Showing papers by "Zoran Vukić published in 2010"
TL;DR: The scientific contributions to the state of the art of underwater and marine system technology of LABUST, based on which the capacity to further and intensify research activity is being built within the CURE project, fall mainly into three categories: unmanned small vessel modeling and identification, distributed coordinated and cooperative control.
5 citations
01 Sep 2010
TL;DR: In this paper, the authors describe a procedure that utilizes a series of off-line algorithms for pre-planning a two-dimensional path for an AUV in a cluttered waterspace.
Abstract: This paper describes a procedure that utilizes a series of off-line algorithms for pre-planning a two-dimensional path for an AUV in a cluttered waterspace. The trajectory is planned as a clothoidal spline or interpolation based on the work of Shin and Singh (1990) between a sequence of objective points. The former are calculated by a method proposed by the authors, based on the traversal of vertices of apriori known obstacles modeled on a concise set of geometrical primitives. The objective points are first sequenced and then extraneous ones are pruned. Finally, the technique of Shin and Singh (1990) and numerical approximation of clothoid parameters is applied to calculating the final path through the obstacle-strewn waterspace.
5 citations
Journal Article•
TL;DR: This simulation shows how the design of guidance controllers for unmanned underwater vehicles based on an assumption that the vessel operates at a constant depth affects the ability of the controller to control the vehicle.
Abstract: When designing guidance controllers for unmanned underwater vehicles, an assumption is often made that the vessel operates at a constant depth. However, in many applications the desired depth often changes with the position of the vessel in the horizontal plane. This paper addresses the problem of three dimensional line following with application to underactuated underwater vehicles. The problem is resolved by separating the desired line into two components. The main contribution of this paper is the design of 3D line following controllers for underactuated underwater vehicles. The control design is based on constant controlled surge speed and a simplified decoupled model of an underwater vehicle. Detailed design procedure is presented. The simulation results are obtained from a complex, coupled model, which proves that the proposed algorithm can be used on real vehicles.
5 citations
01 Sep 2010
TL;DR: In this article, an overactuated laboratory platform developed at the Laboratory for Underwater Systems and Technologies with the purpose of testing control algorithms is described, and the identification method which is used is based on recording open loop step responses.
Abstract: Dynamic positioning is a challenging task in control of marine vessels, with the primary objective of maintaining a desired, predefined position of the vessel. This paper describes an overactuated laboratory platform developed at the Laboratory for Underwater Systems and Technologies with the purpose of testing control algorithms. This paper focuses on the identification of the laboratory platform. The identification method which is used is based on recording open loop step responses. Preliminary experimental results for controllable degrees of freedom are presented. The paper also describes a MOOS (mission oriented operating system) based communication structure used to control the platform.
2 citations
23 Jun 2010
TL;DR: In this paper, the authors describe a modification of authors' previous work on virtual potential methods for planning and guidance of autonomous underwater vehicles (AUVs) along trajectories in ℝ2 andℝ3, allowing for a far more flexible integration of rotors, allowing fine-tuning by revealing analytical relationships between the stator and rotor components of calculated acceleration vectors.
Abstract: This paper describes a modification of authors' previous work on virtual potential methods for planning and guidance of autonomous underwater vehicles (AUVs) along trajectories in ℝ2 and ℝ3. The modification replaces the algebraic sampling procedure of scalar potentials, performed in the previous algorithm in order to allow for the numerical approximation of the true local gradient of the potential, with the direct analytical solution for the local gradient. The modification also allows for a far more flexible integration of rotors, allowing fine-tuning by revealing analytical relationships between the stator and rotor components of calculated acceleration vectors. The modification is critical to the control of holonomically constrained AUVs with finite dynamics and significant lags in response to rudder and change of propeller rpms.
2 citations
24 May 2010
TL;DR: In this article, the authors present a laboratory model of a surface platform for dynamic positioning which has been developed at the Laboratory for Underwater Systems and Technologies, University of Zagreb.
Abstract: Marine robotics is an interesting area for control engineers since these systems are complex, nonlinear and operate in highly unpredictable environment (winds, currents, waves). This paper present a laboratory model of a surface platform for dynamic positioning which has been developed at the Laboratory for Underwater Systems and Technologies, University of Zagreb. The full mathematical model consisting of actuator allocation, dynamic model and kinematic model is described. The platform has primarily been developed for testing and comparison of different control, guidance and navigation algorithms. The platform is overactuated which makes it suitable for fault tolerant control design. The paper describes the procedure of model based line following controller design which ensures stability and zero error line following under the influence of external disturbances.
2 citations