Cock’n’Roll

[mandrin]

Most likely anyone reading TGM will have a hard time understanding what exactly constitutes the difference between accumulator #2 and #3.

The angles, associated with accumulator #2 and #3, are both defined by lead arm and shaft, but yet there is a very different related action.

I had a look at uncocking and rolling, associated respectively with accumulator #2 and #3 in the downswing.

The model used for analysis is like an ‘Iron Byron’ golf robot, but modified to include the roll angle. This makes it effectively a 3D model.

mandrin

 

[Brian Manzella]

Nice work, dude.

 

[mrodock]

I'm most impressed!

Matt

 

[mandrin]

quote:Originally posted by brianman

Nice work, dude.

Brian, I see that you almost instantaneously digested my post which took me quite some time to put together. Very impressive indeed. []

 

[golfbulldog]

Mandrin,

Impresive models. Can follow your argument but lack of physics prevents any real understanding. I think that I understand your conclusion.

If "Release roll (swivel)(2-G)" ( and by "release roll" I think of foreame rotation) is controlled by centrifugal force what happens after seperation?

Homer describes "hinge motions" which are ( from my understanding) jointed at the shoulder but are effectively controlled at the wrist ( if FLW and educated hands) but do not involve forearm rotation. 2-G suggests swivel occurs again after execution of hinge action.

My main question is what happens after seperation to the forces involved in control of release roll? It appears that centrifugal force controls release roll into impact/separation then conscious muscle ( educated hands) controls hinge and then centrifugal force controls finish swivel? I am incertain - help please!

 

[bts]

It seems that the "release of roll angle" (or that "swoosh" sound) occurs due to the inertia of the center of gravity of the orbiting clubhead (beyond certain speed) seeking to be "on-plane" with the orbit, along "in-line" with the swinging arm. It also seems that all the other motions of the arms and wrists are dictated by those tendencies. The golfer is supposed to let it occur naturally.

 

[bbftx]

Interesting theoretical analysis.

In a real swing, the clubface is not almost 90 degrees open about 1 foot before impact, which is the scenario you've graphed. If the roll really happened this quickly, you'd almost never see a straight shot since the clubface is square to the path for the shortest of times, for the shortest of distances during the swing.
Is your conclusion different if you modify the model to account for real world clubface positions just prior to impact?

The golfer's hands and arms are obviously controlling the speed of the roll in the real world, since it doesn't happen as quickly as you've modeled. Some try to eliminate roll prior to impact altogether by controlling the clubface with a strong double action grip for example.

Figure 6 also shows off-plane distances of the head and shaft of less than 0.05 cm, or half a millimeter, from the effect you are trying to analyze. Since clubhead lead and droop are on the order of several centimeters at impact, how do these factors influence the roll characteristics? These movements are on the order of 100 times the roll related movements you're considering.

How about the torque characteristics of the shaft? In a real shaft, this will also have an impact, which you seem to ignore. Would a golfer simply have to "give up control" no matter what shaft he's using? Or would he have to change the swing (control) if he switched shafts?

 

[birdie_man]

I don't understand them.

Ahahahahahaha.

Need to "incubate" this one a few times for sure.

Ur a wildman mandrin......WILDMAN.

 

[birdie_man]

Oh I get it.

Didn't make much sense late last night when I looked at it....just skimmed the captions and I started vibrating and such.

 

[mandrin]

quote:Originally posted by bts

It seems that the "release of roll angle" (or that "swoosh" sound) occurs due to the inertia of the center of gravity of the orbiting clubhead (beyond certain speed) seeking to be "on-plane" with the orbit, along "in-line" with the swinging arm.

It also seems that all the other motions of the arms and wrists are dictated by those tendencies.

The golfer is supposed to let it occur naturally.

It seems…..
It also seems……
The golfer is supposed……

bts, not really quite sure, at least it seems so.

I am curious as to what you had in mind with your post since it is indeed all very much Homer like but not very easy to grasp.

 

[mandrin]

quote:Originally posted by bbftx

Interesting theoretical analysis.

