## 1 Introduction  
The past few decades have seen an exponential growth in medical technology, particularly with regard to the application of robotics to surgery. Robotic surgery, the latest evolution of minimally invasive surgery, overcoming the limits of traditional surgery, has allowed the broadening of therapeutic horizons and represents the gold standard for various clinical applications. Robotics is the center of modern health engineering. The first robot used in the clinical setting to obtain neurosurgical biopsies was the Puma 560 robot in 1985. Since then, more and more advanced surgical robots have been developed [1, 2]. In general, the use of robotic surgery increased significantly from 2012 to 2018, with an increase from 1.8% to 15.1% for all general surgery procedures. Over the same period, the use of both laparoscopic and open surgery declined. For example, the proportional use of open surgery was 42.4% in 2012, compared to 32.4% in 2018 [3]. It has also been witnessed that the use of robotic surgery has increased rapidly and spread widely in numerous procedures during the years following the adoption of this practice in hospitals. Therefore, for most surgeons, it was already considered a safe and effective approach when clinically feasible. Current robotic platforms are designed to incorporate advanced features that allow for increased accuracy by making the execution of operator tasks easier and safer. Additionally, surgical robots have retained the ability to perform surgical operations through smaller incisions. These characteristics aim to improve the results compared to those obtainable through traditional surgical methods. The adoption and diffusion of robotic surgery shows a positive trend in some geographical areas, especially in countries with advanced economies. This is shown by the widespread use of the da Vinci Surgical System (Intuitive Surgical Inc., Sunnyvale, CA, USA), in a multitude of application areas [4]. Currently, the da Vinci Surgical System represents the most widespread surgical system, with over 5000 models implemented worldwide, performing over 7 million surgical procedures in different anatomical areas. The da Vinci Research Kit (dVRK) research platform fits into this context, developed through a collaboration among academic institutions to address the challenges in starting research on surgical robotics. This has led to a significant boost in the development of surgical robotics research over the past decade, and has generated new opportunities for collaboration and linking of a surgical robot to other technologies. Among the advantages introduced by robot-assisted surgery are the reduction in tissue trauma thanks to small incisions, less bleeding, and less need for transfusions, a reduction in hospital stays and post-operative pain, a reduction in recovery times, and a quicker recovery rate in carrying out daily activities and greater ease in the execution of complex surgical tasks, which entails greater safety for the patient. On the other hand, the disadvantages of robotic surgery are mainly linked to the cost of the robotic system, the instrumentation, the system maintenance, and to the fact that, to operate the robot, very high-level skills are required on the part of the surgeon and room staff, to be acquired through specific training [5]. During an open surgery, surgeons can use their hand to locate and diagnose abnormal tissue by direct palpation; instead, in laparoscopic surgery, direct palpation is not feasible, due to the limits of the incision [6,7]. For this reason, one aspect that many studies are focusing on is the lack of haptic feedback during the surgical procedure, in addition to visual feedback [8,9]. Nevertheless, surgeons using robotic technologies could benefit from other types of feedback, such as feedbacks of color, speed, and proximity, to further broaden the fields of the application of surgical robots [10,11].