Routine for Decomposition of Vectors

[lizp]

This is correct as correct can be. Congratulations. The main goal of the code is accomplished.

 

Now, the details. I see when first clicking on the curve (when choosing Manual) the broken lines that connect the vector tips. Why do they disappear upon the second click? Also, it would look nice if there are small leads at the ends of the vectors, if that's not a big hassle.

 

Finally, the net torque, that is, the sum of all torques would be very useful to be calculated (that would save a lot of work in the final analysis) and placed both on the screen and in a special file, probably alongside the name of the file is was calculated from.

 

You did a great job, what can I say.

[SEANT]

Here is a diagram (based on Example.dxf in Post #64 of this thread) describing what I consider one of the “complex” calculations - which may have bearing on Net torque.

exampleAlt.dwg

[Lee Mac]

This is correct as correct can be. Congratulations. The main goal of the code is accomplished.

 

Finally!

 

Now, the details. I see when first clicking on the curve (when choosing Manual) the broken lines that connect the vector tips. Why do they disappear upon the second click? Also, it would look nice if there are small leads at the ends of the vectors, if that's not a big hassle.

 

The highlighted lines are achieved using a negative colour in the grvecs list, and I didn't have these recreated as lines upon click, as I thought they were only for visual aid - but if you want to, I can see what can be done.

 

As for the "leads", I am assuming you mean arrowheads - and this may be a bit hard to accomplish - I would have to draw the heads on manually, and getting all the angles on them correct would be a right palava - not impossible, but tedious.

 

Finally, the net torque, that is, the sum of all torques would be very useful to be calculated (that would save a lot of work in the final analysis) and placed both on the screen and in a special file, probably alongside the name of the file is was calculated from.

 

The net torque should already be placed on screen at the end of the calculations. - it is also written to the file.

 

Here is a diagram (based on Example.dxf in Post #64 of this thread) describing what I consider one of the “complex” calculations - which may have bearing on Net torque.

 

Thanks Sean, nice diagram - I still don't completely follow all the vector representations, but then, what can I say - I'm a mathematician, not a physicist...

[lizp]

The net torque should already be placed on screen at the end of the calculations. - it is also written to the file.

Now I see it. It comes up after the last click. Great.

 

It would be very useful if in addition to writing it to this file to have it written to another, dedicated file, where all the net torques from all the separate calculations would be placed. That'll be the final outcome of the study which will be represented as a graph whereby these net torques will be the values on the ordinate. The abscissa values are the degrees by which the wheel is turned relative to its initial position. I usually put these degrees as part of the name. Wonder if that numerical part of the name could be extracted and placed in another column so that the plotting of the data can be made easier?

 

The highlighted lines are achieved using a negative colour in the grvecs list, and I didn't have these recreated as lines upon click, as I thought they were only for visual aid - but if you want to, I can see what can be done.

Would be good to have them in the final drawing as well. That'll make it clearer where these vector components come from, especially if one is to print it in black and white.

 

As for the "leads", I am assuming you mean arrowheads - and this may be a bit hard to accomplish - I would have to draw the heads on manually, and getting all the angles on them correct would be a right palava - not impossible, but tedious.

No big deal. I thought it might be more visually attractive for these segments to appear as vectors, what they actually are. That's a small detail and if it requires so much work just let it go.

[Lee Mac]

The abscissa values are the degrees by which the wheel is turned relative to its initial position. I usually put these degrees as part of the name. Wonder is that numerical part of the name could be extracted and placed in another column so that the plotting of the data can be made easier?.

 

By "abscissa" values, do you mean "x" coordinate of the point on the curve? or are you just trying to confuse me...

[lizp]

@SEANT,

 

Wonder what effect on the torque you think that might have?

[lizp]

By "abscissa" values, do you mean "x" coordinate of the point on the curve? or are you just trying to confuse me...

These are x-coordinate values of the final plot that would come out from the data in that specially designated Excel file, containing the net torques for all the individual (eight-torque) calculations. The plot in question has nothing to do with the current code. It's the final result of all this effort and is made in Excel. What we need is to have all the net torques placed there in their own column and, if possible, have the degrees of rotation (extracted from the names of the individual drawings) placed in a separate column as the x-axis values. Did I write it a little clearer now or it's still entangled?

[Lee Mac]

What we need is to have all the net torques placed there in their own column and, if possible, have the degrees of rotation (extracted from the names of the individual drawings) placed in a separate column as the x-axis values. Did I write it a little clearer now or it's still entangled?

