Flow driven robotic navigation of microengineered endovascular probes

Minimally invasive medical procedures, such as endovascular catheterization, have considerably reduced procedure time and associated complications. However, many regions inside the body, such as in the brain vasculature, still remain inaccessible due to the lack of appropriate guidance technologies. Here, experimentally and through numerical simulations, we show that tethered ultra-flexible endovascular microscopic probes can be transported through tortuous vascular networks with minimal external intervention by harnessing hydrokinetic energy. Dynamic steering at bifurcations is performed by deformation of the probe head using magnetic actuation. We developed an endovascular microrobotic toolkit with a cross-sectional area that is orders of magnitude smaller than the smallest catheter currently available. Our technology has the potential to improve state-of-the-art practices as it enhances the reachability, reduces the risk of iatrogenic damage, significantly increases the speed of robot-assisted interventions, and enables the deployment of multiple leads simultaneously through a standard needle injection and saline perfusion.

The navigation of catheters through blood vessels requires flexible guiding wires that are pushable and tractable at the same time. Pancaldi et al. rely on hydrodynamic forces and magnetic torque in order to access even rather small capillaries with an ultraflexible magnetomechanical probe.

Progress in Nanorobotics for Advancing Biomedicine

Nanorobotics, which has long been a fantasy in the realm of science fiction, is now a reality due to the considerable developments in diverse fields including chemistry, materials, physics, information and nanotechnology in the past decades. Not only different prototypes of nanorobots whose sizes are nanoscale are invented for various biomedical applications, but also robotic nanomanipulators which are able to handle nano-objects obtain substantial achievements for applications in biomedicine. The outstanding achievements in nanorobotics have significantly expanded the field of medical robotics and yielded novel insights into the underlying mechanisms guiding life activities, remarkably showing an emerging and promising way for advancing the diagnosis & treatment level in the coming era of personalized precision medicine. In this review, the recent advances in nanorobotics (nanorobots, nanorobotic manipulations) for biomedical applications are summarized from several facets (including molecular machines, nanomotors, DNA nanorobotics, and robotic nanomanipulators), and the future perspectives are also presented.

Recent Advances in Design and Actuation of Continuum Robots for Medical Applications

Traditional rigid robot application in the medical field is limited due to the limited degrees of freedom caused by their material and structure. Inspired by trunk, tentacles, and snakes, continuum robot (CR) could traverse confined space, manipulate objects in complex environment, and conform to curvilinear paths in space. The continuum robot has broad prospect in surgery due to its high dexterity, which can reach circuitous areas of the body and perform precision surgery. Recently, many efforts have been done by researchers to improve the design and actuation methods of continuum robots. Several continuum robots have been applied in clinic surgical interventions and demonstrated superiorities to conventional rigid-link robots. In this paper, we provide an overview of the current development of continuum robots, including the design principles, actuation methods, application prospect, limitations, and challenge. And we also provide perspective for the future development. We hope that with the development of material science, Engineering ethics, and manufacture technology, new methods can be applied to manufacture continuum robots for specific surgical procedures.

Protrusion mechanism study in sipunculid worms as model for developing bio-inspired linear actuators

The invertebrates ability to adapt to the environment during motion represents an intriguing feature to inspire robotic systems. We analysed the sipunculid speciesPhascolosoma stephensoni(Sipunculidae, Annelida), and quantitatively studied the motion behaviour of this unsegmented worm. The hydrostatic skeleton and the muscle activity make the infaunalP.stephensoniable to extrude part of its body (the introvert) from its burrow to explore the environment by remaining hidden within the rocky substrate where it settled. The introvert protrusion is associated with changes in the body shape while keeping the overall volume constant. In this study, we employed a marker-less optical tracking strategy to quantitatively study introvert protrusion (i.e. kinematics, elongation percentage and forces exerted) in different navigation media. WhenP.stephensonispecimens were free in sea water (outside from the burrow), the worms reached lengths up to three times their initial ones after protrusion. Moreover, they were able to elongate their introvert inside a viscous medium such as agar-based hydrogel. In this case, the organisms were able to break the hydrogel material, exerting forces up to 3 N and then to navigate easily inside it, producing stresses of some tens of kPa. Our measurements can be used as guidelines and specifications to design and develop novel smart robotic systems.

