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Bipod setup

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06 Aug 2010 08:44 #3603 by dab77
Bipod setup was created by dab77
Hallo everyone,
I'm trying to setup an inverted bipod, for studying purpose.
looked around for a lot, but still I didn't get to the point.
I'm trying to modify the file tripodkins.c to have my_bipod.c to compile, but I'm not sure if what I changed is ok.

I've read about in later versions of EMC2 there was a bipod.c already in ..src/emc/kinematics, but now there's not anymore.

do someone have this file to give me, or can tell me where to find it? ..so i can compare and find out any error.

thanks, dab.

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06 Aug 2010 10:47 #3605 by step4linux
Replied by step4linux on topic Re:Bipod setup
you may want to look here for a bipod example:
www.linuxcnc.org/docview/html//motion_kinematics.html

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09 Aug 2010 08:08 #3643 by dab77
Replied by dab77 on topic Re:Bipod setup
Hi step4linux, and thank you for replying.
in a lot of thread there is a suggestion to read that link, so i found it and read it already many times, and if also i found it very interesting, it doesn't help much, because doesn't tell you how to write the .c kins.

I did modify the file trivkins.cand compiled in this way:
********************************************************************/

#include "kinematics.h"		/* these decls */
#include "rtapi_math.h"

int kinematicsForward(const double *joints,
		      EmcPose * pos,
		      const KINEMATICS_FORWARD_FLAGS * fflags,
		      KINEMATICS_INVERSE_FLAGS * iflags)
{   double Bx = 800;
    double AD2 = joints[0] * joints[0];
    double BD2 = joints[1] * joints[1];
    double x = (AD2 - BD2 + Bx * Bx) / (2 * Bx);
    double y2 = AD2 - x * x;
    if(y2 < 0) return -1;
    pos->tran.x = x;
    pos->tran.y = sqrt(y2);
    return 0;
}

int kinematicsInverse(const EmcPose * pos,
		      double *joints,
		      const KINEMATICS_INVERSE_FLAGS * iflags,
		      KINEMATICS_FORWARD_FLAGS * fflags)
{   double Bx = 800;
    double x2 = pos->tran.x * pos->tran.x;
    double y2 = pos->tran.y * pos->tran.y;
    double xx2 = (Bx - pos->tran.x) * (Bx - pos->tran.x);
    joints[0] = sqrt(x2 + y2);
    joints[1] = sqrt(xx2 + y2);
    return 0;
}

/* implemented for these kinematics as giving joints preference */
int kinematicsHome(EmcPose * world,
		   double *joint,
		   KINEMATICS_FORWARD_FLAGS * fflags,
		   KINEMATICS_INVERSE_FLAGS * iflags)
{
    *fflags = 0;
    *iflags = 0;

    return kinematicsForward(joint, world, fflags, iflags);
}

KINEMATICS_TYPE kinematicsType()
{
    return KINEMATICS_BOTH;
}

#include "rtapi.h"		/* RTAPI realtime OS API */
#include "rtapi_app.h"		/* RTAPI realtime module decls */
#include "hal.h"

EXPORT_SYMBOL(kinematicsType);
EXPORT_SYMBOL(kinematicsForward);
EXPORT_SYMBOL(kinematicsInverse);
MODULE_LICENSE("GPL");

int comp_id;
int rtapi_app_main(void) {
    comp_id = hal_init("trivkins");
    if(comp_id > 0) {
	hal_ready(comp_id);
	return 0;
    }
    return comp_id;
}

void rtapi_app_exit(void) { hal_exit(comp_id); }

then when compiling:
dab-cnc@dab-cnc-desktop:~$ sudo comp --compile trivkins.c
make -C /usr/src/linux-headers-2.6.24-16-rtai SUBDIRS=`pwd` CC=gcc V=0 -o /Module.symvers modules
make[1]: ingresso nella directory «/usr/src/linux-headers-2.6.24-16-rtai»
  CC [M]  /tmp/tmp04BYj4/trivkins.o
  Building modules, stage 2.
  MODPOST 1 modules
WARNING: "hal_init" [/tmp/tmp04BYj4/trivkins.ko] undefined!
WARNING: "hal_exit" [/tmp/tmp04BYj4/trivkins.ko] undefined!
WARNING: "hal_ready" [/tmp/tmp04BYj4/trivkins.ko] undefined!
  CC      /tmp/tmp04BYj4/trivkins.mod.o
  LD [M]  /tmp/tmp04BYj4/trivkins.ko
make[1]: uscita dalla directory «/usr/src/linux-headers-2.6.24-16-rtai»
dab-cnc@dab-cnc-desktop:~$ sudo cp trivkins.ko /usr/realtime-2.6.24-16-rtai/modules/emc2/
dab-cnc@dab-cnc-desktop:~$

