Manipolazione Adattiva: Sviluppo di un Dispositivo di Presa Cedevole Pneumatico a Tre Dita Riconfigurabile con Sensori Integrati

In recent years, soft robotics has gained increasing attention for its potential to revolutionize traditional robotic paradigms through the use of deformable materials and compliant actuation mechanisms. This study combines soft robotics with two emerging technologies, collaborative robotics and additive manufacturing, to design a reconfigurable, sensorized soft pneumatic gripper. The goal is the safe manipulation of objects with different shapes, dimensions, stiffnesses, and masses. To provide context and guide the reader, this thesis presents a concise overview of earlier efforts, highlighting the key findings and design considerations that led to the development of the final externally reinforced and sensorized soft pneumatic actuators. A gripper has been realized by integrating three of these actuators, which act as fingers equally spaced at 120°. Each actuator integrates two 3D-printed sensors directly embedded within the reinforcement: a capacitive sensor measuring the force applied to the object, and a resistive sensor measuring the bending angle. Additionally, a pressure sensor has been added to the air connector to control pressurization via a digital solenoid valve. The latter is managed by a fuzzy logic controller, which adjusts the duty-cycle of the pulse-width modulation command signal, based on the pressure error (strictly correlated to the actuator bending), compensating for the asymmetries in charge and in discharge. Three stepper motors enable adjustment of the radial placement of the actuators, while another adjusts their angular orientation, with respect to the horizontal plane, via a kinematic chain, ensuring high adaptability and versatility. Additive manufacturing played a central role in the design and fabrication of the system, enabling rapid iteration between design and experimental testing and minimizing component mass. Experimental results confirm the accuracy of the proposed analytical model and demonstrate the device's effectiveness, capable of safely manipulating objects with a mass up to 662 g and dimensions up to 148.8 mm without losing contact. The thesis work is organized as follows. Chapter I introduces the background and motivation of the research project. A detailed overview of soft pneumatic actuators is provided in Chapter II. Chapter III presents the development of several soft pneumatic actuators, including the details of their fabrication and experimental characterization. The gripper’s components, modelling, control strategies, and testing are described in Chapter IV. Finally, Chapter V concludes with a summary of the main results and a discussion of possible future improvements.