Andrew, A tripod would not work at all for milling since it is not constrained rotationally. It would just flop around. In fact, the robo-crane was not too stable either. Adding more weight to the platform would help. It could mill styrofoam and had a hard time with wood. However, a real hexapod with solid struts is extremely rigid and one was used for ultra-precise milling of calibration fixtures at NIST.
Fortunately for you, the NIST robocrane actually used EMC to control it. The "genhexkins" kinematics module does the transforms from cartesian coordinates to motor positions. All you have to do (famous last words) is edit core_sim_6.hal so that lines like 'linksp Xpos => axis.0.motor-pos-fb' point to the real motor/pid loop instead. Look at other non-sim configs for inspiration. (and RTFM) There are no computer visualizations of a hexapod in emc yet, but I'd like to write one. It should be easy enough using the vismach.py framework already in place as an example. John Storrs posted some non-visual simulation code on his excellent website "laboratory for micro enterprise" which i have archived here: http://fenn.dyndns.org/pub/www.i-way.co.uk/~storrs/lme/hexapod-1.1.html You should read the rest of that website if you haven't already. Best of luck -fenn On Tue, 2 Oct 2007, [EMAIL PROTECTED] wrote: > Dear Kirk and all: > > Thank you for supplying me with relevant information. I think that Alex > Joni's toy would give me needed information > to implement a step in the right direction. I wonder if a tripod made more > robust could do milling and routing. > > Best regards, > > Andrew > > ----- Original Message ----- > From: "Kirk Wallace" <[EMAIL PROTECTED]> > To: "Enhanced Machine Controller (EMC)" <emc-users@lists.sourceforge.net> > Sent: Tuesday, October 02, 2007 3:30 PM > Subject: Re: [Emc-users] Robocrane > > >> Hello Andrew, >> >> I just looked at the NIST site. The Robocrane is quite a complex >> project. I suspect that EMC should be able to serve as the foundation >> for your project since you can plug in your own kinematics and EMC is >> highly configurable hardware interface wise. I suspect the Robocrane is >> a step further in the hexapod evolution, so you should maybe study a >> search on "hexapod" at linuxcnc.org. Check these: >> >> http://wiki.linuxcnc.org/cgi-bin/emcinfo.pl?Alex_Joni's_Toy >> http://wiki.linuxcnc.org/cgi-bin/emcinfo.pl?Koppi's_Toy >> http://cvs.linuxcnc.org/lxr/source/configs/hexapod-sim/ >> >> Be prepared to create your own C code. >> >> If you haven't already done so, you might want to study the basics by >> getting a demo CD working: >> >> http://www.linuxcnc.org/content/view/21/4/lang,en/ >> >> Then interface an encoder to your parallel port using the etch-servo >> configuration (in Sample Configurations, study etch.ini and etch.hal for >> connection information) and a NetMOS parallel port card ("lspci -v" will >> come in handy). >> >> Then maybe drive a stepper or DC servo motor like this setup: >> >> http://emergent.unpy.net/projects/01142347802 >> >> I found a good motor and encoder in a junk Epson C-80 printer (sure >> hated to see that printer go). >> >> Good luck. I'll try to help, if I can. Others here are better at the >> nitty-gritty stuff. >> >> Kirk Wallace >> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ >> On Mon, 2007-10-01 at 16:29 -0400, [EMAIL PROTECTED] wrote: >>> Dear enc-users: >>> >>> Hello my name is Andrew I am new to this list. I want to make a cable >>> robot milling machine similar to the >>> NIST 1meter robocrane milling machine. Any help would be appreciated. >>> If this list is not relevant >>> to obtain this kind of information, please direct me to where I can >>> obtain it. I am starting from scratch. >>> I want to obtain all relevant information before I start. Are there >>> any simulations software that can be run on >>> a PC. >>> >>> Thank you for your help, >>> >>> Andrew >> >> >> >> ------------------------------------------------------------------------- >> This SF.net email is sponsored by: Microsoft >> Defy all challenges. Microsoft(R) Visual Studio 2005. >> http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ >> _______________________________________________ >> Emc-users mailing list >> Emc-users@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/emc-users >> >> >> -- >> No virus found in this incoming message. >> Checked by AVG Free Edition. >> Version: 7.5.488 / Virus Database: 269.13.39/1044 - Release Date: >> 10/2/2007 11:10 AM >> . > > > ------------------------------------------------------------------------- > This SF.net email is sponsored by: Microsoft > Defy all challenges. Microsoft(R) Visual Studio 2005. > http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2005. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
