CUHK Passions and Pursuits

21 R obots are strong, durable and increasingly smart. They are precise. Science fiction tells us they’ll eventually take over the world. But there’s one thing that they can’t do well: see. Robots can be equipped with cameras, but there’s normally a human set of eyes on the end. Robots that carry out free-flowing movements instead of repetitive tasks must be controlled as a result. That is an obstacle CUHK robotics engineer Liu Yun-hui has overcome. He has pioneered a novel solution that gives robots ‘eyes’ using what is known as vision-based 3D motion control. By programming a robot with that sort of vision, it can operate independently in a factory, warehouse and even the operating theatre, assisting surgeons. The main reason that robots can’t see well is that they have trouble with depth perception. Humans assess depth naturally and instantaneously. But it is very hard for a robot to judge quickly and accurately how far apart objects are, and as a result even to place itself in a room. Whatever it looks at appears like a flat canvas. Professor Liu’s vision-based 3D motion control allows robots to place themselves without using a Global Positioning System, which does not function well indoors. It also allows robots to manipulate soft objects that bend under pressure, that are ‘deformable.’ Professor Liu has applied his work to medicine. He and his team have created two robotic systems in conjunction with the Prince of Wales Hospital that are in testing. One helps with nasal surgery by maneuvering an endoscope intelligently. At the moment, a surgeon must manipulate the endoscope manually with one hand, while the surgeon’s other hand performs surgery, which is obviously inefficient. The new robot can move on its own and be manipulated using a wearable control pedal on the doctor’s foot, freeing up both hands. ‘The idea is to make the surgeon and robot collaborate together,’ Professor Liu said. He believes robots will in the future be able to perform basic medical procedures entirely independently. The issue is whether they will be allowed to do so. Robots enabled with vision can operate independently in a warehouse or factory floor. Working with CUHK’s extension at the Shenzhen Research Institute, Professor Liu has created a ‘smart forklift ’ equipped with his control system. The smart forklift is now moving around parts in a factory in Jiangsu Province making components for high-speed trains. The applications, if not quite endless, are very extensive. Professor Liu wants to see his vision system applied to baggage handling, the manipulation of soft substances such as food, and services such as care for the elderly. ‘There are still many problems to be solved to make robots work reliably and intelligently in the natural environment, like human beings,’ he said. Let There Be Sight Liu Yun-hui gives eyes to robots c c One surgery robot helps with nasal surgery by maneuvering an endoscope mechanically