## 4 The Layout Designing of the Collaborative Workplace Supported by a Modeling Paradigm
### Modeling Paradigm
#### 4.1.1 Elements of Modeling Paradigm  
The collaborative workplace is modeled by defining (i) the physical entities that are part of it; (ii) the performed operations, on the one hand in terms of elementary tasks, and on the other, in terms of the type of robotic application; and (iii) the workspaces. More specifically, the collaborative workplace is described in terms of its tangible components [54]. It consists of resources--a stock or supply of materials, staff, and other assets--that can be drawn on in order to carry out tasks on certain workpieces. The resources may be active or passive resources [35]. Active resources are defined as resources that are trained to perform a certain task. Robot systems and humans are active resources. On another hand, the passive resources such as fixtures, static structures, tables, logistic resources, and even machine tools, are used to perform a certain task. The workpiece is the object of the performed tasks. As already established by [PERSON] et al. [54], it can be composed of the principal component and any sub-components. Then, the workplace is analyzed from a process-related perspective. The operation carried out in the workplace is described in terms of elementary tasks. After, the tasks are classified by type and by level of interaction between human beings and robots. Three main task types are defined:  
* _Process task_ is a valued-added task; it can be performed by humans and/or robots, using either elementary tools or even machine tools. * _Transport task_ is a material handling task; it can be performed by human, cobot, mobile manipulators, simple AGVs, as well as by means of passive resources such as conveyors. * _Control task_ does not contribute materially to the actual processing; it has to be ent trusted to human being since it concerns cobot control tasks. It could be performed by means of a human machine interface (HMI) such as pendant controller, smartwatch, tablet, or computer. Tasks are further characterized by level of interaction between humans and robots. Based on the classifications already given in [27], this work proposes four level of interaction:  
* _Independent tasks_: humans and robots perform different tasks on different workpieces. * _Sequential tasks_: humans and robots perform different tasks on the same workpiece placed in the same position. They share the same workspace but at different times (the robot is inactive when a human enters the collaborative space). * _Parallel tasks_: humans and robots perform separate tasks for the same goal at the same time. There is no physical contact between the human operator and the robot system. This level includes tasks which are performed inline. * _Collaborative tasks_: humans and robots work cooperatively in order to complete the processing of a single workpiece. Contact is allowed (but not strictly necessary) since the robot and human can work \"hand-in-hand\". Furthermore, the collaborative workplace is characterized according to the use made of the cobot(s) within it. The most common applications for which cobots installed by key vendors are employed, are showed in Figure 3. These applications are grouped into four main macro-categories according to their similarities, as follows: (i) _Material handling_ when cobots are involved in the transport of material (e.g., pick and place, machine tending, packaging, pelletizing, and parts orientations); (ii) _Assembly/Disassembly_ when cobotsperform screwdriving, nut fastening, etc. ; (iii) _Precision Machining_ when cobots perform soldering, gluing, milling, cutting, etc. ; (iv) _Inspection_ when cobots perform quality testing, non-destructive testing, and so on. Obviously, a workplace could be composed of multiple cobots used for different categories of application.