Steering ship models are important for the study of autonomous ship manoeuverability and design of ship motion control system. It is always a difficult task to find the mathematical model by first ...

Steering model identification and control design of autonomous ship: a complete experimental study

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.

Embedded System Design for Autonomous Unmanned Surface Vehicles in Laboratory Environment

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.

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

This paper presents the improvement of the wave maker control system. The wave maker is a facility widely used in hydromechanics laboratories to generate waves in towing tanks. It is equipped with an electrohydraulic drive and an actuator submerged into water. The waves are generated to model the environmental conditions for physical experiments, performed on reduced-scale models of maritime objects. The physical experiments allow to predict the behaviour of full-scale objects and prove the results of numerical analyses. The overriding goal of the fluid dynamics experiments is to improve the human safety and survivability of constructions. The reported investigation and application works were vital for the improvement of physical model tests. The optimization of the proportional controllers was performed in terms of the Integral of Squared Error (ISE). The final evaluation was performed in terms of the frequency response characteristic. The results of the proportional control optimization were evaluated versus the previously applied control. The experimental research was conducted in the real towing tank located at the Maritime Advanced Research Centre. The investigation has shown the advantage of the ISE optimized conventional proportional control. It has particularly proven the affordability and swiftness of the optimization process. It also proved a more efficient frequency response of the wave maker obtained within a required and reasonable lead time. The performed investigation has greatly contributed to the development of a new method of physical experiments in white noise waves. The results related to this new more efficient method are presented as well.

https://ieeexplore.ieee.org/ielx7/6287639/6514899/09758743.pdf

Application of the ISE Optimized Proportional Control of the Wave Maker in a Towing Tank

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.

V Jagdeesh Kumar

Papers

Development of autonomous system for scaled ship model for seakeeping tests