quote cushioncrawler:</font><hr>A gadget involving a pendulum might be simpler and more consistent (not the main aim here of course).<hr /></blockquote>I prefer linear motion for an automated tester (more compact, easier to constrain, more drive options [straight cylinder, rack and pinion, belt drive, linear motor, etc.]). The cue ball doesn't care what the stick is doing before or after impact. Also, well-executed piston and pendulum strokes both have the cue stick moving perfectly straight at impact anyway.

<blockquote><font class="small">Quote cushioncrawler:</font><hr>In fact, i woz thinking along the lines of holding (hanging) the cue stationary, and having the ball swing into the cue. Just a thort. madMac.<hr /></blockquote>That's an interesting idea, but I don't think people would be very accepting of this approach.

Thank you for your comments and ideas,
Dave

dr_dave
05-23-2007, 07:46 AM
<blockquote><font class="small">Quote pigbrain:</font><hr> it's fantastic. but i think the machine is a little thin, shaking after impact. won't that affect the results?<hr /></blockquote>These systems are just "prototypes" to test out various concepts for motion and sensing ... they are not usable systems. The mechanical design would need to be much better (stiffer support hardware, more accurate alignment, etc.).

<blockquote><font class="small">Quote pigbrain:</font><hr>or it's just need low stiffness to simulate the cue-hand actions?<hr /></blockquote>The machine should be as stiff as possible; but you make a good point ... the grip should mimic the human grip as well as possible and be adjustable to simulate various human grips.

Thanks,
Dave

SpiderMan
05-23-2007, 07:56 AM
Dave,

Are you going to also make these videos available on your web site?

For some reason, I have never been able to see "youtube" videos, possibly because of our firewall here at work. All I get is a perpetual "loading" notice and a blank screen. There may be others, not commenting, with the same issues.

SpiderMan

dr_dave
05-23-2007, 08:08 AM
<blockquote><font class="small">Quote SpiderMan:</font><hr>Are you going to also make these videos available on your web site?<hr /></blockquote>I wasn't going to put them on my pool website (e.g., in the NV section), because I didn't think they really fit in there. I do have the videos available on my engineering video demonstrations website (http://www.engr.colostate.edu/~dga/video_demos/mechatronics/index.html#PIC_PROJECTS) (see clips 6, 12, and 30 under "PIC microcontroller student design projects").

<blockquote><font class="small">Quote SpiderMan:</font><hr>For some reason, I have never been able to see "youtube" videos, possibly because of our firewall here at work. All I get is a perpetual "loading" notice and a blank screen. There may be others, not commenting, with the same issues.<hr /></blockquote>Sorry about that. I would have thought that YouTube would have been more viewable by most people on most platforms, but I can see why companies would want to block their employees from watching YouTube videos all day.

Regards,
Dave

PS: I'm sorry if you reported this elsewhere (I didn't see it if you did), but how did you and SPetty do in the tournament?

Cornerman
05-23-2007, 11:25 AM
<blockquote><font class="small">Quote dr_dave:</font><hr> FYI, I had several student groups in one of my design courses create prototypes for automated cue-stick squirt testers. The students came up with some interesting ideas. I posted video demonstrations on YouTube (http://www.youtube.com/view_play_list?p=3093FA00CF449A6C) for you guys to check out. The focus of the project (for a "mechatronics" course) was on the electronics and programming, but the students came up with some interesting ideas for how to move the cue stick and for how to automatically measure the amount of squirt. I hope to work with a student group next year to design and build a much better (and usable) system that will utilize some of the ideas from the prototypes.

Please let me know if you guys have any feedback, recommendations, or advice.

Happy viewing,
Dave <hr /></blockquote>From a mechatronics standpoint, I'm both excited and envious. There was no mechatronics course or curriculum when/where I was in school, as they did in other parts of the world (like Japan). The future looks better for our young engineers if these types of courses are more available now.

It would be interesting if all the technologies your students have examined can be cross compared. Since one of the systems used rate metering, there could be some comparison of ball speed and squirt angle and how each system differed.

