I am trying to decide whether to use this or a modification of the "genserkins" module from LinuxCNC.
(The latter has the advantage of being more familiar, but includes some rather "excessive" libraries.)
I am wanting to use forward kins only, to determine the position of the end of a Faro arm. (Which I found cheap on eBay).
andypugh:
I am trying to decide whether to use this or a modification of the "genserkins" module from LinuxCNC.
(The latter has the advantage of being more familiar, but includes some rather "excessive" libraries.)I am wanting to use forward kins only, to determine the position of the end of a Faro arm. (Which I found cheap on eBay).
for my purposes, both FK and RK actually are crucial.
any updates about a adjustable FK+RK lib for 6-7 DOF robotic arms?
AFAIK neither lib of the ones mentioned above would work so far actually for proprietary arm constructions (CMIIW)...?
Hi,
haven been trough this, years ago.
Have done the forward and reverse KIN, from zero.
Reverse KIN is the difficult part.
Unfortunately, I don't have a LIB or something for you.
If your accuracy is not high, you could make a multidimensional ARRAY.
( is a lot of work in case of 6 DOF )
ARRAY [x,y,z, u,v,w] as input and [a, b, c, d, e, f] as output, the 6 angles of the servo's .
x,y,z are the coordinates of the gripper(tip) and u,v,w the orientation.
But this is allmost undoable...
Kind regards.
well, the required precision should be close to 2mm.
The workspace of the arm is a 3/4 sphere by a radius of a about 500mm, that's
4pir³3/4 = 3pi*r³ ≈ 1,250,000,000mm³ .
CMIIW, but that would require ≈100,000,000 (x,y,z) coordinates plus relates joint angles,
plus all additional gripper orientations -
and finally:
I cannot even determine the joint angles because the servos don't return angle positions. 
So unfortunately, I'm afraid, your proposal about look-up tables is really not doable... 
Nonetheless, mathematically it should be solvable though (by theory), using inverse and transposed matrices from FK (but that is far beyond my skills 8) ) .
Sorry, i can't help you further.
I aproached my FW and BW in my own way!
( at the end, it looks like a kinda array/matrix-system, too )
Good luck and succes with the progress!
anyone who knows how to control a 6-7DOF robot arm like the following by Reverse Kinematics?
Just define the spatial coordinates to move the gripper to, and the lib is supposed to calculate either required servo angle?
And the same (easier task) vice versa for Forward Kinematics?
I still can't find a working lib for that purpose... 
\ /
\ / finger length 50 mm
|-| 6 claw spread
| metacarpal length 55 mm
|
o 5 metacarpal rotate
|
| wrist length 95 mm
|
v 4 wrist tilt
|
| forearm segment2 50 mm
|
o 3 forearm rotate
|
| forearm segment1 100 mm
|
v 2 elbow tilt
|
|
| upper arm length 180 mm
|
|
v 1 shoulder tilt
|
| shoulder height 15 mm
o 0 trunc rotate horiz
|
| trunc base 85 mm
|
___ floor
Look at the AR2 robot arm software.
It is all open source. You can set the segment lengths in the python interface, which does all of the inverse kinematics for a 6 axis robot arm. You will have to re-write the Arduino portion to control the servo position, as it is written for a stepper motor instead of a servo.
Did you ever solve this problem?