Abstract: This paper describes the status of the implementation of the upgrades for the RFX-mod2 device, the second major modification of the Reversed Field eXperiment (RFX). The machine's core update consists of a thin copper stabilizing shell placed inside the vacuum vessel to ensure long-term stability of resistive wall modes (RWM) and enable regimes with fast-rotating tearing modes. A comprehensive modernization of the facility's technological plants and diagnostics is being carried out within the NEFERTARI project (New Equipment For the Experimental Research and Technological Advancement for the RFX Infrastructure). Funded by the Italian National Recovery and Resilience Plan (NRRP) under Next Generation EU, NEFERTARI aims to strengthen the RFX infrastructure and its network of partners. Significant plant upgrades include: the refurbishment of the main vacuum system and the development of a new glow discharge cleaning (GDC) system based on eight fixed electrodes for more uniform wall conditioning; a major overhaul of the control and data acquisition system, now featuring a high-resolution multichannel acquisition system with over 1500 channels that eliminates the need for analogue integrators; the enhancement edge plasma characterization and of core diagnostics, such as the high-repetition-rate (up to 3 kHz) Thomson Scattering system and the expanded soft x-ray (SXR) tomography; the upgrade of the existing and installation of new reflectometric system; the restoration of the Diagnostic Neutral Beam Injector (DNBI) for spatially resolved ion temperature measurements. Furthermore, the paper highlights the contributions of the Italian laboratory network, including the BiGyM infrastructure for testing innovative plasma-facing components; the ROMAN remote handling facility for in-vessel maintenance development; dedicated laboratories for the development of neutron detectors and for optical diagnostics for the characterization of surfaces, and for high-voltage electrical insulation testing.

Keywords: 3D boundary | MHD | plasma diagnostic | PWI | remote handling | reversed field pinch | tokamak

Abstract: Pneumatically-driven Soft Growing Robots (SGR) are a new class of continuum robots, which take inspiration from vines, mimicking their capability to evolve along a path from the tip, while being intrinsically safe towards the environment. The SGRs' capabilities can be empowered by providing them with the capability to mount sensors and tools at the tip, thus enabling many applications in unstructured environments, such as object transportation in constrained spaces. However, the tip position of SGRs changes over time during growth, making it challenging to keep tools attached at the tip in the desired configuration. An auxiliary device at the tip is required, which grows with the SGR without hindering the eversion or changing the robot's designed shape. In this work, currently implemented designs in the literature for enabling SGRs tip-attachment are analyzed. Then, a novel tip-mounted Hybrid Magnetic Cap (HMC), composed of textile and rigid components, is presented; this dual nature makes the device both safe and efficient during all the SGR operative phases. To prove its effectiveness, this design is applied to a specific case study: cable delivery along a straight path.

Keywords: Bio-inspired design | Object delivery | Pneumatic actuation | Soft Robotics

Abstract: In the nuclear fusion framework the robots employed for inspection and maintenance tasks, are extremely afflicted by high amplitude oscillation due to the inertial loads that these robots must manage. To optimize space and weight of a robotic end-effector, remove components and not essential mechanism is the first step. However it's crucial to ensure a satisfactory level of precision and performance in terms of grasping of the gripper. Therefore in remote handling all the design aspects have to face with the restricted volume allowed by the environment in which the robotic system has to be employed. The fusion machines, akin tokamaks, are characterized always by narrow access port or confined spaces; these aspects affect the design of the cross–section of the manipulators and of the end-effector. The objective of this work is to evaluate the implementation of an innovative compliant mechanism suitable for remote handling tasks. More specifically in this work an innovative gripper design that significantly reduces the need for complex internal mechanisms and transmissions is presented. This novel approach utilizes a kinematic system based on the deformation of the main body of the gripper itself. By leveraging the intrinsic flexibility and material properties of the structure of the end-effector; this design achieves the necessary motion and force transmission through its own deformation, simplifying the overall design, enhancing reliability and reducing the mass of the manipulator at the tip. The FACT (Freedom And Constraint Topology) is a topological method, employed to obtain a first conceptualization of the kinematic.

Keywords: Compliant-mechanism | Fusion | Gripper | Inspection | Maintenance

Abstract: In this work we describe a preliminary general architecture for control rooms intended for remote handling operations of nuclear fusion reactors. The proposed preliminary control architecture will be implemented and used in the DTT Remote Handling Facility, for the training of operators and the test of remote handling operations. The control architecture is based on a Multi–Server/Multi–Client communication system, with two central servers running the core software modules and exchanging data over five different networks.

