Pure Linux instead of RTAI
"Patrycjusz Szczepaniak" <[email protected]> Fri, 25 Nov 2005 15:22:38 +0100
| Newsgroups | gmane.science.robotics.orocos.user |
|---|---|
| Organization | Nowa Poczta Wirtualnej Polski S.A. http://www.wp.pl/ |
| Message-ID | <[email protected]> |
Hello, I was trying to controll an IRp-6 robot using an Orocos application. The application was communicating with the robot through a device driver (a kernel module). The application used regulators that were designed to work with a 500Hz frequency. All my attempts have failed since Linux could not keep a 2ms constraint. Regulators where executed every different and undeterministic periods. I was thinking about using RTAI. It turned out that I do not have to use RTAI for my application to work. I changed a systemclock frequency (values of a HZ and a CLOCKS_PER_SEC variables located in a /usr/src/linux-2.4.25/include/asm-i386/param.h file) and recompiled a kernel. The old value equal 100 was changed to 1000. It solved my problems. It seems that scheduler switched processes too rarely that is why they were not executed in time. Now my regulators are being executed every 2000us +-2us. I executed my application with the highest priority during a high system load (I was compiling a kernel) and it still worked just fine. Is there any sense in using RTAI if Linux works? ---------------------------------------------------- Zapraszamy do Ĺodzi w dniach 26.11 - 4.12.2005 na Festiwal Filmowy CAMERIMAGE - najwiÄksze miÄdzynarodowe ĹwiÄto kina w Polsce. WiÄcej informacji: wwW.camerimage.pl http://klik.wp.pl/?adr=http%3A%2F%2Fadv.reklama.wp.pl%2Fas%2Fcamerimage2.html&sid=585