Haptic Simulation System Research Articles

Analog Position Estimation for Enhanced Stability and Fidelity of Haptic Systems.

In this paper, we propose three methods to compute low-latency analog position where two of them fuse encoder and rate gyro signals. While one method is based on gyro with bias correction using encoder information, the other one is encoder-referenced combined with a resettable integrator to minimize the staircase form of encoder signals. Experiments on a one degree-of-freedom haptic simulation system have shown that a low-latency analog position with an accuracy over 98% compared to the sampled encoder signal can be obtained. The analog position signals are then utilized to produce analog viscoelastic virtual environments to assess and benchmark the proposed methods through uncoupled stability and perceived fidelity tests. The results have shown that a virtual stiffness range larger than 400% can be obtained with enhanced fidelity compared to common digital implementations.

Combined web and haptic simulation system: A pilot study

ObjectivesSimulation education is increasingly used in otolaryngology training. The objective of this pilot study is to describe a mixed web-based and haptic modular platform for pediatric airway conditions. MethodsA web-based modular case presentation and evaluation system were developed to correspond to a pediatric laryngeal condition represented on the haptic models created using 3D printing and silicone elastomer. The haptic microlaryngoscopy simulation training and web module were evaluated by participants using a Likert scale. The mixed modular apparatus systematized the open web platform and haptic simulator, videos, text, questions, and evaluation to provide a more comprehensive simulation experience. ResultsSeventeen otolaryngology trainees participated, each completing a post-simulation survey. All participants responded 4 or higher (agree or strongly agree) on the Likert scale that the virtual training and case presentations improved their understanding of the pediatric laryngeal conditions presented. ConclusionA modular system constitutes a variety of web-based cases for evaluating, diagnosing, and performing procedures on a haptic surgical simulator taking the physician in training from diagnosis to treatment thereby expanding our current use of haptic simulators in surgical education to include case based learning and decision making.

An Augmented Reality Haptic Training Simulator for Spinal Needle Procedures

This paper presents the prototype for an augmented reality haptic simulation system with potential for spinal needle insertion training. The proposed system is composed of a torso mannequin, a MicronTracker2 optical tracking system, a PHANToM haptic device, and a graphical user interface to provide visual feedback. The system allows users to perform simulated needle insertions on a physical mannequin overlaid with an augmented reality cutaway of patient anatomy. A tissue model based on a finite-element model provides force during the insertion. The system allows for training without the need for the presence of a trained clinician or access to live patients or cadavers. A pilot user study demonstrates the potential and functionality of the system.

Impulse-Based Rendering Methods for Haptic Simulation of Bone-Burring

Bone-burring is a common procedure in orthopedic, dental, and otologic surgeries. Virtual reality (VR)-based surgical simulations with both visual and haptic feedbacks provide novice surgeons with a feasible and safe way to practice their burring skill. However, creating realistic haptic interactions between a high-speed rotary burr and stiff bone is a challenging task. In this paper, we propose a novel interactive haptic bone-burring model based on impulse-based dynamics to simulate the contact forces, including resistant and frictional forces. In order to mimic the lateral and axial burring vibration forces, a 3D vibration model has been developed. A prototype haptic simulation system for the bone-burring procedure has been implemented to evaluate the proposed haptic rendering methods. Several experiments of force evaluations and task-oriented tests were conducted on the prototype system. The results demonstrate the validity and feasibility of the proposed methods.

Graphic and haptic simulation system for virtual laparoscopic rectum surgery

Medical simulators with vision and haptic feedback techniques offer a cost-effective and efficient alternative to the traditional medical trainings. They have been used to train doctors in many specialties of medicine, allowing tasks to be practised in a safe and repetitive manner. This paper describes a virtual-reality (VR) system which will help to influence surgeons' learning curves in the technically challenging field of laparoscopic surgery of the rectum. Data from MRI of the rectum and real operation videos are used to construct the virtual models. A haptic force filter based on radial basis functions is designed to offer realistic and smooth force feedback. To handle collision detection efficiently, a hybrid model is presented to compute the deformation of intestines. Finally, a real-time cutting technique based on mesh is employed to represent the incision operation. Despite numerous research efforts, fast and realistic solutions of soft tissues with large deformation, such as intestines, prove extremely challenging. This paper introduces our latest contribution to this endeavour. With this system, the user can haptically operate with the virtual rectum and simultaneously watch the soft tissue deformation. Our system has been tested by colorectal surgeons who believe that the simulated tactile and visual feedbacks are realistic. It could replace the traditional training process and effectively transfer surgical skills to novices.

Shared control architectures for haptic training: Performance and coupled stability analysis

A novel shared control architecture is presented for dual-user haptic training simulation systems for enhanced interaction between the users and between each user and the virtual environment. The coupled stability of the proposed control architecture against uncertainties in the environment and the user’s dynamics is investigated using the three-port master–slave network model of the dual-user haptic simulation system. For this purpose, Llewellyn’s unconditional stability criterion is applied to an equivalent two-port network model obtained from the corresponding three-port network, considering the environment as a load termination. The kinesthetic performance of the proposed architecture is numerically analyzed for transparency and evaluated against a benchmark control architecture under different operating conditions, such as various types of environments, users’ grasps, and levels of dominance of users over the task. An experimental user study is carried out to assess the effectiveness of the proposed architecture in terms of users’ perception of environment stiffness sensing, device agility, and haptic guidance reception.

FEASIBILITY TEST RESULTS OF BILATERAL TELEOPERATION USING THE ENERGY-BOUNDING ALGORITHM

Time delays in communication channels usually make teleoperation systems unstable. To cope with this, we apply the energy-bounding algorithm (EBA) that had been proposed for stable haptic interaction. The EBA restricts the energy generated by the sample and hold operator to consumable energy by the energy-consuming physical damping in the haptic system and some part of human arm to guarantee the passivity condition of whole system. This algorithm always guarantees stable haptic interactions, but compromises the displayable impedance range of the virtual environment.The EBA can be straightforwardly applied for bilateral teleoperation due to the analogy between the haptic simulation system and the teleoperation system. The video shows some feasibility test results of the EBA for bilateral teleoperation. Various test results for free, contact, and abrupt motions show that the EBA can ensure stable bilateral teleoperation for the fairy large amount of constant/variable time delays (2.5 sec (one-way) for free motion and 300 msec (one-way) for contact motion).

Experiments in Fingertip Perception of Surface Discontinuities

In this paper, we present the results of experiments that explore the ability of the human fingertip to detect haptically simulated first-order and second-order surface discontinuities. A single finger, planar motion fingertip haptic display (FHD) developed at the University of Washington was used by multiple test operators to kinesthetically trace haptically simulated surfaces under a variety of treatment conditions. Experiment variables included the magnitude and type of discontinuity, as well as the stiffness and damping terms used in the haptic simulation algorithm. Test operators were asked to haptically locate a discontinuity on a simulated surface for each treatment condition with the location accuracy being used as the experiment performance metric. The results reveal how the surface discontinuity detection ability is degraded by control gains that are either too low or too high, indicating that a given haptic simulation system may have an optimum set of control gains that will yield the best performance for this type of task.