D. Pena

Bio: D. Pena is an academic researcher from University of A Coruña. The author has contributed to research in topics: Ship model basin & Towing. The author has an hindex of 1, co-authored 1 publications receiving 6 citations.

An autonomous scale ship model for towing tank testing

Abstract: This paper presents the work done for developing a self-propelled scale ship model for towing tank testing, with the main characteristic of not having any material link to a towing device to carry out the tests. This model has been fully instrumented in order to acquire all the significant raw data, process them onboard and communicate with an inshore station, and all this for both seakeeping and resistance tests. In order to illustrate the applicability and advantages of the proposed model, some results obtained by its application on a towing tank test campaign, aimed at developing a parametric roll detection system, are also presented.

Development of autonomous system for scaled ship model for seakeeping tests

Abstract: This paper presents a work carried out to develop an onboard integrated system for a controlled free running ship model using data acquired from a Motion Reference Unit(MRU). Using the reference data, the system performs processing and control through wireless communication (Wi-Fi). The application of free running model is to investigate the sea keeping and maneuvering characteristics of a ship. In such a scenario there are disturbing external forces and hence a time - position data based closed loop control algorithm is essential. The development provides the nucleus for such a controlled autonomous system. The ship based integrated system consists of azimuth propulsion unit, MRU, central processing unit for control, data link and a battery pack for autonomous operation of the ship model. A proportional controller is used with the feedback from the MRU to perform heading control using azimuth propulsion system. Quality of free running model test is improved with this system as compared to traditional facilities with captive model and follower carriage based system.

Embedded System Design for Autonomous Unmanned Surface Vehicles in Laboratory Environment

Abstract: Sea-keeping, maneuvering, and motion tests of surface vehicle/ship model need self-propelled scale model which can perform different maneuvers. The present work describes the design implementation and testing of embedded system of an autonomous system for unmanned surface vehicles (USVs)/ship model in the laboratory environment. This is a first-time national development test in the wave basin has demonstrated full-free running self-controlled model in a disturbance environment. The central unit of the system is an embedded controller, compact reconfigurable input–output (cRIO) which features a field-programmable gate array (FPGA) and a processor running Linux-based real-time operating system. It performs the main propulsion control, rudder control data logging and telemetry. The peripherals are interfaced with main controller through multifunction input–output module. The RS-232 communication is used to interface the MRU sensor with main controller. LabVIEW is used as programming tool to develop a program to control the peripherals connected to the main controller and data acquisition over a wireless link using Wi-Fi. A graphical user interface is developed to send control commands and visualize the 4-degree of motion at base station in real time.

Generic Solution for Generating Towing Tank Carriage Linear Speed Profile Using Stepper Motor

Abstract: Towing tanks are widely used in measuring of hydrodynamic coefficients and study dynamics of marine vehicles at different operating conditions of motion and different geometry characteristics. In this paper, two stepper motors have been used to drive a towing tank carriage and Pulse Width Modulation (PWM) technique is used to control the speed of the towing carriage according to the speed profile calculated in advance depending on the required operating conditions of the test model. AVR microcontroller has been used to linearly control the speed of the stepper motors in three phases, accelerating from zero to its steady state speed, steady state speed and decelerating until stop. The proposed work makes any required speed profile easy to be obtained and fulfilled in real time, such as the profile needed for a single long acceleration phase throughout the most of the length of tank which is needed in the experimental work for added inertia measurement purpose. A general case to reach an assigned constant speed for hull drag measurements with two different phases of acceleration and deceleration is introduced.

A speed control strategy for an autonomous ship model for towing tank testing

Abstract: This paper presents the strategies used to develop a speed control system for a ship model. This speed control is a part of a larger control and data acquisition system on board of an autonomous ship model that is being specifically developed to perform towing tank testing. Taking into account the requirements for this speed control system, and that the speeds to be measured are about one meter per second, a Laser Rangefinder is used as mean for measuring the speed of the model. This is quite unusual because these devices are just intended to measure distances between motionless objects. Various approaches used for setting up the controller are also presented.

Page No. 29 - 42: Wi-Fi Enabled Autonomous Ship Model Tests For Ship Motion Dynamics And Seakeeping Assessment

Abstract: Captive model testing for ship motions, sea-keeping and dynamic effects has been always a challenge due to the large amount of channels of data, the need for continuous data communication for effect feedback control, and in the case of extended studies relating to fleets, the methodology for group fleet control. For the first time a solution is offered by designing a free self-propulsion, self, on-board controlled, surface ship model. The design incorporates Wi-Fi enabled robust communication and control and protocols for data storage, exchange, multiple device control and communication to fleet sister surface ships for fleet control. The design is described in this paper with details of implementation on a demonstration oceanographic research vessel. It illustrates the excellent communication between shore station computer and the on-board system on a wire-free model with robust control and exhibiting all the motion behavior and dynamic effects.