Simulation Environment – A Numerical Environment for Simulations and Prototyping

MARINTEK has been systematically building up a centre of expertise in the field of system integration and simulation technology, combined with top-level competence in cybernetics, hydrodynamics, aerodynamics and marine vehicle operations. Our experience and databases, derived from the development and testing of all types of vehicles for many years, both as models and at full scale, are important aspects of these efforts. The Research Council of Norway supports the competence development process via a Strategic Institute Program called “MS Nautilus”, to which the maritime industry also contributes.

Figure 1. Motion of two ships in waves in real time using MARINTEK’s Simulation Environment.

MARINTEK has developed a Simulation Environment to integrate hydrodynamic and automatic control software. The main idea behind this is to create a test harness and simulation framework for:

• Development and verification of hydrodynamic software modules for wave, wind, current and interaction effects. 
• Development platform for marine control system
• Facility to present results from model test

Examples of projects using the Simulation Environment are given below:

Development of DP Simulator/Product for Rolls-Royce Marine AS

In cooperation with Rolls-Royce Marine AS, MARINTEK has developed a simulation framework known as the Common Simulation Infrastructure (CSI). This simulation framework is an important tool for the development of a Dynamic Positioning (DP) simulator and product. The CSI enables hydrodynamic and automatic control software to be integrated in a very flexible way. In the development of the new framework, we emphasized well-defined interfaces, reusable software and interoperability. Hydrodynamic forces such as waves, winds and currents can easily be configured in the simulator dependent of users needs. The simulation framework now supports multibody dynamics; for example, two ships in waves.

MARINTEK has also developed a numerical six-degrees-of-freedom (DOF) shipmotion model, in which manoeuvering and seakeeping characteristics are merged and verified against existing MARINTEK software packages, model tests and fullscale tests. All hydrodynamic effects/coefficients can be calculated or configured by existing software packages in MARINTEK’s ShipX application and database. A numerical wave model has also been implemented and the corresponding ship motion will be related to the actual wave pattern in real time (Figure 1). 

Propulsion models, including environmental and interaction effects as described above, are also implemented into the simulator. Propulsion vendors can interface their own models using the CSI. 

Numerical models of motion sensors, including gyrocompass, speed log, wind sensor and GPS have also been developed and are currently being interfaced with the CSI. 

Prototyping of a joystick control system for FerryCat

In another project with Rolls-Royce Marine, MARINTEK has developed a joystick control system for the FerryCat™ 120 (Figure 2). The FerryCat™ 120 is a high-speed aluminium catamaran built by Fjellstrand AS and is an innovative concept in the field of commuter ferries. The ferry will have a capacity of 112 cars and 400 passengers, and will be capable of making 22 knots, using a newly developed propulsion system known as Azipull (Azimuthing Pulling Propeller) from Rolls-Royce Marine AS. The propulsion system consists of four propeller units, one at each “corner” of the vessel. The ferry will be steered from a wheelhouse that can be rotated 180 degrees, depending on the direction of travel of the ferry.

This project employs the Simulation Environment to create a common arena for the design, development and understanding of designing a marine control system, covering software-in-the-loop, hardware-in-the-loop and full-scale testing and verification.

The simulator comprises the following modules:

• Ship (hull force, wind and current effects)
• Propulsion (force and power for each Azipull)
• Control system (joystick and autopilot control)
• Navigation (GPS, gyrocompass, speed log and wind sensor)
• Electronic chart (visualisation and navigation tool)
• 3D Terrain (visualisation)
• GUI (Graphical User Interface and 3-axis joystick)

Figure 2. FerryCat 120. Verification and tuning of joystick control system.

Contact person at MARINTEK: Arne Kjørsvik

(Article in MARINTEK Review No 2-2004)