In a real swing, the clubface is not almost 90 degrees open about 1 foot before impact, which is the scenario you've graphed. If the roll really happened this quickly, you'd almost never see a straight shot since the clubface is square to the path for the shortest of times, for the shortest of distances during the swing.
Is your conclusion different if you modify the model to account for real world clubface positions just prior to impact?

The golfer's hands and arms are obviously controlling the speed of the roll in the real world, since it doesn't happen as quickly as you've modeled. Some try to eliminate roll prior to impact altogether by controlling the clubface with a strong double action grip for example.

Figure 6 also shows off-plane distances of the head and shaft of less than 0.05 cm, or half a millimeter, from the effect you are trying to analyze. Since clubhead lead and droop are on the order of several centimeters at impact, how do these factors influence the roll characteristics? These movements are on the order of 100 times the roll related movements you're considering.

How about the torque characteristics of the shaft? In a real shaft, this will also have an impact, which you seem to ignore. Would a golfer simply have to "give up control" no matter what shaft he's using? Or would he have to change the swing (control) if he switched shafts?

bbftx,

Figs 4, 5 and 6 are showing, as noted, the same information in different ways. Hence any reasonable genuinely interested person would have immediately concluded that the vertical ordinate of Fig 6 should have been ‘m’ instead of ‘cm’. Just a typo, no big deal.

There are several variables/parameters which can be varied in many, many ways. I am not writing a PHD thesis but trying to show in a very condensed format, as simple as possible, that roll release is largely an auto-regulated process.

I can vary the timing and the amplitude of the roll torque and yet the roll release still primarily happens when arm and shaft are close to alignment. This is the basic point, math agreeing with a real swing. How practical can one get.

 

[bbftx]

Mandrin,
How many other errors are behind your work? You're pretty quick to point out other people's errata as more than "no big deal." You corrected Fig 6, but I still don't see any units on Fig 4 and 5, so it's pretty hard to tell what the units are "supposed" to be.

Your model does not reflect a real swing at all, given that the roll happens 100 times faster in the model than it does in a real swing. You fail to address the issue that no one has the clubface open almost 90 degrees approximately one foot before impact This leads you to an incorrect conclusion, that you should "give up control to gain control." What does that mean in the real world? What would you tell a student to do?

I think a more actionable approach is to look for techniques to keep the clubface square, or as close as possible to square, for a longer duration near impact.

 

[mandrin]

bbftx, as a MIT graduate I expected a bit more from you. But I don’t mind spelling it out more in detail to help you understand it more readily.

Figs 4, 5 and 6 are using the same information.

In Fig 4 there are the dimensions of the shaft and the clubhead gyration radius to give one a very good idea of the magnitude of the dimensions involved.

In Fig 4 notice that the max separation between white and black dot is about the same as the distance between black and red dot, the latter being the approx 5 cm gyration radius.

It is clearly to be seen that the max separation is of the same order of magnitude as the gyration ration of 5 cm.

It is virtualy impossible to assume the max separation, as you so eagerly did, to be only 0.05 cm and to still show up clearly as it does in Fig 4 and 5. It would require a very strong magnifying glass.

I thought it to be all totally self-evident but if you still need help I will be very obliged to go even into more details.

bbftx, the analysis as done is not quite for everyone, it needs a bit more than kindergarten and also plenty of time to grind through it all, putting it together. You want it all in one sweep and moreover instantaneously, so impatient, give me some slack.

It is interesting to note the sharp contrast between your reaction and all others so far. Perhaps still thinking about gyroscopes and how they are so darned practical for learning to swing a golf club? If you find anything of value please let me know.


Just remember that HK patiently worked away at it all for 40, 50 years. Perhaps thinking about Homer might get you inspired magnanimously to give me a bit more time.

 

[bbftx]

You're requiring the masses to make a lot of assumptions looking at your graphs, when accurate labeling and scaling in the first place would make things much easier.

You also still fail to explain the discrepancy in clubface orientation in your model vs. a real swing in the last foot or so before impact. A better correspondence between the theoretical world and the real one is a hallmark of good science. Your analysis fails this test.

You might want to consider adding the torque applied by the golfer's hands and how it affects the time behavior of theta. It would give you a very different answer on how "automatic" your roll is.

