Publications
219 results found
Blyth WA, Barr DRW, Rodriguez Y Baena F, 2016, A reduced actuation mecanum wheel platform for pipe inspection, 2016 IEEE International Conference on Advanced Intelligent Mechatronics (AIM), Publisher: IEEE, Pages: 419-424
This paper focuses on the design, development and assessment of a novel, 2 degrees-of-freedom magnetic pipe inspection robot. It consists of 4 mecanum wheels, with the diagonals functionally coupled and the system rotation constrained by the surface geometry, maintaining full translational mobility with reduced control and actuation requirements. The system uses positional encoding that is decoupled from the transmission system to overcome the main sources of positional/positioning errors when using mecanum wheels. The kinematic and dynamic models of the system are derived and integrated within the controller. The prototype robot is then tested and shown to follow a scan path at 20mm/s within ±1.5mm whilst correcting for gravitational drift and slip events.
Forte AE, Galvan S, Manieri F, et al., 2016, A composite hydrogel for brain tissue phantoms, Materials and Design, Vol: 112, Pages: 227-238, ISSN: 0264-1275
Synthetic phantoms are valuable tools for training, research and development in traditional and computer aided surgery, but complex organs, such as the brain, are difficult to replicate. Here, we present the development of a new composite hydrogel capable of mimicking the mechanical response of brain tissue under loading. Our results demonstrate how the combination of two different hydrogels, whose synergistic interaction results in a highly tunable blend, produces a hybrid material that closely matches the strongly dynamic and non-linear response of brain tissue. The new synthetic material is inexpensive, simple to prepare, and its constitutive components are both widely available and biocompatible. Our investigation of the properties of this engineered tissue, using both small scale testing and life-sized brain phantoms, shows that it is suitable for reproducing the brain shift phenomenon and brain tissue response to indentation and palpation.
Tan Z, Forte AE, Galvan S, et al., 2016, Composite Hydrogel: a New Tool for Reproducing the Mechanical Behaviour of Soft Human Tissues, Biotribology 2016
Virdyawan V, Oldfield, Rodriguez y Baena, 2016, Laser Doppler based sensing for blood vessel detection with a steerable needle, 6th Joint Workshop on New Technologies for Computer/Robot Assisted Surgery
Darwood A, Secoli R, Bowyer SA, et al., 2016, Intraoperative manufacturing of patient specific instrumentation for shoulder arthroplasty: a novel mechatronic approach, Journal of Medical Robotics Research, Vol: 1, ISSN: 2424-905X
Optimal orthopaedic implant placement is a major contributing factor to the long term success of all common joint arthroplasty procedures. Devicessuch as three-dimensional (3D) printed, bespoke guides and orthopaedic robots are extensively described in the literature and have been shownto enhance prosthesis placement accuracy. These technologies, however, have significant drawbacks, such as logistical and temporal inefficiency,high cost, cumbersome nature and difficult theatre integration. A new technology for the rapid intraoperative production of patient specific instrumentation,which overcomes many of the disadvantages of existing technologies, is presented here. The technology comprises a reusable table sidemachine, bespoke software and a disposable element comprising a region of standard geometry and a body of mouldable material. Anatomicaldata from Computed Tomography (CT) scans of 10 human scapulae was collected and, in each case, the optimal glenoid guidewire position wasdigitally planned and recorded. The achieved accuracy compared to the preoperative bespoke plan was measured in all glenoids, from both a conventionalgroup and a guided group. The technology was successfully able to intraoperatively produce sterile, patient specific guides according toa pre-operative plan in 5 minutes, with no additional manufacturing required prior to surgery. Additionally, the average guide wire placement accuracywas 1.58 mm and 6.82◦ degrees in the manual group, and 0.55 mm and 1.76◦ degrees in the guided group, also demonstrating a statisticallysignificant improvement.
