  The objective of this paper is to develop and evaluate a directional
vibrotactile feedback interface as a guidance tool for postural adjustments
during work. In contrast to the existing active and wearable systems such as
exoskeletons, we aim to create a lightweight and intuitive interface, capable
of guiding its wearers towards more ergonomic and healthy working conditions.
To achieve this, a vibrotactile device called ErgoTac is employed to develop
three different feedback modalities that are able to provide a directional
guidance at the body segments towards a desired pose. In addition, an
evaluation is made to find the most suitable, comfortable, and intuitive
feedback modality for the user. Therefore, these modalities are first compared
experimentally on fifteen subjects wearing eight ErgoTac devices to achieve
targeted arm and torso configurations. The most effective directional feedback
modality is then evaluated on five subjects in a set of experiments in which an
ergonomic optimisation module provides the optimised body posture while
performing heavy lifting or forceful exertion tasks. The results yield strong
evidence on the usefulness and the intuitiveness of one of the developed
modalities in providing guidance towards ergonomic working conditions, by
minimising the effect of an external load on body joints. We believe that the
integration of such low-cost devices in workplaces can help address the
well-known and complex problem of work-related musculoskeletal disorders.