Keywords: Control Architecture | Digital twin | Remote Handling | Robotics

Abstract: In this work, we present a general control architecture for robotic systems dedicated to the remote handling of in-vessel components in fusion machines. This control architecture will be tested for the inspection and maintenance of the first wall components of the RFX-mod2 experiment, in the scope of the New Equipment For the Experimental Research and Technological Advancement for the Rfx Infrastructure (NEFERTARI) project. The architecture is split into low-level and high-level layers. The former is used for the low-level control of the robotics systems and to manage safety; the latter is used for the high-level planning and implements several sub-modules, such as a Virtual Reality (VR) environment for the visualisation of the robot's digital twin. Moreover, an Application Programming Interface (API) is intended to connect the two layers, and the communication between modules and layers is provided by the ROS2 framework. A typical usage of such a framework involves a human operator who is teleoperating the real robot, data from motor encoders are used as inputs for the dynamic model module. This module is used to compute the forward dynamics in real-time, providing an accurate simulation of the robot (digital twin) in the virtual environment.

Keywords: Control architecture | Digital twin | Remote handling | Robotics | ROS2

Abstract: This paper proposes a virtual reality-based dual-mode teleoperation architecture to assist human operators in remotely operating robotic manipulation systems in a safe and flexible way. The architecture, implemented via a finite state machine, enables the operator to switch between two operational modes: the Approach mode, where the operator indirectly controls the robotic system by specifying its target configuration via the immersive virtual reality (VR) interface, and the Telemanip mode, where the operator directly controls the robot end-effector motion via input devices. The two independent control modes have been tested along the task of reaching a glass on a table by a sample population of 18 participants. Two working groups have been considered to distinguish users with previous experience with VR technologies from the novices. The results of the user study presented in this work show the potential of the proposed architecture in terms of usability, both physical and mental workload, and user satisfaction. Finally, a statistical analysis showed no significant differences along these three metrics between the two considered groups demonstrating ease of use of the proposed architecture by both people with and with no previous experience in VR.

Keywords: control mode | digital twin | human-robot interface | man-machine systems | remote control | teleoperation | virtual reality

Abstract: In this work we briefly review some of the current available solutions of long reach manipulators that have been or are serving as robotic equipment for remote maintenance in fusion reactors. These robotic equipment are long reach since they are intended to access inside the fusion reactors through small–scaled access ports and are designed to remotely install/replace in-vessel mechanical components within the reactors. We start the work by analysing the design criteria commonly used and the most interesting concepts from the authors' perspective, where we found a general scheme that could be adopted for the most cases when we study this kind of robots. Finally we present a discussion and draw our conclusions.

Keywords: Fusion Reactors | Long Reach Manipulators | Remote Maintenance

Abstract: Surgical robots have been widely employed to help doctors to perform operations through small incisions with precise control and enhanced vision. However, compared to the human hand, the manipulation capabilities of the instruments used in robotic-Assisted surgeries are still limited. In earlier research, we designed a new needle driver tool inspired by the human hand rolling capabilities. The new tool allowed for needle reorientation with only one hand, unlike the standard tool that requires the use of both hands to reorient the needle during surgical intervention. The present paper extends our previous work by enhancing the design of the new tool, manufacturing 1-1 scale working prototype, mounting and controlling the tool actuators, and integrating a modified master device to remotely control the new tool. The functionality and grasping capabilities of the developed prototype was tested using the research kit of da Vinci surgical system (dVRK). Moreover, the performance of the new tool was evaluated by a group of surgeons based on the standard NASA Task Load Index (TLX). The results validate the proposed design and its manufacturability and suggest that the tool can effectively enhance the needle manipulation and improve the surgeon\'s dexterity.

Keywords: Da Vinci Research Kit (dVRK) | dexterous manipulation | master tool manipulator (MTM) | needle driver with rolling capabilities

Abstract: This paper proposes a design of a miniature gripper that can drive a suture needle in Robot-assisted Surgery. The presented gripper has two more advantages over the standard needle driver of da Vinci surgical robot. Firstly, it has a decoupled wrist that allows all joints to rotate independently of each other with no coupling between them. This in turn lets the control strategy to be less complicated since each DOF is actuated by only one motor. Secondly, it has rolling capabilities, similar to the human hand, that allow re-orienting the needle with only two fingers. The gripper is rapid prototyped and tested using a drive unit that is designed and developed in this work specifically for this purpose. Two experiments are conducted to validate the proposed design; in the first experiment the gripper is actuated about the wrist axis while the end effector position is measured and compared with the expected trajectory. The results showed that the wrist is completely decoupled from the other joints, as only a slight variation of 1% was obtained. In the second experiment, the motion capabilities of the gripper are demonstrated, and the rolling functionality is tested in presence of a surgical needle.

