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RTAI Conference Papers

admin — Sat, 03 Apr 2010 11:04:58 +0000

Last week, I have introduced to RealTime Application Interface for Linux, now I would like to give you some RTAI Conference Papers. Those papers could be a very good reference for everyone who is working with RTAI, as well as people doesn’t play with RTAI before to have more motivation.

1. PC-based feedback acceleration control using Linux RTAI

ABSTRACT
Linux operative system, extended with the real time application interface (RTAI), makes it possible to realize industrial motion controls. This requires general purpose processors (GPPs) instead of dedicated DSPs or microcontrollers. RTAI offers the possibility of designing and developing motion controls using high level object languages (i.e., Simulink). The main advantages brought using Linux-RTAI and a PC as a controller platform are: very reduced time for development, diagnostics, design of controls; cost reduction offered by the open-source status of the operating system; high availability of the hardware. This paper shows that such a system offers adequate digital programming and signal processing capabilities to make real time motion control applications. An industrial-PC based acceleration control is presented and points of strength of RTAI solution are shown.

2. Industrial motion control applications using linux RTAI

ABSTRACT
RTAI extension to Linux operating system makes it possible to perform Hard Real-Time (HRT) controls using a commercial PC and utilizing open-source code. This paper details a software installation process, along with the suitable hardware chosen for realizing motion controls using Linux-RTAI. Advantages offered by the possibility of designing and developing motion controls using the powerful tools of high level object-languages (i.e. Simulink) are described. It is proven that the combination of Simulink as a development environment and Linux-RTAI PC as a controller platform brings advantages that can be greatly appreciated in industrial motion control applications, such as: very reduced time for development, diagnostics, design of controls; adequate control performance; cost reductions offered by the open-source status of the operating system.

3.Scilab/Scicos and Linux RTAI – a unified approach

ABSTRACT
This paper presents a rapid controller prototyping environment completely based on open source software. GNU/Linux with the RTAI extension is used as a hard real-time operating system. The Scilab/Scicos suite permits performance of all phases of the control system design. A modified Scicos code generator directly generates the C-code for the Linux RTAI environment. Finally, the generated hard real-time task runs as a user space application on a standard PC using the COMEDI drivers to interface with the real plant. A GUI application facilitates the user to interact with the running real-time task (data visualization, data collection, parameters tuning) directly from any PC in the network. All needed software is available on the Web and can be freely downloaded. Some applications are presented to demonstrate the potentialities of the presented suite.

4. A Hardware-In-the-Loop Simulation System of Diesel Engine Based on Linux RTAI

ABSTRACT
In this article, the rapid prototyping technology is used to develop a hardware-in-the-loop simulation system for the diesel engine electronic control unit development. The hardware- in-the-loop simulation is based on Linux RTAI system, an open source hard real-time extension of the Linux Operating System, at low costs and within industrial standards. It exploits standard x86-based computing platforms provided with real-time Linux software in combination with generic computer-aided design software (Matlab/Simulink). One of its main characteristics is that it can automatically generate the real-time simulation code for many target processors, which runs under Linux RTAI operating system.

5.Monitoring applications of electrical and climate data for PV systems using Linux RTAI

ABSTRACT
This work presents the design and development of an innovative system aimed at detecting, recording and transmitting electrical and climate data from a PV field. Data are to be taken both from the PV modules and from the power conditioning system of a given PV field, through appropriate sensors, to monitor: climate data (irradiance, temperature), electrical quantities (voltage, current, power), performance of the PV generator as a function of climate parameters, performance of the power conditioning system over different working conditions. The system will exchange data through a communication network (i.e. Ethernet/TCP-IP) to download data, visualize quantities and operative states. The proposed system is designed to be integrated into any PV field, independently from the plant layout, the inverter type, the presence of preexisting data loggers, sensors, etc. Such a result is achieved using an open architecture, which assures an extremely high flexibility of utilization.

6.Real time distributed control systems using RTAI

ABSTRACT
The paper outlines the design and implementation of the Real Time Application Interface (RTAI) for Linux, as used for high performance local/distributed control systems implemented on low cost off the shelf general purpose computers. Its native lean real time middleware layer is described along with its use in an advanced tool to easily manage and monitor complex networked control systems.

