INTEGRATION OF DYNAMIC MODELS AND VIRTUAL REALITY FOR THE TRAINING OF STEAM GENERATOR OPERATORS

Over the past decades, attention towards workplace safety has increased progressively, leading to a strong presence of automation and remote control on hazardous processes and devices. However, human intervention is sometimes necessary. Consequently, inadequate knowledge of equipment, poor maintenance of work tools and underestimation of possible risks can result into work accidents. Therefore, it is fundamental for each worker to be updated about necessary knowledge to run and maintain potentially dangerous work equipment. This knowledge is generally acquired through both theoretical studies and training on real devices, sometimes leading to the acquisition of a specific licence. However, this kind of training can test the ability to run the real system only during its standard behavior, but not during emergency situations or malfunctions. Moreover, the interaction of an unexperienced operator with a potentially hazardous system during the training process can lead to risky scenarios. The goal of the PITSTOP project is to overcome the limits of traditional training and to reduce the possible risks of practical tests, thanks to an innovative integration of dynamic simulation models and a virtual reality environment. In this article, the case study of a small-scale steam generator for industrial applications is considered. However, the methodology proposed by the PITSTOP project could be easily extended to other hazardous systems. A dynamic model of the system was developed in Matlab-Simulink, including all the main devices (i.e., water tank, pump, boiler), actuators (i.e., valves, buttons, switches, levers) and measuring equipment (i.e. temperature probes, pressure sensors, etc). The simulation of the steam generator relies on a mixed physics-based/data-driven approach, based on physical equations, semi-empirical correlations, performance maps and a thermophysical properties tool (Coolprop). The model was designed to simulate the normal operation of the system during stationary and transient scenarios, but also to recreate emergency situations and to show the effect of wrong or inconsistent actions by the operator. The control logics and emergency procedures of the steam generator were included in the model as well. Operating the real system in various conditions, it was possible to collect experimental data characterizing its behavior, and to understand all the possible interactions of the operator with its actuators and their consequences. Experimental data were used to calibrate the Matlab-Simulink component models and to align the performance of the model with the real steam generator. The virtual reality environment was developed in Unity, a graphics engine widely adopted by the videogame industry, using 3D CAD models of the steam generator and its surroundings. The user can access to this immersive system wearing an HTC VIVE headset. No other equipment must be worn, making the experience intuitive and easily accessible. In fact, the movement of the user in the environment is detected by two HTC VIVE cameras installed inside the testing room, while the interaction in the virtual reality environment is guaranteed by hand gestures that are captured and interpreted using Leap Motion controller. Connecting the dynamic model with the virtual reality environment via UDP communication, it is possible to reproduce faithfully the interactions with the steam generator. The actions of the user on the actuators are used as inputs of the model. Simulating the system response over a time step, the outputs of the model (e.g., temperatures and pressures) are sent to the virtual reality environment, providing visual and audio feedbacks to the user.