Abstract: Tip steering by induced deformation constitutes one of the most prominent feature to effectively navigate constrained environments with soft growing robots. In this work, we analyze the effects of design parameters on the tip steering capabilities of pneumatically-actuated soft growing robots built from fabric. More specifically, we consider the variability of material, fabric Pneumatic Artificial Muscles (fPAM) diameter, and backbone internal pressure and statistically quantify the effect on the maximum curvature achieved by the robot when a constant fPAM input pressure is applied. In our considered settings, we found a statistically significant main effect (p<0.05 ) of the fPAM diameter and a relevant interaction effect between this and the material factor. These findings provide useful guidelines for the design of fabric-based PAM-actuated soft growing robots with enhanced tip steering capabilities.

Keywords: Design of bioinspired soft robots | Soft actuators | Soft robotics

Abstract: Autonomous inspection of industrial pipelines in Oil Gas refiners represents an emerging research and application field. In this context, we present a novel hybrid aerial ground mobile platform for inspection tasks. The goal of this platform is to assist human operators to perform non-destructive tests to assess the quality status of pipelines carrying fluids. Thanks to its design, the proposed platform is able to navigate crowded environments to reach and land over industrial pipes and use its motion capabilities to inspect the pipe surface. In this work, we introduce the mechanical design of the hybrid platform discussing its main components, demonstrating its flying and inspection capabilities.

Abstract: Inspection and maintenance of industrial pipes using robots represent an emerging application in Oil Gas and refinery facilities for NonDestructive Tests (NDT). In this work, we present the design and development of a novel articulated mobile robot able to safely navigate over straight and curved pipes for inspection tasks. This rover is meant to be the base of the hybrid aerial-ground platform of the HYFLIERS project that aims to develop novel solutions to perform inspection measurements with reduced exposure to risks and costs. Thanks to the multiple degrees of freedom and onboard sensors, the rover proposed in this paper can stabilize and navigate on a pipe across welding and over curves. After discussed the mechanical design of the rover, we demonstrate its effectiveness in the localization and navigation of curved pipes.

Abstract: Integrating a robotic system into the depalletizing process of a supermarket demands a high level of autonomy, based on strong perceptive capabilities. This letter presents a system for detection, recognition, and localization of heterogeneous cases in a depalletizing robotic cell, using a single RGB-D camera. Such a system integrates apriori information on the content of the pallet with data from the RGB-D camera, exploiting a sequence of 2D and 3D model-based computer-vision algorithms. The effectiveness of the proposed methodology is assessed in an experiment where multiple cases and pallet configurations are considered. Finally, a complete depalletizing process is shown.

Keywords: computer vision for automation | Logistics | object detection | segmentation and categorization

Abstract: Depalletizing robotic systems are commonly deployed to automatize and speed-up parts of logistic processes. Despite this, the necessity to adapt the preexisting logistic processes to the automatic systems often impairs the application of such robotic solutions to small business realities like supermarkets. In this work we propose a robotic depalletizing system designed to be easily integrated into supermarket logistic processes. The system has to schedule, monitor and adapt the depalletizing process considering both on-line perceptual information given by non-invasive sensors and constraints provided by the high-level management system or by a supervising user. We describe the overall system discussing two case studies in the context of a supermarket logistic process. We show how the proposed system can manage multiple depalletizing strategies and multiple logistic requests.

Keywords: AI-based methods | behavior-based systems | Control architectures and programming | intelligent and flexible manufacturing | logistics

Abstract: Automatic depalletizing is becoming a practice widely applied in warehouses to automatize and speed-up logistics. On the other hand, the necessity to adapt the preexisting logistic lines to a custom automatic system can be a limit for the application of robotic solutions into smaller facilities like supermarkets. In this work, we tackle this issue by proposing a flexible and adaptive gripper for robotic depalletizing. The gripper is designed to be assembled on the end-tip of an industrial robotic arm. A novel patent-pending mechanism allows grasping boxes and products from both the upper and the lateral side enabling the depalletizing of boxes with complex shape. Moreover, the gripper is reconfigurable with five actuated degrees of freedom, that are automatically controlled using the embedded sensors to adapt grasping to different shapes and weights.

