Bipod Following Errors

I have been trying for the past couple of days to setup a bipod similar to Koppi's Toy . The code I am working with is the dab_bipodkins.c from user dab77 posted here . dab77 has been very generous the past few days trying to help me to get it working, but I have very little programming experience and I'm still struggling. I have read through Koppi's documentation as well as the emc2hotwinch documentation many times trying to find my error.

The problem I'm running into is a following error. In joint mode the motors jog as expected. But as soon as I switch to world mode, without even trying to jog, I get a following error on joints 1 and 2. I am attaching a ZIP file of my configuration, which includes a screenshot in joint mode and then a screenshot of the following error as soon as I switch to world mode. Initially I had the HOME and HOME_OFFSET set a less than half of the distance between the two motors, which dab 77 pointed out was one problem. Even after correcting that, still the following error.

I am at a loss and any help would be *greatly* appreciated! Thank you.

Another thought, maybe trivial, but you have to be sure that after you HOME your joints, you don't move any joint untill you turn into wolrd mode.
If you didn't already, try it.

Davide.

Thanks Davide, I double checked that and I still get the following error.

Chad

I've re-controlled your kins and they look good.
I would just do these try:
- into your kinematics you can erase the lines:

pos->a = joints[3];
pos->b = joints[4];
pos->c = joints[5];
/* pos->u = joints[6];
pos->v = joints[7];
pos->w = joints[8]; */

and

joints[3] = pos->a;
joints[4] = pos->b;
joints[5] = pos->c;
/* joints[6] = pos->u;
joints[7] = pos->v;
joints[8] = pos->w;*/

.
-try to start with an higher accel and a little higher f.error. let's say:

[AXIS_0]
#X
TYPE = LINEAR
MAX_VELOCITY = 100.0
MAX_ACCELERATION = 10000.0
STEPGEN_MAXACCEL = 11000.0
FERROR = 10.0
MIN_FERROR = 2.5
...cut...

with this config you shouldn't have troubles.

a stupid question:
after changing your bipodkins.c, did you recompile that again?
in case do:
sudo comp --install bipodkins.c
are you using a normal installation or compiled by your self?

Ciao, Davide.

Thanks Davide, I can now jog in world mode at slow speeds w/o the following error! Hope to get back to it later today, my axis is rotated 90 degrees (x vertical) and I want to see if I can up my speed w/o returning to the following errors. I'm also going to go back and pinpoint if it is the modification to the kinematics or INI file, as you suggested, that resolved things. I was anxious and made all of the changes at once...

Hi Davide,

After making your suggested changes the following error issue seems to be resolved. As I mentioned in the previous post, my X,Y axes appears to be rotated 90 degrees, which I think is a sign of another problem. When I run the spiral.ngc file that is in the examples folder of EMC, the spiral, which is circular, is drawn by my bipod with an elliptical shape. I also have a strange thing happening, which you noticed before, that when I home in joint mode and then switch to world mode, my coordinates are changing from (1100,1100) to (659, 870) respectively, as can be seen in the screenshots. Again, that is without jogging prior to switching from joint to world mode. I've double checked that my SCALE is the same for both axes, I'm using identical steppers, and the microstepping settings on the driver board are the same. What else should I be looking at?

Thanks again for all of your help,
Chad

the ellipse is out of dubt given by a mistake in homing.
it means that you set the two axis homes at 1100, but your real lenght of wire from the pulley, to the object isn't 1100. be sure to measure and put the exact lenght when you do homing. (maybe a sign on the wall?)
..or maybe the distance from one pulley to the other isn't perfectly 1320?
then your x and y position should be 660,880. i don't know why you have 659,870..
and i don't know why they are rotated.
J0 is left motor and J1 is right one, is it?