Research Highlights

• Subject Category:
  • Physics

Published online: 15 August 2007 | doi:10.1038/nchina.2007.164

Robotics: Fish moving boxes

Wei Zeng

Introduction

© (2007) Long Wang

The ability to control robots to perform actions collectively has many useful applications, such as in military detection, undersea exploration and management of water pollution. Junzhi Yu and co-workers at Peking University in Beijing¹, have managed to coordinate two robotic fish to push a box at precise locations.

The researchers used two radio-controlled robotic fish comprising a control unit (onboard microprocessor and peripherals), a communication unit (wireless receiver), motors, a supporting body and accessories (including battery, waterproofed skin and tail fin). The fish could propel themselves in the water by moving their bodies and caudal fins (pictured).

In the experiment, the two fish are placed away from each other. To move the box towards a goal, the fish must push the box at specific regions within a specific angle simultaneously. The researchers designed the control unit to demonstrate specific behaviour for path finding and action decision problems, for each situation — 'situated-behaviour'. Afterwards, the action of the robotic fish is processed by fuzzy logic, which deals with synchronization and orientation-control problems. Using such a system, the fish could adjust their swimming speeds to arrive at the box at the same time, and then push the box together towards the goal.

In the complex underwater environment, fish can swim not only individually, but also collectively to avoid predators. So, as well as the engineering applications mentioned above, the findings might also help us understand how real fish synchronize their actions precisely.

The authors of this work are from:
Intelligent Control Laboratory, Department of Mechanics and Space Technologies, College of Engineering, Peking University, Beijing, China; Laboratory of Complex Systems and Intelligent Science, Institute of Automation, Chinese Academy of Sciences, Beijing, China.

Reference

1. Zhang, D., Wang, L. & Yu, J. Coordinated control of two biomimetic robotic fish in pushing-object task. IET Control Theory Appl. 1, 1200–1207 (2007).