Design and develop a buoyancy control module for underwater robot

• Main Author: Zhang, Bin
• Other Authors: Low Kin Huat
• Format: Final Year Project
• Language: English
• Published: 2009
• Subjects: DRNTU::Engineering::Mechanical engineering::Robots
• Online Access: http://hdl.handle.net/10356/16212
• Institution: Nanyang Technological University

Robotics research scientists have been stretching the technology towards the underwater, especially ocean research development. Successful examples were all around the world, but yet challenges keep coming to scientists’ mind, such as stability, robustness, energy saving power source etc for underwater robotics research. Buoyancy control module became an essential component when underwater robotics comes into play. In order to assist underwater robots to function well, effective, robust and low energy consumption, buoyancy control module was designed and developed. The buoyancy control module is based on the idea of Recirculating Compressed Air Ballast System (RCABS). The idea illustrates that the whole system is designed to be slightly negative buoyancy, with air pumping from a water tight container towards a bladder in order to reduce the density of the system, hence it floats; on the other hand, air in the bladder is released to the water tight container by a servo control valve in order to regain its density, hence it submerge. The buoyancy control module is versatile in providing buoyancy control to different underwater robot systems, due to its simplicity and low energy consumption. A certain specialized implementation of the RCABS buoyancy control module is the underwater glider, which uses small changes in its buoyancy in conjunction with wings to convert vertical motion to horizontal, and thereby propel itself forward with very low power consumption. Another implementation of the buoyancy control module was to introduce a tail fin to it. Tail fin provided an assistive propagation motion to the system and once again the versatility of the buoyancy control module was verified. This report illustrates the basic theory of the module’s operating principle, the physical building up process from zero, and also the electronic design and programming of the control system. Besides, this, a detail analysis underwater glider and actual build up description will be provided too. The report also focuses on observations and dynamics control results about the performance of the buoyancy control module and water tight container -glider system.