7. RTAI-based execution environments for function block based control applications

ABSTRACT
The IEC 61499 standard has been recently adopted to promote a more flexible development process in the control and automation domain. The standard mainly deals with modeling issues leaving a lot of model execution details open. Different research groups are already working for the development of execution environments for the defined component model, proposing implementations with different execution semantics. This paper discuss the semantics of the execution environment and presents two execution environments, which although independently developed share a similar view of IEC61499 execution semantics and are both implemented over RTAI (real time application interface), a real-time Linux-based platform.

8. Performance Comparison of VxWorks, Linux, RTAI and Xenomai in a Hard Real-time Application

ABSTRACT
We report on a set of performance measurements executed on VMEbus MVME5500 boards equipped with MPC7455 PowerPC processor, running four different operating systems: Wind River VxWorks, Linux, RTAI, and Xenomai. Some components of RTAI and Xenomai have been ported to the target architecture. Interrupt latency, rescheduling and inter-process communication times are compared in the framework of a sample real-time application. Performance measurements on Gigabit Ethernet network communication have also been carried out on the target boards. To this purpose, we have considered the Linux IP stack and RTnet, an open-source hard real-time network protocol stack for Xenomai and RTAI, which was ported to the considered architecture. Performance measurements show that the tested open-source software is suitable for hard real-time applications

9. RTAI-based execution environments for function block based control applications

10. Rapid control prototyping with Scilab/Scicos/RTAI for PC-based ARM-based platforms

ABSTRACT
This document describes three didactic system with a Rapid Control Prototyping (RCP) suite based on Scilab/Scicos and a PC computer. Servomechanisms with wire signal transmission and PID as well as a fuzzy controller are presented. The servomechanism with wireless signal transmission is also described. As the RCP suite based on Scilab/Scicos/RTAI was successfully used in the servo controller development on a PC platform, the concept of a tool-chain for RCP on an embedded platform with ARM processor is discussed. The TS-7300 embedded system with RTAI real-time operating system is described. The changes in Scilab/Scicos needed to interface the generated controller code to TS-7300 are presented. The didactic use and a possible commercial use of the tool-chain is indicated. The didactic use is focused on controllers tuning, friction and long delays influence on servomechanism control and embedded control system development.

Note: They are all papers I have downloaded and read, so I just share it with the one who wants it.

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Introduce to RealTime Application Interface for Linux

admin — Fri, 26 Mar 2010 15:21:19 +0000

Nowadays, people is looking for RealTime solutions for their products, since their tasks have to be done very accurately. One more reason is Linux OS usually to be integrated into embedded IC ( Arm, PowerPC, … ). In term of Realtime OS, there are several wellknown Real-Time OS: QNX, VxWorks, RTAI.

VxWorks comes from WindRiver company, is the most expensive and well supported Real-Time commercial product. It has been used for many years in many famous labratory to do some real-time needed experiments like human interactions, … It costs around 4000$ per license. In additions, WindRiver has a university program which can donate to your university for several licenses for 3 years, read more.

I am not familiar with QNX so just have a look at Wikipedia:

As a microkernel-based OS, QNX is based on the idea of running most of the OS in the form of a number of small tasks, known asservers. This differs from the more traditional monolithic kernel, in which the operating system is a single very large program composed of a huge number of “parts” with special abilities. In the case of QNX, the use of a microkernel allows users (developers) to turn off any functionality they do not require without having to change the OS itself; instead, those servers are simply not run.

The system is quite small, with earlier versions fitting on a single floppy disk.

QNX Neutrino (2001) has been ported to a number of platforms and now runs on practically any modern CPU that is used in the embedded market. This includes the PowerPC, x86 family, MIPS, SH-4 and the closely related family of ARM, StrongARM and XScale CPUs.

Those two QNX and VxWorks for commercial purposes and short-time development products, but, by contrast RTAI is the best choice for one who doesn’t want to spend big money, since it supports a lot of platforms. RTAI stands for RealTime Application Interface for Linux, which lets you write applications and runs it in real time (strict timing constraints) for your Linux distributions. In fact, RTAI is not a RealTime OS, it is just a patch for your Linux distributions since Linux OS itself doesn’t have realtime feature. Like Linux OS, RTAI is totally free and having a big community which can support you during developing your system.The famous and wellknown distributor is Roberto.

