Alessandro Diodato

Feedback Control of Soft Robot Actuators via Commercial Flex Bend Sensors

Soft robotics is an emerging field that takes advantage of compliant materials and makes use of nonstandard actuators. Flexible fluid actuators (FFAs) use fluid pressure to produce high deformation of elastomeric-based structures. However, closed-loop control of such actuators is still very challenging due to the lack of robust, reliable, and inexpensive sensors that can be integrated onto highly deformable actuator structures, involving very low cost materials and manufacturing. This paper presents a systematic approach to implement the feedback control of FFA-based soft robotic bending modules by using commercial flex bend sensors. A flex bend sensor detects the module curvature in one direction, and its response is processed by an on board microcontroller and sent to the central control system. Such sensor integration enables the closed-loop control of modular robotic architectures, often used in soft robotics. Once integrated with the soft module, the sensor response was calibrated by the use of a ground truth electro-magnetic tracking system in order to characterize its behavior when combined with the relative FFA. A feedback control using a low-pass filter and a proportional-integral controller was designed and used to evaluate the dynamic response and the position accuracy of the integrated module. With such closed-loop control, the module tip is positioned with less than 1 mm accuracy, which can be considered a relevant result in the soft robotics field.

A novel linear elastic actuator for minimally invasive surgery: development of a surgical gripper

Minimally invasive surgery (MIS) applications require lightweight actuators that can generate a high force in a limited volume. Among pressure driven actuators, fluid elastic actuators demonstrate high potential for use in the medical field. They are characterized by nearly no friction and wear and they can be made of low-cost biocompatible elastomers. However, when compared to traditional piston-cylinder fluid actuators, fluid elastic actuators often result in smaller output forces as well as weaker return forces. This work is about the design of a linear elastic actuator (LEA) which is able to develop relevant pulling-pushing force in one direction. The LEA is composed of entirely disposable materials and it requires a simple manufacturing process. Thanks to its design, the LEA can be compared to traditional piston-cylinders actuators in terms of output forces (up to 7 N) with the advantage of using relative low working pressures (0, 2 MPa). The actuator has been used for the actuation of a gripper for MIS, as a case study. The whole range of gripping forces developed by the tool actated by the LEA has been evaluated, thus verifying that the gripping device, is able to meet the force requirements for accomplishing typical surgical tasks.

A computer-assisted robotic platform for Focused Ultrasound Surgery: Assessment of high intensity focused ultrasound delivery.

In the last century, medicine showed considerable advancements in terms of new technologies, devices and diagnostic/therapeutic strategies. Those advantages led to a significant reduction of invasiveness and an improvement of surgical outcomes. In this framework, a computer-assisted surgical robotic platform able to perform non-invasive Focused Ultrasound Surgery (FUS) - the FUTURA platform - has the ambitious goal to improve accuracy, safety and flexibility of the treatment, with respect to current FUS procedures. Aim of this work is to present the current implementation of the robotic platform and the preliminary results about high intensity focused ultrasound (HIFU) delivery in in-vitro conditions, under 3D ultrasound identification and monitoring. Tests demonstrated that the average accuracy of the HIFU delivery is lower than 0.7 mm in both X and Y radial directions and 3.7 mm in the axial direction (Z) with respect to the HIFU transducer active surface.

Smart sensorized polymeric skin for safe robot collision and environmental interaction

Supervised robotic platforms, able to perform a non-invasive therapy or minimal invasive surgery, represent one of the main achievements in recent years. Robotic-assisted medical procedures with medical doctor, patient and medical assistants interacting with a robotic platform can be seen as a paradigmatic example of the coexistence between system autonomy and human action in medicine. However, this can involve unpredicted and dangerous contacts between robotic structures and humans, contacts that have to be managed with appropriate safety strategies, often embedding specific sensitive components into the robot itself. In this paper, a smart sensorized polymeric skin based on textile multi-touch piezoresistive sensors, able to sense and safely manage pressure exerted during a collision with the surrounding environment (e.g., humans), has been designed, fabricated, integrated on a robotic manipulator and tested. The proposed system shows promising results in managing the pressure exerted during the collision, with a close correlation with the analytical analysis (difference lower than 5.6 kPa - error of 9%).

