Evolution of the biomechanical dimension of the professional gestures of grinders when using a collaborative robot

Using cobot could relieve workers of strenuous and repetitive tasks while preserving their expertise. To understand the consequences of using cobot on the occurrence of MSDs, within a theoretical framework based on the activity-centred ergonomics, an example of a cobot used in grinding activities in real work situation is studied. This paper analyse the evolution of the biomechanical dimension of the professional gestures of grinders when using the cobot. The effort linked to tool carrying and the vibrations perceived reduce. The repetitiveness decreased but the workers didn't accomplish the entirety of their task. The work postures did improve for different joints but not for all, which shows the advantage of varying the contexts of using a cobot and taking into account workers' strategies diversity. To investigate other explanatory elements of the effects on MSDs, these results must be linked to the evolution of the other dimensions of professional gestures.

Temporal leeway: can it help to reduce biomechanical load for older workers performing repetitive light assembly tasks?

Current industrial production systems allow assembly of customised products which include additional elements distinguishing them from a reference model. This customisation can result in significant additional time constraints which compel workers to complete their tasks faster, which may pose problems for older workers. The objective of this laboratory study was to investigate the impact of restrictive or flexible pacing during assembly of customised products among groups of younger and older participants. The data gathered were used to analyse cycle-time, assembly performance, muscular load, and kinematic adaptations. The flexible pacing condition was found to improve production performance, increasing customised assembly cycle-time and reducing biomechanical load, for both young and older participants. However, as the task required fine manual dexterity, older participants were subjected to a higher biomechanical load, even in the flexible pacing scenario. These results should encourage assembly-line designers to allow flexible time constraints as much as possible and to be particularly attentive to the needs of older workers.