CRF has been working for years in the research of technological solutions for supporting workers, for instance in the modification of workstations and work methods or in the implementation of innovative tools, equipment, or exoskeletons. Innovation in this field is highly dynamic. Several new assistive technologies have emerged or are emerging in recent years, with the aim of applying concepts such as human centred manufacturing, IoT ecosystems, data analytics for preventive or predictive interventions with the dual purpose of improving the operators’ working conditions and enhancing efficiency and quality of the production process. This trend is even more important in recent years due to the general ageing of the population and in particular of the working population.
All the new aiding technologies need to be selected and tested carefully before initiating the implementation plan to introduce them in the industrial environment. The selection phase is important to define if the adoption of the new technology fits the needs of workstations and work tasks during the work activity.
Recently CRF developed a methodology to approach the evaluation of new products or prototypes and new technologies for assistive work for the Stellantis plants.
The methodology was developed in particular for exoskeletons introduction in FCA and CHNI assembly plants. It gathers the experience of several years of testing new technologies for the improvement of workstations and is intended to guide the testing and the introduction of new assisting innovative solutions at present and in the future.
Exoskeletons are external mechanical structures, active or passive, that support the worker in specific work tasks . These systems are designed to give physical support in certain body districts; those addressed to the industrial world are mainly oriented to assist the back and upper limbs with targets of postural assistance, applied force reduction, manual material handling and supporting tools.
The procedures for exoskeleton evaluation are mainly focused on performances assessment of the device . SEMG (Surface Electro MyoGraphy) is often the discriminating instrument used for effectiveness estimation, but it’s complicated to apply it in the production environment . Several methods developed for practical evaluation are available according to the experience of the case ,, but need to be generalized and linked to the needs of the workstation. Since no standard evaluation method was available in the literature, CRF developed a new methodology that assesses and compares functionalities, performances, usability and applicability of passive devices in simulated and real workplaces.
The proposed methodology improved the exoskeletons evaluation because based on objective and standard criteria linked to the workstation needs and made possible a comparison among different devices.
The first objective is to detect the most suitable exoskeleton for the workstation appointed for a specific task. This objective is focused on the fulfillment of the needs of the work task and the related workstation including the equipment. The second objective is to estimate the level of fitting and the compliance degree between the selected exoskeleton and the workstation under analysis. This requires to know the performances and functionalities of the exoskeletons available on the market, and put them in relationship with the workstation needs. Finally, the third objective is to improve the workstation ergonomics increasing the worker well-being. This objective is achievable by the fulfillment of the previous two objectives, and by the fulfillment of usability requirements for the selected exoskeleton.
The proposed methodology aims to mathematize qualitative evaluation and to make a correlation between the needs of the production system (made of workstation, work task and worker) and the exoskeleton performances. The best matching between production system needs and exoskeleton performances helps the worker in his task, increasing ergonomics and wellbeing perception.
The methodology consists of two phases: the first phase is the exoskeleton selection through laboratory testing. The second phase is the exoskeleton evaluation in real environment by its application to a pilot case.
The first phase is based on three main steps. The first step is the workstation characterization and focuses on the detection of the workstation needs, considering the following main items: ergonomics postures, workplace geometrical characteristics, work cycle time, loads to be moved. The second step investigates performances and functionalities of exoskeletons to define effects on the human body, through objective evaluations. Two items of the usability analysis (efficacy and efficiency) are considered. This evaluation is carried out by measurement instruments and biomechanical simulation tools, in comparative tests on working tasks performed with and without the exoskeleton. This part of the work is carried out in the laboratory on real-like tasks, in order to classify exoskeletons and build a database of the main functionalities. Filling a correlation matrix for crossing workstation needs and exoskeleton performances is the last step. The correlation matrix is based on a scoring, giving the level of fulfillment of exoskeleton performance in respect to the needs of the workstation. This step is developed by routine that fill in the matrix automatically gathering info from the database about workstation characteristics. It is an iterative process that leads to the exoskeleton selection.
figure 1: method
Figure 2: Correlation matrix
The second phase consists in exoskeletons testing on real workplaces in production line (in particular on those from which the real-like tasks derive). This is made to gather operators’ feedback about the support received by the device, and its usability (subjective item: satisfaction), applicability (vs. technical and managerial constraints) and acceptability (of the social environment).
The proposed methodology was successfully applied in more than 20 workstations analysis in CNH Industrial productions plants, returning a score that summarizes the goodness of the coupling between exoskeleton and workstation. The application of the methodology pointed out the importance of a first evaluation stage (in the laboratory) that helps the second phase (in plants) reducing the number of issues that could be found in the real pilot case. Finally it emerged that the user “acceptability item” is a key element and if is not good it can compromise the successful exoskeleton implementation.
All the proposed evaluation phases gives us the global effect of introducing an exoskeleton on a specific workstation considering the realistic context of use. Based on the whole methodology we are able to provide guideline to the FCA/CNHI production plants for exoskeleton choice and application.
The methodology defined in details for exoskeleton implementation gives also a guideline to decline similar evaluation methods for many other new assisting technologies. Among them, also the Final Integrated Prototype that will be the final output of the sustAGE project.