Imperial College London

ProfessorFerdinandoRodriguez y Baena

Faculty of EngineeringDepartment of Mechanical Engineering

Co-Director of Hamlyn Centre, Professor of Medical Robotics
 
 
 
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Contact

 

+44 (0)20 7594 7046f.rodriguez Website

 
 
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Location

 

718City and Guilds BuildingSouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
to

168 results found

Franco E, Rodriguez y Baena F, Astolfi A, 2020, Robust dynamic state feedback for underactuated systems with linearly parameterized disturbances, International Journal of Robust and Nonlinear Control, Vol: 30, Pages: 4112-4128, ISSN: 1049-8923

This article investigates the control problem for underactuated port‐controlled Hamiltonian systems with multiple linearly parameterized additive disturbances including matched, unmatched, constant, and state‐dependent components. The notion of algebraic solution of the matching equations is employed to design an extension of the interconnection and damping assignment passivity‐based control methodology that does not rely on the solution of partial differential equations. The result is a dynamic state‐feedback that includes a disturbance compensation term, where the unknown parameters are estimated adaptively. A simplified implementation of the proposed approach for underactuated mechanical systems is detailed. The effectiveness of the controller is demonstrated with numerical simulations for the magnetic‐levitated‐ball system and for the ball‐on‐beam system.

Journal article

Hu X, Fabrizio C, Tatti F, Rodriguez y Baena Fet al., 2020, Automatic calibration of commercial optical see-through head-mounted displays for medical applications, 2020 IEEE Conference on Virtual Reality and 3D User Interfaces, Publisher: IEEE, Pages: 754-755

The simplified, manual calibration of commercial Optical See-Through Head-Mounted Displays (OST-HMDs) is neither accurate nor convenient for medical applications. An interaction-free calibration method that can be easily implemented in commercial headsets is thus desired. State-of-the-art automatic calibrations simplify the eye-screen system as a pinhole camera and tedious offline calibrations are required. Furthermore, they have never been tested on original commercial products. We present a gaze-based automatic calibration method that can be easily implemented in commercial headsets without knowing hardware details. The location of the virtual target is revised in world coordinate according to the real-time tracked eye gaze. The algorithm has been tested with the Microsoft HoloLens. Current quantitative and qualitative user studies show that the automatically calibrated display is statistically comparable with the manually calibrated display under both monocular and binocular rendering mode. Since it is cumbersome to ask users to perform manual calibrations every time the HMD is re-positioned, our method provides a comparably accurate but more convenient and practical solution to the HMD calibration.

Conference paper

Virdyawan V, Dessi O, Rodriguez y Baena F, 2020, A novel sensing method to detect tissue boundaries during robotic needle insertion based on laser Doppler flowmetry, IEEE Robotics and Automation Letters, Vol: 5, Pages: 1524-1531, ISSN: 2377-3766

This study investigates the use of Laser Doppler Flowmetry (LDF) as a method to detect tissue transitions during robotic needle insertions. Insertions were performed in gelatin tissue phantoms with different optical and mechanical properties and into ex-vivo sheep brain. The effect of changing the optical properties of gelatin tissue phantoms was first investigated and it was shown that using gelatin concentration to modify the stiffness of samples was suitable. Needle insertion experiments were conducted into both one-layer and two-layer gelatin phantoms. In both cases, three stages could be observed in the perfusion values: tissue loading, rupture and tissue cutting. These were correlated to force values measured from the tip of the needle during insertion. The insertions into ex-vivo sheep brain also clearly showed the time of rupture in both force and perfusion values, demonstrating that tissue puncture can be detected using an LDF sensor at the tip of a needle.

Journal article

Franco E, Garriga Casanovas A, Rodriguez y Baena F, Astolfi Aet al., 2019, Model based adaptive control for a soft robotic manipulator, 58th IEEE Conference on Decision and Control, Publisher: IEEE

The application of model based adaptive control to an underactuated system representative of a class of soft continuummanipulators is investigated. To this end, a rigid-linkmodel with elastic joints is employed and an energy shaping controller is designed. Additionally, model uncertainties and external disturbances, both matched and unmatched, are compensated with an adaptive algorithm. This results in a control law that only depends on the orientation and on the angular velocity of the distal link and it is therefore independent of the number of links. Finally, stability conditions are discussed and the effectiveness of the controller is verified via simulations.