Biologically Inspired Surgical Needle Steering: Technology and Application of the Programmable Bevel-Tip Needle

Percutaneous interventions via minimally invasive surgical systems can provide patients with better outcomes and faster recovery times than open surgeries. Accurate needle insertions are vital for successful procedures, and actively steered needles can increase system precision. Here, we describe how biology inspired the design of a novel Programmable Bevel-Tip Needle (PBN), mimicking the mechanics and control methods of certain insects ovipositors. Following an overview of our unique research and development journey, this paper explores our latest, biomimetic control of PBNs and its application to neurosurgery, which we validate within a simulated environment. Three modalities are presented, namely a Direct Push Controller, a Cyclic Actuation Controller, and a newly developed Hybrid Controller, which have been integrated into a surgical visual interface. The results of open loop, expert human-in-the-loop and a non-expert user study show that the Hybrid Controller is the best choice when considering system performance and the ability to lesson strain on the surrounding tissue which we hypothesis will result in less damage along the insertion tract. Over representative trajectories for neurosurgery using a Hybrid Controller, an expert user could reach a target along a 3D path with an accuracy of 0.70±0.69 mm, and non-expert users 0.97±0.72 mm, both clinically viable results and equivalent or better than the state-of-the-art actively steered needles over 3D paths. This paper showcases a successful example of a biologically inspired, actively steered needle, which has been integrated within a clinical interface and designed for seamless integration into the neurosurgical workflow.

Dynamic Analysis of an Underwater Cable-Driven Manipulator with a Fluid-Power Buoyancy Regulation System

This article presents an underwater cable-driven manipulator (UCDM) with a buoyancy regulation system (BRS), which is controlled by a fluid-power system. The manipulator consists of five sections, and each section is embedded with a buoyancy adjustment unit. By regulating buoyancy at each section, the static and dynamic states of the manipulator will be changed, promising a new operating mode of an underwater manipulator driven by buoyancy. In this article, a dynamic model of the manipulator is established by the Newton-Euler equation, considering cable tension, inter-joint force, buoyancy, water resistance and other variables. With a numerical method, the dynamic model is solved and the values of cable tension are obtained, which are used to evaluate the buoyancy-driven operating mode of underwater manipulator. This research will be useful for manipulator operating in fluid environments, such as underwater manipulator in the ocean, micro-manipulator in a blood vessel, and so on.

Robotics Applications in COVID-19: A Review

The COVID-19 outbreak has resulted in the manufacturing and service sectors being badly hit globally. Since there are no vaccines or any proven medical treatment available, there is an urgent need to take necessary steps to prevent the spread of this virus. As the virus spreads with human-to-human interaction, lockdown has been declared in many countries, and the public is advised to observe social distancing strictly. Robots can undertake human-like activities and can be gainfully programmed to replace some of the human interactions. Through this paper, we identify and propose the introduction of robots to take up this challenge in the fight against the COVID-19 pandemic. We did a comprehensive review of the literature to identify robots’ possible applications in the management of epidemics and pandemics of this nature. We have reviewed the available literature through the search engines of PubMed, SCOPUS, Google Scholar, and Research Gate. A comprehensive review of the literature identified different types of robots being used in the medical field. We could find several vital applications of robots in the management of the COVID-19 pandemic. No doubt technology comes with a cost. In this paper, we identified how different types of robots are used gainfully to deliver medicine, food, and other essential items to COVID-19 patients who are under quarantine. Therefore, there is extensive scope for customising robots to undertake hazardous and repetitive jobs with precision and reliability.

A Shapeshifting Ferrofluidic Robot

To create a miniature shapeshifting robot capable of controlled movement, subdivision, regeneration, passage through small channels, engulfment of particles, object manipulation, and flow manipulation, a droplet of magnetically responsive ferrofluid is used. The ferrofluidic robot can achieve the aforementioned functions when both its position and shape are controlled using a custom electromagnetic field generation system. It is demonstrated that the proposed robot can perform these functions with submillimeter and subdegree error. A robot having these capabilities can remotely perform medical and microassembly tasks requiring fine dexterity that are currently difficult or impossible.

