The goal of the RoboShop project is to make a robot for services into a shopping mall. From the hardware point of view, we are using two wheeled robots, equipped with a laser SICK 300 range finder, as well IR and sonar telemeters (see Picture 1). Each robot has a pole that is about 1.5 m heigh. It holds a tablet PC and Pan/Tilt camera.
Picture 1: Robots we use for the RoboShop project
On the software side, we have chosen the ROS middleware. The rational behind this choice is that ROS is backed by an active community, structured around Willow Garage and more recently the Open Source Robotics Foundation (OSRF). On the programming side, we took the reflective language Pharo. As Object-Oriented experts, we believe that Pharo is among the best (if not THE best) object-oriented programming language. Besides, it’s available under a free software license, and it’s community (backed by the INRIA french public research organization dedicated to computer science) is continuously improving it.
The first step was to develop a ROS client in Pharo: PhaROS = PHAro + ROS (initially named RoSt). So far, we have a first complete, running version. We have also developed a ROS node to control our robot. As a first validation, we drove the robot inside our lab and make it build a map (see Picture 2). That was also an opportunity to test our client with a third party ROS node, namely gmapping. We fed this Synchronous Localization And Mapping (SLAM) algorithm with data from the laser embedded on the robot.
Picture 2: Our lab’s map built by a robot
We are currently working on automatic map construction. The robot should be able to roam autonomously to build the map. This will lead us to test other parts of our infrastructure. Ultimately, the robot should be able to navigate in the building based on the existing map. It should be able to plan its trajectories to reach it destination while avoiding obstacles even if they are not on its initial map. Such obstacles include moving ones such as people or other robots.
During the execution of object-oriented applications, several millions of objects are created, used and then collected if they are not referenced. Problems appear when objects are unused but cannot be garbage-collected because they are still referenced from other objects. This is an issue because those objects waste primary memory and applications use more primary memory than they actually need.
Relying on the operating system’s (OS) virtual memory is not always enough since it cannot take into account the domain and structure of applications. At the same time, applications have no easy way to parametrize nor cooperate with memory management.
In our latest paper published in JOT, we present Marea, an efficient application-level object graph swapper for object-oriented programming languages. Its main goal is to offer the programmer a novel solution to handle application-level memory. Developers can instruct our system to release primary memory by swapping out unused yet referenced objects to secondary memory. Our approach has been qualitatively and quantitatively validated. Our experiments and benchmarks on real-world applications show that Marea can reduce the memory footprint between 23% and 36%.
This end of the year comes with good news. Our research on robotic exploration and mapping received a two years funding from the Région Nord-Pas de Calais for a proposal entitled: CAIRE. This project that will be kicked off in 2013 involves two other partners: the RMoD team from INRIA Lille, and the Telice team from the IEMN lab of Lille.
The goal of the CAIRE project is to propose a methodology as well as an infrastructure for developing modular software to control robot for building maps of unknown buildings. One originality of our approach is that we fully rely on dynamic languages and more specifically on the Pharo reflective language. Dynamicity enables fast development and eases debugging. Besides, we rely on reflective and meta-level facilities for building tools and adapting the language to fit our needs.
Research we will be conducting in the CAIRE project will complement our previous work on cooperative exploration of unknown terrain using a fleet of robots. CAIRE is also related to our ongoing project RoboShop which aims at experimenting with robots in a shopping mall. In both projects we are using human size wheeled robots. They also share the same middleware: the de facto standard ROS, from the Open Source Robotics Foundation.
Last october the 29th, Mariano Martinez Peck successufuly defended his PhD entitled “Application-Level Virtual Memory for Object-Oriented Systems“. The jury agreed on the importance and the quality of the contributions that were published in different journals and conferences. If you are interested learn more, you can find below the slides of the defense, as well as the video recording of Mariano’s talk.
I’m happy to announce the arrival of a new colleague: Dr. Jannik Laval.
Officially, Jannik started working for our team since Friday 2nd november 2012. That was a Pharo sprint day hosted by our partner the RMoD INRIA Lille team. This was the opportunity to revive our dormant project: OCEAN. Luc Fabresse, Jannik Laval and my self are the main contributors of this new network library for Pharo. We worked a on it while Jannik was doing his PhD. An now that he is back, we have new energy to get this project done.
However, the main effort that we all concetrate on is Robotics. With the rest of the CAR team, we target models, software infrastructures and tools to ease the development of control architectures for robots. We expect to produce soon some cool demos.
As a response to a question in the Pharo-dev mailing list, Esteban Lorenzano explains how to make an iOS app that makes use of Pharo. There should be soon a web page on the Pharo web site that summarizes this and provides other details. In the meanwhile, I would like to share with you this solution. Note that Esteban also announced that in a couple of weeks there will be a jenkins job to build iOS VMs.
Assuming that you already has in your system:
1) Xcode (I’m using version 4.4)
2) CMake (I’m using version 2.8.8)
And assuming also that you already has an iOS development user.
For use pharo in your iPad you need to follow the following steps:
1) clone https://git.gitorious.org/~estebanlm/cogvm/cog-osx.git
2) in ./image dir prepare a VMMaker image (using pharo 1.4):
Dr. Luc Fabresse, Ecole des Mines de Douai, Université de Lille Nord de France (co-supervisor)
Dr. Noury Bouraqadi, Ecole des Mines de Douai, Université de Lille Nord de France (co-supervisor)
You’ll find below a summary of the thesis:
Application-Level Virtual Memory for Object-Oriented Systems
During the execution of object-oriented applications, several millions of objects are created, used and then collected if they are not referenced. Problems appear when objects are unused but cannot be garbage-collected because they are still referenced from other objects. This is an issue because those objects waste primary memory and applications use more primary memory than what they actually need. We claim that relying on operating systems (OS) virtual memory is not always enough since it is completely transparent to applications. The OS cannot take into account the domain and structure of applications. At the same time, applications have no easy way to control nor influence memory management.
In this dissertation, we present Marea, an efficient application-level virtual memory for object-oriented programming languages. Its main goal is to offer the programmer a novel solution to handle application-level memory. Developers can instruct our system to release primary memory by swapping out unused yet referenced objects to secondary memory.
Marea is designed to: 1) save as much memory as possible i.e., the memory used by its infrastructure is minimal compared to the amount of memory released by swapping out unused objects, 2) minimize the runtime overhead i.e., the swapping process is fast enough to avoid slowing down primary computations of applications, and 3) allow the programmer to control or influence the objects to swap.
Besides describing the model and the algorithms behind Marea, we also present our implementation in the Pharo programming language. Our approach has been qualitatively and quantitatively validated. Our experiments and benchmarks on real-world applications show that Marea can reduce the memory footprint between 25% and 40%
After an experiment with MediaWiki, we chose to switch to WordPress. We prefer this latter because we get quickly a nice look and feel. Even if WordPress is not a wiki, we can still collaboratively fill it with contents. One can easily create and edit pages. The blog part of it eases sharing our team’s news, and other stories about our experiments especially the cool ones with robots. Stay tuned!