When the Ball Bearing on the Bucket-Wheel Excavator Needs to Be Changed | CHECK.point eLearning
Virtual training

When the Ball Bearing on the Bucket-Wheel Excavator Needs to Be Changed

Magdeburg (GER), December 2012 - The use of virtual technologies provides a valuable complement to existing training programs. Training in technical processes can already be done interactively on virtual models in ways that make the functionality inside of machinery and equipment tangible. In LEARNTEC 2013's "Technology" section on 29 January at 3:45 pm, Dipl.-Ing. Tina Haase from the Fraunhofer Institute for Factory Operation and Automation (IFF) in Magdeburg will explain what makes virtual learning environments so attractive.




Why is the use of virtual technologies superior to existing training programs?

Tina Haase: Virtual learning environments provide a useful complement to traditional training courses, which are usually done with slide presentations. Through the use of virtual technologies, the roles of the participants and the teachers in the seminar change. In the past, seminar participants were often only passively involved. Now they work with actively, for example on a laptop where they can work interactively on learning tasks and, with the instructor's support, develop solutions by themselves. This is similar to real-life experience in the work process and improves long-term learning. The teacher is no longer the "solo entertainer", but rather becomes a learning facilitator.

The visual possibilities offered by the virtual learning environment increase the users' comprehension of the processes and relationships involved. This strengthens their professional competence during actual operation and optimally prepares them for their practical work. Even during the training, participants will already have a very good orientation on the technical equipment and become familiar with the procedures to be performed. This means the practical training takes less time.

At the Fraunhofer IFF in Magdeburg, we-˜ve been developing virtual learning environments for industrial use for about fifteen years. For example, we produced a virtual model of a bucket-wheel excavator for RWE Power that can be used in the planning of maintenance, including the replacement of the huge ball-bearing assembly. The virtual learning environment is now being used in the planning to prepare the employees involved in the various trades for the tasks to be undertaken and to discuss the procedures with the help of clear visual images of what's to be done.

In which areas is virtual training particularly relevant and useful?

Tina Haase: Learning in a virtual environment is particularly useful for applications when training on real machines, systems, or operating equipment is difficult or impossible. In many fields the machines used are dangerous, for example high-voltage equipment, where every step of the process has to be perfect. Virtual models make it possible to learn from mistakes, and the necessary competence can be developed without exposing the workers to peril.

Keeping track of processes and technical functions is often impossible on the actual machine due to limited visible access, but this understanding is crucial for safe operation in many areas of work, such as maintenance. The ball bearings in the rotation assembly to be replaced on a bucket-wheel excavator are not visible from the outside. Onsite instruction is extremely difficult and the people involved have no clear view of the interior of the ball-bearing assembly. To show them, it would be necessary to hoist the top housing and crane of the excavator - which weighs many tons.

In the virtual model of the machine, each component can be made visible and the details of how it functions shown. The procedures can be controlled at any speed and thus precisely understood.

When new machines and equipment are developed, the future operators can be trained on virtual models before the actual operation begins. This saves time.

However, virtual learning environments are not only suitable for use in seminars. In the work process, they can be used as a virtual knowledge base. Older people with extensive experience whose knowledge is in danger of being lost as a result of demographic change can fully document their expertise so it can be passed on to junior employees. During the maintenance of the bucket-wheel excavator, employees on site documented the work with photos and videos. These were incorporated into the virtual model and now can be used for similar future work.

What theoretical approaches are used?

Tina Haase: In technical applications, the basis for the development of virtual learning environments is 3D construction data. In general, this data is already available in the company for manufacturing. In the course of a work-process analysis, typical tasks are identified and specified. Besides the detailed description of the steps, external conditions can influence the work process. For example, the client can set a deadline for the job.

Learning tasks can be derived from the work orders. These are prepared in accordance with the well-known German vocational-education principle called "vollständige Handlung", which is variously translated as "self-contained activity" or "the complete action model". It includes the phases of information, planning, decision making, implementation, reflection, and evaluation. The learner can not only acquire information in the learning environment about the structure and function of the machine, but also about the occupational-safety regulations and the optimal way to undertake a task.

Planning and decision making are related to the choice of the proper equipment and tools, as well as the most appropriate required steps. In the simplest case, the trainee can then interactively perform the planned procedures with a mouse and keyboard.

Key question are used to direct the students in the virtual learning environment. This replaces what used to be done by the instructor in a classroom seminar.

What practical experience have you already assembled and evaluated?

Tina Haase: In the context of the ViERforES project funded by the German Ministry of Education and Research, a virtual learning application was evaluated for acceptability, usability, and learning results. The application was very well accepted by the participants, who saw it as an added value for their own work and expressed the desire to use it in the future. Even learners with no computer knowledge found it easy to use, and it allowed them to familiarize themselves with the subject matter quickly.

Can findings be transferred to non-technical areas?

Tina Haase: The didactic approaches of action orientation can be applied to non-technical fields such as medicine. Here, too, as in maintenance, a high level of problem-solving skills is necessary. In equipment maintenance, error analysis can lead to the proper corrective action in order to repair a technical problem. In medical terms this might be seen as the proper diagnosis being made and the correct therapy ordered based upon a specific symptom.

However, in contrast to equipment repair, a medical learning environment is not based on design data, but rather on layer data sets (MRI, CT) from which 3D models, e.g. of organs, are reconstructed.