RTAI Homepage: https://www.rtai.org/

At this moment, RTAI supports following architectures:

x86 (with and without FPU and TSC)
x86_64
PowerPC
ARM (StrongARM; ARM7: clps711x-family, Cirrus Logic EP7xxx, CS89712, PXA25x)
m68k (supporting both MMU and NOMMU cpus)

The latest version is RTAI 3.8 which was released in 02/16/2010.

How to get started ?

I am sure that you will get a lot of issues during playing with RTAI, so you can get supports from serveral sources:

RTAI website: https://www.rtai.org/
Install RTAI & Comedi & ScicosLab & QRtaiLab on Kubuntu Jaunty
RTAI mailing list: https://mail.rtai.org/cgi-bin/mailman/listinfo/rtai

Note: You need to add RTAI certification in your web browser to view RTAI contents, otherwise you can’t access it.

Some useful articles out there:

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Real-Time Application Interface: RTAI 3.7.1 available

admin — Mon, 15 Jun 2009 15:44:48 +0000

Today, I get email from RTAI mailing list that they announce RTAI 3.7.1 to all users and developers which are using RTAI for their system.

The RTAI 3.7.1 release is available at

It contains:

- Substantial updates to RTAI-Lab (Roberto Bucher):
- A better support to install different versions of Scilab: scilab-4.12, scicoslab-4.3 and scilab-5.1.1
- Addition of new icons to scicoslab pal-trer
- Scilab/Scicos Log added (thanks to Holger Nahrstaedt)
- Support of multiple COMEDI counters and encoders in Scilab/Scicos (thanks to Guillaume Millet)
- Added support for COMEDI comedi_get_subdevice_flags (Guillaume Millet)
- x86 and Powerpc upgrade to Linux-2.6.29
- Various reworks of async Linux servers, including support of mpxed socket calls
- Few fixes of build glitches
- More consistent behavior for self changed priorities (Matthias Richly)

Not in this release but to be noticed are the new Linux Board Support Package supports for RTAI-3.6.2/mcf54455 and RTAI-3.7/mcf5329 available at RTAI home site, contributed by Freescale Semiconductor (Valentin Pavlyuchenko).

In my option, RTAI nowadays they releases new version very often. It can support newer kernel version which in the newer Linux distros.

Get fun!

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How to install RTAI, ComediLib in Ubuntu 8.10, Ubuntu 9.04

admin — Mon, 15 Jun 2009 05:36:16 +0000

Last several months ago, I have done to install RTAI, ComediLib in Ubuntu 8.04. Actually, I have spent a lot of time to config Ubuntu system. It faces a lot of problems but finally it has finished.

Now new RTAI package version 3.7 which supports Linux kernel 2.6.28 has been released with a lot of features:

support for m68knommu (NEW) (Valentin Pavlyuchenko)
upgraded ARM (Torsten Koschorrek)
lots of RTAI-Lab upgrades (Roberto Bucher; note that RTAI now integrates to Scilab 5.1
multi port serial driver with shared interrupts (Renato Castello)
rt_poll on mbx and sems
SMP locks as for Linux ticket way
RTDM support upgrade
improved watch dog
revised COMEDI support, async services and insn list work now
revised Linux sync-async servers
Linux support up to 2.6.28
netrpc 32/64 bits inter operation
shortened locking and timer replay in scheduler
upgraded TLSF mem allocator
rtai-py (python support)
more so called “minor fixes”

Now I base on this tutorials from QRtaiLab, I hope it is better tutorial for Ubuntu 8.04 and Ubuntu 9.10. QRtaiLab is a QT based application, it is better than XRtaiLab. You can see the comparision here.