Retrospective in silico evaluation of optimized preoperative planning for temporal bone surgery

Purpose

Robot-assisted surgery at the temporal bone utilizing a flexible drilling unit would allow safer access to clinical targets such as the cochlea or the internal auditory canal by navigating along nonlinear trajectories. One key sub-step for clinical realization of such a procedure is automated preoperative surgical planning that incorporates both segmentation of risk structures and optimized trajectory planning.

Methods

We automatically segment risk structures using 3D U-Nets with probabilistic active shape models. For nonlinear trajectory planning, we adapt bidirectional rapidly exploring random trees on Bézier Splines followed by sequential convex optimization. Functional evaluation, assessing segmentation quality based on the subsequent trajectory planning step, shows the suitability of our novel segmentation approach for this two-step preoperative pipeline.

Results

Based on 24 data sets of the temporal bone, we perform a functional evaluation of preoperative surgical planning. Our experiments show that the automated segmentation provides safe and coherent surface models that can be used in collision detection during motion planning. The source code of the algorithms will be made publicly available.

Conclusion

Optimized trajectory planning based on shape regularized segmentation leads to safe access canals for temporal bone surgery. Functional evaluation shows the promising results for both 3D U-Net and Bézier Spline trajectories.

Development and Preclinical Trials of a Novel Steerable Cannula for 360° Arthroscopic Capsular Release in Minimally Invasive Surgery

Many of the surgical devices for minimally invasive surgery have struggled to navigate in tight spaces and to safely address to surgical sites. This research demonstrates a scalable steerable cannula for 360° arthroscopic capsular release (ACR) of the glenohumeral joint. The steerable cannula mainly consists of the pre-curved inner tube of nitinol, the straight outer tube of stainless steel, and the controller part. Using anisotropic patterns and heat treatment, the inner tube has a high degree of curvature. The mechanism controls the distal end with the two degrees of freedom. The inner tube can be translated and rotated relative to the outer tube. The steerable cannula was designed to avoid the axillary nerve under the inferior glenoid to minimize the risk of iatrogenic injury while keeping flexed to match the bony curvature of the glenohumeral joint. The cylindrical cannula can fit various surgical tools and can be sterilized after use. In porcine shoulder test and workspace analysis, the proposed cannula addressed the inferior glenoid that is not reachable by the conventional rigid cannula. Thus, the proposed mechanism can navigate through the narrow and curved anatomical space of the glenoid cavity and reduce the unreachable area for ACR.Clinical Relevance- The propose cannula can be used for 360° arthroscopic capsular release (ACR) in minimally invasive surgery (MIS). This cannula can prevent damage to the axillary nerves which is one of the main complications of ACR. The mechanism has the potentials to reduce the unreachable area in MIS for knee and hip joints.

Differential Image Based Robot to MRI Scanner Registration with Active Fiducial Markers for an MRI-Guided Robotic Catheter System

In magnetic resonance imaging (MRI) guided robotic catheter ablation procedures, reliable tracking of the catheter within the MRI scanner is needed to safely navigate the catheter. This requires accurate registration of the catheter to the scanner. This paper presents a differential, multi-slice image-based registration approach utilizing active fiducial coils. The proposed method would be used to preoperatively register the MRI image space with the physical catheter space. In the proposed scheme, the registration is performed with the help of a registration frame, which has a set of embedded electromagnetic coils designed to actively create MRI image artifacts. These coils are detected in the MRI scanner's coordinate system by background subtraction. The detected coil locations in each slice are weighted by the artifact size and then registered to known ground truth coil locations in the catheter's coordinate system via least-squares fitting. The proposed approach is validated by using a set of target coils placed withing the workspace, employing multi-planar capabilities of the MRI scanner. The average registration and validation errors are respectively computed as 1.97 mm and 2.49 mm. The multi-slice approach is also compared to the single-slice method and shown to improve registration and validation by respectively 0.45 mm and 0.66 mm.

[Robotic assistance systems for surgery : Current developments and focus of research]

As robotic systems are now technically mature and widely available, they also play an increasingly important role in the clinical environment. Thus, numerous robotic assistance systems for diagnosis and therapy have shown their potential for supporting patient care. After a brief review of the history, this article describes currently available robotic assistance systems for surgery, especially those originating in Germany and Europe as well as current focal topics of research. In addition, challenges in this field as well as possibilities for close active and interdisciplinary cooperation between stakeholders from hospitals, industry and science to overcome such challenges are presented.

