Bionic intelligent experimental team of Northeast University : from simulation to reality machine turtle 

As a bionic underwater robot, the robot turtle can make full use of its bionic structure and bionic movement to interact with the environment and other robots or creatures, breaking through the problems of clumsy mobility and poor concealment of traditional underwater submersibles, and has received extensive attention. In order to enable the bionic machine to perform tasks in the water environment, it is necessary to find a new motion control method. In recent years, the vigorous development of science and technology has provided new vitality for robots. However, due to the complex coupling motion of the turtle in the swimming process, how to decouple the analysis and design a single steering gear multi-degree-of-freedom control fin movement in the real world is still a challenge. 

Recently, it has been learned that the research content of the bionic intelligent experimental team of Northeastern University is a kind of motion control of single-drive multi-degree-of-freedom robot turtle from simulation to reality. The expected motion effect has been obtained in the simulation, and the prototype in the real world has achieved satisfactory performance. 

The bionic robot turtle can control the swing motion and swing motion of the turtle 's wing limbs only through the rotation effect of a steering gear, the hydrofoil and webbed wing motion effect of the bionic turtle. In the real world, spatial motion is realized by a simple two-dimensional swing mechanism combined with an underactuated mechanism. By using the underactuated mechanism, the propulsion efficiency of the bionic turtle wing limb can be increased by 50 %, and better motion effect and performance than the traditional bionic machine can be obtained. 

Further, the fins are propelled by the same actuator. The flapping phase of the two fins is adjusted to be consistent before the motion, which can make the fins in the same frequency and motion attitude, and improve the propulsion efficiency. As an auxiliary propulsion device for bionic turtles, webbed wings can reduce the complexity of the control system and reduce the mass by using a single actuator. With a reasonable mechanism, it can well imitate the motion posture of webbed wings when turtles accelerate swimming. Swim to expire at the desired speed.

      The team 's previous generation of robots has been tested underwater and can move steadily and quickly in the water.