 

[bts]

quote:Originally posted by mandrin

quote:Originally posted by bts

It seems that the "release of roll angle" (or that "swoosh" sound) occurs due to the inertia of the center of gravity of the orbiting clubhead (beyond certain speed) seeking to be "on-plane" with the orbit, along "in-line" with the swinging arm.

It also seems that all the other motions of the arms and wrists are dictated by those tendencies.

The golfer is supposed to let it occur naturally.

It seems?.
It also seems?
The golfer is supposed?

bts, not really quite sure, at least it seems so.

I am curious as to what you had in mind with your post since it is indeed all very much Homer like but not very easy to grasp.

Never mind, because they're based on my instinct and experience.

Basically what I mean is the club(head) will do the "work" all by itself, if the golfer doesn't interfere in pure swinging.

 

[mandrin]

quote:Originally posted by bbftx

You're requiring the masses to make a lot of assumptions looking at your graphs, when accurate labeling and scaling in the first place would make things much easier.

You also still fail to explain the discrepancy in clubface orientation in your model vs. a real swing in the last foot or so before impact. A better correspondence between the theoretical world and the real one is a hallmark of good science. Your analysis fails this test.

You might want to consider adding the torque applied by the golfer's hands and how it affects the time behavior of theta. It would give you a very different answer on how "automatic" your roll is.

bbftx,

You are a very stubborn fellow. All this childish complaining about scaling. I invite you to have another look at Figs 4 and 5 and tell me what you see. Yes that is correct. The xyz ordinates are scaled. You probably forgot to put on your glasses. Next step, you are going probably to criticize my use of colors, not quite being to your liking.

From your comments it is very clear that you have not the slightest idea of the complexity of the mathematics involved. Simply releasing the constraint on the arm to remain in the plane, hence introducing just one more variable, made the handling of the governing equations immediately awkwardly slow and impractical. Poor computer. I push it so hard. I sometimes wonder how it feels grinding through all those endless calculations. But it never seems to get tired.

I invite to look everywhere and report back if you can find anywhere published something like I have done. That is the destiny of all people doing original work, they are often meeting resistance and slandering. However, just for fun, imagine that either Brian or Yoda posted my ideas. All the available bandwidth would then be occupied with an endless stream of flattering remarks.

bbftx, I thought that you claimed to have changed into a hardnosed practical engineer after having gone into the oil business and left behind you the fancy engineering stuff of MIT. I really doubt it. The human machine is incredible complex to translate into a model. There are so many small motions/rotations we can do of which we are not even aware and which have an impact. A model can isolate some basic motions but never quite simulate exactly a human golfer.

I will repeat it again, varying the magnitude and/or the timing of the roll torque will vary somewhat the slope of the roll release but basically is still happening when ‘arm’ and ‘shaft’ are close to being aligned. This constituing hence a clear indication of a self-regulatory process. Very much in agreement with the practical advice to let the club do the swinging.

If a flat wrist and straight left arm than one has roll/turn and (un)cocking motions for the left arm/hand/wrist. Your suggestion to add another independent torque for the hands is hence relating to bending/arching which should be avoided.

Regarding the orientation of the clubface. This is simple a matter of choosing another set of values for the parameters/variables in the governing equations and I will have whatever is desired as outcome. I just don’t know what you have in mind with all your negative comments, other than simple being negative for the wrong motives. []

 

[dbl]

Mandrin, surely you'd admit your model has some "simplifications", and reasonable people could differ about the importance of some of yours. I think bbftx's 4/25 7:40am post was on target about this, but not everyone has time to dig through things to see what they are.

If indeed clubface roll is automatic, I haven't see it in all of my swings, but only about 1/6th of them (body dominated swings, arm swings, hitting, etc.)

 

[bbftx]

quote:Originally posted by mandrin
If a flat wrist and straight left arm than one has roll/turn and (un)cocking motions for the left arm/hand/wrist. Your suggestion to add another independent torque for the hands is hence relating to bending/arching which should be avoided.

