Considerations about the development of a Ballbot = Considerations about the development of a Ballbot

In this document are developed considerations about the design and control of a particular system located in the field of mobile robotics, called Ballbot. A Ballbot has a particular structure that allows to present a new concept of mobility, it is a dynamically stable mobile robot that must balance itself on a sphere that guarantees the omnidirectionality movement. Principally, it was analyzed a Ballbot with a ball drive-mechanism composed of three omnidirectional wheels. In the first instance, a two-dimensional modeling of the system, considered as an inverted pendulum, was studied on the two decoupled XZ, YX planes. Congruently, to achieve the system stability, a control system was developed through the use of Matlab software and its Simulink tool. In particular,was employed an optimal control theory implemented by an LQR (Linear Quadratic Regulator). Using Simscape, a Matlab tool that allows the modeling and the simulation of a multidomain physical system, a simplification of the physical model of the thought ballbot has been built. To simulate the behavior of the Ballbot model, the balancing commands developed by the LQR controller were used as input for the Simscape model. Various tests on balancing of the simplified Ballbot prototype were performed by varying the initial state-target of the ballbot, giving an inpulsive stimuli and evaluating the balancing capacity of the system in Simscape simulation environment. At a later time, the attention was dedicated on the Electronics that allows the control of the sphere. An Arduino-MKR1000 has been chosen as microcontroller, therefore it follows a description of the affiliated sensors necessary for the ballbot system. Consequently, using appropriate support packages and libraries, a possible control system was conceived in Simulink considering a Simulink-Arduino interface about sensoring and actuators. As a future work, it is expected to be able to perform the Simulink code-generation of the model of the developed controller, the consequent update of the code on the Arduino board and, in an optimistic view, to execute tests on a physical ballbot system.