Soft Robotic Manipulator for Improving Dexterity in Minimally Invasive Surgery

Background. Combining the strengths of surgical robotics and minimally invasive surgery (MIS) holds the potential to revolutionize surgical interventions. The MIS advantages for the patients are obvious, but the use of instrumentation suitable for MIS often translates in limiting the surgeon capabilities (eg, reduction of dexterity and maneuverability and demanding navigation around organs). To overcome these shortcomings, the application of soft robotics technologies and approaches can be beneficial. The use of devices based on soft materials is already demonstrating several advantages in all the exploitation areas where dexterity and safe interaction are needed. In this article, the authors demonstrate that soft robotics can be synergistically used with traditional rigid tools to improve the robotic system capabilities and without affecting the usability of the robotic platform. Materials and Methods. A bioinspired soft manipulator equipped with a miniaturized camera has been integrated with the Endoscopic Camera Manipulator arm of the da Vinci Research Kit both from hardware and software viewpoints. Usability of the integrated system has been evaluated with nonexpert users through a standard protocol to highlight difficulties in controlling the soft manipulator. Results and Conclusion. This is the first time that an endoscopic tool based on soft materials has been integrated into a surgical robot. The soft endoscopic camera can be easily operated through the da Vinci Research Kit master console, thus increasing the workspace and the dexterity, and without limiting intuitive and friendly use.

Highly dexterous 2-module soft robot for intra-organ navigation in minimally invasive surgery

For some surgical interventions, like the Total Mesorectal Excision (TME), traditional laparoscopes lack the flexibility to safely maneuver and reach difficult surgical targets. This paper answers this need through designing, fabricating and modelling a highly dexterous 2‐module soft robot for minimally invasive surgery (MIS).

Motion compensation with skin contact control for high intensity focused ultrasound surgery in moving organs

High intensity focused ultrasound (HIFU) is an emerging therapeutic solution that enables non-invasive treatment of several pathologies, mainly in oncology. On the other hand, accurate targeting of moving abdominal organs (e.g. liver, kidney, pancreas) is still an open challenge. This paper proposes a novel method to compensate the physiological respiratory motion of organs during HIFU procedures, by exploiting a robotic platform for ultrasound-guided HIFU surgery provided with a therapeutic annular phased array transducer. The proposed method enables us to keep the same contact point between the transducer and the patients skin during the whole procedure, thus minimizing the modification of the acoustic window during the breathing phases. The motion of the target point is compensated through the rotation of the transducer around a virtual pivot point, while the focal depth is continuously adjusted thanks to the axial electronically steering capabilities of the HIFU transducer. The feasibility of the angular motion compensation strategy has been demonstrated in a simulated respiratory-induced organ motion environment. Based on the experimental results, the proposed method appears to be significantly accurate (i.e. the maximum compensation error is always under 1 mm), thus paving the way for the potential use of this technique for in vivo treatment of moving organs, and therefore enabling a wide use of HIFU in clinics.

Robotic Platform for High-Intensity Focused Ultrasound Surgery Under Ultrasound Tracking: The FUTURA Platform

Focused Ultrasound Therapy Using Robotic Approaches (FUTURA) is a European seventh research framework programme project aimed at creating an innovative platform for Focused Ultrasound Surgery (FUS). Merging robotics together with noninvasive ultrasound monitoring and therapy has the goal to improve flexibility, precision and accuracy of the intervention, thus enabling a large use of FUS for the treatment of different pathologies. The FUTURA platform, based on FUS therapy under US tracking, has been set up with the first clinical target of kidney cancer treatment. Experiments for assessing the accuracy of the FUS delivery with the FUTURA platform have been carried out under in vitro static conditions and presented here as preliminary outcomes of this study.