Unmanned Systems Technology 033 l SubSeaSail Gen6 USSV l Servo actuators focus l UAVs insight l Farnborough 2020 update l Transforma XDBOT l Strange Development REVolution l Radio telemetry focus

62 Digest | Transforma Robotics XDBOT technological foundations. These included a UGV being developed for autonomous mobile spray-painting (the Pictobot) and another UGV being developed to perform mobile quality inspections on finished walls and structures (the Quicabot). Aspects of both systems were combined to complete the initial XDBOT prototype, in late March. This was the version that subsequently received so much attention in the local and international news media. The company first tested the XDBOT at NTU, given its proximity to Transforma’s facility, the fact that few staff were still on site there and that clean conditions were needed in which to work. On April 8 though, the Singaporean government instituted its ‘circuit breaker’ measures. Most of the economy was locked down and people were ordered to stay indoors (except to procure essentials). Transforma’s team therefore continued their programming, data analysis and CAD work at home, communicating with each other remotely. “Singapore was locked down for two months, and in the middle of that, on May 1, we started work on the XDBOT’s second [and current] prototype,” Prof Chen says. “This has a very slimmed-down chassis compared to the first version. It too took six weeks to develop, with actual construction starting on June 2 after the circuit breaker was lifted, and we trialled it in Singapore General Hospital on June 19.” At the time of writing, Transforma was developing its third version, which will be almost identical to the second prototype but with a few chassis alterations to protect it against moisture and dust, and some weight reduction. Series production of that version is expected to follow after sufficient testing has been carried out. The chassis has largely been fabricated in-house, with key aspects of the electronics supplied by a mixture of local and international companies. With local manufacturers having returned to work by June, Transforma also had no problems with procuring the parts they needed from international suppliers. Degrees of autonomy The company recognises that, depending on the regularity with which a location needs to be disinfected, the required mode of operation by the XDBOT’s end- users will change. That has driven it to develop a spectrum of autonomy levels across which the UGV can be used, with ROS (Robotic Operating System) serving as the middleware for software installation and programming. The first mode to be trialled and tested was semi-autonomous. Here, a remote operator controls the vehicle’s traction speed and steering, typically from a handheld GCS connected by a 2.4 GHz wi-fi link. Meanwhile, the spraying device acts with full autonomy, scanning ahead of the UGV’s path and recognising high-frequency touch surfaces via an integrated camera, using embedded feature-recognition software from Transforma’s partners working in AI. It targets and prioritises these points for spraying, and its software manages the electromechanical actuations for height and angle to aim the nozzle as needed. Semi-autonomous mode would be appropriate when a modicum of human situational awareness is needed – as in public spaces after large-scale gatherings where there are pedestrians – and where August/September 2020 | Unmanned Systems Technology The current version of the XDBOT has been redesigned for differential steering, and has a narrower chassis, for easier navigation in rooms and corridors