Optimization of a High Fidelity Virtual Model of a Hydraulic Hoisting System for Real-Time Simulations

Abstract

Abstract Nowadays, modeling and simulation software enhancing design and development of hydraulic-mechanical drilling machinery becomes increasingly popular in the offshore industry. The current work presents an efficient way to optimize large, high fidelity models of such equipment. First, a complex virtual model of the selected hoisting system is created and compared with the reference data logs recorded on a full-scale rig. Second, rules and guidelines for conversion of a complex model to a low fidelity model which could be simulated in a real-time (RT) environment are formulated. Typically, a complex model of offshore machinery is suitable only for offline tests. Therefore, to perform RT simulations it is necessary to optimize it. The methodology presented in the current paper provides for interaction with a virtual model in real-time via a full-scale control hardware and software. This in turn allows to perform a hardware-in-the-loop (HIL) test and evaluate developed control systems as well as to verify if chosen control equipment meets the desired performance. Simulation results prove that both high and low fidelity models yield comparable outcomes which correspond well to the reference real world rig measurements. It is concluded that to simplify a model it is important to determine how its particular components affect computational efficiency of the simulation hardware and to clearly understand functions of the considered machine. The paper contributes in two areas. Primary - a high fidelity virtual model of an existing hoisting system is established. The simulated model is benchmarked against real measurements from the offshore drilling rig. Secondary - such a complex model is reduced and confirmed to be applicable for real-time HIL simulations. RT performance can be difficult to achieve even on modern computers due to the stiff nature of hydraulic-mechanical models and high demands on computational power. Introduction High level of technological sophistication, high price and small production numbers are the features that characterize the offshore equipment produced nowadays. According to Bak et al. (2011), manufacturers of offshore machinery are required to have a high level of experience and skills to design and develop their products due to the fact that normally it is not possible to construct prototypes to evaluate if a new design will work. Consequently, design engineers are constantly challenged to find the best possible trade-off between reliability, capacity, and cost of the produced equipment. Therefore, an increasing attention of the offshore industry is directed towards tools and methods that allow virtual prototyping and simulation of new designs which in turn makes it possible for engineers to test, redesign, adjust, and optimize a solution before it is manufactured.