Secoli R, Rodriguez y Baena F, 2016, Adaptive path-following control for bio-inspired steerable needles, 6th IEEE RAS/EMBS International Conference on Biomedical Robotics and Biomechatronics, Publisher: IEEE
Needle steering systems have shown potential ad-vantages in minimally invasive surgery in soft-tissue due to theirability to reach deep-seated targets while avoiding obstacles. Ingeneral, the control strategies employed to drive the insertionuse simplified kinematic models, providing limited control ofthe trajectory between an entry site and a deep seated targetin cases of unmodelled tissue-needle dynamics. In this work,we present the first Adaptive Path-Following (APF) controllerfor a bio-inspired multi-part needle, able to steer along three-dimensional (3D) paths within a compliant medium by meansof the cyclical motion of interlocked segments and without theneed for duty-cycle spinning along the insertion axis.The control strategy is outlined in two parts: a high-level con-troller, which provides driving commands to follow a predefined3D path smoothly; and a low-level controller, able to counteractunmodelled tissue-needle nonlinearities and kinematic modeluncertainties. A simulation that mimics the needle’s mechanicalbehavior during insertion is achieved by using an ExperimentalFitting Model (EFM), obtained from previous experimentaltrials. The Simulation results demonstrate the robustness andadaptability of the proposed control strategy.
Leibinger A, Oldfield M, Rodriguez y Baena F, 2016, Minimally disruptive needle insertion: a biologically inspired solution, Interface Focus, Vol: 6, ISSN: 2042-8898
The mobility of soft tissue can cause inaccurate needle insertions. Particularly in steering applications that employ thin and flexible needles, l arge deviationscan occur between preoperative images of the patient, from which a procedure is planned, and the intraoperative scene, where a procedure is executed. Whereas many approaches for reducing tissue motion focus on external constraining or manipulation, little attention has been paid to the way the needle is inserted and actuated within soft tissue. Using our biologically inspiredsteerable needle, we present a methodof reducing the disruptivenessof insertionsby mimicking the burrowing mechanism of ovipositing wasps. Internal displacements and strains in three dimensionswithin a soft tissue phantom are measured at the needle interface,using ascanninglaser basedimage correlation technique.Compared to a conventional insertion methodwith an equally sized needle,overall displacementsand strainsin the needle vicinity arereduced by 30% and 41%, respectively.The results show that, for a given net speed,needle insertion can be made significantly less disruptive with respect to its surroundings by employing our biologically inspired solution. This will have significant impact on both the safety and targeting accuracy of percutaneous interventions along both straight and curved trajectories
Liu F, Garriga-Casanovas A, Secoli R, et al., 2016, Fast and adaptive fractal tree-based path planning for programmable bevel tip steerable needles, IEEE Robotics and Automation Letters, Vol: 1, Pages: 601-608, ISSN: 2377-3766
Steerable needles are a promising technology for minimally invasive surgery, as they can provide access to difficult to reach locations while avoiding delicate anatomical regions. However, due to the unpredictable tissue deformation associated with needle insertion and the complexity of many surgical scenarios, a real-time path planning algorithm with high update frequency would be advantageous. Real-time path planning for nonholonomic systems is commonly used in a broad variety of fields, ranging from aerospace to submarine navigation. In this letter, we propose to take advantage of the architecture of graphics processing units (GPUs) to apply fractal theory and thus parallelize real-time path planning computation. This novel approach, termed adaptive fractal trees (AFT), allows for the creation of a database of paths covering the entire domain, which are dense, invariant, procedurally produced, adaptable in size, and present a recursive structure. The generated cache of paths can in turn be analyzed in parallel to determine the most suitable path in a fraction of a second. The ability to cope with nonholonomic constraints, as well as constraints in the space of states of any complexity or number, is intrinsic to the AFT approach, rendering it highly versatile. Three-dimensional (3-D) simulations applied to needle steering in neurosurgery show that our approach can successfully compute paths in real-time, enabling complex brain navigation.
