Peking University, June 15, 2012: A team of over 10 students led by Associate Professor Xie Guangming, director of Intelligent Control Lab, College of Engineering, Peking University (PKU) took part in 2012 Underwater Robot Competition of China at Nanjing University from May 19 to 20. Apart from their excellent performance in the competition, an amphibious robot named “Chinese Dragon” newly developed by the lab made its debut and became the center of the attention. Liu Ao, the student leader of PKU team readily agreed to share more details about the mysterious robot.

PKU team from COE at the competition

The amphibious “Chinese Dragon” is a four-foot robot which can shift between land mode and water mode, imitating salamander, an amphibian in the nature. At the initial stage of designing, the structure of “four feet and five segments of body” was determined through repetitive observations and analysis of how a salamander moves, and the optimal length of the body and that of the foots joint are decided through continuous data collecting from experiments and analysis.

the amphibious "Chinese Dragon"

In terms of power, “Chinese Dragon” is equipped with 9 steering engines driving the 9 joints respectively. The power is supplied by 13 nickel-hydrogen batteries. To facilitate the charging process, plugs of different types have been installed at the end of the body to adapt different voltages of charging supply.

In terms of mechanical structure, aluminum materials are used to reduce the weight of the robot as well as the resistance it encounters when walking on land. The design also makes it possible to float on water and swim through coordinated swaying of different parts of the body. The two steering engines at the first joint of the head enable the head to move up and down so as to move upwards and downwards in water. A fish tail made of hard rubber can sway regularly with the steering engine at the tail and thus propel the robot to move in water, the speed of which can be adjusted by the frequency of the swaying. Water-proof, flexible rubber skin is attached to each joint to ensure that it works in a supple way.

"Chinese Dragon” has two kinds of control platforms, one is a converted remote control panel and the other is developed on a VC platform. Both control platforms share the same communication protocol, transmitting control signals via wireless channel. At the same time, the main board inside the robot also sends out feedback signals. This kind of mechanism makes it ideal to communicate between human and the robot.

Through a year’s R&D work, “Chinese Dragon” has now been able to fully function in both land mode and water mode and shift real-time between the two modes. Exterior sensors have been added to improve its performance in mode shifting and environment detecting. Also the control methods of the steering engines have been modified so that the head can sway more smoothly and elegantly. It is now a much better complete piece than the first prototype.

students who made the robot

The group is determined to improve the robot to achieve its best performance by doing sufficient experiments and theory proving. The continuous process of experimenting, modifying and then experimenting again is time-consuming but it did bring about breakthroughs in its performance. In the future, they will carry on the good work and develop new functions for the robot to make it move better, in a way as similar to the living creature as possible.

One day, the amphibious “Chinese Dragon” will be a star at PKU.

Extended Reading

College of Engineering excels in 2012 Underwater Robot Competition

Reported by: Chen Long
Source: Intelligent Control Lab, College of Engineering