Variable Buoyancy (VB) systems are vital parts of most of the underwater systems.
They are proven to be power efficient and are widely used in the field of underwater robotics for their ease-of-use to achieve heave motion underwater.
The main advantage of VB systems is that they consume power only during motion, unlike the conventional rotary actuators.
The potential of variable buoyancy system as a stand-alone system for heave motion underwater has not been given due importance and is still an unexplored area.
A stand-alone VB module, vBuoy, based on ‘change of volume’ concept of variable buoyancy has been developed as part of this project.
By expanding/compressing the metallic bellow, the buoyancy is varied and thereby the heave motion can be achieved.
Three case studies explaining the capabilities of vBuoy and its potential underwater applications were presented.
In the first case, application of cascaded vBuoys for selective deployment was presented.
Multiple, depth controllable, vBuoys can be cascaded and selectively deployed at different depths for a long duration, which opens multiple underwater applications ranging from coastal surveillance, selective deployment for ocean sampling etc.
The second case study was the development of an underwater robotic glider RoBuoy using the concept of vBuoy.
It uses a minimal number of parts compared to the existing gliders, reducing the overall complexity of the system.
The third case study is the use of vBuoys as actuators in underwater manipulators.
These modules are connected to the rigid links of the manipulator, replacing the conventional rotary joint actuators.
By varying the buoyancy of the module, planar motion can be achieved.
Development of the stand-alone vBuoy modules with inbuilt depth controller and analysis of its applications were the major contributions of this work.
Journal publications
- Thiyagarajan Ranganathan, Ridhi Puppala and Asokan Thondiyath,
"Design Optimisation and Performance Investigations of a Novel Underwater Glider, RoBuoy",
Note: Manuscript under preparation.
- Thiyagarajan Ranganathan, Vijendra Singh and Asokan Thondiyath,
"Theoretical and Experimental Investigations on the Design of a Hybrid Depth Controller for a Standalone Variable Buoyancy System – vBuoy,"
IEEE Journal of Oceanic Engineering,
pp. 1--16, October 2018,
doi: 10.1109/JOE.2018.2875576.
- Thiyagarajan Ranganathan, Vijendra Singh and Asokan Thondiyath,
"Estimation of Hydrodynamic Parameters for Underwater Systems Using a Simple Offline Regression Method: A Case Study,"
Journal of Marine Science and Technology,
vol. 24, no. 3, pp. 968--983, October 2018,
doi: 10.1007/s00773-018-0599-2.
- Thiyagarajan Ranganathan, Vijendra Singh, Ranjith Nair and Asokan Thondiyath,
"Design of a Controllable Variable Buoyancy Module and its Performance Analysis as a Cascaded System for Selective Underwater Deployment,"
Proceedings of the Institution of Mechanical Engineers,
Part M: Journal of Engineering for Maritime Environment,
vol. 231, no. 4, pp. 888-901, January 2017,
doi: 10.1177/1475090216688819.
Patents
- Thiyagarajan Ranganathan and Asokan Thondiyath,
"Underwater Manipulator using Variable Buoyancy Actuators,"
Indian Patent Application No. 201741036720, October 16, 2017,
Note: PCT in progress.
- Thiyagarajan Ranganathan and Asokan Thondiyath,
"Underwater Glider with Flexible Chamber for Variable Buoyancy,"
Indian Patent Application No. 201741036333, October 12, 2017,
Note: PCT in progress.
- Thiyagarajan Ranganathan and Asokan Thondiyath,
"Controllable Variable Buoyancy System Based on Actuated Flexible Members or Structures and their Uses,"
Indian Patent Application No. 4683/CHE/2015, September 04, 2015.
- Ganeshram Nandakumar, Thiyagarajan Ranganathan and Asokan Thondiyath,
"A Multirotor with a Vertically Offset Overlapping Configuration and Uses Thereof,"
Indian Patent Application No. 5621/CHE/2014, November 07, 2014.
Conference publications
- Abhijeet Vyas, Akshay Molawade, Nikhil Sivadasan, Ridhi Puppala, Thiyagarajan Ranganathan and Asokan Thondiyath,
"Design and Dynamic Analysis of a Novel Hybrid Aerial - Underwater Robot – Acutus,"
Note: Submitted to OCEANS 2019.
- Thiyagarajan Ranganathan, Sundaravalli Aravazhi, Sambit Mishra and Asokan Thondiyath,
"Design and Analysis of a Novel Underwater Glider – RoBuoy,"
in IEEE International Conference on Robotics and Automation (ICRA’18),
Brisbane, QLD, 2018, pp. 2089-2094,
doi: 10.1109/ICRA.2018.8462921.
- Thiyagarajan Ranganathan and Asokan Thondiyath,
"Design and Analysis of Cascaded Variable Buoyancy Systems for Selective Underwater Deployment,"
in Proceedings of the 13th International Conference on Informatics in Control, Automation and Robotics (ICINCO '16),
Lisbon, Portugal, 2016, vol. 2, pp. 319--326,
doi: 10.5220/0005979903190326.
- Thiyagarajan Ranganathan, John Pattery, and Asokan Thondiyath,
"Design and Analysis of Cable-Connected Metallic Bellows as Variable Buoyancy Modules,"
in IEEE International Conference on Underwater Technology (UT),
Chennai, India, 2015,
doi: 10.1109/UT.2015.7108289.
- Ganeshram Nandakumar, Thiyagarajan Ranganathan, B. J. Arjun and Asokan Thondiyath,
"Design and Analysis of a Novel Quadrotor System - VOOPS",
in IEEE International Conference on Robotics and Automation (ICRA’15),
Seattle, WA, USA, 2015, pp. 1692--1697,
doi: 10.1109/ICRA.2015.7139415.
- Thiyagarajan Ranganathan, Silla Pavan Kumar and Asokan Thondiyath,
"Design and Analysis of an Underwater Quadrotor - AQUAD,"
in IEEE International Conference on Underwater Technology (UT),
Chennai, India, 2015,
doi: 10.1109/UT.2015.7108290.
- Thiyagarajan Ranganathan and Asokan Thondiyath,
"Variable Buoyancy Mechanisms for AUVs,"
presented at the International Workshop on Underwater Technologies, NIOT Chennai, India, 2014.
Faculty in-charge: Prof. Asokan Thondiyath
Students: Dr. Thiyagarajan Ranganathan, Mr. Vijendra Singh
