Hello
> I haven't looked at this in any detail, but it would possibly make
> more sense to leave scarakins as an XYZC kinematics, but to map axis C
> to joint 5.
> However I think that might leave us with spare axes in the display.
It does not work for me either.
As you wrote, linuxcnc has 1:1 mapping from joints to axes, where
world->c is mapped to joint[5]. I think it does not work because
scarakins.c does not calculate with this mapping problem:
Scarakins inverse kinematics:
joint[0] = q0;
joint[1] = q1;
joint[2] = D1 + D3 - D5 - z;
joint[3] = c - ( q0 + q1); ////////// joint[3]
joint[4] = world->a;
joint[5] = world->b;
Scarakins forward kinematics:
world->tran.x = x;
world->tran.y = y;
world->tran.z = z;
world->c = c * 180 / PM_PI; /////////// axis C
world->a = joint[4];
world->b = joint[5];
I understand your point about axis naming, but using world->a seems to
be a straight forward solution of this issue. Correct me if I am wrong
somewhere.
Bence
2012/10/23 andy pugh <[email protected]>:
> On 23 October 2012 12:34, Bence Kovács
> <[email protected]> wrote:
>
>> What is the advantage of using axis C in scarakins?
>
> Typically the C axis is the rotational axis that rotates about Z, so
> from a conventional naming point of view it makes some sense.
> The scarakins file is a bit strange, though, as that takes the unusual
> step of mapping Axis C to Joint 3. There is a general (and
> wrong/annoying) assumption in other parts of LinuxCNC that there is a
> 1:1 mapping from joints to axes.
>
>> I am new to LinuxCNC source, I am just investigating the code
>> structure. If you have idea where can be the problem, I can make
>> further investments. Don’t you think we should just modify scarakins
>> to use axis X Y Z A?
>
> I haven't looked at this in any detail, but it would possibly make
> more sense to leave scarakins as an XYZC kinematics, but to map axis C
> to joint 5.
> However I think that might leave us with spare axes in the display.
>
> --
> atp
> If you can't fix it, you don't own it.
> http://www.ifixit.com/Manifesto
>
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