Regarding the orientation of the clubface. This is simple a matter of choosing another set of values for the parameters/variables in the governing equations and I will have whatever is desired as outcome. I just don’t know what you have in mind with all your negative comments, other than simple being negative for the wrong motives. []

I'm talking about roll/turn torque from the hands, not bending/arching. You've modeled a shaft that seems to have nothing on the grip end to either inhibit roll (hand/arm mass for example) or a roll torque that a golfer can apply.
If the model becomes too complex by adding such a torque, perhaps as an intermediate step, you might want to add a mass at the grip end to represent hand and arm. Wouldn't this slow down the roll rate?
I think it would. Might help make the model more realistic by giving you a roll rate more akin to a real swing.

And yes, I think you should pick a more realistic clubface orientation for your scenario, as this appears to be easy for you to do.

As for the negative comments, I started by asking questions, which you have greeted with condescending remarks, along with veiled and not so veiled personal insults about my educational background, etc. I think everyone can see this in my first post on the topic and what has followed.

I'm making suggestions to make your model more realistic, which would enhance the credibility of the analysis. You seem very defensive about this and I'm sorry if you take offense.
Best regards,

 

[Erik_K]

quote:Originally posted by bbftx

quote:Originally posted by mandrin
If a flat wrist and straight left arm than one has roll/turn and (un)cocking motions for the left arm/hand/wrist. Your suggestion to add another independent torque for the hands is hence relating to bending/arching which should be avoided.

Regarding the orientation of the clubface. This is simple a matter of choosing another set of values for the parameters/variables in the governing equations and I will have whatever is desired as outcome. I just don’t know what you have in mind with all your negative comments, other than simple being negative for the wrong motives. []

I'm talking about roll/turn torque from the hands, not bending/arching. You've modeled a shaft that seems to have nothing on the grip end to either inhibit roll (hand/arm mass for example) or a roll torque that a golfer can apply.
If the model becomes too complex by adding such a torque, perhaps as an intermediate step, you might want to add a mass at the grip end to represent hand and arm. Wouldn't this slow down the roll rate?
I think it would. Might help make the model more realistic by giving you a roll rate more akin to a real swing.

And yes, I think you should pick a more realistic clubface orientation for your scenario, as this appears to be easy for you to do.

As for the negative comments, I started by asking questions, which you have greeted with condescending remarks, along with veiled and not so veiled personal insults about my educational background, etc. I think everyone can see this in my first post on the topic and what has followed.

I'm making suggestions to make your model more realistic, which would enhance the credibility of the analysis. You seem very defensive about this and I'm sorry if you take offense.
Best regards,

bbftx,

You forget that mandrin has a God-complex. It's OK for him to try and explain things the way he sees it, but when an inquistive fellow, such as yourself, asks a few questions...well we can't have that.

Hey, mandrin just wondering...have you ever published stuff in a refereed journal? I have. And no, I don't cry and make disparaging remarks when other experts in the area ask questions about my work.

 

[mandrin]

quote:Originally posted by Erik_K

bbftx,

You forget that mandrin has a God-complex. It's OK for him to try and explain things the way he sees it, but when an inquistive fellow, such as yourself, asks a few questions...well we can't have that.

Hey, mandrin just wondering...have you ever published stuff in a refereed journal? I have. And no, I don't cry and make disparaging remarks when other experts in the area ask questions about my work.

Erik_K,

You have a funny discourse for a TGMer, since TGM forums are well known to be reluctant to accept anything which in one way or another can be viewed as the slightest critical appraisal of HK and his gospel.

Hence, you therefore see Yoda and Cuck as having a God-complex since they have banned any form of critique from their forums. Brian is different he likes a good fight but many of the posters here are still as intolerant as on the other two forums mentioned.

It would be an interesting and revealing exercise to put together in one post all the mud slinging in my direction since I started to post. The problem for me is to recognize in the mud slinging crowd the one or two persons who are genuine and not out to have some quick fun throwing some eggs and over ripe tomatoes.

Rest assured, I have all the scientific qualifications required to post on a TGM forum, including refereed papers. [8)] Moreover, just between you and me, it is sometimes rather amusing to redirect some of the mud.