• low-melting-point alloys
• minimally invasive surgery
• soft robotics
• variable stiffness

The field of surgery is under continuous evolution, surgeons explore new approaches to improve outcomes for patients by making procedures safer and more effective. The transition from traditional surgery to minimally invasive surgery (MIS) has significantly improved the patient's quality of life. However, MIS is more demanding for the surgeon, to open surgery, yielding an increase in the technical complexity of the procedure. Therefore, novel articulated portable devices were designed and manufactured in such a way to be provided with additional degrees of mobility. These highly flexible and dexterous devices offer greater maneuverability, allowing safe interaction with the target tissues, at the expense of less stability and the ability to exert the required forces to operate in surgical procedures. Therefore, researchers focus on studying the animal and plant world to develop devices with variable stiffness, capable of having the stability and strength of rigid systems, but also provided with the properties of soft structures. In the world of soft robotics, variable stiffness mechanisms may exploit semiactive actuators. In particular, low melting point alloys (LMPAs) are metal alloys that become liquid at relatively low temperatures (42–62 °C, depending on the alloy composition). They have relatively high stiffnesses and maintain their solid, load-bearing state without energy consumption. This thesis work focuses on the above-mentioned barriers and presents a soft robotic surgical device for MIS. The actuation relies on pneumatic principles and the variable stiffness mechanism is based on LMPAs. The aim of the work concerns the effective integration of the stiffening system which does not interfere with the presence of the pneumatic chambers and the operative channel. The device is subjected to a mechanical characterization, to investigate the performance, especially the modules are evaluated in terms of dexterity and variable stiffness capability also in comparison to analytical models and other stiffening technologies