Papers by Francisco C Teixeira
International Journal of Adaptive Control and Signal Processing, 2016
The work described in this paper is motivated by the need to develop efficient and robust estimat... more The work described in this paper is motivated by the need to develop efficient and robust estimation filters with application to terrain-aided navigation of underwater robotic vehicles. One of the main problems addressed is the development of navigation particle filters that can deal with the scarcity of landmarks and the terrain ambiguity that characterize vast regions of the ocean floor. As a contribution to solve this problem, the paper proposes three novel particle filter algorithms and assesses their estimation efficiency and robustness to non-informative measurements using two well-known benchmarking tests. The performance of the new filters in these tests demonstrates their potential to solve a class of nonlinear problems that include, but are not limited to, the type of underwater navigation problem that motivated the present work. Our study concludes by examining the performance of the filters in terms of determining the position and velocity of an autonomous underwater vehicle in the presence of unknown ocean currents. When applied to terrain-aided navigation, the novel particle filter formulations formulations mitigate filter divergence issues frequently caused by terrain symmetries and are more robust than other well-known versions when used in scenarios with poor terrain information. The theoretical developments presented and the results obtained in simulations are validated using real data acquired during tests with an autonomous marine robot.
Ocean Engineering, 2010
This article appeared in a journal published by Elsevier. The attached copy is furnished to the a... more This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier's archiving and manuscript policies are encouraged to visit: http://www.elsevier.com/copyright
This paper addresses the problem of simultaneous depth tracking and attitude control of an underw... more This paper addresses the problem of simultaneous depth tracking and attitude control of an underwater towed vehicle. The system proposed uses a two-stage towing arrangement that includes a long primary cable, a gravitic depressor, and a secondary cable. The towfish motion induced by wave driven disturbances in both the vertical and horizontal planes is described using an empirical model of the depressor motion and a spring-damper model of the secondary cable. A nonlinear, Lyapunov-based, adaptive output feedback control law is designed and shown to regulate pitch, yaw, and depth tracking errors to zero. The controller is designed to operate in the presence of plant parameter uncertainty. When subjected to bounded external disturbances, the tracking errors converge to a neighbourhood of the origin that can be made arbitrarily small. In the implementation proposed, a nonlinear observer is used to estimate the linear velocities used by the controller thus dispensing with the need for costly sensor suites. The results obtained with computer simulations show that the controlled system exhibits good performance about different operating conditions when subjected to sea-wave driven disturbances and in the presence of sensor noise. The system holds promise for application in oceanographic missions that require depth tracking or bottom-following combined with precise vehicle attitude control.
SUMMARY Terrain-aided navigation (TAN) is steadily gaining acceptance as a viable methodology to ... more SUMMARY Terrain-aided navigation (TAN) is steadily gaining acceptance as a viable methodology to solve the problem of long-range autonomous underwater navigation without incurring the costs of high-grade inertial navigation sensors or the cumbersome deployment and calibration of long acoustic baselines. The potential of TAN to provide high AUV localization accuracy using a standard dead reckoning unit and bathymetric sensors has been demonstrated recently during trials performed over different types of terrain. Despite the encouraging advances, there are still a number of open problems that need to be solved to make TAN a truly mature navigation methodology. Among the latter, one of paramount importance is that of developing efficient navigation filters that are efficient and sufficiently robust to deal with the scarcity of landmarks and the terrain ambiguity that characterize vast regions of the ocean floor. Current implementations of the TAN concept rely essentially on a class of nonlinear filters commonly designated particle filters (PF), due to their versatility and robustness. In some practical applications, these estimators have demonstrated superior performance relatively to parametric estimation algorithms (e.g. Kalman-based filters) and terrain-matching methods such as the TERCOM. However, standard PF algorithms may still fail to address in a satisfactory manner the issues of efficiency and robustness mentioned above. As a contribution to overcoming this problem, the present paper proposes three novel particle filter algorithms and assesses their efficacy using two well-known benchmarking tests. The performance of the new filters in these tests demonstrates their potential to solve a class of nonlinear problems that include, but are not limited to, the type of underwater navigation problems that motivated the present work. Our study concludes by examining the performance of the two new filter versions that achieved superior estimation accuracy in terms of determining the position and velocity of an AUV in the presence of unknown ocean currents. When applied to TAN, the new PF formulations mitigate filter divergence issues frequently caused by terrain symmetries and are more robust than other well-known versions when used in scenarios with poor terrain information. The theoretical developments presented and the results obtained in simulations are validated using real data acquired during tests with an autonomous marine robot.
This paper addresses the design and implementation of terrain-aided navigation (TAN) methods for ... more This paper addresses the design and implementation of terrain-aided navigation (TAN) methods for small autonomous underwater vehicles (AUVs) that rely on standard navigation sensors and dispense with the need for dedicated sensors for terrain data acquisition. The research described focuses on the problem of TAN implementation in underwater scenarios characterized by smooth sea-bottom topography and very shallow water, where the terrain information available for navigation is scarce. The navigation algorithms and the data fusion methods whose tests are documented in the paper build upon and expand prior theoretical work published by the authors; the TAN solutions adopted exploit the terrain information and the navigation data acquired with an inexpensive Doppler velocity logger (DVL) and a standard motion reference unit, respectively. The position estimation methods analyzed include a bi-dimensional particle filter (PF) and a four-dimensional Rao-Blackwellized PF that was designed to estimate the unknown Doppler velocity measurement biases responsible for the unbound localization errors typically observed in dead-recknoning navigation. The positioning accuracy achieved with these filters is compared with the output a of novel method, also proposed in the paper, that mechanizes a complementary-like filter designed to fuse the output of a TAN estimator with the velocity measurements provided by a DVL. Experimental results obtained during field tests with an autonomous marine vehicle are reported and analyzed.