Petersen J, Bowyer S, Rodriguez y Baena F, 2016, Mass and friction optimization for natural motion in hands-on robotic surgery, IEEE Transactions on Robotics, Vol: 32, Pages: 201-213, ISSN: 1552-3098
In hands-on robotic surgery, the surgical tool is mounted on the end-effector of a robot and is directly manipulated by the surgeon. This simultaneously exploits the strengths of both humans and robots, such that the surgeon directly feels tool-tissue interactions and remains in control of the procedure, while taking advantage of the robot's higher precision and accuracy. A crucial challenge in hands-on robotics for delicate manipulation tasks, such as surgery, is that the user must interact with the dynamics of the robot at the end-effector, which can reduce dexterity and increase fatigue. This paper presents a null-space-based optimization technique for simultaneously minimizing the mass and friction of the robot that is experienced by the surgeon. By defining a novel optimization technique for minimizing the projection of the joint friction onto the end-effector, and integrating this with our previous techniques for minimizing the belted mass/inertia as perceived by the hand, a significant reduction in dynamics felt by the user is achieved. Experimental analyses in both simulation and human user trials demonstrate that the presented method can reduce the user-experienced dynamic mass and friction by, on average, 44% and 41%, respectively. The results presented robustly demonstrate that optimizing a robots pose can result in a more natural tool motion, potentially allowing future surgical robots to operate with increased usability, improved surgical outcomes, and wider clinical uptake.
Bowyer SA, Rodriguez y Baena F, 2016, A Hybrid Constraint-Penalty Proxy Method for Six Degree-of-Freedom Haptic Display of Deforming Objects, 22nd ACM Conference on Virtual Reality Software and Technology (VRST), Publisher: ASSOC COMPUTING MACHINERY, Pages: 173-182
Leibinger A, Forte AE, Tan Z, et al., 2015, Soft tissue phantoms for realistic needle insertion: a comparative study, Annals of Biomedical Engineering, Vol: 44, Pages: 2442-2452, ISSN: 1573-9686
Phantoms are common substitutes for soft tissues in biomechanical research and are usually tuned to match tissue properties using standard testing protocols at small strains. However, the response due to complex tool-tissue interactions can differ depending on the phantom and no comprehensive comparative study has been published to date, which could aid researchers to select suitable materials. In this work, gelatin, a common phantom in literature, and a composite hydrogel developed at Imperial College, were matched for mechanical stiffness to porcine brain, and the interactions during needle insertions within them were analyzed. Specifically, we examined insertion forces for brain and the phantoms; we also measured displacements and strains within the phantoms via a laser-based image correlation technique in combination with fluorescent beads. It is shown that the insertion forces for gelatin and brain agree closely, but that the composite hydrogel better mimics the viscous nature of soft tissue. Both materials match different characteristics of brain, but neither of them is a perfect substitute. Thus, when selecting a phantom material, both the soft tissue properties and the complex tool-tissue interactions arising during tissue manipulation should be taken into consideration. These conclusions are presented in tabular form to aid future selection.
Forte AE, 2015, BRAIN TISSUE BIOMECHANICS: NEW TISSUE PHANTOMS, MECHANICAL CHARACTERISATION AND MODELLING STRATEGIES FOR ENHANCED SURGICAL PROCEDURES
Bowyer SA, Rodriguez y Baena F, 2015, Dissipative control for physical human-robot interaction, IEEE Transactions on Robotics, Vol: 31, Pages: 1281-1293, ISSN: 1552-3098
Physical human-robot interaction is fundamental to exploiting the capabilities of robots in tasks and environments where robots have limited cognition or comprehension and is virtually ubiquitous for robotic manipulation in highly unstructured environments, as are found in surgery. A critical aspect of physical human-robot interaction in these cases is controlling the robot so that the individual human and robot competencies are maximized, while guaranteeing user, task, and environment safety. Dissipative control precludes dangerous forcing of a shared tool by the robot, ensuring safety; however, it typically suffers from poor control fidelity, resulting in reduced task accuracy. In this study, a novel, rigorously formalized, n-dimensional dissipative control strategy is proposed that employs a new technique called “energy redirection” to generate control forces with increased fidelity while remaining dissipative and safe. Experimental validation of the method, for complete pose control, shows that it achieves a 90% reduction in task error compared with the current state of the art in dissipative control for the tested applications. The findings clearly demonstrate that the method significantly increases the fidelity and efficacy of dissipative control during physical human-robot interaction. This advancement expands the number of tasks and environments into which safe physical human-robot interaction can be employed effectively.
