Latest entries for tag 'project'

MongoDB Logging presented at ROSCon 2013

Last weekend some of us went to ROSCon 2013 to listen to all the great stuff happening in the ROS eco system and present some of our own work.

The item which probably gained most attention was the presentation and announcement of the MoveIt release. It's definitely something to look into and a platform to consider in the future for doing mobile manipulation. Another interesting presentation was on the Robot Web Tools. While the presentation's balance leaned a bit from technical to fancy (probably a web people thing) it showed some very nice integration possibilities. Depending on how platform agnostic it is it could be re-used for Fawkes. Another thing to look into is tf2. It seems to finally get rolled out in ROS, making it worthwhile to consider it for integration again.

A particular thing that was talked much about was ROS 2.0, the magic next version which solves everything and makes all dreams come true -- sort of. It shows a lot of promise and the open process by which its design decisions should be made is appealing. Some of the things that were discussed indicate that ROS 2.0 might be much easier to integrate with other non-ROS software.

On our end Ingo Lütkebohle (Bielefeld University) and Tim Niemueller(RWTH Aachen University) presented data recording and evaluation techniques. The MongoDB-based logging received quite some attention. It seems to be time to backport the advancements we made on the Fawkes logger version back to ROS. Additionally the RobotMetaLogger was presented that might benefit by supporting the MongoDB-logger as an input source.

On-line Use of Recorded Data from Database

On particular example we presented is the use of data recording to remember point clouds and other data. Certain times of observation points are recorded during a run. Then later the data and associated transforms is restored and the point clouds are merged to fill shadows and occlusions in the data for a complete perception run. Below are some screenshots of the visualization documenting the process. You can find a video of the process in our recent video on deliberative active perception employing hybrid reasoning.

Posted by Tim Niemueller on May 16, 2013 13:36

Video about Hybrid Reasoning on the PR2

We have posted a video introducing the DFG Research Unit on Hybrid Reasoning in general, and the C1 Robotics sub-project in particular. We present a demo on the PR2 robot that will serve as a baseline system and testbed for further research. The C1 project is a joint effort of the Research Lab Autonomous Intelligent Systems, University of Freiburg, the Knowledge-Based Systems Group, RWTH Aachen University, and the Research Group Foundations of Artificial Intelligence, University of Freiburg.

The Hybrid Reasoning C1 Robotics project investigates effective and efficient ways to combine quantitative and qualitative aspects of knowledge representation and reasoning. In the video in particular, we implemented a baseline system to work on active perception. We want the robot to reason on its current beliefs and if necessary decide what to do to improve them.

The base system was based on ROS for the PR2 and the TidyUpRobot demo from Freiburg. The PDDL-defined planning domain was adapted for action planning in our active perception scenario. The perception system was based on Fawkes' tabletop-objects plugin and the generic robot database recording with MongoDB. The planner decided on a sequence of positions to move to and waited a short time at each position and noted the timestamp at such a position. The database recording was running all the time, storing in particular transforms, images, and point clouds of the Kinect. After each position, the pcl-db-merge plugin was triggered by the planner as another action to merge and align the point clouds. The data for the recorded time stamps was retrieved from the database. The initial point cloud offset estimate was based on the robot's AMCL ( Fawkes port) pose information (at the respective recording time of the point cloud). Then, the point clouds were further aligned using pair-wise ICP alignment (implemented using PCL). The perception pipeline itself was improved to determine cylinder-shaped objects like certain cups. The pipeline was run on the merged point clouds, eventually leading to better results because occlusion shadows and incomplete object shapes had been resolved by taking data from multiple perspectives into account.

In the future, we want to integrate the system with Readylog to model the belief states and reason on their current quality.

The Fawkes related code is available in the timn/pcl-db-merge and abdon/tabletop-recognition branches. The planning code is in the hybris_c1-experimental branch of the alufr-ros-pkg repository.

Posted by Tim Niemueller on March 18, 2013 14:59

Generic Logging to MongoDB

Autonomous mobile robots produce an astonishing amount of run-time data during their operation. Data is acquired from sensors and actuator feedback, processed to extract information, and further refined as the basis for decision making or parameter estimation. In today’s robot systems, this data is typically volatile. It is generated, used, and disposed right away. However, some of this data might be useful later, for example to analyze faults or evaluate the robot’s performance. A system is required to store this data as well as enable efficient and flexible querying mechanisms.

We have created systems based on the document-oriented, schema-free database MongoDB that is able to store any and all data transmitted via Fawkes blackboard interfaces or ROS topics. A particularly important property is that the interface or message type structure is inherited by the database document, thus allowing selective queries on the stored data. By creating appropriate indexes access is also very efficient. The architecture has been implemented and released as Open Source software for Fawkes and ROS.

This work has recently been accepted for publication at IROS 2012 in the paper "A Generic Robot Database and its Application in Fault Analysis and Performance Evaluation" (Niemueller, Lakemeyer, Srinivasa). The work has been conducted in a cooperation of the Personal Robotics Lab at The Robotics Institute of the Carnegie Mellon University and the Knowledge-based Systems Group of the Computer Science Department of the RWTH Aachen University.

The data can open the door to a wide array of applications, two of which we sketch in the paper. For one, we develop a model of robot data processing and make use of this model to guide our way to manual data-driven fault analysis. For another, we use the MapReduce paradigm to query the data for performance data like number of successful executions and average run times of the behavior system for a particular time range.

The project is described in detail on the Generic MongoDB logging project page.

Posted by Tim Niemueller on July 31, 2012 18:24