Experimental Evaluation of a Haptic Interface for Endoscopic Simulation

The main goal of virtual reality based surgery simulators with haptic feedback is to provide an alternative to traditional training methods on animals, cadavers or real patients. Haptic feedback is a key feature for every surgery simulator for the training of hand-eye coordination. To address the need for higher fidelity and complexity in an endoscopic simulator, we have designed a new haptic interface, instrumented a clinical endoscope and integrated it with a software simulation for colonoscopy. The proposed haptic interface provides high translational force and rotational torque with combined electrical motors and passive brakes. This paper presents the evaluation of the haptic interface. Experimental analyzes are performed for characterization and performance evaluation. A model-based feed-forward control is implemented and the results show that the control successfully compensates for the device dynamics and nonlinearities such as Coulomb and viscous friction

Force feedback facilitates multisensory integration during robotic tool use

The present study investigated the effects of force feedback in relation to tool use on the multisensory integration of visuo-tactile information. Participants learned to control a robotic tool through a surgical robotic interface. Following tool-use training, participants performed a crossmodal congruency task, by responding to tactile vibrations applied to their hands, while ignoring visual distractors superimposed on the robotic tools. In the first experiment it was found that tool-use training with force feedback facilitates multisensory integration of signals from the tool, as reflected in a stronger crossmodal congruency effect with the force feedback training compared to training without force feedback and to no training. The second experiment extends these findings by showing that training with realistic online force feedback resulted in a stronger crossmodal congruency effect compared to training in which force feedback was delayed. The present study highlights the importance of haptic information for multisensory integration and extends findings from classical tool-use studies to the domain of robotic tools. We argue that such crossmodal congruency effects are an objective measure of robotic tool integration and propose some potential applications in surgical robotics, robotic tools, and human-tool interactio

Knot-tying with Visual and Force Feedback for VR Laparoscopic Training

Real-time simulation of thread and knot-tying with visual and force feedback is an essential part of virtual reality laparoscopic training. This paper presents a physics-based thread simulator that enables realistic knot tying at haptic rendering rate. The virtual thread follows Newton's law and behaves naturally. The model considers main mechanical properties of the real thread such as stretching, compressing, bending and twisting, as well as contact forces due to self-collision and interaction with the environment, and the effect of gravity. The structure of the system has essential advantages over geometrically based approaches, as was illustrated in an implementation on the Xitact simulator

Development of a Microsurgery Training System

Surgeons require significant training to acquire sufficient dexterity and hand-eye coordination to manipulate objects skilfully under the microscope. This paper presents a computer-based real-time simulation of microsurgery as well as the hardware setup. It presents a realistic physics-based elastic suture and blood vessel model, fast collision detection techniques, suture insertion process and novel approach of a haptic forceps. The simulation environment demonstrates a complete vascular suturing system to train skills such as grasping, suture placement, needle insertion and knot-tying running at 500 Hz, sufficient for physical realism

Magnetic wheels optimization and application to the MagneBike climbing robot

Magnetic wheels are a powerful solution to design inspection climbing robots with excellent mobility. Magnetic wheels optimization based on simulations and the results that were obtained on prototypes are presented. The measured adhesion was doubled between the classic configuration and a novel multilayer one sharing exactly the same four magnets and the same total volume of iron. This know-how is then applied to optimize magnetic wheels for the existing robot called MagneBike. The adhesion force has been multiplied by 2 to 3 times depending on the conditions. Those amazing improvements open new possibilities for miniaturization of climbing robots or payload's increase

Cy-mag3D: a simple and miniature climbing robot with advance mobility in ferromagnetic environment

