The used architecture in NDT training process suppose the existence of the real NDT scanning device as well as the control (trainer’s) computer (figure 3) completed with an experimental DB used as tested experiments repository.
In the real environment, the trainer/user may setup the experiment parameters and control the real scanning device on the three axes through the SMMC interface. Based on three levels, SMMC module permits the control of the crane-like mechanical device based on step-by-step engines. The most visible layer represents a configurable user interface which detects the user commands and transmits them to the intermediary level. At the intermediary level, the user commands are coded according to the adopted system solution. Using a specific driver, the intermediary level is linked to the low-level layer. This level contains the specific hardware drivers (parallel and USB ports, and acquisition card SMC4 – Physical Acoustic Corporation). According to the scanning device movements and the experiment conditions, it obtains the ultrasound signal for analysis and characterization. The real experimental measurements were obtained by the immersion testing method, where the transducer is placed in the water, above the test object, and a beam of sound is projected (Zagan 2003).
The tutor is working with real architecture system to collect the signals received by the transducer (echo waveforms) from different samples, were sent to an oscilloscope, where their amplitude and velocity were read directly from the sampler which performs the sampling of the signals. The current experiments’ parameters, material characterization and analysis results obtained using the real setup are all stored for later use in (self) training sessions.
The real experimental setup is extended with virtual copies of the real scanning device, copies that implements the full functionalities of the real ones, together with correspondent trainee’s computers. This way, the trainer actions within real environment may be broadcasted in real-time at all active 3D virtual copies of the scanning configuration, through EngView. This actually represents the basis in our educational and training process.
EngView propose a friendly user interface which accomplish the level of NDT equipment networking with latest IT/VR/AR technology, and enables subjects to achieve practical and theoretical skills needed by NDT to be integrated in standard program. As shown in figure 1.b), EngView integrates SMMC module at each trainee working station. Using this interface, the students may controls the movements of the virtual 3D scanning installation and may repeat the shown experiments. When the real configuration is available, they may test it in real conditions (but not concurrently).
Moreover, the trainee obtained experimental parameters are compared and analyzed at the trainer site in order to identify, characterize and publish the ultrasound signals. This way, the trainer is able to evaluate the trainee achievement of knowledge/skills level concerning individual NDT operation methodology.
We have considered the virtual environment as a space of human experience, as proposed in (Popovici, 2004), an reactive agent-based model that permits the user’s setting in the situation, the perception of space by its user, as well as the user’s evolution in this space. In other words, everything inside the virtual space is an agent, able to perceive, decide, and react based on its profile, internal structure, and tasks, to the environment evolution, so to the user actions also; as virtual scanning installation movement components.
The EngView is mainly based on the ARéVi API, developed by CERV (European Virtual Reality Centre, Brest, France), for the user immersion within the simulated virtual environment, as well as on C++ software components (as SMMC) that connects the virtual environment to the scanning machine control software (Reignier et al., 1998). ARéVi API has the advantage that is open source, is C++ and OpenGL based, and is adaptive to very different configurations starting from desktop systems, and ending with 3D stereoscopic immersion systems. |