ValveTech: A Novel Robotic Approach for Minimally Invasive Aortic Valve Replacement

OBJECTIVE

Aortic valve disease is the most common heart disease in the elderly calling for replacement with an artificial valve. The presented surgical robot aims to provide a highly controllable instrument for efficient delivery of an artificial valve by the help of integrated endoscopic vision.

METHODS

A robot (called ValveTech), intended for minimally invasive surgery (MIS) and consisting of a flexible cable driven manipulator, a passive arm, and a control unit has been designed and prototyped. The flexible manipulator has several features (e.g., stabilizing flaps, tiny cameras, dexterous introducer and custom cartridge) to help the proper valve placement. It provides 5 degrees of freedom for reaching the operative site via mini-thoracotomy; it adjusts the valve and expands it at the optimal position. The robot was evaluated by ten cardiac surgeons following a real surgical scenario in artificial chest simulator with an aortic mockup. Moreover, after each delivery, the expanded valve was evaluated objectively in comparison with the ideal position.

RESULTS

The robot performances were evaluated positively by surgeons. The trials resulted in faster delivery and an average misalignment distance of 3.8 mm along the aorta axis; 16.3 degrees rotational angle around aorta axis and 8.8 degrees misalignment of the valve commissure plane to the ideal plane were measured.

CONCLUSION

The trials successfully proved the proposed system for valve delivery under endoscopic vision.

SIGNIFICANCE

The ValveTech robot can be an alternative solution for minimally invasive aortic valve surgery and improve the quality of the operation both for surgeons and patients.

Cost-Effective Smartphone-Based Articulable Endoscope Systems for Developing Countries: Instrument Validation Study

Background

Endoscopes are widely used for visualizing the respiratory tract, urinary tract, uterus, and gastrointestinal tracts. Despite high demand, people in underdeveloped and developing countries cannot obtain proper access to endoscopy. Moreover, commercially available endoscopes are mostly nonarticulable as well as not actively controlled, limiting their use. Articulating endoscopes are required for some diagnosis procedures, due to their ability to image wide areas of internal organs. Furthermore, actively controlled articulating endoscopes are less likely to harm the lumen than rigid endoscopes because they can avoid contact with endothelial tissues.

Objective

The study aimed to demonstrate the feasibility and acceptability of smartphone-based wide-field articulable endoscope system for minimally invasive clinical applications in developing and less developed countries.

Methods

A thin articulable endoscope system that can be attached to and actively controlled by a smartphone was designed and constructed. The system consists of a flexible endoscopic probe with a continuum mechanism, 4 motor modules for articulation, a microprocessor for controlling the motor with a smartphone, and a homebuilt app for streaming, capturing, adjusting images and video, and controlling the motor module with a joystick-like user interface. The smartphone and motor module are connected via an integrated C-type On-The-Go (OTG) USB hub.

Results

We tested the device in several human-organ phantoms to evaluate the usability and utility of the smartphone-based articulating endoscope system. The resolution (960 × 720 pixels) of the device was found to be acceptable for medical diagnosis. The maximum bending angle of 110° was designed. The distance from the base of the articulating module to the tip of the endoscope was 45 mm. The angle of the virtual arc was 40.0°, for a curvature of 0.013. The finest articulation resolution was 8.9°. The articulating module succeeded in imaging all 8 octants of a spherical target, as well as all 4 quadrants of the indices marked in human phantoms.

Conclusions

The portable wide-field endoscope was successfully controlled using a smartphone, yielding clear images with a resolution of 960 × 720 pixels at realistic focal distances. Actively and precisely controlled articulating movements have resulted in minimally invasive monitoring in the narrow space of internal organs providing a wide-area view. We found our smartphone-based active articulated endoscope to be suitable for point-of-care applications in developing and less developed countries.

