Design and evaluation of different digital control technologies of a mobile manipulator

The term Industry 4.0 indicates the fourth industrial revolution. It consists of a production and business management model based on the interconnection between physical and digital devices. In particular, the manufacturing sector is experiencing a new era of development powered by a series of emerging high technologies such as human-robot collaboration, the Industrial Internet of Things (IIoT), cyber-physical systems, augmented reality, machine learning, and artificial intelligence. These features are necessary to analyse, interpret, and predict the real behaviour of machines and devices used in the manufacturing sector, such as autonomous robots and automated guided vehicles (AGVs). One of the main benefits of the digital transition driven by Industry 4.0 is the real-time accessibility of comprehensive information from devices involved in the manufacturing processes, acquired by integrated sensors embedded in the machines and camera systems that monitor the shop floor, and transmitted through the internet network. As a result, these data can be stored for further processing and readily accessed and utilized to build a virtual environment as faithful as possible to the real one. In recent years, the concept of Digital Twin (DT) has gained significant importance in this field of research. It was created to operate in parallel and interact with real-world physical production equipment, enabling a bidirectional data transmission. Indeed, the DT can receive data from the factory floor and can also transmit data back to trigger specific actions in the manufacturing process. The DT can be used for a variety of purposes, including remote supervision, condition monitoring, and testing and validation. The advantages of this technology are: • The possibility to analyse hypothetical scenarios and plan future changes, thus reducing implementation time and costs. • The anticipation of potential problems that may arise in the future. • The reduction of accidents since it can simulate all kinds of situations. • The increase of productivity and optimization of costs. • Avoiding the risks of damages and possible harmful actions for humans. In addition to the Digital Twin concept, mention should be made of the Digital Model (DM) and the Digital Shadow (DS), other virtual simulation technologies used especially for the static analysis and real-time monitoring of the physical working environment. The main difference is the data transmission modality. Indeed, the Digital Model does not use any form of automated data exchange, whereas the Digital Shadow allows only one-way data flow. This means that a change in the states of a real physical object leads to a modification in the digital one, but not the opposite situation. The objective of this thesis is twofold. First, to develop a DM of a Mobile Manipulator (MoMa) pick and place application, assessing its accuracy by comparing the simulation results with the reference ones obtained by means of Optitrack Motive, a real-time 3D tracking camera system. Second, the attempt to implement a DT, employing the ROS environment to acquire real-time data from the physical objects connected to the same network as the ROS machine. In this way, it is possible to monitor the movements of the robots in real-time, simulate possible scenarios, and communicate with the physical world in both directions. Finally, the Matlab ROS Toolbox provides the ability to acquire the data directly in this simulation workspace and, through Simulink, implement real-time control operations