## 1 Introduction  
Industry 4.0 is largely responsible for transformations throughout the production chain, from project areas to the internal structure of companies [1]. Technology and robotics drive markets, providing solutions capable of raising productivity and stimulating business. The biggest advantage of robots is that they can be used in dangerous and unhealthy activities, allowing professionals to coordinate tasks in a safe environment, without risking their health [2]. According to IRF [3], the installation of industrial robots is increasing annually, although there was a decrease in 2019 due to COVID-19, Figure 1 shows the number of robots installed between 2009 and 2019. An average increase of 12% is expected between 2020 and 2022. Robotics are characterized as a multidisciplinary and vast application area. In addition to the figures presented above, which are closely related to production and higher quality, the collaboration of robotics and human has caused a new robotics branch to emerge called collaborative robotics. This robotics branch has gained prominence for its great applicability and simplicity. Figure 2 shows the evolution of collaborative robots in relation to traditional robots. Many industrial sectors are increasingly opting for robotic applications to solve and perform tasks due to a number of reasons: technological advances, worldwide population increase (need for large-scale production and services), improving and optimizing the quality of products and/or operations (due to uncertainty, errors, and human sensitivity), due to non-favorable tasks and the need to reduce accidents in some applications [4]. Thus, robots are becoming a very important mechanism for industries due to their wide applications, quick adaptation, and continuous working ability. The reduction in the cost of technological solutions for scientific purposes that provide good results, combined with low-cost materials, as well as new solutions and methods, can be proposed to accelerate Industry 4.0. For example, Ref. [5] adapts engineering education to Industry 4.0, and [6] presents a scoping review on digital English and education in Industry 4.0. When the term collaborative robotics is mentioned, issues such as safety, flexibility, and cost are usually raised. The Robotic Industries Association [7] presents the benefits of collaborative robots against these issues. As for safety, collaborative robots are designed to minimize the risk of accidents and injuries in the workplace by being equipped with sensors to prevent collisions, force limitations, and overload protection (increased electrical current), and passive compliance in case of accidental contact. These safety standards follow standard regulations [8]. As for flexibility, collaborative robots can be easily programmed, even by workers with no knowledge of robot programming. As for cost, the ease of programming a collaborative robot reduces the time and resources needed for its integration into the process, which reduces investments in automation. Collaborative robots come equipped with safety features and do not require fences or other industrial safety equipment, further reducing costs and integration time. The factors that influence the acquisition of a collaborative robot are internal (structure, size, infrastructure, etc. ), external (suppliers, competitors, funding and government agencies, customers, etc.) and technological (economic analysis, degree of innovation, compatibility, speed to perform tasks, complexity, reliability) [9]. Human-robot interactions can categorize the workspace into different forms and, consequently, different classifications [10], namely:  
Figure 1: Numbers (\(\times\)1000) of industrial robots installed per year [3]. Figure 2: Annual evolution of the acquisition (\(\times\)1000) of collaborative robots versus traditional robots [3]. coexistence, synchronization, cooperation, and collaboration.