Conference paper

Terzano M, Dini D, Rodriguez y Baena F, Spagnoli A, Oldfield Met al., 2020, An adaptive finite element model for steerable needles, Biomechanics and Modeling in Mechanobiology, ISSN: 1617-7940

Penetration of a flexible and steerable needle into a soft target material is a complex problem to be modelled, involving several mechanical challenges. In the present paper, an adaptive finite element algorithm is developed to simulate the penetration of a steerable needle in brain-like gelatine material, where the penetration path is not predetermined. The geometry of the needle tip induces asymmetric tractions along the tool–substrate frictional interfaces, generating a bending action on the needle in addition to combined normal and shear loading in the region where fracture takes place during penetration. The fracture process is described by a cohesive zone model, and the direction of crack propagation is determined by the distribution of strain energy density in the tissue surrounding the tip. Simulation results of deep needle penetration for a programmable bevel-tip needle design, where steering can be controlled by changing the offset between interlocked needle segments, are mainly discussed in terms of penetration force versus displacement along with a detailed description of the needle tip trajectories. It is shown that such results are strongly dependent on the relative stiffness of needle and tissue and on the tip offset. The simulated relationship between programmable bevel offset and needle curvature is found to be approximately linear, confirming empirical results derived experimentally in a previous work. The proposed model enables a detailed analysis of the tool–tissue interactions during needle penetration, providing a reliable means to optimise the design of surgical catheters and aid pre-operative planning.

Journal article

Liu H, Rodriguez y Baena F, 2020, Automatic markerless registration and tracking of the bone for computer-assisted orthopaedic surgery, IEEE Access, Vol: 8, Pages: 42010-42020, ISSN: 2169-3536

To achieve a simple and less invasive registration procedure in computer-assisted orthopaedicsurgery, we propose an automatic, markerless registration and tracking method based on depth imagingand deep learning. A depth camera is used to continuously capture RGB and depth images of the exposedbone during surgery, and deep neural networks are trained to first localise the surgical target using the RGBimage, then segment the target area of the corresponding depth image, from which the surface geometry ofthe target bone can be extracted. The extracted surface is then compared to a pre-operative model of the samebone for registration. This process can be performed dynamically during the procedure at a rate of 5–6 Hz,without any need for surgeon intervention or invasive optical markers. Ex vivo registration experiments wereperformed on a cadaveric knee, and accuracy measurements against an optically tracked ground truth resultedin a mean translational error of 2.74 mm and a mean rotational error of 6.66◦. Our results are the firstto describe a promising new way to achieve automatic markerless registration and tracking in computerassisted orthopaedic surgery, demonstrating that truly seamless registration and tracking of the limb is withinreach. Our method reduces invasiveness by removing the need for percutaneous markers. The surgeon is alsoexempted from inserting markers and collecting registration points manually, which contributes to a moreefficient surgical workflow and shorter procedure time in the operating room.

Journal article

Virdyawan V, Rodriguez y Baena F, 2019, A long short-term memory network for vessel reconstruction based on laser doppler flowmetry via a steerable needle, IEEE Sensors Journal, Vol: 19, Pages: 11367-11376, ISSN: 1530-437X

Hemorrhage is one risk of percutaneous intervention in the brain that can be life-threatening. Steerable needles can avoid blood vessels thanks to their ability to follow curvilinear paths, although knowledge of vessel pose is required. To achieve this, we present the deployment of laser Doppler flowmetry (LDF) sensors as an in-situ vessel detection method for steerable needles. Since the perfusion value from an LDF system does not provide positional information directly, we propose the use of a machine learning technique based on a Long Short-term Memory (LSTM) network to perform vessel reconstruction online. Firstly, the LSTM is used to predict the diameter and position of an approaching vessel based on successive measurements of a single LDF probe. Secondly, a "no-go" area is predicted based on the measurement from four LDF probes embedded within a steerable needle, which accounts for the full vessel pose. The network was trained using simulation data and tested on experimental data, with 75 % diameter prediction accuracy and 0.27 mm positional Root Mean Square (RMS) Error for the single probe network, and 77 % vessel volume overlap for the 4-probe setup.

