The authors aim to investigate the observability properties of the process of simultaneous localization and mapping of an autonomous underwater vehicle (AUV), a challenging and important problem in marine robotics, and illustrate the derived results through computer simulations and experimental results with a real AUV.
The authors address the single/multiple beacon observability analysis of the process of simultaneous localization and mapping of an AUV by deriving the nonlinear mathematical model that describes the process; then applying a suitable coordinate transformation, and subsequently a time-scaling transformation to obtain a linear time varying (LTV) system. The AUV considered is equipped with a set of inertial sensors, a depth sensor, and an acoustic ranging device that provides relative range measurements to a set of stationary beacons. The location of the beacons does not need to be necessarily known and in that case, the authors are also interested to localize them. Numerical tests and experimental results illustrate the derived theoretical results.
The authors show that if either the position of one of the beacons or the initial position of the AUV is known, then the system is at least locally weakly observable, in the sense that the set of indistinguishable states from a given initial configuration contains a finite set of isolated points. The simulations and experiments results illustrate the findings.
In the single and multiple beacon case and for manoeuvres with constant linear and angular velocities both expressed in the body-frame, known as trimming or steady-state trajectories, the authors derive conditions under which it is possible to infer the state of the resulting system (and in particular the position of the AUV). The authors also describe the implementation of an advanced continuous time constrained minimum energy observer combined with multiple model techniques. Numerical tests and experimental results illustrate the derived theoretical results.
This paper has been developed from the paper: “Observability analysis of the simultaneous underwater vehicle localization and mapping based on ranging measurements” by Mohammadreza Bayat, ISR/IST; A. Pedro Aguiar, IST/ISR, which received an Industrial Robot Journal “Highly Commended” award when it was first presented at Controlo 2012, University of Madeira, July 16-18, 2012. The authors gratefully acknowledge the DSOR team for their efforts in the development of the MEDUSA vehicles and their support and collaboration on the planning and execution of the sea trials, especially J. Botelho, P. Góis, J. Ribeiro, M. Rufino, L. Sebastião, and J. Soares. The authors would also like to express their sincere gratitude to Antonio M. Pascoal for his constant support, enthusiasm, and encouragement for the research. This work was supported in part by projects MORPH (EU FP7 under grant agreement No. 288704), CONAV/FCT-PT (PTDC/EEA- CRO/113820/2009), and the FCT [PEst-OE/EEI/LA0009/2013].
Bayat, M. and Pedro Aguiar, A. (2014), "Underwater localization and mapping: observability analysis and experimental results", Industrial Robot, Vol. 41 No. 2, pp. 213-224. https://doi.org/10.1108/IR-09-2013-398Download as .RIS
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