Keywords: grippers and other end-effectors | Logistics | mechanism design

Abstract: Minimally invasive robotic surgery (MIRS) has revolutionized surgical procedures. However, compared to classic laparoscopy, the surgeon must rely only on visual perception because of the lack of force feedback. In this article, a new noninvasive force feedback system is proposed and evaluated. Extending the work by Fontanelli (2017), where preliminary results were presented, a solution based on a novel force sensor placed in the terminal part of the trocar is shown in detail. With respect to the state of the art, our system allows measuring the interaction forces between the surgical instrument and the environment inside the patient\'s body without any changes to the instrument structure and with full adaptability to different robotic platforms and surgical tools. Using a commercial force-torque sensor as ground truth, the static and dynamic characterization of the sensor is provided together with an extensive experimental validation. Finally, a simple and intuitive application of the proposed sensing system in a realistic surgical scenario is presented.

Keywords: Force estimation | force sensor | minimally invasive surgery | robotic surgery

Abstract: This chapter aims the broadcasting of the results achieved by the RoDyMan project about the task planning manipulation of deformable objects, and the nonprehensile manipulation control. The final demonstrator of the project is a pizza-making process. After an introduction to the general topic of nonprehensile manipulation, the mechatronic design and the high-level software architecture are described. Then, the smoothed particle hydrodynamic formulation is briefly introduced, along with the description of a detection method for a deformable object. The task planning for stretching a modelling clay, emulating the pizza dough, is sketched. After, the problematic control objective is split into several nonprehensile motion primitives: holonomic and nonholonomic rolling, friction-induced manipulation, and tossing are the described primitives. This chapter highlights the achievements reached so far by the project, and pave the way towards future research directions.

Keywords: Deformable object Perception | Nonprehensile dynamic manipulation | Robot control | Robot planning

Abstract: This letter addresses the task of stabilizing a wheeled unmanned aerial vehicle on a pipe, which is an emerging application in oil and gas facilities for nondestructive measurements. After the derivation of the dynamic model of the system, a discrete-time nonlinear model predictive controller is designed over a finite horizon. The analysis of the asymptotic stability of the designed controller is carried out. Numerical tests show the performance and the robustness of the proposed solution.

Keywords: nondestructive testing | Nonlinear model predictive control | wheeled unmanned aerial vehicle

Abstract: Background: Keyhole surgery is characterized by loss of dexterity of surgeon\'s movements because of the limited workspace, nonintuitive motor skills of the surgical systems, and loss of tactile sensation that may lead to tissue damage and bad execution of the tasks. Methods: In this paper, a three-fingered underactuated miniature tool for robot-aided laparoscopic surgery is presented. The design is conceived to realize a closed-hand configuration allowing the insertion of the tool into the abdominal cavity through the trocar in one step and to reach different grasping as well as pushing/holding configurations once in the cavity. Results: Aiming to replicate human hand dexterity and versatility, different solutions for the kinematic structure of the hand are analyzed using quality indices to evaluate the manipulability and stability of the grasp. Furthermore, a first prototype of fingertip force sensor based on fiber Bragg grating (FBG) technology has been realized and tested. The design choices of the prototype are described and discussed with the aid of experiments. Conclusions: The whole concept and the need for such anthropomorphic tool are discussed with surgeons to highlight constraints and potentials in surgical tasks. The feedback by expert surgeons is used to provide specifications and improvements to the kinematics and mechanical design. The investigations of different designs allow identifying the optimal solution to improve grasping and manipulation capabilities. The tests on FBG sensors led to the conclusion that this technology guarantees good performance and can be a good solution for applications in surgical robotics.

Abstract: Research activity in Minimally Invasive Robotic Surgery (MIRS) has gained a considerable momentum in the last years, due to the availability of reliable and clinically relevant research platforms like the da Vinci Research Kit (dVRK). However, despite the wide sharing of the dVRK in the research community, access to the platform remains limited because of high maintenance costs and difficulty in replacing components. In this work we complete a robotic simulator of the dVRK, previously developed by our group, with cheap haptic interfaces and an Oculus Rift to replicate and extend the functionalities of the Master console. The complete system represents an efficient, safe and low-cost tool, useful to design and validate new surgical instruments and control strategies, as well as provide an easyto- access educational tool to students.