Experimental study of the optimum puncture pattern of robot-assisted needle insertion into hyperelastic materials

The robot-assisted insertion surgery plays a crucial role in biopsy and therapy. This study focuses on determining the optimum puncture pattern for robot-assisted insertion, aiming at the matching problem of needle insertion parameters, thereby to reduce the pain for patients and to improve the reachability to the lesion point. First, a 6-degrees of freedom (DOFs) Computed Tomography (CT)-guided surgical robotic system for minimally invasive percutaneous lung is developed and used to perform puncture experiments. The effects of four main insertion factors on the robotic puncture are verified by designing the orthogonal test, where the inserting object is the artificial skin-like specimen with high transparent property and a digital image processing method is used to analyze the needle tip deflection. Next, the various phases of puncture process are divided and analyzed in detail in view of the tissue deformation and puncture force. Then, short discussion on the comparison of puncture force with different effect factors for the same beveled needle is presented. The same pattern can be observed for all of the cases. Finally, based on the experimental data, the formulations of the puncture force and needle deflection which depends on Gauge size, insertion velocity, insertion angle, and insertion depth are developed using the multiple regression method, which can be used to get an optimum puncture pattern under the constrains of minimum peak force and minimum needle tip deflection. The developed models have the effectiveness and applicability on determining the optimum puncture pattern for one puncture event, and which can also provide insights useful for the setting of insertion parameters in clinical practice.

Searching and Intertwining: Climbing Plants and GrowBots

Applications in remote inspection and medicine have motivated the recent development of innovative thin, flexible-backboned robots. However, such robots often experience difficulties in maintaining their intended posture under gravitational and other external loadings. Thin-stemmed climbing plants face many of the same problems. One highly effective solution adopted by such plants features the use of tendrils and tendril-like structures, or the intertwining of several individual stems to form braid-like structures. In this paper, we present new plant-inspired robotic tendril-bearing and intertwining stem hardware and corresponding novel attachment strategies for thin continuum robots. These contributions to robotics are motivated by new insights into plant tendril and intertwining mechanics and behavior. The practical applications of the resulting GrowBots is discussed in the context of space exploration and mining operations.

Design and Integration of a Parallel, Soft Robotic End-Effector for Extracorporeal Ultrasound

OBJECTIVE

In this work we address limitations in state-of-the-art ultrasound robots by designing and integrating a novel soft robotic system for ultrasound imaging. It employs the inherent qualities of soft fluidic actuators to establish safe, adaptable interaction between ultrasound probe and patient.

METHODS

We acquire clinical data to determine the movement ranges and force levels required in prenatal foetal ultrasound imaging and design the soft robotic end-effector accordingly. We verify its mechanical characteristics, derive and validate a kinetostatic model and demonstrate controllability and imaging capabilities on an ultrasound phantom.

RESULTS

The soft robot exhibits the desired stiffness characteristics and is able to reach 100% of the required workspace when no external force is present, and 95% of the workspace when considering its compliance. The model can accurately predict the end-effector pose with a mean error of 1.18±0.29 mm in position and 0.92±0.47° in orientation. The derived controller is, with an average position error of 0.39 mm, able to track a target pose efficiently without and with externally applied loads. Ultrasound images acquired with the system are of equally good quality compared to a manual sonographer scan.

CONCLUSION

The system is able to withstand loads commonly applied during foetal ultrasound scans and remains controllable with a motion range similar to manual scanning.

SIGNIFICANCE

The proposed soft robot presents a safe, cost-effective solution to offloading sonographers in day-to-day scanning routines. The design and modelling paradigms are greatly generalizable and particularly suitable for designing soft robots for physical interaction tasks.

Stable Robotic Grasping of Multiple Objects using Deep Neural Networks

Optimal grasping points for a robotic gripper were derived, based on object and hand geometry, using deep neural networks (DNNs). The optimal grasping cost functions were derived using probability density functions for each local cost function of the normal distribution. Using the DNN, the optimum height and width were set for the robot hand to grasp objects, whose geometric and mass centre points were also considered in obtaining the optimum grasping positions for the robot fingers and the object. The proposed algorithm was tested on 10 differently shaped objects and showed improved grip performance compared to conventional methods.

Continuum Robots for Manipulation Applications: A Survey

This paper presents a literature survey documenting the evolution of continuum robots over the past two decades (1999–present). Attention is paid to bioinspired soft robots with respect to the following three design parameters: structure, materials, and actuation. Using this three-faced prism, we identify the uniqueness and novelty of robots that have hitherto not been publicly disclosed. The motivation for this study comes from the fact that continuum soft robots can make inroads in industrial manufacturing, and their adoption will be accelerated if their key advantages over counterparts with rigid links are clear. Four different taxonomies of continuum robots are included in this study, enabling researchers to quickly identify robots of relevance to their studies. The kinematics and dynamics of these robots are not covered, nor is their application in surgical manipulation.