Packages:

UBUNTU 8.10 (works also on 9.04)

general:
sudo apt-get install cvs subversion build-essential
kernel:
sudo apt-get install kernel-package linux-source libncurses5-dev
rtai:
sudo apt-get install libtool automake
comedi-lib:
sudo apt-get install bison flex
comedi-calibrate:
sudo apt-get install libboost-dev libboost-program-options-dev libgsl0-dev
scilab 4.1.2:
sudo apt-get install gfortran sablotron tcl8.5-dev tk8.5-dev xaw3dg-dev libpvm3 pvm-dev libgtkhtml2-dev libzvt-dev libvte-dev
qrtailab:
sudo apt-get install libqt4-dev libqwt5-qt4-dev

Sources

LINUX (kernel.org)

cd /usr/src
sudo wget http://www.kernel.org/pub/linux/kernel/v2.6/linux-2.6.28.7.tar.bz2
sudo tar xjvf linux-2.6.28.7.tar.bz2
sudo ln -s linux-2.6.28.7 linux

RTAI (https://www.rtai.org) (cvs-Version)

cd /opt
sudo cvs -d:pserver:anonymous@cvs.gna.org:/cvs/rtai co magma
sudo ln -s magma rtai

RTAI (https://www.rtai.org) (tar.gz-Version)

You have to use a Version of 3.7 or newer, because older version are not compatible with gcc 4.3.3!

cd /opt
sudo wget –no-check-certificate https://www.rtai.org/RTAI/rtai-3.7.tar.bz2
sudo tar xjvf rtai-3.7.tar.bz2
sudo ln -s rtai-3.7 rtai

COMEDI (www.comedi.org)

cd /opt
sudo cvs -d :pserver:anonymous@cvs.comedi.org:/cvs/comedi login
sudo cvs -d :pserver:anonymous@cvs.comedi.org:/cvs/comedi co comedi
sudo cvs -d :pserver:anonymous@cvs.comedi.org:/cvs/comedi co comedilib
sudo cvs -d :pserver:anonymous@cvs.comedi.org:/cvs/comedi co comedi_calibrate
sudo cvs -d :pserver:anonymous@cvs.comedi.org:/cvs/comedi co comedi-nonfree-firmware

Scilab 4.1.2 (www.scilab.org)

cd /opt
sudo wget http://www.scilab.org/download/4.1.2/scilab-4.1.2-src.tar.gz
sudo wget http://www.scilab.org/download/4.1.2/man-eng-scilab-4.1.2.zip

QRTAILab (www.qrtailab.sf.net) (svn – version)

cd /opt
sudo svn co https://qrtailab.svn.sourceforge.net/svnroot/qrtailab/trunk qrtailab

QRTAILab (www.qrtailab.sf.net) (tar.gz – version)

cd /opt
sudo wget http://downloads.sourceforge.net/qrtailab/QRtaiLab-0.1.6.tar.gz
sudo tar xvzf QRtaiLab-0.1.6.tar.gz

Installation

Kernel

PATCH Linux Kernel

cd /usr/src/linux
sudo su
patch -p1 < /opt/rtai/base/arch/x86/patches/hal-linux-2.6.28.7-x86-2.2.06.patch

Configure Kernel

At first you should find out your architecture:

dpkg –print-architecture

for i386:

A sample config-file for i386 is available from here

cd /usr/src/linux
sudo wget http://hart.sourceforge.net/files/config-2.6.28-rtai_i386
sudo cp config-2.6.28-rtai_i386 .config

for amd64:

cd /opt sudo tar xvzf scilab-4.1.2-src.tar.gz sudo unzip man-eng-scilab-4.1.2.zip sudo mv man-eng-scilab-4.1.2 scilab-4.1.2/man/eng/ cd scilab-4.1.2 sudo ./configure --with-gfortran --with-tk --with-gtk2 sudo make all sudo ln -s /opt/scilab-4.1.2/bin/scilab /usr/local/bin/scilab

QRTAILAB

If you use a tar.gz-version please replace qrtailab with qrtailab-x.x.x (x.x.x is the number of your installed version )

cd /opt/qrtailab

Edit qrtailab.config and replace ‘/usr/include/qwt/’ with ‘/usr/include/qwt-qt4/’ and ‘-lqwt’ with ‘-lqwt-qt4′. Here is my qrtailab.config content:

##############################################
# library path
##############################################
DEPENDPATH += . /usr/local/qwt-5.2.0-svn/lib
INCLUDEPATH += . /usr/realtime/include /usr/include/qwt-qt4/
LIBS +=  -lqwt-qt4
#CONFIG += debug
#############
# do same tests
############

#CONFIG += QRLtests

Now we are going to compile QRtaiLab:

sudo qmake-qt4
sudo make
sudo make install

It is demo running RTAI, QRtaiLab on Ubuntu 8.04 I did before:

Click here to view the embedded video.

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