Journal article

Rodriguez y Baena F, Liu H, 2019, Letter to the editor on "augmented reality based navigation for computer assisted hip resurfacing: a proof of concept study", Annals of Biomedical Engineering, Vol: 47, Pages: 2154-2154, ISSN: 0090-6964

Journal article

Darwood A, Hurst S, Villatte G, Fenton R, Tatti F, El-Daou H, Reilly P, Emery R, Rodriguez Y Baena Fet al., 2019, Towards a commercial system for intraoperative manufacture of patient-specific guides for shoulder arthroplasty, CAOS 2019. The 19th Annual Meeting of the International Society for Computer Assisted Orthopaedic Surgery, Publisher: EasyChair, Pages: 110-114

The accurate placement of orthopaedic implants according to a biomechanically derived preoperative plan is an important consideration in the long-term success of these interventions. Guidance technologies are widely described however, high cost, complex theatre integration, intraoperative inefficiency and functional limitations have prevented the widespread use. A novel, intraoperative mechatronics platform is presented, capable of the rapid, intraoperative manufacture of low-cost patient-specific guides. The device consists of a tableside robot with sterile drapes and some low cost, sterile disposable components. The robot comprises a 3D optical scanner, a three-axis sterile computer numerical control (CNC) drill and a two-axis receptacle into which the disposable consumables may be inserted. The sterile consumable comprises a region of rapidly setting moldable material and a clip allowing it to be reversibly attached to the tableside robot. In use, patient computed tomography (CT) imaging is obtained at any point prior to surgery and a surgical plan is created on associated software. This plan describes the axis and positioning of one or more guidewires which may, in turn, locate the prosthesis into position. Intraoperatively, osseous anatomy is exposed, and the sterile disposable is used to rapidly create a mould of the joint surface. Once set, the mould is inserted into the robot and an optical scan of the surface is taken followed by automatic surface registration, bringing the optical scan into the same coordinate frame of reference as the CT data and plan. The CNC drill is orientated such that the drill axis and position exactly matches the planned axis and position with respect to the moulded surface. A guide hole is drilled into the mould blank, which is removed from the robot and placed back into the patient with the moulded surface ensuring exact replacement. A wire is subsequently driven through the guide hole into the osseous anatomy in accordance with

Conference paper

Iqbal H, Tatti F, Rodriguez Y Baena F, 2019, Augmented-reality within computer assisted orthopaedic surgery workflows: a proof of concept study, CAOS 2019. The 19th Annual Meeting of the International Society for Computer Assisted Orthopaedic Surgery, Publisher: EasyChair

The integration of augmented-reality (AR) in medical robotics has been shown to reduce cognitive burden and improve information management in the typically cluttered environment of computer-assisted surgery. A key benefit of such systems is the ability to generate a composite view of medical-informatics and the real environment, streamlining the pathway for delivering patient-specific data. Consequently, AR was integrated within an orthopaedic setting by designing a system that captured and replicated the user- interface of a commercially available surgical robot onto a commercial head mounted see through display. Thus, a clinician could simultaneously view the operating-site and real- time informatics when carrying out an assisted patellofemoral-arthroplasty (PFA). The system was tested with 10 surgeons to examine its usability and impact on procedure- completion times when conducting simulated PFA on sawbone models. A statistically insignificant mean increase in procedure completion-time (+23.7s, p=0.240) was found, and the results of a post-operative qualitative-evaluation indicated a strongly positive consensus on the system, with a large majority of subjects agreeing the system provided value to the procedure without incurring noticeable physical discomfort. Overall, this study provides an encouraging insight into the high levels of engagement AR has with a clinical audience as well as its ability to enhance future generations of medical robotics.

Conference paper

Munford MJ, Baena FRY, Bowyer S, 2019, Stereoscopic Near-Infrared Fluorescence Imaging: A Proof of Concept Toward Real-Time Depth Perception in Surgical Robotics, FRONTIERS IN ROBOTICS AND AI, Vol: 6, ISSN: 2296-9144

Journal article

Zhan W, Rodriguez y Baena F, Dini D, 2019, Effect of tissue permeability and drug diffusion anisotropy on convection-enhanced delivery, Drug Delivery, Vol: 26, Pages: 773-781, ISSN: 1071-7544

Although convection-enhanced delivery (CED) can successfully facilitate a bypass of the blood brain barrier, its treatment efficacy remains highly limited in clinic. This can be partially attributed to the brain anisotropic characteristics that lead to the difficulties in controlling the drug spatial distribution. Here, the responses of six different drugs to the tissue anisotropy are examined through a parametric study performed using a multiphysics model, which considers interstitial fluid flow, tissue deformation and interlinked drug transport processes in CED. The delivery outcomes are evaluated in terms of the penetration depth and delivery volume for effective therapy. Simulation results demonstrate that the effective penetration depth in a given direction can be improved with the increase of the corresponding component of anisotropic characteristics. The anisotropic tissue permeability could only reshape the drug distribution in space but has limited contribution to the total effective delivery volume. On the other hand, drugs respond in different ways to the anisotropic diffusivity. The large delivery volumes of fluorouracil, carmustine, cisplatin and doxorubicin could be achieved in relatively isotropic tissue, while paclitaxel and methotrexate are able to cover enlarged regions into anisotropic tissues. Results obtained from this study serve as a guide for the design of CED treatments.