Optic Nerve Sheath Fenestration With a Multi-Arm Continuum Robot

This article presents a medical robotic system for deep orbital interventions, with a focus on Optic Nerve Sheath Fenestration (ONSF). ONSF is a currently invasive ophthalmic surgical approach that can reduce potentially blinding elevated hydrostatic intracranial pressure on the optic disc via an incision on the optic nerve. The prototype is a multi-arm system capable of dexterous manipulation and visualization of the optic nerve area, allowing for a minimally invasive approach. Each arm is an independently controlled concentric tube robot collimated by a bespoke guide that is secured on the eye sclera via sutures. In this article, we consider the robot's end-effector design in order to reach/navigate the optic nerve according to the clinical requirements of ONSF. A prototype of the robot was engineered, and its ability to penetrate the optic nerve was analysed by conducting ex vivo experiments on porcine optic nerves and comparing their stiffness to human ones. The robot was successfully deployed in a custom-made realistic eye phantom. Our simulation studies and experimental results demonstrate that the robot can successfully navigate to the operation site and carry out the intervention.

Exploring non-assembly 3D printing for novel compliant surgical devices

In minimally invasive surgery, maneuverability is usually limited and a large number of degrees of freedom (DOF) is highly demanded. However, increasing the DOF usually means increasing the complexity of the surgical instrument leading to long fabrication and assembly times. In this work, we propose the first fully 3D printed handheld, multi-steerable device. The proposed device is mechanically actuated, and possesses five serially controlled segments. We designed a new compliant segment providing high torsion and axial stiffness as well as a low bending stiffness by merging the functions of four helicoids and a continuum backbone. Compliant segments were combined to form the compliant shaft of the new device. In order to control this compliant shaft, a control handle was designed that mimics the shaft structure. A prototype called the HelicoFlex was built using only three 3D printed parts. HelicoFlex, with its 10 degrees of freedom, showed a fluid motion in performing single and multi-curved paths. The multi-steerable instrument was 3D printed without any support material in the compliant shaft itself. This work contributes to enlarge the body of knowledge regarding how additive manufacturing could be used in the production of multi-steerable surgical instruments for personalized medicine.

High-Resolution Optical Fiber Shape Sensing of Continuum Robots: A Comparative Study

Flexible medical instruments, such as Continuum Dexterous Manipulators (CDM), constitute an important class of tools for minimally invasive surgery. Accurate CDM shape reconstruction during surgery is of great importance, yet a challenging task. Fiber Bragg grating (FBG) sensors have demonstrated great potential in shape sensing and consequently tip position estimation of CDMs. However, due to the limited number of sensing locations, these sensors can only accurately recover basic shapes, and become unreliable in the presence of obstacles or many inflection points such as s-bends. Optical Frequency Domain Reflectometry (OFDR), on the other hand, can achieve much higher spatial resolution, and can therefore accurately reconstruct more complex shapes. Additionally, Random Optical Gratings by Ultraviolet laser Exposure (ROGUEs) can be written in the fibers to increase signal to noise ratio of the sensors. In this comparison study, the tip position error is used as a metric to compare both FBG and OFDR shape reconstructions for a 35 mm long CDM developed for orthopedic surgeries, using a pair of stereo cameras as ground truth. Three sets of experiments were conducted to measure the accuracy of each technique in various surgical scenarios. The tip position error for the OFDR (and FBG) technique was found to be 0.32 (0.83) mm in free-bending environment, 0.41 (0.80) mm when interacting with obstacles, and 0.45 (2.27) mm in s-bending. Moreover, the maximum tip position error remains sub-millimeter for the OFDR reconstruction, while it reaches 3.40 mm for FBG reconstruction. These results propose a cost-effective, robust and more accurate alternative to FBG sensors for reconstructing complex CDM shapes.

Learning the Complete Shape of Concentric Tube Robots

Concentric tube robots, composed of nested pre-curved tubes, have the potential to perform minimally invasive surgery at difficult-to-reach sites in the human body. In order to plan motions that safely perform surgeries in constrained spaces that require avoiding sensitive structures, the ability to accurately estimate the entire shape of the robot is needed. Many state-of-the-art physics-based shape models are unable to account for complex physical phenomena and subsequently are less accurate than is required for safe surgery. In this work, we present a learned model that can estimate the entire shape of a concentric tube robot. The learned model is based on a deep neural network that is trained using a mixture of simulated and physical data. We evaluate multiple network architectures and demonstrate the model's ability to compute the full shape of a concentric tube robot with high accuracy.

