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

64 The sprayer’s current gimbal mechanism can tilt from -45 º to 45 º vertically, and 270 º horizontally. A gantry- like system mounts the sprayer gimbal and electromechanically elevates it to meet the range needed for spraying prioritised points for disinfection. This system has been deemed far more useful – and much simpler – than a z -axis rolling actuator. “We are very familiar with a range of industrial robots, and the third degree of freedom would be useful for painting, so you don’t visibly miss any spots,” Prof Chen says. “For disinfection though it isn’t critical, because with the system we’ve set up the only important points of orientation are direction and distance.” He further explains that the XDBOT incorporates an electrostatic spraying capability to overcome the aforementioned problem of needing to cover and surround objects such as doorknobs and railings with disinfectant. “It is not so much a robotics problem as a fluid mechanics problem,” he remarks. “Luckily though, we have students and interns from NTU who specialise in this area. “When the fluid particles leave the nozzle, they do so with a negative charge. As they diffuse through the air, they repel each other to ensure a wide area of effect, but as they encounter the object they’ve been propelled towards, they’ll be attracted towards it, while still maintaining something of an equal distance from other droplets. “That causes them to wrap around objects, so the robot ends up distributing droplets with a consistent and comprehensive coverage. Electrostatic technology is used in spray-painting as well, but it’s perhaps even more useful here because disinfectant doesn’t need to be sprayed as thickly or visibly as paint on walls.” Power and motion Although exact operations will differ between locations, the XDBOT typically moves at 1 m/s (3.6 kph). Prof Chen notes however that it can travel much faster. “1 m/s is the ISO standard for these kinds of robots in hospital environments. That speed still means we can disinfect a normal 20 m 2 hospital room in 5 to August/September 2020 | Unmanned Systems Technology Dimensions: 120 x 45 x 45 cm Empty weight: 50 kg Operating speed: 1 m/s Max speed: 4 m/s Payload: 10 litres of disinfectant Power: lithium-ion battery Drive: differential wheel-hub motors Some key suppliers Lidar: Slamtec Camera: Intel Electric traction motors: Shen Zhen Zhongling Technology Machine vision: Hand Plus Robotics Mobile device interface: Maju Robotics Specifications An Intel Realsense D435i depth camera is fitted on the nozzle, and embedded with AI from Hand Plus Robotics to recognise where to spray The electrostatic sprayer enables wide dispersion and equal distribution of disinfectant droplets around surfaces and objects