Department Publications

In planetary rover missions, there exist severe communication constraints, which make it difficult to control rovers from a long distance (eg from the Earth). Therefore, there is a need to address the important issue of onboard local autonomy to allow deployed rovers to make their own decisions, which contributes to increased scientific return. To achieve this, robot algorithms should be constantly improved and innovative hardware mechanisms should be sought. In this context, simulators play a major role as they can help researchers develop novel technologies even without having access to expensive hardware components. In this paper, the authors present ongoing work on the planetary rover simulation environment that have been developed for testing and validating autonomous navigation of a planetary exploration rover using opensource tools. The simulation system has been developed using Gazebo, an open source 3D multi-robot simulation framework and ROS. The developed simulator provides an essential tool for visualization of the rover functionality for many state-of-art algorithms.

This paper introduces techniques for designing and implementing remotely controllable outdoor robots with the ability to localize itself while traversing in hazardous environments. The robot platform designed is a semi-autonomous tiller modified as required by the application. Localization based on wireless sensor network which has been a research interest of is addressed here with the use of Zigbee protocol. A Kalman filter was applied for the initial gathering of training data. For the improvement of the accuracy of position estimation, a fuzzy inference system is introduced. An extended Kalman filter is applied at the end in order to fuse the encoder data with the filtered RSS data. Results prove that a metric accuracy varying from 2m to 10m is achievable depending on the location of the robot with respect to the sensor nodes.

Developing autonomous mobile robots that can coexist with human in populated environments is still considered a big challenge. To address this problem the authors propose a novel scheme to assist mobile robots by providing localization information externally. This scheme combines the autonomous navigation and target tracking research fields to arrive at a structured assistance system for autonomous mobile robots. In the proposed scheme, the environment is sensed using a laser range finder and a camera based sensor unit. Using the Rao-Blackwellized particle filter technique, the robots that need assistance are continuously tracked. In contrast with conventional laser range finder based tracking systems, the placement of the sensor is changed to a level above average human height and the mobile robots are modified by attaching a cylindrical pole. The experiments showed the validity of the proposed …

第 22 回アストロダイナミクスシンポジウム (2012 年 7 月 30-31 日. 宇宙航空研究開発機構宇宙科学研究所 (JAXA)(ISAS)), 相模原市, 神奈川県