Dentronics: Towards robotics and artificial intelligence in dentistry

OBJECTIVES

This paper provides an overview of existing applications and concepts of robotic systems and artificial intelligence in dentistry. This review aims to provide the community with novel inputs and argues for an increased utilization of these recent technological developments, referred to as Dentronics, in order to advance dentistry.

METHODS

First, background on developments in robotics, artificial intelligence (AI) and machine learning (ML) are reviewed that may enable novel assistive applications in dentistry (Sec A). Second, a systematic technology review that evaluates existing state-of-the-art applications in AI, ML and robotics in the context of dentistry is presented (Sec B).

RESULTS

A systematic literature research in pubmed yielded in a total of 558 results. 41 studies related to ML, 53 studies related to AI and 49 original research papers on robotics application in dentistry were included. ML and AI have been applied in dental research to analyze large amounts of data to eventually support dental decision making, diagnosis, prognosis and treatment planning with the help of data-driven analysis algorithms based on machine learning. So far, only few robotic applications have made it to reality, mostly restricted to pilot use cases.

SIGNIFICANCE

The authors believe that dentistry can greatly benefit from the current rise of digital human-centered automation and be transformed towards a new robotic, ML and AI-enabled era. In the future, Dentronics will enhance reliability, reproducibility, accuracy and efficiency in dentistry through the democratized use of modern dental technologies, such as medical robot systems and specialized artificial intelligence. Dentronics will increase our understanding of disease pathogenesis, improve risk-assessment-strategies, diagnosis, disease prediction and finally lead to better treatment outcomes.

Electronic skins and machine learning for intelligent soft robots

Soft robots have garnered interest for real-world applications because of their intrinsic safety embedded at the material level. These robots use deformable materials capable of shape and behavioral changes and allow conformable physical contact for manipulation. Yet, with the introduction of soft and stretchable materials to robotic systems comes a myriad of challenges for sensor integration, including multimodal sensing capable of stretching, embedment of high-resolution but large-area sensor arrays, and sensor fusion with an increasing volume of data. This Review explores the emerging confluence of e-skins and machine learning, with a focus on how roboticists can combine recent developments from the two fields to build autonomous, deployable soft robots, integrated with capabilities for informative touch and proprioception to stand up to the challenges of real-world environments.

A Compression Valve for Sanitary Control of Fluid-Driven Actuators

With significant research focused on integrating robotics into medical devices, sanitary control of pressurizing fluids in a precise, accurate and customizable way is highly desirable. Current sanitary flow control methods include pinch valves which clamp the pressure line locally to restrict fluid flow; resulting in damage and variable flow characteristics over time. This paper presents a sanitary compression valve based on an eccentric clamping mechanism. The proposed valve distributes clamping forces over a larger area, thereby reducing the plastic deformation and associated influence on flow characteristic. Using the proposed valve, significant reductions in plastic deformation (up to 96%) and flow-rate error (up to 98%) were found, when compared with a standard pinch valve. Additionally, an optimization strategy presents a method for improving linearity and resolution over the working range to suit specific control applications. The valve efficacy has been evaluated through controlled testing of a water jet propelled low-cost endoscopic device. In this case, use of the optimized valve shows a reduction in the average orientation error and its variation, resulting in smoother movement of the endoscopic tip when compared to alternative wet and dry valve solutions. The presented valve offers a customizable solution for sanitary control of fluid driven actuators.

Energy-shaping control of soft continuum manipulators with in-plane disturbances

Soft continuum manipulators offer levels of compliance and inherent safety that can render them a superior alternative to conventional rigid robots for a variety of tasks, such as medical interventions or human–robot interaction. However, the ability of soft continuum manipulators to compensate for external disturbances needs to be further enhanced to meet the stringent requirements of many practical applications. In this paper, we investigate the control problem for soft continuum manipulators that consist of one inextensible segment of constant section, which bends under the effect of the internal pressure and is subject to unknown disturbances acting in the plane of bending. A rigid-link model of the manipulator with a single input pressure is employed for control purposes and an energy-shaping approach is proposed to derive the control law. A method for the adaptive estimation of disturbances is detailed and a disturbance compensation strategy is proposed. Finally, the effectiveness of the controller is demonstrated with simulations and with experiments on an inextensible soft continuum manipulator that employs pneumatic actuation.

