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Continuum robots offer the dexterity and obstacle circumvention capabilities necessary to enable surgery in deep surgical sites. They also can enable joint-level ex situ force sensing (JEFS), which provides an estimate of end-effector wrenches given joint-level forces. Prior works on JEFS relied on a restrictive embodiment with minimal actuation line friction and captured model and frictional actuation transmission uncertainties using a configuration space formulation. In this work, we overcome these limitations. First, frictional losses are canceled using a feed-forward term based on support vector regression in joint space. Then, regression maps and their interpolation are used to account for actuation hysteresis. The residual joint-force error is then further minimized using a least-squares model parameter update. An indirect hybrid force/position controller using JEFS is presented with evaluation carried out on a realistic pre-clinically deployable insertable robotic effectors platform (IREP) for single-port access surgery. Automated mock force-controlled ablation, exploration, and knot tightening are evaluated. A user study involving the daVinci Research Kit surgeon console and the IREP as a surgical slave was carried out to compare the performance of users with and without force feedback based on JEFS for force-controlled ablation and knot tightening. Results in automated experiments and a user study of telemanipulated experiments suggest that intrinsic force-sensing can achieve levels of force uncertainty and force regulation errors of the order of 0.2 N. Using JEFS and automated task execution, repeatability, and force regulation accuracy is shown to be comparable to using a commercial force sensor for human-in-the-loop feedback. [ABSTRACT FROM AUTHOR]

The navigation of magnetic medical robots typically relies on localizing an actuated, intracorporeal, ferromagnetic body and back-computing a necessary field and gradient that would result in a desired wrench on the device. Uncertainty in this localization degrades the precision of force transmission. Reducing applied force uncertainty may enhance tasks such as in vivo navigation of miniature robots, actuation of magnetically guided catheters, tissue palpation, as well as simply ensuring a bound on forces applied on sensitive tissue. In this paper, we analyze the effects of localization noise on force uncertainty by using sensitivity ellipsoids of the magnetic force Jacobian and introduce an algorithm for uncertainty reduction. We validate the algorithm in both a simulation study and in a physical experiment. In simulation, we observe reductions in estimated force uncertainty by factors of up to 2.8 and 3.1 when using one and two actuating magnets, respectively. On a physical platform, we demonstrate a force uncertainty reduction by a factor of up to 2.5 as measured using an external sensor. Being the first consideration of force uncertainty resulting from noisy localization, this paper provides a strategy for investigators to minimize uncertainty in magnetic force transmission. [ABSTRACT FROM AUTHOR]

Currently, surgical continuum robots (CRs) are predominantly used as telemanipulators where modeling errors are overcome by the user. Such errors preclude their use for autonomous tasks. In this paper, we investigate the calibration of CRs with specific focus on capturing joint space errors due to homing offsets, assembly errors causing twist about the robot's backbone, and uncertainty in the equilibrium bending shapes of segments of these robots. A kinematic framework focusing on multibackbone CR is presented with emphasis on deriving calibration identification Jacobians. This framework captures the coupling between twist and the equilibrium shapes of a continuum segment as a function of its bending angle. To capture equilibrium shape variations as a function of bending, a homotopy of curves is defined and represented by respective modal coefficients. The estimation of the calibration parameters is cast as a nonlinear least-squares problem. The framework is validated by simulations and experimentally using a single-port access surgery robot. We believe this calibration framework will facilitate semiautomation of surgical tasks carried out by CRs. [ABSTRACT FROM AUTHOR]

The recent growth of surgical applications exploiting continuum robots demands for new control paradigms that ensure safety by controlling interaction forces of tele-operated end-effectors. In this paper, we present the modeling, sensing and control of multi-backbone continuum robots in a unified framework for hybrid motion/force control. Multi-backbone continuum robots allow to estimate forces and torques at the operational point by monitoring loads along their actuation lines without the need for a dedicated transducer at the operational point. This capability is indeed crucial in emerging fields such as robotic surgery where cost and strict sterilization guidelines prevent the adoption of a dedicated sensor to provide force feedback from the sterile field. To advance further the force sensing capabilities of multi-backbone continuum robots, we present a new framework for hybrid motion and force control of continuum robots with intrinsic force sensing capabilities. The framework is based on a kinetostatic modeling of the multi-backbone continuum robot with, a simplified model for online estimate of the manipulator’s compliance, and a new strategy for merging force and motion control laws in the configuration space of the manipulator. Experimental results show the ability to sense and regulate forces at the operational point and evaluate the framework for shape exploration and stiffness imaging in flexible environments. [ABSTRACT FROM AUTHOR]