This would also be a good time to quantify deceleration of the ball by comparing rate at the current rate sensor distance vs. a rate sensor distance of one foot, 1/2 foot. etc.

And just like the Jacksonville Experiment, it would also be interesting to compare the difference between the systems' current clamping mechanism with a flexible/compliant (e.g. bubblewrap) type of grip.

Not that you need any technical help, but if you need questions answered or are looking for a application solution as it pertains to your class, my profession dictates that I'm supposed to be able to answer.

Fred

dr_dave
05-23-2007, 12:04 PM
<blockquote><font class="small">Quote Cornerman:</font><hr> <blockquote><font class="small">Quote dr_dave:</font><hr> FYI, I had several student groups in one of my design courses create prototypes for automated cue-stick squirt testers. The students came up with some interesting ideas. I posted video demonstrations on YouTube (http://www.youtube.com/view_play_list?p=3093FA00CF449A6C) for you guys to check out. The focus of the project (for a "mechatronics" course) was on the electronics and programming, but the students came up with some interesting ideas for how to move the cue stick and for how to automatically measure the amount of squirt. I hope to work with a student group next year to design and build a much better (and usable) system that will utilize some of the ideas from the prototypes.

Please let me know if you guys have any feedback, recommendations, or advice.

Happy viewing,
Dave <hr /></blockquote>From a mechatronics standpoint, I'm both excited and envious. There was no mechatronics course or curriculum when/where I was in school, as they did in other parts of the world (like Japan). The future looks better for our young engineers if these types of courses are more available now.<hr /></blockquote>I am also excited about mechatronics and what mechanical engineers now learn (at good schools anyway). I also had no course like this when I went through school. I co-wrote a textbook on mechatronics, and I love teaching the course we offer at Colorado State University. Mechatronics education is my passion, second to pool (of course).

<blockquote><font class="small">Quote Cornerman:</font><hr>It would be interesting if all the technologies your students have examined can be cross compared. Since one of the systems used rate metering, there could be some comparison of ball speed and squirt angle and how each system differed.<hr /></blockquote>I agree. Unfortunately, the prototypes had many problems, and they weren't very reliable, and they have already been scavenged for parts to be used elsewhere. I hope to develop one or more usable systems within the next year that will incorporate all of the best ideas from all of the prototypes (and have sound mechanical design).

<blockquote><font class="small">Quote Cornerman:</font><hr>This would also be a good time to quantify deceleration of the ball by comparing rate at the current rate sensor distance vs. a rate sensor distance of one foot, 1/2 foot. etc.<hr /></blockquote>Agreed. This would be relatively straightforward, and it would help characterize the cloth sliding-friction and rolling resistance.

<blockquote><font class="small">Quote Cornerman:</font><hr>And just like the Jacksonville Experiment, it would also be interesting to compare the difference between the systems' current clamping mechanism with a flexible/compliant (e.g. bubblewrap) type of grip.<hr /></blockquote>Agreed. It would be nice to have a clamping mechanism (with appropriate materials) that could mimic the full range of human grips. Any other ideas would be greater appreciated here.

<blockquote><font class="small">Quote Cornerman:</font><hr>Not that you need any technical help, but if you need questions answered or are looking for a application solution as it pertains to your class, my profession dictates that I'm supposed to be able to answer.<hr /></blockquote>Do you consider yourself a "mechatronics" engineer?

Fred,
Thanks for your feedback, ideas, and willingness to help,
Dave

Cornerman
05-23-2007, 12:36 PM
<blockquote><font class="small">Quote dr_dave:</font><hr> Do you consider yourself a "mechatronics" engineer?

<hr /></blockquote>At some point in my career, that's what I would have been called. Today, they call me an "Automation Engineer."

I'm a degreed Mechanical Engineer, with a career's worth of electronic, motion controls, sensor, pneumatic and overall automation and robotics systems design, build &amp; programming. I'm also the Controls Lead mentor for our FIRST Robotics program ( http://www.usfirst.org ) which tends to be mechatronics-oriented (the Controls Group, that is). We also currently use the PIC Microcontroller.

