Throughout the TORONE project, that main aim has been to create a robot on which sensors are attached to perform in-situ analysis and mapping of radioactive sites throughout the world. Because of this, one of the main focuses of the project has been the choice of robot used to house these sensors.
From the conception of the project, the focus has been using a stable platform that can meet a multitude of criteria: Able to hold multiple sensors, easily controllable, have in built capabilities to record its travel and location, and dust resistant due to the nature of the environments in which it will be operating.
The first steps in this process included trying to create a ‘proof of concept’, so a platform in which the sensors could be mounted and test the location mapping, as well as starting to develop automated processes. This involved the use of the ‘Turtlebot2’ from Yujin Robot, which has been used over recent months to demonstrate the capabilities of the project, such as helping to demonstrate 3D Lidar mapping, as well as radiation detection during tests.
The Turtlebot (pictured left) is loosely based on a ‘Roomba’ type robotic vacuum cleaning robot, with a small circular segment at the base which houses the motors, batteries and electronics. The shelves above the base allow for sensors to be mounted to the robot. Though a very capable and simple robot, it is not able to handle the heavy weight of some of the desired instruments being designed for TORONE, moreover, it has very little ground clearance. Being close to the ground is great for a vacuum cleaner, but risks getting stuck on obstacles in cluttered nuclear environments.
In order to fit in more with the project brief, a more rugged, smarter, and dust resistant robot has been acquired. The Clearpath Jackal (pictured below) will provide a more robust and larger platform on which the sensors can sit, boasting a payload weight of 20 kg, and greater ground clearance. As both the Turtlebot and the Jackal use the Robot Operating System (ROS), getting the new robot working has been more streamlined, allowing for the algorithms used for navigation and obstacle avoidance to be copied directly over. With the TORONE project hoping to reach nuclear environments worldwide, a specialised carry case has been commissioned in order to allow the robot to be transported on commercial air travel. Along with this, modular batteries which are safe for air travel have had to be created in order for them to be transported, while still providing the same required output.
Furthermore, as the TORONE project wishes to use a range of different sensing capabilities, it is required to easily swap and change sensors in the field. A special mount was required, as well as easy to use methods of attaching sensors had to be looked in to in order to provide the easiest user experience while setting up the platform, but not compromise on mechanical strength. It was settled that the most secure and easy option was to Schunk FWS manual tool change adaptors designed for changing tools on robot arms. They are secured using a twist motion, locking in place quickly, but also easy to remove, speeding up the disassembly process, while also making it easy to change sensors when required.
As the project approaches deployment into radioactive environments the Clearpath Jackal will offer a more rugged platform on which bespoke instruments can be utilised, but a heartfelt thanks goes out to the adorable Turtlebot2 and all the progress it has allowed the project.
Dr Andrew West