 

I'm still not sure what you mean by the x-values - but as for the degree of rotation - what is the format of the dwg name? (so that I know how to breakdown the string).

[lizp]

I'm still not sure what you mean by the x-values - but as for the degree of rotation - what is the format of the dwg name? (so that I know how to breakdown the string).

Probably an example of a file name would give you an idea of the format. Say, it can be Wheel35.dxf or maybe even shorter W35.dxf. The number 35 stands for the degrees of rotation of the wheel with respect to a position of the wheel which we have accepted to be at 0degrees. That value 35 would be the x-axis value in the final Excel plot of a point whose y-axis value is the corresponding net torque we have calculated using the code from all the eight torques derived from the drawing named Wheel35.dxf.

[Lee Mac]

I see now.

 

You confused me with the abscissa, and x-values, as I thought these referred to an element in the actual drawing itself.

 

Can I assume the drawing name will be "W35"?

 

As an inconsistent drawing name makes extracting the degree measurement a nightmare...

[lizp]

Sure. W35 is just fine.

 

Unfortunately, I have to go now and won't be able to participate till later today. I'll check the thread as soon as I can. Talk to you later.

[Lee Mac]

No probs mate - I'll see what I can knock together in that time

[Lee Mac]

OK, I have modified a few things in this version:

 

• Net Torque is now written to a new file, and the drawing name is extracted and written too.

• All Vector Directions should be correct.

The rest is clearly visible.

Vector Analysis.lsp

[SEANT]

@SEANT,

 

Wonder what effect on the torque you think that might have?

 

I think it will influence the torque values anywhere the circular weight is in contact with any surface in addition to the slotted wheel.

 

Presumably we are all discounting friction, for the time being – to keep matters reasonably straightforward. But even friction aside, to counter a ForceA with ForceB applied at an angle, then that ForceB must equal ForceA/Sin(Angle) . See additional diagram.

 

The discrepancy between the force and counterforce would only act to compress the “rollers” and not result in useful work. The torque would have to be considered, however, in any net torque calculations.

 

If all this is indeed true, then the example attached at post #64 shows a torque value of 1069.8437 which may actually be 1442.377

Basic.dwg

[Lee Mac]

Great illustration Sean - well explained.

[SEANT]

 

 

I still don't completely follow all the vector representations, but then, what can I say - I'm a mathematician, not a physicist...

 

Actually, one of the cool things about many of the “Vector” based calculations in physics is that they can be computed graphically. Say there was two forces applied to an object, one 10 kilos at 60 degrees, another 15 kilos at 150 degrees.

 

Even if I were "math impaired”, the resultant force and direction could be determined with a line from the origin @10

[Lee Mac]

Actually, one of the cool things about many of the “Vector” based calculations in physics is that they can be computed graphically. Say there was two forces applied to an object, one 10 kilos at 60 degrees, another 15 kilos at 150 degrees.

 

Even if I were "math impaired”, the resultant force and direction could be determined with a line from the origin @10

 

I can see what you are saying, but I don't quite follow what all the vectors in this example represent. I understand that they are the tangential and normal vectors etc, but I don't see what physical quantities they represent.

[SEANT]

This can get a bit cloudy. Especially when analyzing torque, which deals with two vectors.

 

The base vector represents the weight of each of the 8 rollers. The length, 27 units, presumable means 27 grams (likely, given the Net torque expression as Newton/Meters, though it could just as easily represent some other unit of weight).

 

The Line your routine draws from the Circle center to a point on the “ellipse” is actually a linear measure (here, probably centimeters).

 

Both vectors need to be broken down based on their respective angle within the entire system. The complicated part is that the path of the rollers is not always pointed in the same direction as the applied force.

 

The result of each calculation, Torque, is based on two vectors, Direction/Magnitude of Force and Angle/Length of Lever Arm.

[Lee Mac]

I understand a lot better now Sean, thanks

[lizp]

Wow, you’ve put also the leads. Looks great on most places but at places where the resultant vectors are too short (as at the bottom) it appear somewhat messy because the arrows happen to be of the same, even greater length than the resultant vector itself.

 

Also, the broken lines which appear upon the first click turn into solid lines after the second click. Can they be retained as broken lines in the final drawing? In the meantime (when clicking the second time) I also get an error message saying HIDDEN Linetype could not be Found. Is this to be expected or something is going wrong?