Search results for "robotics"
showing 10 items of 484 documents
Feeling of control of an action after supra and subliminal haptic distortions
2015
Here we question the mechanisms underlying the emergence of the feeling of control that can be modulated even when the feeling of being the author of one’s own action is intact. With a haptic robot, participants made series of vertical pointing actions on a virtual surface, which was sometimes postponed by a small temporal delay (15 or 65 ms). Subjects then evaluated their subjective feeling of control. Results showed that after temporal distortions, the hand-trajectories were adapted effectively but that the feeling of control decreased significantly. This was observed even in the case of subliminal distortions for which subjects did not consciously detect the presence of a distortion. Our…
Increased gait variability during robot-assisted walking is accompanied by increased sensorimotor brain activity in healthy people
2019
Abstract Background Gait disorders are major symptoms of neurological diseases affecting the quality of life. Interventions that restore walking and allow patients to maintain safe and independent mobility are essential. Robot-assisted gait training (RAGT) proved to be a promising treatment for restoring and improving the ability to walk. Due to heterogenuous study designs and fragmentary knowlegde about the neural correlates associated with RAGT and the relation to motor recovery, guidelines for an individually optimized therapy can hardly be derived. To optimize robotic rehabilitation, it is crucial to understand how robotic assistance affect locomotor control and its underlying brain act…
Blurring the boundaries between frame-based and frameless stereotaxy: feasibility study for brain biopsies performed with the use of a head-mounted r…
2015
OBJECT Frame-based stereotactic interventions are considered the gold standard for brain biopsies, but they have limitations with regard to flexibility and patient comfort because of the bulky head ring attached to the patient. Frameless image guidance systems that use scalp fiducial markers offer more flexibility and patient comfort but provide less stability and accuracy during drilling and biopsy needle positioning. Head-mounted robot-guided biopsies could provide the advantages of these 2 techniques without the downsides. The goal of this study was to evaluate the feasibility and safety of a robotic guidance device, affixed to the patient’s skull through a small mounting platform, for …
Evaluation of robot-guided minimally invasive implantation of 2067 pedicle screws
2017
ObjectiveRecent studies have investigated the role of spinal image guidance for pedicle screw placement. Many authors have observed an elevated placement accuracy and overall improvement of outcome measures. This study assessed a bi-institutional experience following introduction of the Renaissance miniature robot for spinal image guidance in Europe.MethodsThe medical records and radiographs of all patients who underwent robot-guided implantation of spinal instrumentation using the novel system (between October 2011 and March 2015 in Mainz and February 2014 and February 2016 in Regensburg) were reviewed to determine the efficacy and safety of the newly introduced robotic system. Screw posit…
Training at maximal power in resisted sprinting: Optimal load determination methodology and pilot results in team sport athletes.
2018
Aims: In the current study we investigated the effects of resisted sprint training on sprinting performance and underlying mechanical parameters (force-velocity-power profile) based on two different training protocols: (i) loads that represented maximum power output (Lopt) and a 50% decrease in maximum unresisted sprinting velocity and (ii) lighter loads that represented a 10% decrease in maximum unresisted sprinting velocity, as drawn from previous research (L10). Methods: Soccer [n = 15 male] and rugby [n = 21; 9 male and 12 female] club-level athletes were individually assessed for horizontal force-velocity and load-velocity profiles using a battery of resisted sprints, sled or robotic r…
PATIENT SELECTION FOR LESS UROLOGICAL SURGERY
2012
Laparoendoscopic single-site surgery (LESS) should theoretically improve perioperative results and cosmesis minimizing skin incision. LESS surgery is technically demanding and the result of any procedure depends on the surgeon skill and experience, on the condition to be treated and finally on careful patient selection. As cosmesis is the main advantage over standard laparoscopy, LESS is particularly indicated in young patients with low BMI. While at the beginning LESS surgery was limited to demolitive procedures, increasing experience lead to widen indications to reconstructive and more challenging conditions. New technologies and robotics may increase LESS indications in the next future.
The internal calcar septum and its contact with the virtual stem in THR: a computer tomographic evaluation.
2003
The internal calcar septum is a ridge of cortical bone protruding from the inner cortical wall of the proximal femur into the medullary canal. It extends from the lesser trochanter into the femoral neck and narrows the femoral cavity in its dorsal third. This region is essential for THR stability, but the degree of contact between the septum and standard THR implants has never been studied. We obtained CT scans of 50 arthrotic hip joints from patients requiring THR. Virtual stems (50 straight/wedge-shaped and 50 anatomic stems) were placed in CT images of the femora using a PC-based preoperative planning unit. The dimensions of the septum, degree and location of contact between the septum a…
A robust aerial image registration method using Gaussian mixture models
2014
Aerial image registration is one of the bases in many aerospace applications, such as aerial reconnaissance and aerial mapping. In this paper, we propose a novel aerial image registration algorithm which is based on Gaussian mixture models. First of all, considering the characters of the aerial images, the work uses a shape feature detector which computes the boundaries of regions with nearly the same gray-value to extract invariant feature. Then, a Gaussian mixture models (GMM) based image registration model is built and solved to estimate the transformation matrix between two aerial images. Furthermore, the proposed method is applied on real aerial images, and the results demonstrate the …
A Precessing Ferromagnetic Needle Magnetometer
2016
A ferromagnetic needle is predicted to precess about the magnetic field axis at a Larmor frequency $\Omega$ under conditions where its intrinsic spin dominates over its rotational angular momentum, $N\hbar \gg I\Omega$ ($I$ is the moment of inertia of the needle about the precession axis and $N$ is the number of polarized spins in the needle). In this regime the needle behaves as a gyroscope with spin $N\hbar$ maintained along the easy axis of the needle by the crystalline and shape anisotropy. A precessing ferromagnetic needle is a correlated system of $N$ spins which can be used to measure magnetic fields for long times. In principle, by taking advantage of rapid averaging of quantum unce…
Guest editors' introduction: special issue on sensor evolution.
2001
Artificial life researchers, in their attempts to create life-as-it-could-be, have widely studied both the behavior of animals and artifacts. Early precursors of life-like artificial systems such as Grey Walter’s tortoises [4] or Valentino Braitenberg’s vehicles [1] were already demonstrating that ALife research is strongly motivated by the desire to understand and create life-like behavior and (neural) control. Creating life-like behavior in simulations or robots has increased our understanding of the design and evolution of controllers for artificial systems. Despite the interrelationship between behavior, sensors, and other morphological characteristics of animal systems, the evolution o…