Journal article

Watts TE, Secoli R, Rodriguez y Baena F, 2019, A mechanics-based model for 3D steering of programmable bevel-tip needles, IEEE Transactions on Robotics, Vol: 35, Pages: 371-386, ISSN: 1552-3098

We present a model for the steering of programmable bevel-tip needles, along with a set of experiments demonstrating the 3D steering performance of a new, clinically viable, 4-segment, pre-production prototype. A multi-beam approach, based on Euler-Bernoulli beam theory, is used to model the novel multi-segment design of these needles. Finite element simulations for known loads are used to validate the multi-beam deflection model. A clinically sized (2.5 mm outer diameter), 4-segment programmable bevel-tip needle, manufactured by extrusion of a medical-grade polymer, is used to conduct an extensive set of experimental trials to evaluate the steering model. For the first time, we demonstrate the ability of the 4-segment needle design to steer in any direction with a maximum achievable curvature of 0.0192±0.0014 mm⁻¹. Finite element simulations confirm that the multi-beam approach produces a good model fit for tip deflections, with a root-mean-square deviation (RMSD) in modeled tip deflection of 0.2636 mm. We perform a parameter optimization to produce a best-fit steering model for the experimental trials, with a RMSD in curvature prediction of 1.12×10⁻³ mm⁻¹.

Journal article

Pinzi M, Galvan S, Rodriguez y Baena F, 2019, The adaptive hermite fractal tree (AHFT): a novel surgical 3D path planning approach with curvature and heading constraints, International Journal of Computer Assisted Radiology and Surgery, Vol: 14, Pages: 659-670, ISSN: 1861-6429

PurposeIn the context of minimally invasive neurosurgery, steerable needles such as the one developed within the Horizon2020-funded EDEN2020 project (Frasson et al. in Proc Inst Mech Eng Part H J Eng Med 224(6):775–88, 2010. https://doi.org/10.1243/09544119JEIM663; Secoli and y Baena in IEEE international conference on robotics and automation, 2013) aspire to address the clinical challenge of better treatment for cancer patients. The direct, precise infusion of drugs in the proximity of a tumor has been shown to enhance its effectiveness and diffusion in the surrounding tissue (Vogelbaum and Aghi in Neuro-Oncology 17(suppl 2):ii3–ii8, 2015. https://doi.org/10.1093/neuonc/nou354). However, planning for an appropriate insertion trajectory for needles such as the one proposed by EDEN2020 is challenging due to factors like kinematic constraints, the presence of complex anatomical structures such as brain vessels, and constraints on the required start and target poses.MethodsWe propose a new parallelizable three-dimensional (3D) path planning approach called Adaptive Hermite Fractal Tree (AHFT), which is able to generate 3D obstacle-free trajectories that satisfy curvature constraints given a specified start and target pose. The AHFT combines the Adaptive Fractal Tree algorithm’s efficiency (Liu et al. in IEEE Robot Autom Lett 1(2):601–608, 2016. https://doi.org/10.1109/LRA.2016.2528292) with optimized geometric Hermite (Yong and Cheng in Comput Aided Geom Des 21(3):281–301, 2004. https://doi.org/10.1016/j.cagd.2003.08.003) curves, which are able to handle heading constraints.ResultsSimulated results demonstrate the robustness of the AHFT to perturbations of the target position and target heading. Additionally, a simulated preoperative environment, where the surgeon is able to select a desired entry pose on the patient’s skull, confirms the ability of the method to generate multiple feasible trajectories for a patient-specific case

Journal article

Matheson E, Watts T, Secoli R, Rodriguez y Baena Fet al., 2019, Cyclic motion control for programmable bevel-tip needles 3D steering: a simulation study, ROBIO - IEEE International Conference on Robotics and Biomimetics, Publisher: IEEE

Flexible, steerable, soft needles are desirable inMinimally Invasive Surgery to achieve complex trajectorieswhile maintaining the benefits of percutaneous interventioncompared to open surgery. One such needle is the multi-segmentProgrammable Bevel-tip Needle (PBN), which is inspired by themechanical design of the ovipositor of certain wasps. PBNscan steer in 3D whilst minimizing the force applied to thesurrounding substrate, due to the cyclic motion of the segments.Taking inspiration also from the control strategy of the wasp toperform insertions and lay their eggs, this paper presents thedesign of a cyclic controller that can steer a PBN to produce adesired trajectory in 3D. The performance of the controller isdemonstrated in simulation in comparison to that of a directcontroller without cyclic motion. It is shown that, while thesame steering curvatures can be attained by both controllers,the time taken to achieve the configuration is longer for thecyclic controller, leading to issues of potential under-steeringand longer insertion times.

