Open Access

Ergonomic assessment of manual work processes is important to prevent workplace injuries. Virtual reality simulations can be used to carry out an evaluation of work equipment and workplaces very early on. In combination with motion tracking analyses, data on posture during task performance and product use can then be collected. However, not all work situations can be equally represented in a virtual simulation. In particular, the virtual analysis of load handling poses a challenge in simulation, as body posture changes under the influence of external load weights. The aim is to increase immersion to bring the body movements in the virtual simulation closer to those in the real simulation with weights. For building up VR simulations with different aspects of visual, auditory and haptic immersion a scheme called immersion cube is presented. In order to be able to simulate load handling in VR, the immersion cube is used to investigate how much haptic immersion is needed to obtain sufficiently good data for the body movements measured in a VR setting. The first study showed that the deviation between real and virtual executions depends heavily on the task (lifting from the ground, move while standing, lifting over the shoulder). In some tasks, virtual and real simulation are very close to one another for certain body movements and could therefore in principle be used for ergonomic assessment. On the other hand there are still movements that vary between these two forms of execution and therefore show a need for increasing the immersion.

In several domains of product design - like medical device design - risk related use scenarios have to be analyzed in an early stage of design process. Virtual reviews with users make it possible to get early insights in use problems. Also, situations that are difficult to imitate in reality can be modeled and simulated in virtual reality without risking the health of user. Therefore, virtual usability tests are a promising approach which allow testing different scenarios under controlled conditions. We chose a sample scenario from medical device design and compare and evaluate different technical systems which can be used for virtual usability tests. Aim is to derive guidance for virtual usability tests including systems that can be used for specific conditions and the qualitative and quantitative data, which can be collected with these systems. A formative test is performed to evaluate and compare different systems. Also, a summative test is performed to evaluate the selected systems. Results show that virtual usability tests make it possible to test scenarios with users in an early stage and thus to encounter possible interaction problems. But there are also many additional and new things to consider compared to normal usability tests, such as checking motion sickness, maintaining presence and the extensive operation of the technology. Finally, a proposed method for virtual usability testing is described which also comprises our equipment recommendations for virtual usability tests.