Keywords: da Vinci | Simulator | virtual reality

Abstract: The da Vinci Research Kit (dVRK) is a first generation da Vinci robot repurposed as a research platform and coupled with software and controllers developed by research users. An already quite wide community is currently sharing the dVRK (32 systems in 28 sites worldwide). The access to the robotic system for training surgeons and for developing new surgical procedures, tools and new control modalities is still difficult due to the limited availability and high maintenance costs. The development of simulation tools provides a low cost, easy and safe alternative to the use of the real platform for preliminary research and training activities. The Portable dVRK, which is described in this work, is based on a V-REP simulator of the dVRK patient side and endoscopic camera manipulators which are controlled through two haptic interfaces and a 3D viewer, respectively. The V-REP simulator is augmented with a physics engine allowing to render the interaction of new developed tools with soft objects. Full integration in the ROS control architecture makes the simulator flexible and easy to be interfaced with other possible devices. Several scenes have been implemented to illustrate performance and potentials of the developed simulator.

Keywords: Minimally invasive robotic surgery | Robotic surgery simulators | Virtual reality

Abstract: In Minimally Invasive Robotic Surgery (MIRS) a robot is interposed between the surgeon and the surgical site to increase the precision, dexterity, and to reduce surgeon\'s effort and cognitive load with respect to the standard laparoscopic interventions. However, the modern robotic systems for MIRS are still based on the traditional telemanipulation paradigm, e.g. the robot behaviour is fully under surgeon\'s control, and no autonomy or assistance is implemented. In this work, supervised and shared controllers have been developed in a vision-free, human-in-the-Ioop, control framework to help surgeon during a surgical suturing procedure. Experiments conducted on the da Vinci Research Kit robot proves the effectiveness of the method indicating also the guidelines for improving results.

Abstract: In this work we present a V-REP simulator for the da Vinci Research Kit (dVRK). The simulator contains a full robot kinematic model and integrated sensors. A robot operating system (ROS) interface has been created for easy use and development of common software components. Moreover, several scenes have been implemented to illustrate the performance and potentiality of the developed simulator. Both the simulator and the example scenes are available to the community as an open source software.

Abstract: During robot-aided surgical interventions, the surgeon can be benefitted from the application of virtual fixtures (VFs). Though very effective, this technique is very often not practicable in unstructured surgical environments. In order to comply with the environmental deformation, both the VF geometry and the constraint enforcement parameters need to be online defined/adapted. This letter proposes a strategy for an effective use of VF assistance in minimally invasive robotic surgical tasks. An online VF generation technique based on the interaction force measurements is presented. Pose and geometry adaptations of the VF are considered. Passivity of the overall system is guaranteed by using energy tanks passivity-based control. The proposed method is validated through experiments on the da Vinci Research Kit.

Keywords: compliance and impedance control | laparoscopy | physical human-robot interaction | Surgical robotics

Abstract: The goal of this article is to disseminate the planning and control strategies for robotic nonprehensile manipulation results achieved so far with the Robotic Dynamic Manipulation (RoDyMan) project. The goal of the project is to advance the state of the art of nonprehensile dynamic manipulation of rigid and deformable objects to enhance the possibility of employing robots in anthropic environments. RoDyMan project\'s final demonstration will be acting as an autonomous pizza maker. This article highlights the lessons learned and paves the way toward critical discussions and future research.

Abstract: Three new image-based visual-impedance control laws are proposed in this letter allowing physical interaction of a dual-arm unmanned aerial manipulator equipped with a camera and a force/torque sensor. Namely, two first-order impedance behaviors are designed based on the transpose and the inverse of the system Jacobian matrix, respectively, while a second-order impedance behavior is carried out as well. Visual information is employed both to coordinate the camera motion in an eye-in-hand configuration with the assigned task executed by the other robot arm, and to define the elastic wrench component of the proposed hybrid impedance equations directly in the image plane.

Keywords: Aerial Systems | force control | perception and autonom | visual servoing

Abstract: In laparoscopic minimally invasive robotic surgery, a teleoperated robot is interposed between the patient and the surgeon. Despite the robot aid, the manipulation capabilities of surgical instruments are far from those of the human hand. In this letter, we want to make a step forward toward robotic solutions that can improve manipulation capabilities of the surgical instruments. A new concept of needle-driver tool is presented, which takes inspiration from the human hand model. The idea is to modify a standard laparoscopic tool by introducing an additional degree of freedom, which allows in-hand reorientation of the suturing needle. A 3D printed prototype has been built to validate the tool design. The improved manipulation capabilities have been assessed quantitatively by evaluating a weighted dexterity index along a single stitch trajectory. Moreover, a comparison between our tool and a standard needle driver has been done in terms of time required for the execution of a complete suturing sequence.