Conference paper

Ng KCG, El Daou H, Bankes M, Rodriguez y Baena F, Jeffers Jet al., 2019, Hip joint torsional loading before and after cam femoroacetabular impingement surgery, American Journal of Sports Medicine, Vol: 47, Pages: 420-430, ISSN: 0363-5465

Background: Surgical management of cam femoroacetabular impingement (FAI) aims to preserve the native hip and restore joint function, though it is unclear how the capsulotomy, cam deformity, and capsular repair influence joint mechanics to balance functional mobility.Purpose: The purpose was to examine the contributions of the capsule and cam deformity to hip joint mechanics. Using in vitro, cadaveric methods, we examined the individual effects of the surgical capsulotomy, cam resection, and capsular repair towards passive range of motion and resistance of applied torque.Study Design: Descriptive laboratory study.Methods: Twelve cadaveric hips with cam deformities (n = 12) were skeletonized to the capsule and mounted onto a robotic testing platform. The robot positioned each intact hip in multiple testing positions: 1) Extension, 2) Neutral 0°, 3) Flexion 30°, 4) Flexion 90°, 5) flexion-adduction and internal rotation (FADIR), 6) flexion-abduction and external rotation (FABER); and performed applicable internal and external rotations, recording the neutral path of motion until a 5-Nm torque was reached in each rotational direction. Each hip then underwent a series of surgical stages (T-capsulotomy, cam resection, capsular repair) and was retested to reach 5 Nm internal and external torque again after each stage. In addition, during the capsulotomy and cam resection stages, the initial intact hip’s recorded path of motion was replayed to measure changes in resisted torque.Results: Examining changes in motion, external rotation increased substantially after capsulotomies, but internal rotation only further increased at Flexion 90° (change = +32%, P = .001, d = .58) and FADIR (change = +33%, P < .001, d = .51) after cam resections. Capsular repair provided marginal restraint for internal rotation, but restrained the external rotation compared to the capsulotomy stage. Examining changes in torque, both internal and external torque resistance dec

Journal article

Garriga Casanovas A, Rodriguez y Baena F, 2019, Kinematics of continuum robots with constant curvature bending and extension capabilities, Journal of Mechanisms and Robotics, Vol: 11, ISSN: 1942-4302

Continuum robots are becoming increasingly popular due to the capabilities they offer, especially when operating in cluttered environments, where their dexterity, maneuverability, and compliance represent a significant advantage. The subset of continuum robots that also belong to the soft robots category has seen rapid development in recent years, showing great promise. However, despite the significant attention received by these devices, various aspects of their kinematics remain unresolved, limiting their adoption and obscuring their potential. In this paper, the kinematics of continuum robots with the ability to bend and extend are studied, and analytical, closed-form solutions to both the direct and inverse kinematics are presented. The results obtained expose the redundancies of these devices, which are subsequently explored. The solution to the inverse kinematics derived here is shown to provide an analytical, closed-form expression describing the curve associated with these redundancies, which is also presented and analyzed. A condition on the reachable end-effector poses for robots with six actuation degrees-of-freedom (DOFs) is then distilled. The kinematics of robot layouts with over six actuation DOFs are subsequently considered. Finally, simulated results of the inverse kinematics are provided, verifying the study.

Journal article

Virdyawan V, Rodriguez y Baena F, 2019, Vessel pose estimation for obstacle avoidance in needle steering surgery using multiple forward looking sensors, 2018 IEEE/RSJ International Conference on Intelligent Robots and Systems, Publisher: IEEE

During percutaneous interventions in the brain, puncturing a vessel can cause life-threatening complications. To avoid such a risk, current research has been directed towards the development of steerable needles. However, there is a risk that vessels of a size which is close to or smaller than the resolution of commonly used preoperative imaging modalities (0.59 x 0.59 x 1 mm) would not be detected during procedure planning, with a consequent increase in risk to the patient. In this work, we present a novel ensemble of forward-looking sensors based on laser Doppler flowmetry, which are embedded within a biologically inspired steerable needle to enable vessel detection during the insertion process. Four Doppler signals are used to classify the pose of a vessel in front of the advancing needle with a high degree of accuracy (2$^{\circ}$ and 0.1 mm RMS errors), where relative measurements between sensors are used to correct for ambiguity. By using a robotic-assisted needle insertion process, and thus a precisely controlled insertion speed, we also demonstrate how the setup can be used to discriminate between tissue bulk motion and vessel motion. In doing so, we describe a sensing apparatus applicable to a variety of needle steering systems, with the potential to eliminate the risk of haemorrhage during percutaneous procedures.