Design and Development of a Growing Pneumatic Soft Robot

Soft continuum robots are getting more popular in areas such as minimally invasive surgery, search and rescue, and inspection due to their inherent compliance and flexibility. However, most of the conventional continuum robots still lack the ability to significantly change size and length. Growth as a means of robotic locomotion is a novel actuation method that can be used to overcome this disadvantage. In this study, we introduce a growing pneumatic soft robot made up of pressurized thin-walled tubings that can move in three-dimensional space with an extension ratio only limited by manufacturing capabilities. Besides the ability to grow from the tip, this design provides active steering by controlling the speed of each tubing separately, controllable stiffness that can be changed during motion, and capability to carry a tool channel. We present models to estimate tip force and position and experimentally verify the force model and robot kinematics. Open-loop speed controller has an overall root mean square error of 2.69% for speeds between 20 and 300 mm/s. The position controller based on the kinematic model has a mean positioning error of 13.9 mm at 100 mm and 22.6 mm at 200 mm longitudinal distance. Robot can produce a tip force of 20.1 N at 150 kPa tubing pressure and reach a maximum speed of 1490 mm/s at 100 kPa. We also demonstrate the navigation capabilities of the robot both in open field and in constrained environments.

Positioning and stiffening of an articulated/continuum manipulator for implant delivery in minimally invasive surgery

BACKGROUND

Hollow, bendable manipulators can advance implant delivery in minimally invasive surgery, by circumventing the drawbacks of straight-line delivery and fostering single-port approaches. Variable stiffness manipulators are sought to be safe and effective.

METHODS

We designed and experimentally assessed a cable-driven articulated/continuum manipulator, devised for cardiac valve delivery. Positioning and stiffening were teleoperated, based on cable shortening. Stiffening was parameterized by using the leading tension (LT, ie, tension of the cables driving bending). We assessed positioning (repeatability/reversibility along eight/two bending directions) and stiffening (eight bent configurations).

RESULTS

We achieved good repeatability and reversibility (mean errors <1% and 1.5%, respectively, of the workspace characteristic length). Stiffening was effective (up to 9-fold increase, depending on pose). Stiffening was linearly correlated (R² = 0.92) with LT for all the considered configurations.

CONCLUSION

We accurately positioned and effectively stiffened the manipulator in several bent configurations. The proposed stiffness modulation strategy can be extended to other manipulators.

Continuum Robot With Follow-the-Leader Motion for Endoscopic Third Ventriculostomy and Tumor Biopsy

BACKGROUND

In a combined endoscopic third ventriculostomy (ETV) and endoscopic tumor biopsy (ETB) procedure, an optimal tool trajectory is mandatory to minimize trauma to surrounding cerebral tissue.

OBJECTIVE

This paper presents wire-driven multi-section robot with push-pull wire. The robot is tested to attain follow-the-leader (FTL) motion to place surgical instruments through narrow passages while minimizing the trauma to tissues.

METHODS

A wire-driven continuum robot with six sub-sections was developed and its kinematic model was proposed to achieve FTL motion. An accuracy test to assess the robot's ability to attain FTL motion along a set of elementary curved trajectory was performed. We also used hydrocephalus ventricular model created from human subject data to generate five ETV/ETB trajectories and conducted a study assessing the accuracy of the FTL motion along these clinically desirable trajectories.

RESULTS

In the test with elementary curved paths, the maximal deviation of the robot was increased from 0.47 mm at 30 ° turn to 1.78 mm at 180 ° in a simple C-shaped curve. S-shaped FTL motion had lesser deviation ranging from 0.16 to 0.18 mm. In the phantom study, the greatest tip deviation was 1.45 mm, and the greatest path deviation was 1.23 mm.

CONCLUSION

We present the application of a continuum robot with FTL motion to perform a combined ETV/ETB procedure. The validation study using human subject data indicated that the accuracy of FTL motion is relatively high. The study indicated that FTL motion may be useful tool for combined ETV and ETB.