My first engineering job was as a manufacturing engineer in a Japanese automotive plant. To them, there was no separation between mechanical and electrical engineering. In fact, every Japanese engineer that I worked with had training in "Mechatronics." I believe it's an actual degreed course curriculum. So, by on the job/trial by fire training, that's the direction my career path went.

Fred

cushioncrawler
05-23-2007, 04:33 PM
<blockquote><font class="small">Quote dr_dave:</font><hr>...By "table reaction," what exactly do you mean? Are you referring to swerve? With the prototypes, the cue stick is perfectly horizontal to eliminate swerve as a factor. Also, the double IR beam squirt sensors (see the "motorized" prototype) take readings just after the cue ball leaves the tip, so even if there were swerve (and there shouldn't be any), the squirt results would not be affected much. Now, if you are referring to cloth effects during impact, I think the effect on the squirt angle would be negligible. Even if there were an effect here, I would want to include it since it would be part of the squirt "equation."<hr /></blockquote>By table-reaction i meant the bed forces during cue-to-ball impact (including that first ball-to-bed bounce, the "bobble") and then the bed forces during the following bounces etc (ie masse swerve). But, as u say, a horizontal cue'n'stroke would eliminate most of this -- in which case it could be said that this (theze) tests do indeed meazure "pure squirt". But, from my experience, the "bobble" starts to raize its ugly head whenever a ball is re-pozitioned in one place for a large number of tests. I found that the ball started to create a deep footprint, and that the bobble got worse and worse as the hole deepened, ie the qball looses or gains a bit of angle whilst coming out of its footprint -- a lubricated (?) small plate would fix that -- in fact, there duznt appear to be any real need for a bed-cloth at all, a big hard plate would do the trick (as long as the cue is held'n'stroked horizontally).

<blockquote><font class="small">Quote Dr Dave:</font><hr>...I'll have to try the pendulum trick one day. How do you quickly and accurate set up for each shot with the pendulum? Also, how do you get accurate readings for tip offset and squirt angle?<hr /></blockquote>I manually hit the qball (hanging on a cotton pendulum) uzing aim'n'feel for consistent aim and offset and speed. I prooved to myself that pure squirt is larger at slower speeds (ok), and i think that i did other tests that showed that a stiffer cue gave more pure squirt (not so ok, koz changing cues makes for inconsistency). I aimed the cue'n'stroke for the edge of the garage door, and estimated the distance that the qball (pendulum) missed the edge -- i could have (if i wanted) used some toilet paper in front of bluetack stuck to lumber to get accurate measurements of trajectory -- and (if i wanted) i could have found the qtip chalk-mark on the qball, and measured the offset relative to some sort of centerline marked on the ball.

<blockquote><font class="small">Quote Dr Dave:</font><hr><blockquote><font class="small">Quote cushioncrawler:</font><hr>Theze comments are aimed at maximizing the helpfullness to the billiards industry, i think, which of course is (must be) secondary, and iz a big-ask anyhow.<hr /></blockquote>I don't know what you mean by this. To me, the whole point is to be able to characterize and compare different cue sticks.<hr /></blockquote>I woz looking at it from the point of view that the main purpose is (rightly) for the students to learn about gadgets, even if (at this time) manual tests and measurements might (in part) be simpler quicker cheaper or more accurate, even at the risk of over-doing the use of gadgetry.

<blockquote><font class="small">Quote Dr Dave:</font><hr><blockquote><font class="small">Quote cushioncrawler:</font><hr>In fact, i woz thinking along the lines of holding (hanging) the cue stationary, and having the ball swing into the cue. Just a thort...<hr /></blockquote>That's an interesting idea, but I don't think people would be very accepting of this approach.... <hr /></blockquote>The qball would bounce out at perhaps 90dg, but i think that the rezult would have a simple relationship to the equivalent angle (dg) of pure squirt. madMac.