Conference paper

El Daou H, Ng KC, van Arkel R, Jeffers J, Rodriguez y Baena Fet al., 2019, Robotic hip joint testing: Development and experimental protocols, Medical Engineering and Physics, Vol: 63, Pages: 57-62, ISSN: 1350-4533

The use of robotic systems combined with force sensing is emerging as the gold standard for in vitro biomechanical joint testing, due to the advantage of controlling all six degrees of freedom independently of one another. This paper describes a novel robotic platform and the experimental protocol used for hip joint testing. An experimental protocol implemented optical tracking and registration techniques in order to define the position of the hip joint centre of rotation (COR) in the coordinate system of the robot's end effector. The COR coordinates defined the origin of the task-related coordinate system used to control the robot, with a hybrid force/position law to simulate standard clinical tests. The axes of this frame were defined using the International Society of Biomechanics (ISB) anatomical coordinate system.Experiments were carried out on two cadaveric hip joint specimens using the robotic testing platform and a mechanical testing rig previously developed and described by our group. Simulated internal-external and adduction/abduction laxity tests were carried out with both systems and the resulting peak range of motion (ROM) was measured. Similarities and differences were observed in these experiments, which were used to highlight some of the limitations of conventional systems and the corresponding advantages of robotics, further emphasising their added value in vitro testing.

Journal article

Tan Z, Dini D, Rodriguez y Baena F, Forte Aet al., 2018, Composite hydrogel: A high fidelity soft tissue mimic for surgery, Materials and Design, Vol: 160, Pages: 886-894, ISSN: 0264-1275

Accurate tissue phantoms are difficult to design due to the complex non-linear viscoelastic properties of real soft tissues. A composite hydrogel, resulting from a mix of poly(vinyl) alcohol and phytagel, is able to reproduce the viscoelastic responses of different soft tissues due to its compositional tunability. The aim of this work is to demonstrate the flexibility of the composite hydrogel in mimicking the interactions between surgical tools and various soft tissues, such as brain, lung and liver. Therefore compressive stiffness, insertion forces and frictional forces were used as matching criteria to determine the hydrogel compositions for each soft tissue. A full map of the behaviour of the synthetic material is provided for these three characteristics and the compositions found to best match the mechanical response of brain, lung and liver are reported. The optimised hydrogel samples are then tested and shown to mimic the behaviour of the three tissues with unprecedented fidelity. The effect of each hydrogel constituent on the compressive stiffness, needle insertion and frictional forces is also detailed in this work to explain their individual contributions and synergistic effects. This study opens important opportunities for the realisation of surgical planning and training devices and tools for in-vitro tissue testing.

Journal article

Franco E, Rodriguez y Baena F, Astolfi A, 2018, Robust balancing control of flexible inverted-pendulum systems, Mechanism and Machine Theory, Vol: 130, Pages: 539-551, ISSN: 0094-114X

This work studies the balancing control problem for flexible inverted-pendulum systems and investigates the relationship between system parameters and robustness to disturbances. To this end, a new energy-shaping controller with adaptive disturbance-compensation for a class of underactuated mechanical systems is presented. Additionally, a method for the identification of key system parameters that affect the robustness of the closed-loop system is outlined. The proposed approach is applied to the flexible pendulum-on-cart system and a simulation study is conducted to demonstrate its effectiveness. Finally, the control problem for a classical pendulum-on-cart system with elastic joint is discussed to highlight the similarities with its flexible-link counterpart.

Journal article

Watts T, Secoli R, Rodriguez y Baena F, 2018, Needle Steerability Measures: Definition and Application for Optimized Steering of the Programmable Bevel-tip Needle, 2018 IEEE International Conference on Robotics and Biomimetics (IEEE ROBIO 2018)

Conference paper

Garriga Casanovas A, Collison I, Rodriguez y Baena F, 2018, Towards a common framework for the design of soft robotic manipulators with fluidic actuation, Soft Robotics, Vol: 5, Pages: 622-649, ISSN: 2169-5172

