Skyscraper window cleaning and the inspection and maintenance of glass curtain walls hundreds of meters above the ground remains the most dangerous job in the United Kingdom and in many other countries around the world.
They're among the most dangerous jobs in the United States. In New York, famous for its many and fearsome skyscrapers, some 15 window cleaners or maintenance people are involved in accidents related to this dangerous job each day, injuring most and killing some.
The three tallest buildings in China -- the Shanghai Tower, the Ping An Finance Centre in Shenzhen and the Guangzhou CTF Finance Centre -- each stand over 500 meters tall.
Traditionally, window cleaning and high-rise window maintenance are still conducted bthe y humans sa uspended above ground on wobbly gondola systems that can be very dangerous, costly and inefficient.
Last week, however, Chinese researchers at the Shenyang Institute of Automation (SIA), Chinese Academy of Sciences revealed a promising -- and far safer -- alternative to these dangerous jobs. They've developed an aerial contact aerial manipulator system with high flexibility and strong mission adaptability. SIA, whose research focuses on robotics, intelligent manufacturing and opto-electronic information technology, also said its new aerial robot represents a major advance in safety and efficiency.
The aerial robot is equipped with a single-degree-of-freedom manipulator cube-frame end effector. Compared with general wall-climbing robots, the one from SIA is capable of avoiding obstacles and even jumping over grooves on wall surfaces.
It can also conduct interactive operations while in flight. More important, the system was designed so that its contact force can be controlled precisely without any force sensors.
"How to control the force is considered the most difficult problem, since flying robots usually are sensitive to external force," said Meng Xiangdong, the robot's designer.
Meng said the research team first had to make a flying robot with closed loop control behave like a regular spring system. He said the elastic coefficient could then be easily changed by altering the control parameters.
"It means that we can take the robot as a spring system so that the contact process can be safe enough."
The research team also tested the system. In one of these tests, they fixed a light switch to a wall, then had the robot press the switch to turn the light on and off. The robot was able to safely and smoothly operate the switch via precise force control.
In another experiment, the robot smoothly moved along a glass wall, exerting fixed pressure. The robot then used a pen attached to the end of the aerial manipulator to write "SIA" - for Shenyang Institute of Automation - on the glass wall.
"In the near future, we might see an extensive use of this new system in large infrastructure maintenance, and other special applications, such as scientific sampling," said Meng.