ras314
05-23-2007, 07:05 PM
<blockquote><font class="small">Quote dr_dave:</font><hr> PS: I'm sorry if you reported this elsewhere (I didn't see it if you did), but how did you and SPetty do in the tournament? <hr /></blockquote>
Dr. Dave, I'm probaly out of place here, but the team of Spiderman&amp;SPetty was out early, slow starters? Then Spetty's team ( Lady TableSharks) did well and finished in the money. Spidey also finished in the money in singles, don't know how his team wound up. Good showing for the Dallas folks. /ccboard/images/graemlins/grin.gif

SpiderMan
05-24-2007, 08:18 AM
<blockquote><font class="small">Quote dr_dave:</font><hr> PS: I'm sorry if you reported this elsewhere (I didn't see it if you did), but how did you and SPetty do in the tournament? <hr /></blockquote>

Dave,

We didn't do well, and I have no good explanation. After snagging second in the "Texas State SWEL" tournament a few weeks earlier, we played like a couple of blind quadraplegics (with Parkinson's) in 'Vegas.

Once that humiliation subsided (as RAS mentioned), I cruised to the open singles' finals board in the winner's bracket before dropping, and both my own and SPetty's 5-man open teams cashed as well.

Just wait 'til next year!

SpiderMan

dr_dave
05-24-2007, 10:15 AM
<blockquote><font class="small">Quote cushioncrawler:</font><hr> <blockquote><font class="small">Quote dr_dave:</font><hr>...By "table reaction," what exactly do you mean? Are you referring to swerve? With the prototypes, the cue stick is perfectly horizontal to eliminate swerve as a factor. Also, the double IR beam squirt sensors (see the "motorized" prototype) take readings just after the cue ball leaves the tip, so even if there were swerve (and there shouldn't be any), the squirt results would not be affected much. Now, if you are referring to cloth effects during impact, I think the effect on the squirt angle would be negligible. Even if there were an effect here, I would want to include it since it would be part of the squirt "equation."<hr /></blockquote>By table-reaction i meant the bed forces during cue-to-ball impact (including that first ball-to-bed bounce, the "bobble") and then the bed forces during the following bounces etc (ie masse swerve). But, as u say, a horizontal cue'n'stroke would eliminate most of this -- in which case it could be said that this (theze) tests do indeed meazure "pure squirt". But, from my experience, the "bobble" starts to raize its ugly head whenever a ball is re-pozitioned in one place for a large number of tests. I found that the ball started to create a deep footprint, and that the bobble got worse and worse as the hole deepened, ie the qball looses or gains a bit of angle whilst coming out of its footprint -- a lubricated (?) small plate would fix that -- in fact, there duznt appear to be any real need for a bed-cloth at all, a big hard plate would do the trick (as long as the cue is held'n'stroked horizontally).<hr /></blockquote>Thank you for the clarifications. No disagreements here. Thank you also for using proper English. It does make it much easier to read your messages. When you use the weird Australian-dialect phonetic spelling, I often find myself skipping over much of what you write (because it hurts my brain too much to decipher). I also think the English language sucks, and I wish everyone were taught and used phonetic spelling, but that's not the reality we live in.

<blockquote><font class="small">Quote cushioncrawler:</font><hr><blockquote><font class="small">Quote Dr Dave:</font><hr>...I'll have to try the pendulum trick one day. How do you quickly and accurate set up for each shot with the pendulum? Also, how do you get accurate readings for tip offset and squirt angle?<hr /></blockquote>I manually hit the qball (hanging on a cotton pendulum) uzing aim'n'feel for consistent aim and offset and speed. I prooved to myself that pure squirt is larger at slower speeds (ok), and i think that i did other tests that showed that a stiffer cue gave more pure squirt (not so ok, koz changing cues makes for inconsistency). I aimed the cue'n'stroke for the edge of the garage door, and estimated the distance that the qball (pendulum) missed the edge -- i could have (if i wanted) used some toilet paper in front of bluetack stuck to lumber to get accurate measurements of trajectory -- and (if i wanted) i could have found the qtip chalk-mark on the qball, and measured the offset relative to some sort of centerline marked on the ball.<hr /></blockquote>Thanks for the info.