Soft robotic manipulators with fluidic actuation are devices with easily deformable structures that comprise a set of chambers that can be pressurized to achieve structural deflection. These devices have experienced a rapid development in recent years, which is not least due to the advantages they offer in terms of robustness, affordability, and compliance. Nowadays, however, soft robotic manipulators are designed mostly by intuition, which complicates design improvement and hampers the advancement of the field. In this paper, a general study of the the design of soft robotic manipulators with fluidic actuation is presented, using an analytical derivation. The study relies on a novel approach that is applicable to a general design, and thus provides a common framework for the design of soft robots. In the study, two design layouts of interest are first justified, which correspond to extending and contracting devices. Design principles for each of the layouts are subsequently derived, both for planar and 3D scenarios, and considering operation to support any external loading and to provide any desired deflection. These principles are found to agree with the main design trends in literature, although they also highlight the potential for improvement in specific aspects of the design geometry and stiffness distribution. The principles are used to identify the most suitable design for both extending and contracting devices in 2D and 3D, and extract insight into their behavior.. To showcase the use of these design principles, a prototypical scenario in minimally invasive surgery requiring a manipulator segment capable of bending in any direction is defined, where the objective is to maximize its lateral force. The principles are applied to determine the most suitable design. These also highlight the need for numerical analysis to optimize two design parameters. Finite element simulations are developed, and their results are reported.

Journal article

Liu H, Auvinet E, Giles J, Rodriguez y Baena Fet al., 2018, Augmented reality based navigation for computer assisted hip resurfacing: a proof of concept study, Annals of Biomedical Engineering, Vol: 46, Pages: 1595-1605, ISSN: 0090-6964

Implantation accuracy has a great impact on the outcomes of hip resurfacing such as recovery of hip function. Computer assisted orthopedic surgery has demonstrated clear advantages for the patients, with improved placement accuracy and fewer outliers, but the intrusiveness, cost, and added complexity have limited its widespread adoption. To provide seamless computer assistance with improved immersion and a more natural surgical workflow, we propose an augmented-reality (AR) based navigation system for hip resurfacing. The operative femur is registered by processing depth information from the surgical site with a commercial depth camera. By coupling depth data with robotic assistance, obstacles that may obstruct the femur can be tracked and avoided automatically to reduce the chance of disruption to the surgical workflow. Using the registration result and the pre-operative plan, intra-operative surgical guidance is provided through a commercial AR headset so that the user can perform the operation without additional physical guides. To assess the accuracy of the navigation system, experiments of guide hole drilling were performed on femur phantoms. The position and orientation of the drilled holes were compared with the pre-operative plan, and the mean errors were found to be approximately 2 mm and 2°, results which are in line with commercial computer assisted orthopedic systems today.

Journal article

Tan Z, Forte A, Rodriguez y Baena F, Dini Det al., 2018, Needle-tissue interactions during convection enhanced drug delivery in neurosurgery, International Conference on BioTribology

Conference paper

Watts T, Secoli R, Rodriguez y Baena F, 2018, Modelling the deformation of biologically inspired flexible structures for needle steering, The first International Congress for the Advancement of Mechanism, Machine, Robotics and Mechatronics Sciences 2017, Publisher: Springer, Pages: 67-80, ISSN: 2211-0984

Recent technical advances in minimally invasive surgery have been enabled by the development of new medical instruments and technologies. To date, the vast majority of mechanisms used within a clinical context are rigid, contrasting with the compliant nature of biological tissues. The field of robotics has seen an increased interest in flexible and compliant systems, and in this paper we investigate the behaviour of deformable multi-segment structures, which take their inspiration from the ovipositor design of parasitic wood wasps. These configurable structures have been shown to steer through highly compliant substrates, potentially enabling percutaneous access to the most delicate of tissues, such as the brain. The model presented here sheds light on how the deformation of the unique structure is related to its shape, and allows comparison between different potential designs. A finite element study is used to evaluate the proposed model, which is shown to provide a good fit (root-mean-square deviation 0.2636 mm for 4-segment case). The results show that both 3-segment and 4-segment designs are able to achieve deformation in all directions, however the magnitude of deformation is more consistent in the 4-segment case.

