Re[10]: emc really needs a copyleft cad/cam package

Ballendo,

Yes, I see it easier this morning then last night! It was hard to see
how both could be correct. Guess I'll leave RP&Y to 'planes 'n boats! I
think I have the axis and signs under control on my small mill. I'll
start working on the right hand rule, should be useful as you said for
G02, G03!

Funny thing is, driving the motors for the three axis, It appears that
you can't always turn the motor the same way to get + axis movement.
That is, I THINK that's the case. If I remember, for MaxNC, you "make
the axis move in the + direction" by selecting the phase sequences.
Same sequence for all three motors results in Gcode files working
properly. But I'm having to swap some of the directions (in my program)
for the key directions to come out right. I must have something
reversed somewhere. A + Y movement when used for the rotary table A
axis appears to yield the reverse direction! I guess I need to map it
all out (yeah design the code FIRST), and see where the proper places to
make the swap are.

Lets see, clockwise feeds in, and that's why the Y axis is left handed?
Well, one of them is anyway. At least it's easy to make changes in the
software. I probably just need a "sign table", so I can map directions
at will.

For handwheels, is clockwise always +? an IN? If you face a rotary
table, is clockwise rotation always +? It would seem that you'd want
the table to turn clockwise if you rotate the encoder clockwise, or push
the right-hand arrow key, up key, or page up key. Are these the favored
keys?

I like the encoder for jogs. Four jogs, .000125, .001, .01 and .1 seem
useful, however using the cursor and page keys seem to require different
rates for smooth controllable movement. Still working on that. I know,
map it out.

Sorry for all the questions, but I'd like to learn/do it right the first
time (OK, most of it correct the first time). ;>)

ballendo@... wrote:

>
> Alan,
>
> No, you're not confused. You've got it right. Funny thing is; so does
> Jon E!
>
> And the reason is WHY we don't want to use roll,pitch and yaw to
> describe rotation. Most people who are familiar with R,P & Y know
> that it relates to the direction we're "going", or "facing".
>
> Jon said that: Facing(standing in front of) his BP mill, A is pitch,
> B is roll, C is Yaw. You can see that a pitch down or up (from this
> positions' reference, standing in front of the mill) WILL be rotation
> around the mills' X axis! The others are similarly correct. And
> confusing, IF you're thinking of the X axis positive being
> the "faced" direction.
>
> So if you stand at the LEFT END of the mill and look "down the
> table", THEN you see roll as A, pitch as B, and yaw as C.
>
> Notice that the AXIS definition ISN'T changing; just the CORRELATION
> to R,P & Y. If we stand on a ladder and look down at the mill, we get
> the third set of correlations. Three more (behind,to the right of,
> ans under) will be the same as the first three with the plus/minus's
> reversed.
>
> THIS is why roll, pitch, and yaw are not used to define axes! A,B,
> and C remove the possibility for mis-interpretation. And the "right
> hand rule" takes it one step further, to define whether the rotation
> is in the "plus" or "minus" direction. So we know whether to use G02
> or G03.
>
> Hope this helps.
>
> Ballendo
>
> Alan wrote:
> >Jon,
> >I guess I'm still getting the axis confused. Isn't A rotation around
> >the X axis? And B around the Y axis, and C around the Z axis? Which
> >way is the plane flying?
> >Alan (probably flyin' inverted) No Scottie, we can't loop the boat!
>