<blockquote><font class="small">Quote cushioncrawler:</font><hr><blockquote><font class="small">Quote Dr Dave:</font><hr><blockquote><font class="small">Quote cushioncrawler:</font><hr>Theze comments are aimed at maximizing the helpfullness to the billiards industry, i think, which of course is (must be) secondary, and iz a big-ask anyhow.<hr /></blockquote>I don't know what you mean by this. To me, the whole point is to be able to characterize and compare different cue sticks.<hr /></blockquote>I woz looking at it from the point of view that the main purpose is (rightly) for the students to learn about gadgets, even if (at this time) manual tests and measurements might (in part) be simpler quicker cheaper or more accurate, even at the risk of over-doing the use of gadgetry.<hr /></blockquote>I'm not sure about the "more accurate" part ... but definitely quicker, easier, and cheaper.

Regards,
Dave

dr_dave
05-24-2007, 10:22 AM
"blind quadriplegics (with Parkinson's)" /ccboard/images/graemlins/grin.gif /ccboard/images/graemlins/grin.gif

I hope you guys are still proud of your accomplishments. Very few of us make it to the "big leagues" like you guys did.

Regards,
Dave

<blockquote><font class="small">Quote SpiderMan:</font><hr> <blockquote><font class="small">Quote dr_dave:</font><hr> PS: I'm sorry if you reported this elsewhere (I didn't see it if you did), but how did you and SPetty do in the tournament? <hr /></blockquote>

Dave,

We didn't do well, and I have no good explanation. After snagging second in the "Texas State SWEL" tournament a few weeks earlier, we played like a couple of blind quadraplegics (with Parkinson's) in 'Vegas.

Once that humiliation subsided (as RAS mentioned), I cruised to the open singles' finals board in the winner's bracket before dropping, and both my own and SPetty's 5-man open teams cashed as well.

Just wait 'til next year!

SpiderMan <hr /></blockquote>

SPetty
05-25-2007, 03:08 PM
<blockquote><font class="small">Quote SpiderMan:</font><hr> We didn't do well, and I have no good explanation. <hr /></blockquote>Maybe I can help... Your partner had the unfortunate experience of losing her game for a couple of weeks. That time disappointingly corresponded to the week in Vegas. There obviously wasn't a problem with your game...<blockquote><font class="small">Quote SpiderMan:</font><hr> I cruised to the open singles' finals board in the winner's bracket before dropping<hr /></blockquote>I'm so proud! /ccboard/images/graemlins/laugh.gif<blockquote><font class="small">Quote SpiderMan:</font><hr> Just wait 'til next year!<hr /></blockquote>I hope you're still up for Scotch doubles with me. Really, I can do better... /ccboard/images/graemlins/crazy.gif

SpiderMan
05-25-2007, 04:04 PM
I assume that a series of events, which must have included both the common and the improbable, led us both to have a simultaneous bad day. Statistically, that has to happen now and then. Unfortunately, it was at the BCA Nationals this time.

It's highly unlikey that this "bad biorhythm" will recur as a 365-day cycle. So, as I said, wait 'til next year /ccboard/images/graemlins/smile.gif

SpiderMan

Jal
05-26-2007, 11:20 PM
<blockquote><font class="small">Quote dr_dave:</font><hr> FYI, I had several student groups in one of my design courses create prototypes for automated cue-stick squirt testers. ...<hr /></blockquote>Dr. Dave, I finally got around to downloading your videos (dialup), and thoroughly enjoyed them. Thanks for the posting. I thought the pneumatic drive was the sexiest, but was impressed by all of them. The automated offset positioning and speed/deflection detection were nice touches.

A couple of questions. Which type of drive would be the easiest to engineer if you needed a very precise pre-determined stick speed (not counting Mac's pendulum which has high merit in this regard), and did you get the chance to test a Predator?

Jim

dr_dave
05-27-2007, 06:39 PM
<blockquote><font class="small">Quote Jal:</font><hr> <blockquote><font class="small">Quote dr_dave:</font><hr> FYI, I had several student groups in one of my design courses create prototypes for automated cue-stick squirt testers. ...<hr /></blockquote>Dr. Dave, I finally got around to downloading your videos (dialup), and thoroughly enjoyed them. Thanks for the posting. I thought the pneumatic drive was the sexiest, but was impressed by all of them. The automated offset positioning and speed/deflection detection were nice touches.