Conference paper

Matheson E, Secoli R, Burrows C, Leibinger A, Rodriguez y Baena Fet al., 2018, Cyclic motion control for programmable bevel-tip needles to reduce tissue deformation, Journal of Medical Robotics Research, Vol: 4, ISSN: 2424-905X

Robotic-assisted steered needles aim to accurately control the deflection of the flexible needle’s tip to achieve accurate path following. In doing so, they can decrease trauma to the patient, by avoiding sensitive regions while increasing placement accuracy. This class of needle presents more complicated kinematics compared to straight needles, which can be exploited to produce specific motion profiles via careful controller design and tuning. Motion profiles can be optimized to minimize certain conditions such as maximum tissue deformation and target migration, which was the goal of the formalized cyclic, low-level controller for a Programmable Bevel-tip Needle (PBN) presented in this work. PBNs are composed of a number of interlocked segments that are able to slide with respect to one another. Producing a controlled, desired offset of the tip geometry leads to the corresponding desired curvature of the PBN, and hence desired path trajectory of the system. Here, we propose a cyclical actuation strategy, where the tip configuration is achieved over a number of reciprocal motion cycles, which we hypothesize will reduce tissue deformation during the insertion process. A series of in vitro, planar needle insertion experiments are performed in order to compare the cyclic controller performance with the previously used direct push controller, in terms of targeting accuracy and tissue deformation. It is found that there is no significant difference between the target tracking performance of the controllers, but a significant decrease in axial tissue deformation when using the cyclic controller.

Journal article

Secoli R, Rodriguez y Baena F, 2018, Experimental validation of curvature tracking with a programmable bevel-tip steerable needle, International Symposium on Medical Robotics, Publisher: IEEE

Needle steering systems are a topic of increasing research interest due to the many potential advantages associated with the ability to reach deep-seated targets while avoiding obstacles. Existing embodiments, such as those designed around a fixed bevel tip, are necessarily disruptive to the substrate, with the potential to cause a target to move away from the insertion trajectory, as well as potentially increasing the extent of tissue trauma at the needle interface, when compared to straight needles. To alleviate these issues, we proposed a biologically inspired design, which can steer without the need for duty-cycle spinning along the insertion axis or any active mechanisms at the tip. In this work, we demonstrate for the first time that our needle is able to steer within a deformable substrate, along with a user-defined trajectory in three-dimensional space. A simplified kinematic model is reported, which is subsequently used to design an adaptive strategy enabling the tracking of arbitrary curvatures along any given reference plane. Experimental results in gelatin are used to validate our model, as well as the performance of the controller under laboratory conditions.

Conference paper

Brett PN, Du X, Assadi MZ, Rodriguez y Baena F, Liu F, Hinchliffe R, Thompson Met al., 2018, Design and experimental demonstration of a mechatronic solution for endovascular catheters, Mechatronics and Machine Vision in Practice 3, Pages: 247-252, ISBN: 9783319769462

© Springer International Publishing AG, part of Springer Nature 2018. This paper describes a mechatronics approach that provides vascular surgeons with the perception of movement and tissue interaction in the vicinity of the tip of a catheter in endovascular procedures. The current system described is experimental and used in phantom units. It integrates 3D visualization generated from scan with real-time tactile sensing in the vicinity of the tip of the catheter to update on the nature of tissue interaction, the curvature and relative orientation of the catheter sleeve and guide wire. This approach offers superior perception by the clinician, in contrast with current application of catheters used in this application. By being well informed of conditions at the working environment of the catheter tip the clinician will be able to administer therapies with greater precision in the surgical task and within a reduced operating time. The approach will reduce risk for patients and significantly reduce risks for the clinician, who is currently exposed to high doses of ionizing radiation during the process of catheter guidance.

Book chapter

Garriga Casanovas A, ’Athif Mohd Faudzi A, Hiramitsu T, Rodriguez y Baena F, Suzumori Ket al., 2018, Multifilament pneumatic artificial muscles to mimic the human neck, IEEE International Conference on Robotics and Biomimetics, 2017, Publisher: IEEE

Pneumatic Artificial Muscles (PAMs) are actuators that resemble human muscles, and offer an attractive performance in various aspects including robustness, simplicity, high specific power and high force for a given volume. These characteristics render them good candidates for use in humanoid robots. The use of traditional PAMs to closely mimic human structures, however, is difficult due to their relatively large size and relatively fixed designs. The recent development of multifilament PAMs enables the realization of humanoid robots that more closely mimic the human anatomy. In this paper, the application of multifilament PAMs to mimic the human neck is presented. First, the main structures of the human neck anatomy in terms of bones, ligaments and muscles are identified and detailed. The design to mimic each of these structures is subsequently described, together with the most relevant parts of the manufacturing process. The integrated neck is then presented, and the method to actuate it is outlined. The results of motion of the artificial neck when actuating different groups of muscles that mimic those in the human anatomy are reported, confirming a motion that is equivalent to that of the human neck. The results also indicate a range of motion of the robot neck somewhat lower than that of its human counterpart, and the reasons for this are discussed. Finally, future directions for improved motion range, stability, durability and efficiency are outlined.

Conference paper

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