Burrows C, Liu F, Rodriguez y Baena F, 2015, Smooth on-line path planning for needle steering with non-linear constraints, IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), Publisher: IEEE, Pages: 2653-2658, ISSN: 2153-0858
Percutaneous intervention is a commonly used surgicalprocedure for many diagnostic and therapeutic operations.Target motion in soft tissue during an intervention caused bytissue deformation is a common problem, along with needledisplacement. In this work, we present a deformation plannerthat generates continuous curvature paths with a boundedcurvature derivative that can be used on-line to reach a movingtarget. This planner is computationally inexpensive and can beused for any robotic system, which has finite angular velocity,to reach a mobile target. The deformation planner, is integratedinto a needle steering system using a novel, biologically inspiredneedle, STING, to track a simulated moving target. In-vitroresults in gelatin demonstrate accurate 2D tracking of a movingtarget (mean 0.27 mm end positional error and 0.80◦approachangle error) over 3 target movement rates.
Oldfield MJ, Leibinger A, Seah TE, et al., 2015, Method to Reduce Target Motion Through Needle-Tissue Interactions., Annals of Biomedical Engineering, Vol: 43, Pages: 2794-2803, ISSN: 1573-9686
During minimally invasive surgical procedures, it is often important to deliver needles to particular tissue volumes. Needles, when interacting with a substrate, cause deformation and target motion. To reduce reliance on compensatory intra-operative imaging, a needle design and novel delivery mechanism is proposed. Three-dimensional finite element simulations of a multi-segment needle inserted into a pre-existing crack are presented. The motion profiles of the needle segments are varied to identify methods that reduce target motion. Experiments are then performed by inserting a needle into a gelatine tissue phantom and measuring the internal target motion using digital image correlation. Simulations indicate that target motion is reduced when needle segments are stroked cyclically and utilise a small amount of retraction instead of being held stationary. Results are confirmed experimentally by statistically significant target motion reductions of more than 8% during cyclic strokes and 29% when also incorporating retraction, with the same net insertion speed. By using a multi-segment needle and taking advantage of frictional interactions on the needle surface, it is demonstrated that target motion ahead of an advancing needle can be substantially reduced.
Beretta E, De Momi E, Rodriguez y Baena F, et al., 2015, Adaptive hands-on control for reaching and targeting tasks in surgery, International Journal of Advanced Robotic Systems, Vol: 12, ISSN: 1729-8814
Cooperatively controlled robotic assistants can be used in surgery for the repetitive execution of targeting/reaching tasks, which require smooth motions and accurate placement of a tool inside a working area. A variable damping controller, based on a priori knowledge of the location of the surgical site, is proposed to enhance the physical human-robot interaction experience. The performance of this and of typical constant damping controllers is comparatively assessed using a redundant light-weight robot. Results show that it combines the positive features of both null (acceleration capabilities > 0.8m/s2) and optimal (mean pointing error < 1.5mm) constant damping controllers, coupled with smooth and intuitive convergence to the target (direction changes reduced by 30%), which ensures that assisted tool trajectories feel natural to the user. An application scenario is proposed for brain cortex stimulation procedures, where the surgeon’s intentions of motion are explicitly defined intra-operatively through an image-guided navigational system.