... National Institute of Oceanography, Marine Instrumentation Division, Dona Paula, Goa - 403004... more ... National Institute of Oceanography, Marine Instrumentation Division, Dona Paula, Goa - 403004, India (email: pramod.maurya@gmail.com). ... approach which consists essentially in matching a set of measure-ments obtained by the vehicle with a previously acquired map of the ...
... Pramod Maurya ∗,∗∗ Francisco Curado Teixeira ∗∗∗ António Pascoal ∗ ... Map based navigation, ... more ... Pramod Maurya ∗,∗∗ Francisco Curado Teixeira ∗∗∗ António Pascoal ∗ ... Map based navigation, also called Terrain-Aided Navigation (TAN), holds good poten-tial to be used for long range missions without incurring in a cost escalate. ...
This paper addresses the problem of simultaneous depth tracking and precise attitude control of a... more This paper addresses the problem of simultaneous depth tracking and precise attitude control of an underwater towed vehicle integrated in a two-stage towing arrangement. A nonlinear Lyapunov-based output feedback controller is designed to operate in the presence of plant parameter uncertainty and proven to regulate pitch, yaw, and depth tracking errors to zero. When subjected to bounded external disturbances, the tracking errors converge to a neighborhood of the origin that can be made arbitrarily small. In the implementation proposed, a nonlinear observer is used to estimate the linear velocities used by the controller. The results obtained with computer simulations including sea wave driven disturbances and sensor noise, show that the controlled system exhibits good performance about different operating conditions and holds considerable potential for oceanographic missions that require simultaneous depth and attitude control.
9th IFAC Conference on Manoeuvring and Control of Marine Craft, 2012, 2012
ABSTRACT This paper addresses the challenging problem of achieving truly autonomous long range na... more ABSTRACT This paper addresses the challenging problem of achieving truly autonomous long range navigation of underwater vehicles relying on affordable navigation sensors. Terrain-aided navigation (TAN) is a methodology that holds potential to solve this problem by dispensing with the need to use high-grade, inertial navigation sensors and the deployment and calibration of acoustic beacons. To implement TAN without incurring the additional cost of expensive dedicated sensors, we propose the utilization of a Doppler velocity logger (DVL) which is an equipment of widespread utilization in oceanography and also a standard instrument in underwater navigation. We avail ourselves of a less exploited characteristic of DVL sensors that consists in the ability to acquire, simultaneously with the velocity data, a set of accurate range measurements relatively to a reflective interface. The combination of these sensing capacities enables Doppler units to be used not only in dead-recknoning navigation but also in terrain based localization of underwater vehicles. The main contribution of the paper is the design of a complementary filter (CF) for fusion of TAN estimates with DVL measurements. The CF approach is motivated by the need to reduce the short-term variability of position estimates that is typically observed in conventional TAN. The solution proposed is analysed in comparison with a well-known Rao-Blackwellized particle filter set-up which is shown to implement a data fusion filter designed in a stochastic estimation framework. The results obtained in Monte Carlo simulations performed with real bathymetric data evidence the superior performance of the complementary filter approach in terms of position estimation accuracy and long term output signal stability.
9th IFAC Conference on Control Applications in Marine Systems (2013), 2013
ABSTRACT This paper proposes novel methods with the potential to improve the performance of navig... more ABSTRACT This paper proposes novel methods with the potential to improve the performance of navigation and tracking systems in underwater environments. The work relies on well-established methods of potential field inversion and introduces a new analytic formulation designed to stabilize the solution of the inverse problem in real-time applications. The navigation method proposed exploits the terrain information associated with geomagnetic field anomalies, without the need of a priori maps. The procedure can also be applied to track a moving vehicle based on its associated disturbance of the environmental magnetic field. We envision the integration of theses methods in terrain-aided navigation systems, simultaneous localization and mapping algorithms, and tracking applications.
3rd IFAC Workshop on Navigation, Guidance and Control of Underwater Vehicles, 2012
... National Institute of Oceanography, Marine Instrumentation Division, Dona Paula, Goa - 403004... more ... National Institute of Oceanography, Marine Instrumentation Division, Dona Paula, Goa - 403004, India (email: pramod.maurya@gmail.com). ... approach which consists essentially in matching a set of measure-ments obtained by the vehicle with a previously acquired map of the ...
3rd IFAC Workshop on Navigation, Guidance and Control of Underwater Vehicles, 2012
... Pramod Maurya ∗,∗∗ Francisco Curado Teixeira ∗∗∗ António Pascoal ∗ ... Map based navigation, ... more ... Pramod Maurya ∗,∗∗ Francisco Curado Teixeira ∗∗∗ António Pascoal ∗ ... Map based navigation, also called Terrain-Aided Navigation (TAN), holds good poten-tial to be used for long range missions without incurring in a cost escalate. ...
Journal of Marine Research, 2011
1. INTRODUCTION The continental shelf of Azores is being subjected to sand exploitation. Unfortun... more 1. INTRODUCTION The continental shelf of Azores is being subjected to sand exploitation. Unfortunately, the industry has started exploitation in almost all islands, without previous geological studies. Under these circumstances, the Marine Geology Department (DGM) of the ...
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Papers by Francisco C Teixeira