Simulation of an unmanned underwater vehicle (UUV): a multi-rate simulation

ABSTRACT

The problem of developing real-time simulations that include both high-speed (<10 μS frame time) and slower components can be alleviated using multi-rate simulation. Collaboration between California State University, Chico; the University of South Carolina; and the University of Glasgow, aims to develop a multi-rate demonstration example that includes a power electronic subsystem requiring high-speed simulation. The selected application is an unmanned underwater vehicle (UUV) that uses a battery as its energy source feeding an a.c. motor drive through a d.c. to a.c. converter. The drive powers the vessel which is modeled as a 6-degree of freedom platform with control surfaces.

The model separates the system into subsystems that are simulated with different frame rates: the converter (fast), its controller (fast medium) the motor drive (slow medium), and the vessel and the battery (slow). The initial effort aims to combine the subsystems within a VTB environment using a new VTB multi-rate solver. Three different programming approaches have been used for the subsystems. The converter and controller are programmed using C++ code developed for high-speed real-time simulation at Chico. The electric drive uses native VTB models and the model for the vessel is written in Matlab.

REFERENCES

• 1: Dale Word , John J. Zenor , Richard Bednar , Roy E. Crosbie , Narain G. Hingorani, Multi-rate real-time simulation techniques, Proceedings of the 2007 summer computer simulation conference, July 16-19, 2007, San Diego, California
• 2: Fossen, T. I., Guidance and Control of Ocean Vehicles, John Wiley & Sons Ltd, Chichester, 1994.
• 3: Dougal, R. A., "Design Tools for Electric Ship Systems" in Proceedings of IEEE Electric Ship Technologies Symposium, Philadelphia PA, July 2005 pp. 8--11, IEEE.
• 4: Pearce, J. G. "Interfacing the ESL Simulation Language to the Virtual Test Bed" in Proceedings of 2007 Western Simulation Multiconference, San Diego, CA, January 2007.
• 5: J. J. Zenor , J. G. Pearce , R. Bednar, Testing of multi-rate simulations using the ESL simulation language, Proceedings of the 2007 summer computer simulation conference, July 16-19, 2007, San Diego, California

INDEX TERMS

Keywords:
continuous system simulation, multi-rate simulation, power electronics, underwater vehicle