Requirements engineering in industry 4.0: State of the art and directions to continuous requirements engineering

The 4th Industrial Revolution, also known as Industry 4.0, intends to transform manufacturing processes into smart factories with full digitalization and intelligent, decentralized, and flexible production. In this scenario, Industry 4.0 systems (i.e., software-intensive systems that automate smart factories) have required rigorous and continuous development, but smart factory companies often have difficulty dealing with Requirements Engineering (RE) where requirements continuously change and emerge at runtime to support the changeability of complex production processes. Such requirements encompass engineering (e.g., mechanical, electrical, electronic, production/manufacturing) and business areas and involve the vertical and horizontal integration of heterogeneous manufacturing systems. There is also a lack of a panorama of how Industry 4.0 projects have performed with RE activities. The main goal of this paper is to present the state-of-the-art research concerning RE in Industry 4.0 and draw attention to the next most urgent steps. For this, we selected and examined studies that address RE for Industry 4.0, noting that much of this literature is recent but does not fully address the complexity and dynamism of the requirements for Industry 4.0. Grounded on these studies and our academic and industry experience, we highlight the need for Continuous Requirements Engineering (CRE) for Industry 4.0.Significance and Practitioner Points: The main implications of this paper are: (i) For researchers: It offers the state of the art of RE in the context of Industry 4.0 and points out several important open issues that require an urgent investigation through new research topics; and (ii) For practitioners: It provides directions for new or even existing Industry 4.0 projects on how to deal with RE activities aiming to overcome the several challenges to perform them.