Secoli R, Robinson M, Brugnoli M, et al., 2015, A low-cost, high-field-strength magnetic resonance imaging-compatible actuator, PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART H-JOURNAL OF ENGINEERING IN MEDICINE, Vol: 229, Pages: 215-224, ISSN: 0954-4119
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- Citations: 12
Liu F, Petersen J, Rodriguez y Baena F, 2015, Parallel Moduli Space Sampling: Robust and Fast Surgery Planning for Image Guided Steerable Needles, IEEE International Conference on Robotics and Biomimetics (ROBIO), Publisher: IEEE, Pages: 626-631
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- Citations: 1
Leibinger A, Burrows C, Oldfield MJ, et al., 2015, Tissue Motion Due to Needle Deflection, 37th Annual International Conference of the IEEE-Engineering-in-Medicine-and-Biology-Society (EMBC), Publisher: IEEE, Pages: 1873-1876, ISSN: 1557-170X
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- Citations: 1
Petersen JG, Rodriguez y Baena F, 2014, Mass and inertia optimization for natural motion in hands-on robotic surgery, Pages: 4284-4289
Cattilino M, Secoli R, Galvan S, et al., 2014, Development of a Dynamic Soft Tissue Phantom for Cooperative Control Testing in Robotic Surgery, Hamlyn Symposium
Bowyer SA, Rodriguez y Baena F, 2014, Deformation invariant bounding spheres for dynamic active constraints in surgery, PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART H-JOURNAL OF ENGINEERING IN MEDICINE, Vol: 228, Pages: 350-361, ISSN: 0954-4119
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- Citations: 8
Merican AM, Ghosh KM, Baena FRY, et al., 2014, Patellar thickness and lateral retinacular release affects patellofemoral kinematics in total knee arthroplasty, KNEE SURGERY SPORTS TRAUMATOLOGY ARTHROSCOPY, Vol: 22, Pages: 526-533, ISSN: 0942-2056
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- Citations: 27
Oldfield MJ, Burrows C, Kerl J, et al., 2014, Highly resolved strain imaging during needle insertion: results with a novel biologically inspired device, Journal of The Mechanical Behavior of Biomedical Materials, Vol: 30, Pages: 50-60, ISSN: 1751-6161
Percutaneous needle insertions are a common part of minimally invasive surgery. However, the insertion process is necessarily disruptive to the substrate. Negative side effects are migration of deep-seated targets and trauma to the surrounding material. Mitigation of these effects is highly desirable, but relies on a detailed understanding of the needle–tissue interactions, which are difficult to capture at a sufficiently high resolution.Here, an adapted Digital Image Correlation (DIC) technique is used to quantify mechanical behaviour at the sliding interface, with resolution of measurement points which is better than 0.5 mm, representing a marked improvement over the state of the art. A method for converting the Eulerian description of DIC output to Lagrangian displacements and strains is presented and the method is validated during the simple insertion of a symmetrical needle into a gelatine tissue phantom. The needle is comprised of four axially interlocked quadrants, each with a bevel tip. Tests are performed where the segments are inserted into the phantom simultaneously, or in a cyclic sequence taking inspiration from the unique insertion strategy associated to the ovipositor of certain wasps. Data from around the needle–tissue interface includes local strain variations, material dragged along the needle surface and relaxation of the phantom, which show that the cyclic actuation of individual needle segments is potentially able to mitigate tissue strain and could be used to reduce target migration.