Laparoscopic and Single Port Access Surgery (SPAS) present unique dexterity challenges related to dual-arm operations in confined spaces and tele-manipulation of highly dexterous surgical slaves. In an effort to reduce tele-manipulation burden, new paradigms for semi-automating surgical tasks are needed. This paper presents a new minimal constraint suturing and automated choice of handedness for anthropomorphic dual-arm robots. The automated choice of handedness supports surgeons during tele-manipulation of complex robotic slaves where dexterity and workspace constraints are difficult to learn. This criterion is also used to support automated dual-arm rendezvous for quicker suture exchange during dual-arm suturing. The minimal constraint algorithm presented in this paper allows surgeons to operate within a shared-control tele-manipulation framework whereby the surgeon controls the needle insertion speed and the robot controls the needle orientation while respecting a minimalistic set of tissue constraints. This framework is evaluated on a novel insertable robotic end-effectors platform for SPAS. A simulation study demonstrates the effectiveness of the automated choice of handedness criterion through a study of dexterity limitations of each arm. Additional simulations show the proposed algorithm for automated rendezvous and suture exchange. [ABSTRACT FROM AUTHOR]

This paper presents a kinetostatic modeling framework for flexible cannulas (concentric tubing robots) subject to tip loads. Unlike existing methods that allow fast computation of the beam tip position, this modeling framework provides fast computation of both the tip position and the entire shape of the deflected robot. A method for online force sensing based on inverse kinetostatic solution is also proposed and assistive telemanipulation control methods for microstent delivery are presented. The modeling framework uses polynomial approximation and linear interpolation based on elliptic integral solutions to the deflection of lightweight beams. To date, there are no systems capable of stent deliv-ery in retinal vasculature. The modeling and control frameworks of this paper are vali-dated experimentally on pilot studies for microstent delivery. We believe that the methods presented in this paper open the way for robot-assisted retinal microvascular stenting that may potentially revolutionize the treatment of blinding retinal vasculature diseases. [ABSTRACT FROM AUTHOR]

In this paper, we present a novel kinematic-based framework for collision detection and estimation of contact location along multisegment continuum robots. Screw theory is used to define a screw motion deviation (SMD) as the distance between the expected and the actual instantaneous screw axis (ISA) of motion. The expected ISA is computed based on the unconstrained kinematics model of the robot, while the actual ISA is computed based on sensory information. Collisions with rigid environments at any point along the robot are detected by monitoring the SMD. Contact locations are estimated by the minimization of the SMD between the ISA that is obtained from a constrained kinematic model of the continuum robot and the one that is obtained from sensor data. The proposed contact detection and localization methods only require the relative motion of each continuum segment with respect to its own base. This strategy allows the straightforward generalization of these algorithms for an n -segment continuum robot. The framework is evaluated via simulations and experimentally on a three-segment multibackbone continuum robot. Results show that the collision-detection algorithm is capable of detecting a single collision at any segment, multiple collisions occurring at multiple segments, and total-arm constraint. It is also shown that the estimation of contact location is possible at any location along the continuum robot with an accuracy better than 20% of the segment nominal length. We believe this study will enhance manipulation safety in unstructured environments and confined spaces. [ABSTRACT FROM PUBLISHER]

