Design and Simulation of Multilevel Interacting Mobile Robots for Space and Industrial Applications

When studying and planning to use mobile robots that need to be deployed in any application scenario, these robots are always subjected to different kind of interactions. These can be classified into three major groups: interactions between robots and their surroundings, interactions between the robot and other robotic devices, and interactions between robots and humans. Therefore, it becomes necessary, in the study and design phase, to take into account, study, model, and address these interactions to achieve proper and optimal performance of the robot, and to to avoid unpleasant situations. In this dissertation, the interactions occurring on deployed mobile robots are addressed in different contexts. Specifically, this dissertation is divided into two main declinations: mobile robotics for space applications and for the industrial settings. Finally, with a focus on robot interactions, considerable attention is placed on the development of methods needed to address and solve them. The main achievements obtained for the space applications field are the control of vehicles for space exploration in exotic applications, e.g. manipulation of objects via towing, and the study of the dynamics of complex robotic systems, e.g. articulated planetary rovers and landers. For the industrial settings field, instead, are the development of a framework for the synthesis of a fleet manager that controls a fleet of tethered robots, and the setup of a framework for the development of smart controllers for mobile robots navigating moving crowds. This dissertation is structured into four major chapters. The first provides an introduction to mobile robotics from a very general point of view, along with a classification of the various types of interactions that occur on robots. An overview of the use of mobile robots in the two macro fields of application considered, in general, is also provided, along with the problems and challenges characteristic of each of these fields. Finally, it provides a brief overview of the methodology and tools that will be used in subsequent chapters. The second chapter focuses on the development and application of mobile robots in the context of space mobile robotics. The problem of soft-landing of an innovative robotic lander for space exploration is presented. Next, an innovative prototype named Archimede, of a four-wheel steerable rover is featured. Its design includes a suspension system, which ensures higher operational speeds. Moreover, every single aspect and component of the rover is first described, followed by a focus on steering capability and impact dissipation. The interaction between the wheels and the ground is then studied. Finally, it proposes a detailed study on a technique for manipulating ground-resting loads, i.e. towing through elastic elements. In this context, the employment of this technique on the Archimede rover is studied and validated. The third focuses on the development and application of mobile robots in the field of industrial mobile robotics. A problem characterised by robot-environment and robot-robot interactions is first addressed. Specifically, a multi-robot problem is considered where individual robots are chained together with cables, to meet the existing demands of a specific industrial context. Therefore, a high-level controller is presented, which assumes the role of the fleet-manager using techniques specific to redundant manipulators. This system aims to manage the fleet while allowing robots to perform tasks. Next, one kind of human-robot interaction is presented, i.e. the problem of navigating a mobile robot through a moving crowd. Specifically, the controller of the mobile robot is based on artificial neural networks, and trained in appropriate simulation environments using Reinforcement Learning techniques. The performance of the controller is then validated numerically and experimentally. The fourth and final chapter reports the conclusions of this dissertation work.