Bowyer SA, Davies BL, Rodriguez y Baena F, 2014, Active Constraints/Virtual Fixtures: A Survey, IEEE TRANSACTIONS ON ROBOTICS, Vol: 30, Pages: 138-157, ISSN: 1552-3098
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- Citations: 180
Blyth WA, Barr DRW, Hankinson N, et al., 2014, An assessment of mecanum wheels for non-destructive testing (NDT) applications
We present a study into the suitability of mecanum wheels for obtaining holonomic motion on complex geometries, such as those encountered within NDT. There are a number of industrial inspections with challenging requirements for sensors positioning, such as ultrasonic inspection of nozzle welds in pressure vessels. These challenging trajectories necessitate additional degrees of control over conventional two-axis approaches, for example crawlers or X-Y frame systems, which are restrictive. Mecanum wheels in principle offer an excellent advantage for NDT crawlers, enabling unlimited motion within the plane, however the accurate and controllable behaviour of these wheels on non-planar and non-horizontal surfaces is not well understood. In this paper we illustrate the interactions between a mecanum wheel based crawler and complex geometries and construct a model to assess the performance of the mecanum wheels with respect to the requirements of NDT, to smoothly and precisely follow complex trajectories. The potential of mecanum wheel systems is then contrasted against other wheeled systems in terms of NDT demands, and we conclude that the applicability of mecanum wheels to some tasks offers potential gains yet presents additional challenges in others.
Leibinger A, Oldfield M, Rodriguez y Baena F, 2014, Multi-objective design optimization for a steerable needle for soft tissue surgery, Pages: 420-423, ISSN: 1680-0737
A novel steerable probe is being developed to access deep seated targets within soft tissue, with the aim of improving the accuracy of minimally invasive percutaneous needle insertions. Consisting of multiple axially interlocked segments that independently slide along each other, miniaturization of the design is required in order for the needle to be used in surgery. Within this study, a set of parameters which minimizes the risk of both buckling and separation is identified and a design optimization procedure based on finite element models is developed for the needle geometry. Four significant design variables are defined for a genetic multi-objective optimization algorithm. Loads and interactions between the four parts due to curved paths taken inside the soft tissue are modeled using generalized plane strain elements. The optimized set of non-dominated solutions is analyzed. By applying a decision- making process based on the value path method, the nondominated solutions are compared across the four objectives. It is found that smaller and less pronounced interlock features reduce contact forces and improve the sliding performance between needle segments. This results in a trade-off relationship between sliding performance and interlock strength and the most feasible design showing the best performance across all objectives is selected. The outcome is a new optimized design for the needle, which will be manufactured and tested with a suitable controller both in vitro and ex vivo.
Oldfield M, Leibinger A, Kaufmann P-A, et al., 2014, Needle Geometry, Target Migration and Substrate Interactions in High Resolution, 36th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), Publisher: IEEE, Pages: 852-855, ISSN: 1557-170X
Recent investigations considering flexible, steerableneedles for minimally invasive surgery have shown thesignificance of needle shape in determining the needle-tissueinteractions leading to the access of targets. Digital ImageCorrelation has enabled internal deformation and strain causedby needle insertions to be seen in a soft tissue phantom at highresolution for the first time. Here, the impact of tip designon strains and displacements of material around the insertionaxis is presented using Digital Image Correlation in a stable,plane-strain configuration. Insight into the shape of needles tominimise tissue trauma and generate interactions that wouldenable optimal steering conditions is provided. Needle tipswith an included bevel angle up to 40◦result in asymmetricdisplacement of the surrounding tissue phantom. Increasingthe included tip angle to 60◦results in more predictabledisplacement and strains that may enhance steering forces withlittle negative impact on the phantom.
Bowyer SA, Rodriguez y Baena F, 2014, Dynamic Frictional Constraints in Translation and Rotation, IEEE International Conference on Robotics and Automation (ICRA), Publisher: IEEE, Pages: 2685-2692, ISSN: 1050-4729
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- Citations: 11
Secoli R, Rodriguez y Baena F, 2014, Rate Dependency during Needle Insertions with a Biologically Inspired Steering System: an Experimental Study, 36th Annual International Conference of the IEEE-Engineering-in-Medicine-and-Biology-Society (EMBC), Publisher: IEEE, Pages: 856-859, ISSN: 1557-170X
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- Citations: 1
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