In this paper we present the clinical motivation, design specifications, kinematics, statics, and actuation compensation for a newly constructed telerobotic system for Minimally Invasive Surgery (MIS) of the throat. A hybrid dual-arm telesurgical slave, with 20 joint-space Degrees-of-Freedom (DoFs), is used in this telerobotic system to provide the necessary dexterity in deep surgical fields such as the throat. The telerobotic slave uses novel continuum robots that use multiple super-elastic backbones for actuation and structural integrity. We present the kinematics of the telesurgical slave and methods for actuation compensation to cancel the effects of backlash, friction, and flexibility of the actuation lines. A method for actuation compensation is presented in order to overcome uncertainties of modeling, friction, and backlash. This method uses a tiered hierarchy of two novel approaches of actuation compensation for remotely actuated snake-like robots. The tiered approach for actuation compensation uses compensation in both joint space and configuration space of the continuum robots. These hybrid actuation compensation schemes use intrinsic model information and external data through a recursive linear estimation algorithm and involve compensation using configuration space and joint space variables. Experimental results validate the ability of our integrated telemanipulation system through experiments of suturing and knot tying in confined spaces. [ABSTRACT FROM AUTHOR]

This paper presents the theoretical analysis and the experimental validation of the force sensing capabilities of continuum robots. These robots employ superelastic NiTi backbones and actuation redundancy. The paper uses screw theory to analyze the limitations and provide geometric interpretation to the sensible wrenches. The analysis is based on the singular value decomposition of the Jacobian mapping between the configuration space and the twist space of the end effector. The results show that the sensible wrenches belong to a 2-D screw system and the insensible wrenches belong to a 4-D screw system. The theory presented in this paper is validated through simulations and experiments. It is shown that the force sensing errors have an average of 0.34 g with a standard deviation of 0.83 g. Another experiment of generating the stiffness map of a silicone strip suggests possible medical application of palpation for tumor detection. The presented study allows force sensing in challenging environments where placing force sensors at the distal end of a robot is not possible due to limitations such as size and MRI compatibility. [ABSTRACT FROM AUTHOR]

Focuses on the stiffness synthesis problem of variable geometry double planar parallel robots. Calculation of the free geometrical variables as a solution of a corresponding polynomial system; Use of Grobner bases that determine the solvability of the stiffness synthesis polynomial systems; Transformation of systems into corresponding eigenvalue problems using multiplication tables.

Analyzes the singularity among a class of composite serial in-parallel robots. Application of line geometry methods in obtaining singular configurations of in-parallel robots; Mechanical design of a three-legged six degree-of-freedom parallel manipulator; Synthesis of parallel robots for medical applications.

The purpose of this study is to validate a Jacobian-based iterative method for real-time localization of magnetically controlled endoscopic capsules. The proposed approach applies finite-element solutions to the magnetic field problem and least-squares interpolations to obtain closed-form and fast estimates of the magnetic field. By defining a closed-form expression for the Jacobian of the magnetic field relative to changes in the capsule pose, we are able to obtain an iterative localization at a faster computational time when compared with prior works, without suffering from the inaccuracies stemming from dipole assumptions. This new algorithm can be used in conjunction with an absolute localization technique that provides initialization values at a slower refresh rate. The proposed approach was assessed via simulation and experimental trials, adopting a wireless capsule equipped with a permanent magnet, six magnetic field sensors, and an inertial measurement unit. The overall refresh rate, including sensor data acquisition and wireless communication was 7 ms, thus enabling closed-loop control strategies for magnetic manipulation running faster than 100 Hz. The average localization error, expressed in cylindrical coordinates was below 7 mm in both the radial and axial components and 5$^\circ$ in the azimuthal component. The average error for the capsule orientation angles, obtained by fusing gyroscope and inclinometer measurements, was below 5$^\circ$. [ABSTRACT FROM PUBLISHER]