Keywords: contact modeling | dexterous manipulation | grippers and other end-effectors | laparoscopy | mechanism design | Surgical robotics

Abstract: The da Vinci Research Kit (DVRK) is a telerobotic surgical research platform endowed with an open controller that allows position, velocity and current control. We consider the problem of modelling and identification of both the Patient Side Manipulators (PSMs) and of the Master Tool Manipulators (MTMs) of the platform. This problem is relevant when realistic dynamic simulations have to be performed using standard software tools, but also for the design of model-based control laws, and for the implementation of sensorless strategies for collision detection or contact force estimation. A LMI-based approach is used for the identification of the robot dynamics in order to guarantee the physical feasibility of the parameters that is not ensured by standard least-squares methods. The identified models are validated experimentally.

Abstract: Minimally invasive robotic surgery holds a fundamental role in modern surgery. However, one of its major limitations compared to classic laparoscopy is that the surgeon can only rely on visual perception, for the lack of haptic force feedback. A new solution for a force sensor placed at the end-tip of the trocar is presented here. This solution allows measuring the interaction forces between the surgical instrument and the environment without any changes to the instrument structure and with full adaptability to different robot platforms and surgical tools. A prototype of the sensor has been realized with 3D printed technology for a proof of concept. The static and dynamic characterization of the sensor is provided together with experimental validation.

Abstract: In this work, we present an approach to imitation learning and flexible execution of dual-arm structured tasks. The proposed framework exploits imitation learning and attentional supervision to learn both a set of motion primitives and the associated tasks structure. During the teaching phase, attentional supervision allows the teacher to exploit attention manipulation, like object and verbal cueing, to facilitate the demonstration. In this phase, motion data are automatically segmented, annotated and learned in a compact form for on-line motion generation. During the execution phase, the learned task structure is exploited to synchronize left and right arm movements and to adapt task execution to the operative context. The proposed approach is demonstrated in a simulated kitchen scenario considering a pizza preparation task.

Keywords: Arm movements | Dual arm | Execution phasis | Imitation learning | Learn+ | Motion data | Motion generation | Motion primitives | Task structure | Teachers'

Abstract: This paper presents a method for tracking a 3D textureless object which undergoes elastic deformations, using the point cloud data provided by an RGB-D sensor and in real-time. This solution is expected to be useful for enhanced manipulation of humanoid robotic systems, especially in the case of pizza dough to be ideally manipulated by a pizza chef robot. Our tracking framework relies on a prior visual segmentation of the object in the image. The segmented point cloud is registered first in a rigid manner and then by non-rigidly fitting the mesh, based on the Finite Element Method to model elasticity, and on geometrical point-to-point correspondences to compute external forces exerted on the mesh. The system has been evaluated on synthetic and real data, and by integrating it into manipulation experiments on the RoDyMan1http://www.rodyman.eu/. The research leading to these results has been supported by the RoDyMan project, which has received funding from the European Research Council(FP7 IDEAS) under Advanced Grant agreement number 320992. The authors are solely responsible for its content. It does not represent the opinion of the European Community and the Community is not responsible for any use that might be made of the information contained therein. humanoid robotic platform.

Keywords: Deformable object modeling | Perception | Registration | Robotic manipulation

Abstract: In this paper we propose a method to estimate the force applied to a manipulated deformable object by processing information provided by an external vision sensor, in this case a consumer RGB-D camera. By measuring the deformations undergone by the object through a registration technique, the idea is to retrieve the contact force which minimises the deviation between the measured and the simulated deformations, given a simple interaction model and by employing a fitting process. The system resorts to a realistic mesh-based Finite Element Method model to accurately model deformations, whose elastic parameters are estimated in advance using the vision system and a force sensor. Experimental results are presented for the case of a compressive point-wise contact force applied, at static equilibrium, on a deformable object.

Keywords: Deformable objects | Force estimation | Physical modelling

Abstract: The aim of this work is to integrate a soft-rigid collision detection algorithm in the open source physics engine Bullet Physics. In surgical applications these types of collisions occur, for example, when a clamp grabs deformable organic material or a spatula opens a brain fissure. The goal is to handle the collision between the soft body (deformable organ) and the rigid body (surgical tool), assuming that the position of the rigid body in the space is given by the Novint Falcon 3D. The visual rendering has been realized using OpenGL, a cross-language for rendering 2D and 3D vector graphics. Moreover, the simulator allows to provide force feedback to the surgeon through the haptic device.