Cy-mag3D is a miniature climbing robot with advanced mobility and magnetic adhesion. It is very compact: a cylindrical shape with 28 mm of diameter and 62 mm of width. Its design is very simple: two wheels, hence two degrees of freedom, and an advanced magnetic circuit. Despite its simplicity, Cy-mag3D has an amazing mobility on ferromagnetic sheets. From an horizontal sheet, it can make transition to almost any intersecting sheet from 10° to 360° - we baptise the last one surface ip. It passes inner and outer straight corners in any almost inclination of the gravity. Cy-mag3D opens new possibilities to use mobile robots for industrial inspection with stringent size limitations, as found in generators. A patent is pending on this system

Quantifying the role of motor imagery in brain-machine interfaces

Despite technical advances in brain machine interfaces (BMI), for as-yet unknown reasons the ability to control a BMI remains limited to a subset of users. We investigate whether individual differences in BMI control based on motor imagery (MI) are related to differences in MI ability. We assessed whether differences in kinesthetic and visual MI, in the behavioral accuracy of MI, and in electroencephalographic variables, were able to differentiate between high- versus low-aptitude BMI users. High-aptitude BMI users showed higher MI accuracy as captured by subjective and behavioral measurements, pointing to a prominent role of kinesthetic rather than visual imagery. Additionally, for the first time, we applied mental chronometry, a measure quantifying the degree to which imagined and executed movements share a similar temporal profile. We also identified enhanced lateralized μ-band oscillations over sensorimotor cortices during MI in high- versus low-aptitude BMI users. These findings reveal that subjective, behavioral, and EEG measurements of MI are intimately linked to BMI control. We propose that poor BMI control cannot be ascribed only to intrinsic limitations of EEG recordings and that specific questionnaires and mental chronometry can be used as predictors of BMI performance (without the need to record EEG activity)

Tendon-Based Transmission for Surgical Robotics: Systematic Experimental Friction Modeling.

Increased miniaturization of surgical instruments is essential to successfully perform surgical procedures in restricted areas as in many applications of minimally-invasive surgery. Miniaturization permits increase in dexterity and decrease in access incisions which are required in many sur- gical procedures. Tendon-based transmissions provide several important advantages for the mechanical design of miniaturized surgical devices. Reflected mass and inertia are reduced since tendon-based transmissions allow to locate the motors far apart from the actuated joint. In spite of providing several important advantages, they introduce several non linear effects that must be considered and modeled to achieve suitable performance. In this paper tendon-based transmission system for surgical robotics is illustrated. And nonlinear friction, due to direct sliding of synthetic fiber cables over small fixed pulleys (pins) is discussed and models aiming at compensating these nonlinearities are presented

Collision-free motion planning for fiber positioner robots: discretization of velocity profiles

The next generation of large-scale spectroscopic survey experiments such as DESI, will use thousands of fiber positioner robots packed on a focal plate. In order to maximize the observing time with this robotic system we need to move in parallel the fiber-ends of all positioners from the previous to the next target coordinates. Direct trajectories are not feasible due to collision risks that could undeniably damage the robots and impact the survey operation and performance. We have previously developed a motion planning method based on a novel decentralized navigation function for collision-free coordination of fiber positioners. The navigation function takes into account the configuration of positioners as well as their envelope constraints. The motion planning scheme has linear complexity and short motion duration (~2.5 seconds with the maximum speed of 30 rpm for the positioner), which is independent of the number of positioners. These two key advantages of the decentralization designate the method as a promising solution for the collision-free motion-planning problem in the next-generation of fiber-fed spectrographs. In a framework where a centralized computer communicates with the positioner robots, communication overhead can be reduced significantly by using velocity profiles consisting of a few bits only. We present here the discretization of velocity profiles to ensure the feasibility of a real-time coordination for a large number of positioners. The modified motion planning method that generates piecewise linearized position profiles guarantees collision-free trajectories for all the robots. The velocity profiles fit few bits at the expense of higher computational costs.Comment: SPIE Astronomical Telescopes + Instrumentation 2014 in Montr\'eal, Quebec, Canada. arXiv admin note: substantial text overlap with arXiv:1312.164