Introduction: Transurethral resection of bladder tumor (TURBT) and pathological staging are both standard surgical therapies for nonmuscle-invasive bladder cancer and integral parts of the diagnostic evaluation and progression monitoring of all bladder tumors. We developed and tested a dexterous robot that can fit through a standard resectoscope for evaluation for possible en bloc resection of bladder tumors, especially tumors along the dome and anterior wall of the bladder. Materials and Methods: Our dexterous robot uses a continuum (snake-like) mechanical architecture with three working channels through which a fiberscope, biopsy graspers, and a holmium laser were placed. The continuum robot has two segments. Using indigo carmine, injections were performed through the detrusor muscle into the mucosa of the ex vivo bovine bladders at a total of 11 positions throughout all quadrants of the bladder. The snake robot was used in conjunction with the holmium laser to ablate nine of the lesions; two additional lesions were resected en bloc using the grasper and the laser down through the muscle layer. Results: Both experiments showed that the robotic system was able to directly visualize all 11 targets. In both the bladders, we were able to resect en bloc two tumors using the grasper and 200 μm holmium laser fiber down to the muscle layer indicating a good resection. All of the other targets were completely ablated using the holmium laser. Conclusion: The dexterous robot allowed for visualization as well as provided adequate ablation and en bloc resection of bladder lesions throughout the entire bladder. [ABSTRACT FROM AUTHOR]

During exploration through tortuous unstructured passages by continuum robots, methods are required to minimize the force interaction between the environment and the robot along its length. This paper presents and evaluates an algorithm for compliant motion control of continuum robots subjected to multiple unknown contacts with the environment. A mapping of external wrenches to a generalized force in the configuration space of a multisegment continuum robot is presented and related to measured joint-level actuation forces. These measurements are applied as inputs to a low-level compliant motion controller. Friction and modeling uncertainties, presenting an unknown nonlinear deviation from the nominal system model, are corrected via a feed-forward estimate provided by a support vector machine. The controller is evaluated on Ø9 and Ø5 mm multisegment continuum robots. We quantify the minimal interaction forces needed to generate compliant motion and demonstrate the ability of the controller to minimize interaction forces during insertion through tortuous passages. [ABSTRACT FROM PUBLISHER]

Objective: This paper introduces a methodology to design intuitive, low-cost, and portable devices for visual inspection of the upper gastrointestinal tract. Methods: The proposed approach mechanically couples a multi-backbone continuum structure, as the user interface, and a parallel bellows actuator, as the endoscopic tip. Analytical modeling techniques derived from continuum robotics were adopted to describe the endoscopic tip motion from user input, accounting for variations in component size and pneumatic compressibility. The modeling framework was used to improve intuitiveness of user-to-task mapping. This was assessed against a 1:1 target, while ease-of-use was validated using landmark identification tasks performed in a stomach simulator by one expert and ten non-expert users; benchmarked against conventional flexible endoscopy. Pre-clinical validation consisted of comparative trials in in-vivo porcine and human cadaver models. Results: Target mapping was achieved with an average error of $5^\circ$ in bending angle. Simulated endoscopies were performed by an expert user successfully, within a time comparable to conventional endoscopy ($< $ 1 min difference). Non-experts using the proposed device achieved visualization of the stomach in a shorter time (9 s faster on average) than with a conventional endoscope. The estimated cost is $< $ 10 USD and $< $ 30 USD for disposable and reusable parts, respectively. Significance and Conclusions: Flexible endoscopes are complex and expensive devices, actuated via non-intuitive cable-driven mechanisms. They frequently break, requiring costly repair, and necessitate a dedicated reprocessing facility to prevent cross contamination. The proposed solution is portable, inexpensive, and easy to use, thus lending itself to disposable use by personnel without formal training in flexible endoscopy. [ABSTRACT FROM AUTHOR]