then when i run the machine in joint mode it's all ok, then i zero my axes, but when i try to change into world mode i have this error (in the terminal):
dab-cnc@dab-cnc-desktop:~$ emc /home/dab-cnc/emc2/configs/Prova_Bipod/Prova_Bipod.ini
EMC2 - 2.4.3
Machine configuration directory is '/home/dab-cnc/emc2/configs/Prova_Bipod'
Machine configuration file is 'Prova_Bipod.ini'
Starting EMC2...
*********************************WARN_ONCE*********************************
File r300_render.c function r300Fallback line 470
Software fallback:ctx->Line.StippleFlag
***************************************************************************
[b]joint 1 following error
emc/task/taskintf.cc 611: Error on axis 1, command number 111[/b]
Shutting down and cleaning up EMC2...
Cleanup done
dab-cnc@dab-cnc-desktop:~$

Can you help me?

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09 Aug 2010 08:37 - 09 Aug 2010 08:47 #3644 by step4linux
Replied by step4linux on topic Re:Bipod setup
hi dab,

I did a dualbipod, and started like you did with trivkins.
You can find it here code.google.com/p/emc2hotwinch/ .

From your code two things I see:

1. You must insert the name of your own kinematics here, instead of trivkins:
comp_id = hal_init("trivkins");
EDIT: okay I have seen you still use the the name trivkins for your own kinematics

2. you should leave all the simple equations in the code, like
joints[2] = pos.tran->z
etc
pos.tran->z = joints[2]
etc
for all joints and all axis.
EDIT: of course except for those you have your own equation.

Gerd
Last edit: 09 Aug 2010 08:47 by step4linux.

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09 Aug 2010 09:42 #3647 by dab77
Replied by dab77 on topic Re:Bipod setup
ok, i'm trying to replace the other axes kins.

thanks!

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09 Aug 2010 09:46 #3648 by dab77
Replied by dab77 on topic Re:Bipod setup
mmmmh.. no. isn't going to work.
it return the same error.

code now is:
#include "kinematics.h"		/* these decls */
#include "rtapi_math.h"

int kinematicsForward(const double *joints,
		      EmcPose * pos,
		      const KINEMATICS_FORWARD_FLAGS * fflags,
		      KINEMATICS_INVERSE_FLAGS * iflags)
{   double Bx = 800;
    double AD2 = joints[0] * joints[0];
    double BD2 = joints[1] * joints[1];
    double x = (AD2 - BD2 + Bx * Bx) / (2 * Bx);
    double y2 = AD2 - x * x;
    if(y2 < 0) return -1;
    pos->tran.x = x;
    pos->tran.y = sqrt(y2);
    pos->tran.z = joints[2];
    pos->a = joints[3];
    pos->b = joints[4];
    pos->c = joints[5];
    pos->u = joints[6];
    pos->v = joints[7];
    pos->w = joints[8];
    return 0;
}

int kinematicsInverse(const EmcPose * pos,
		      double *joints,
		      const KINEMATICS_INVERSE_FLAGS * iflags,
		      KINEMATICS_FORWARD_FLAGS * fflags)
{   double Bx = 800;
    double x2 = pos->tran.x * pos->tran.x;
    double y2 = pos->tran.y * pos->tran.y;
    double xx2 = (Bx - pos->tran.x) * (Bx - pos->tran.x);
    joints[0] = sqrt(x2 + y2);
    joints[1] = sqrt(xx2 + y2);
    joints[2] = pos->tran.z;
    joints[3] = pos->a;
    joints[4] = pos->b;
    joints[5] = pos->c;
    joints[6] = pos->u;
    joints[7] = pos->v;
    joints[8] = pos->w;
    return 0;
}

/* implemented for these kinematics as giving joints preference */
int kinematicsHome(EmcPose * world,
		   double *joint,
		   KINEMATICS_FORWARD_FLAGS * fflags,
		   KINEMATICS_INVERSE_FLAGS * iflags)
{
    *fflags = 0;
    *iflags = 0;

    return kinematicsForward(joint, world, fflags, iflags);
}

KINEMATICS_TYPE kinematicsType()
{
    return KINEMATICS_BOTH;
}

#include "rtapi.h"		/* RTAPI realtime OS API */
#include "rtapi_app.h"		/* RTAPI realtime module decls */
#include "hal.h"

EXPORT_SYMBOL(kinematicsType);
EXPORT_SYMBOL(kinematicsForward);
EXPORT_SYMBOL(kinematicsInverse);
MODULE_LICENSE("GPL");

int comp_id;
int rtapi_app_main(void) {
    comp_id = hal_init("trivkins");
    if(comp_id > 0) {
	hal_ready(comp_id);
	return 0;
    }
    return comp_id;
}

void rtapi_app_exit(void) { hal_exit(comp_id); }

any other idea?

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  1. Configuring LinuxCNC
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