A couple of questions. Which type of drive would be the easiest to engineer if you needed a very precise pre-determined stick speed (not counting Mac's pendulum which has high merit in this regard)<hr /></blockquote>I think any approach (springs, electric motor, or pneumatic cylinder) could yield good control over speed if the system is designed well. I think the spring idea would be the easiest to build. (Mac's pendulum is really just a simple spring, where gravity provides the force; although, tension springs can be much stronger than gravity, and can provide either linear or rotary motion.) The pneumatics gives the best range of power (with a simple design). A servomotor (direct linear or rack-and-pinion or chain/belt drive) would provide the most accurate speed control. Regardless of the type of actuator, if the speed is measured with accurate sensors, I think it is less important that the actuator be so perfect. More important is a solid frame and a good linear guide or bearings that can keep the stick on the desired line.

<blockquote><font class="small">Quote Jal:</font><hr>did you get the chance to test a Predator?<hr /></blockquote>We didn't use the prototypes to do any real testing because they were only "prototypes" used to test out various concepts. I hope to design and build a sturdy, reliable, and usable system for accurate testing by the end of the year.

Regards,
Dave

Snapshot9
05-29-2007, 06:55 AM
Dr_Dave .... It must take you an inordinate amount of time to have sex .... I mean with all those technical instructional method books layed out on the bed and all .... LOL

As one experienced real good player told me one time, 'Just hit it a little more to the right, son'.

dr_dave
05-29-2007, 09:40 AM
<blockquote><font class="small">Quote Snapshot9:</font><hr> Dr_Dave .... It must take you an inordinate amount of time to have sex ....<hr /></blockquote>Actually, it does take a little longer than it used to. I guess I'm not a teenager anymore. /ccboard/images/graemlins/frown.gif

<blockquote><font class="small">Quote Snapshot9:</font><hr>I mean with all those technical instructional method books layed out on the bed and all .... LOL<hr /></blockquote>You joke about this. But actually, there are some awesome books out there that can add spice to anybody's sex life. I recommend: "The Guide to Getting It On," as long as you can also convince your love interest to read it. It's one of the best books I've ever read. Although, as with pool, it is best to read before you play. It's not so fun (or productive) to have the book out on the table (or bed) while you play.

<blockquote><font class="small">Quote Snapshot9:</font><hr>As one experienced real good player told me one time, 'Just hit it a little more to the right, son'.<hr /></blockquote>I think that's great advice for a player that misses to the left every time. If everybody could fix their game with such simple advice, everybody would be as good as Efren. Fortunately, the game is complicated enough so that will never happen.

Regards,
Dave

SpiderMan
05-29-2007, 11:03 AM
<blockquote><font class="small">Quote dr_dave:</font><hr> <blockquote><font class="small">Quote Snapshot9:</font><hr> Dr_Dave .... It must take you an inordinate amount of time to have sex ....<hr /></blockquote>Actually, it does take a little longer than it used to. /ccboard/images/graemlins/frown.gif
Regards,
Dave <hr /></blockquote>

I'm sure your wife appreciates the extra time taken /ccboard/images/graemlins/grin.gif

SpiderMan

dr_dave
05-29-2007, 11:17 AM
<blockquote><font class="small">Quote SpiderMan:</font><hr> <blockquote><font class="small">Quote dr_dave:</font><hr> <blockquote><font class="small">Quote Snapshot9:</font><hr> Dr_Dave .... It must take you an inordinate amount of time to have sex ....<hr /></blockquote>Actually, it does take a little longer than it used to. /ccboard/images/graemlins/frown.gif
Regards,
Dave <hr /></blockquote>

I'm sure your wife appreciates the extra time taken /ccboard/images/graemlins/grin.gif

SpiderMan <hr /></blockquote>Actually, I was divorced about 5 years ago; but my current girlfriend seems to be OK with the bonus time. /ccboard/images/graemlins/wink.gif

Dave