Introduction: Transurethral resection of bladder tumors (TURBTs) can be a challenging procedure, primarily due to limitations in tooltip dexterity, visualization, and lack of tissue depth information. A transurethral robotic system was developed to revolutionize TURBTs by addressing some of these limitations. The results of three pilot in vivo porcine studies using the novel robotic system are presented and potential improvements are proposed based on experimental observations. Materials and Methods: A transvesical endoscope with a mounted optically tracked camera was placed through the bladder of the swine under general anesthesia. Simulated bladder lesions were created by injecting HistoGel processing gel mixed with blue dye, transabdominally, into various locations in the bladder wall under endoscopic visualization. A 7-degree-of-freedom (DoF) robot was then used for transurethral resection/ablation of these simulated tumors. An independent 2-DoF distal laser arm (DLA) was deployed through the robot for laser ablation and was assisted by a manually controlled gripper for en bloc resection attempts. Results: Lesions were created and ablated using our novel endoscopic robot in the swine bladder. Full accessibility of the bladder, including the bladder neck and dome, was demonstrated without requiring bladder deflation or pubic compression. Simulated lesions were ablated using the holmium laser. En bloc resection was demonstrated using the DLA and a manual grasper. Conclusion: Feasibility of robot-assisted en bloc resection was demonstrated. Main challenges were lack of depth perception and visual occlusion induced by the transvesical endoscope. Recommendations are given to enhance robot-assisted TURBTs. Lessons learned through these pilot swine studies verify the feasibility of robot-assisted TURBTs while informing designers about critical aspects needed for future clinical deployment. [ABSTRACT FROM AUTHOR]

Abstract: A completely automated, high-throughput biodosimetry workstation has been developed by the Center for Minimally Invasive Radiation Biodosimetry at Columbia University over the past few years. To process patients’ blood samples safely and reliably presents a significant challenge in the development of this biodosimetry tool. In this paper, automated failure recognition methods of robotic manipulation of capillary tubes based on a torque/force sensor are described. The characteristic features of sampled raw signals are extracted through data preprocessing. The 12-dimensional (12D) feature space is projected onto a two-dimensional (2D) feature plane by the optimized Principal Component Analysis (PCA) and Fisher Discrimination Analysis (FDA) feature extraction functions. For the three-class manipulation failure problem in the cell harvesting module, FDA yields better separability index than that of PCA and produces well separated classes. Three classification methods, Support Vector Machine (SVM), Fisher Linear Discrimination (FLD) and Quadratic Discrimination Analysis (QDA), are employed for real-time recognition. Considering the trade-off between error rate and computation cost, SVM achieves the best overall performance. [Copyright &y& Elsevier]

Purpose: Over the past five years the Center for Minimally Invasive Radiation Biodosimetry at Columbia University has developed the Rapid Automated Biodosimetry Tool (RABiT), a completely automated, ultra-high throughput biodosimetry workstation. This paper describes recent upgrades and reliability testing of the RABiT. Materials and methods: The RABiT analyses fingerstick-derived blood samples to estimate past radiation exposure or to identify individuals exposed above or below a cut-off dose. Through automated robotics, lymphocytes are extracted from fingerstick blood samples into filter-bottomed multi-well plates. Depending on the time since exposure, the RABiT scores either micronuclei or phosphorylation of the histone H2AX, in an automated robotic system, using filter-bottomed multi-well plates. Following lymphocyte culturing, fixation and staining, the filter bottoms are removed from the multi-well plates and sealed prior to automated high-speed imaging. Image analysis is performed online using dedicated image processing hardware. Both the sealed filters and the images are archived. Results: We have developed a new robotic system for lymphocyte processing, making use of an upgraded laser power and parallel processing of four capillaries at once. This system has allowed acceleration of lymphocyte isolation, the main bottleneck of the RABiT operation, from 12 to 2 sec/sample. Reliability tests have been performed on all robotic subsystems. Conclusions: Parallel handling of multiple samples through the use of dedicated, purpose-built, robotics and high speed imaging allows analysis of up to 30,000 samples per day. [ABSTRACT FROM AUTHOR]

This paper presents a unified mathematical frame-work for modeling and evaluating the performance of multiple robotic arms that operate on hollow suspended organs. This frame-work is applied to a novel two-armed hybrid robotic system being developed for ophthalmic vitreous surgeries. Four cases are designated to capture the general movements required for any surgical procedure associated with hollow suspended organs. Dexterity measures, based on multiple characteristic lengths, are presented for procedures corresponding to these manipulation cases. Simulation results of the dual-arm robotic system for ophthalmic surgery are presented for all four manipulation cases. A comparison of this robotic system with current surgical tools shows a significant improvement in intraocular dexterity. [ABSTRACT FROM AUTHOR]