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94 Digest | Clearpath Robotics Jackal in Clearpath’s Husky. That enabled the team to transfer knowhow in setting up the PC, microcontroller, motor controller and power systems, and allowed it to set up the software to the latest standards in ROS and make use of its navigation demo code relatively easily. Jackal in the wild On sale since 2014, the Jackal has proved popular with universities and military r&d organisations. MIT, for example, has developed a configuration capable of navigating autonomously among crowds of pedestrians. Elsewhere, a team at the Nanyang Technology University in Singapore has produced a building quality assessment robot for use on construction sites, while a group at the University of Virginia has configured a Jackal to survey the historic Blue Ridge railway tunnel ahead of its reopening as a tourist footpath. On a more military note, the US Naval Surface Warfare Center ran a competition in which teams used Jackals to developed fully autonomous robots that could navigate an area with obstacles to detect and identity a number of targets and shoot at them with Nerf guns, which fire harmless foam rubber darts. In a similar application, the US Army Research Laboratory tested a robot’s ability to act as a soldier’s team mate to check out potentially dangerous situations. This involved learning tactical behaviours from a few human demonstrations, such as how to navigate from point to point while staying near the edge of a road, and how to move covertly using buildings as cover. By 2013, Edwards notes, it was clear that open source software in general and ROS in particular were becoming important in robotics research. He adds that Clearpath’s CTO Ryan Garipey and early software team member Mike Purvis had close ties with the ROS community and contributed to the software’s development. Navigation and autonomy Clearpath offers indoor and outdoor navigation software that can be used on most of its platforms, and the Jackal comes with example configurations of ROS navigation packages. The company’s Autonomy Research Kit (ARK) indoor navigation software uses simultaneous localisation and mapping, processing information from one Lidar on the front of the vehicle and another on the back. This software has been developed by sister company Otto Motors, which uses it to navigate materials-handling robots around large factories and warehouses. Edwards emphasises that the ARK uses path planning, control and localisation technology that is controlled through a web-based or ROS interface. Clearpath writes its own outdoor navigation software, he says, using some elements from the indoor package including the model-predictive path follower while relying on GPS for localisation, with precision enhanced by real-time kinematics (RTK) functionality. The outdoor package is a newer product that, for the moment, uses a GUI built using the free and open source Qt (pronounced ‘cute’) widget toolkit. The GUI runs on Linux, and enables users to set up networks of paths made up of waypoints and to ‘call’ any of their own functions as a task in the software. A typical set of instructions might be to point a pan-tilt-zoom camera at a target location and record an image. “We’ve found that having RTK heading data from a dual antenna GNSS system such as the Swift Navigation Duro gives great results with our ground vehicles,” Edwards says. “This software is also capable of re-planning paths around obstacles and can be augmented with other navigation sensors such as the Intel T265 tracking camera.” Control and comms For most users, the GCS is simply their own laptop, on which they can run the RVIZ configuration of the Jackal that enables them to visualise sensor data and to access the GUI of the navigation packages. RVIZ is the 3D visualisation tool for ROS. While web- and Qt-based GUIs that come with some of the navigation packages display an overhead view of the map, sensor data and paths, for many users the Jackal interface is the Linux command line, which they use to execute the software they have developed for the UGV. The most common comms system used with the Jackal is 802.11 wi-fi, although there is the option of a Microhard PX2 wi-fi radio which, when used with April/May 2020 | Unmanned Systems Technology The physical interface for payload hardware such as cameras and so on consists of adapter plates that bolt to the deck