Progetto e realizzazione di una piattaforma scalabile per la robotica mobile

The main objective of my activity, was to create a mobile platform with a focus on two aspects: teaching and some particular applications in the real world. Regarding education, the fundamental choice has been to develop internally most of the components rather than acquire them from third parties; this choice has encouraged the full knowledge of every single part of the mobot, whether mechanical, hw or sw, leaving open any future development and replication of the system. The result is a device on which you can conduct research in mobile robotics and articial intelligence, enabling students to gain experience in the field of automatic controls at various levels of development: sw, fw, hw and mechanic. As regards the real world applications, special attention was paid to two areas of employ of these devices: the mobot for service (i.e trays door mobot, surveillance staff,...) and assistance to disabled and elderly people. Following are reported some of the main aspects that have characterized SabotOne development. - The name SabotOne Sabot is the acronym for Scalable mobot (i.e mobile robots). The main focus which drive the design of each component, was to create a modular system allowing expandability of mobot. - Machanics The design of the mechanical parts has been made through the 3D-CAD modeling. All the parts were then made from aluminum and assembled to form the entire SabotOne device. The platforms are modular, providing accommodation of the electronics in the lower levels, leaving the higher ones to specific uses depending on field of use of the mobot. The kinematics of the mobot, reects the unicycle physical model which provides mobility of the device even in tight spaces and is very similar to that of wheelchairs for the disabled people. - Electronics It has been designed and realized a board for electrical axis control in position loop. The board can control two direct current motors used in the mobot traction. It was realized firmware and designed the communication protocols in order to make this card appropriate in robotics applications in which it was used. The board has been equipped with signal condition electronic to provide acquisition of sensory signals (A/D converter, GPIO). Moreover, three communication protocols are made available on the board: CAN, TCP/IP (802.11b/g, RJ45) and Modbus on RS485. On the ethernet interface a web server is available to set conguration parameters board, while the serial interface enable the board to exchange information with a smart unit such as an embedded-pc equipped with an operating system. - Software { Development of Sabot Workbench It is a tool that is used to remote monitoring all Sabots connected to a network. It was developed using the modern framework Eclipse Java-RCP. This framework has enabled the modeling of all the features of the Workbench through the paradigm of the plugin. This allows to add functionality to the application without having to modify the application core. { Design of Communication protocol between Workbench and Sabot It is based on Jabber/XMPP protocol and the specification SensML/SWE (designed by Open Geospatial Consor- tium). It is designed to integrate XMPP (used as information carrier) and SensML/SWE that defines the ontologies for describing measurable phenomena and relative sensors. It has been dened the concept of identity of a controlled system and integrated within XMPP protocol. The SensML specification has been extended to support the concept of actuator. The protocol designed, was denoted with the acronym ControlML. { Development of trajectory control, path planning and autolocalization algorithms Path planning has been developed in C++ implementing LPN algorithm. It was built a sim- ulator to verify the algorithm efficiency and completeness. It has seen that the algorithm is complete (can always and a path toward a target qual'ora this exists) and is efficient (planning a course in less than 100ms over a space partitioned into 10.000 cells). The trajectory control was achieved by implementing two different algorithms, the first based on pseudoinversion of dynamic system characterized from non-holonomic constraints, the second conducted by the dy- namic feedback linearization. It was built a simulator to verify the tracking error of controllers and we have seen that both controllers are able to undo the following error. For autolocalization, it has been acquired an inertial platform on which was implemented a Kalman Filter for the \fusion" of various sensory data (accelerometers, gyroscopes and magnetometers). It has seen that the inertial data should have to be \merged" with references to absolute position (feature extracted from images or RFID tag) because of the intrinsic drift of inertial sensors. { Development of SabotSabot smart unit software architecture It has been designed and developed an abstaction of operating system using object oriented paradigm (design pattern) to decouple the application-level from O.S adopted in this application (linux). It has developed an architecture that can realize the concept of run-time plugin by lazy-loading of libraries in linux. In this framework are integrated the algorithms for planning trajectory, for autolocalizing and avoiding obstacle. The communication protocol ControlML takes care to keep in touch the Sabots and the control stations with Workbench. The framework was designed in UML language using strategies oriented to Items and criteria for \Design Pattern" and \Real time design pattern" inertial sensors.