# Human-Robot Interaction for Improving Fuselage Assembly Tasks: A Case Study
## 1 Introduction  
In the new industrial era, ergonomics is crucial for occupational safety and productivity improvement in different manufacturing sectors such as the automotive and aerospace industry, which is one of the largest and most demanding production areas. Therefore, safety is a fundamental aspect that is sought through the use of improved tools in production processes, and the implementation of efficient and safe techniques to adapt people to work in order to optimize well-being and to increase productivity. Focusing on the aerospace field, the design of appropriate workstations is essential to improve occupational health, safety and work efficiency [1]. Even if aerospace production is not as systematized as automotive production--with much longer cycle times--it is equally affected by ergonomic issues. On the contrary, in many working activities characterizing aerospace production lines, the biomechanical load is very high due to awkward postures, lifting heavy components, exerting high forces and repetitive actions. Even in the case of the aerospace industry, if workers are subject to these factors, the risk of injury and muscle fatigue is high [2]. Many studies show that interactions among humans, technologies, organizations and working environments are strictly influenced by ergonomics. Often, the main causes of quality deficiencies are associated with ergonomic issues in terms of environmental conditions, suitable design of technology and an inappropriate organization [3]. Therefore, ergonomics may become the driving force for the improvement of new quality processes and production strategies. In aerospace field, improving ergonomics allows reaching the aim of producing high quality aircraft through the study of human specifications for the suitable design of the living and working environment [4]. Tools, devices, machines, appliances and the environment all lead to the advancement of the safety levels, well-being and human performances, as suggested by [PERSON] et al. [5]. In industry, humans represent the primary production resource, and their efficiency in performing working tasks represents the main factor of productivity, a primary factor of economic activity [6]. In the literature concerning aerospace applications, it is possible to find many studies on the analysis of ergonomic aspects such as the safety and comfort in the passenger cabin and passenger compartment. These studies are mainly focused on the assessment of key factors, such as head and legroom and the ease with which the stowage can be reached. However, from the production process point of view, rarely ergonomic factors have been analyzed during the assembly phases, applying ergonomics principles only in borderline situations and in limited space, a typical condition to which the operators are exposed, which increase the risk of musculoskeletal injuries [7]. In this sense, studies were conducted during the wing assembly phases which, as most aerospace components, require static and uncomfortable postures that increase the risk of physical illness and hinder the execution of tasks. Different solutions to optimize the assembly process were investigated [8; 9], by changing the orientation and accessibility of the product through the introduction of a rotating device capable of keeping the entire wing in an open box condition and allowing the operator to assume ergonomic postures. However, except in rare case, since ergonomics has never been adequately considered, the need to design new production lines, based on ergonomics principles, arises; in this case, simulation tools and virtual ergonomics are essential to design safe and high-performance workstations [10]. Indeed, in the recent years the industrial world is experiencing a massive implementation of digital technological systems. These could be useful for better verifying and validating the ergonomic factors in the design, production and maintenance processes and, in general, for testing the design solutions and the functionality of machines or robots.