Haptic Interface With Hybrid Actuator for Virtual Tissue Cutting

2015 ◽  
Author(s):  
Berk Gonenc ◽  
Hakan Gurocak
Keyword(s):  
Haptic Device ◽  
Haptic Interface ◽  
Haptic Interfaces ◽  
Virtual Training ◽  
Tissue Properties ◽  
Tissue Cutting ◽  
Control Scheme ◽  
Rat Tissue ◽  
Dc Servomotor ◽  
Hybrid Actuator

Surgical training is an important and recent application where haptic interfaces are used to enhance the realism of virtual training simulators. Tissue cutting with surgical scissors is a common interaction mode in the simulations. The haptic interface needs to render a range of tissue properties and resistance forces accurately. In this research, we developed a hybrid haptic device made up of a DC servomotor and a magnetorheological (MR) brake. The motor can provide fast dynamic response and compensate for inertia and friction effects of the device. But it cannot supply high force levels and the sensation of stiff interaction with hard tissues such as tendons. On the other hand, the MR-brake can provide very high and stiff interaction forces yet cannot reflect fast dynamics that are encountered as the virtual scissors go through the tissue. Design details of the hybrid actuator and the haptic device are presented. A control scheme was developed to decompose the actuator command signal into two branches considering each actuator’s capabilities. Virtual tissue cutting experiments were conducted using three different scissor types and four types of rat tissue. Results are presented and discussed. Forces in a wider amplitude range compared to just using a DC motor could be generated by the hybrid actuator. It also enabled simulation of multiple scissor types using the same haptic interface due to the extended force amplitude range.

Virtual Tissue Cutting With Haptic Feedback Using a Hybrid Actuator With DC Servomotor and Magnetorheological Brake

2016 ◽  
Vol 16 (3) ◽  
Author(s):  
Berk Gonenc ◽  
Hakan Gurocak
Keyword(s):  
Haptic Feedback ◽  
Fast Response ◽  
Virtual Training ◽  
Tissue Properties ◽  
Tissue Cutting ◽  
Wide Range ◽  
Force Profile ◽  
Rat Tissue ◽  
Dc Servomotor ◽  
Hybrid Actuator

Surgical training is an important and recent application where haptic interfaces are used to enhance the realism of virtual training simulators. Tissue cutting with surgical scissors is a common interaction mode in the simulations. The haptic interface needs to render a wide range of tissue properties and resistance forces accurately. In this research, we developed a hybrid haptic device made of a DC servomotor and a magnetorheological (MR) brake. The motor can provide fast dynamic response and compensate for inertia and friction effects of the device. But alone, it cannot supply high force levels and the sensation of stiff interaction with hard tissues such as tendons. On the other hand, the MR-brake can provide very stiff interaction forces yet cannot reflect fast dynamics that are encountered as the virtual scissors go through the tissue. The hybrid actuator developed in this work combines the two based on a control scheme that decomposes the actuator command signal into two branches considering each actuator's capabilities. It is implemented on a compact single degree-of-freedom (DOF) interface to simulate virtual tissue cutting with three different scissor types (Mayo, Metzenbaum, Iris) and four types of rat tissue (liver, muscle, skin, tendon). Results have shown close tracking of the desired force profile in all cases. Compared to just using a DC motor, the hybrid actuator provided a wider range of forces (up to 18 N) with fast response to render quick force variations without any instability for all simulated tissue and scissor types.

Design and evaluation of a high-performance haptic interface

Robotica ◽  
1996 ◽  
Vol 14 (3) ◽  
pp. 321-327 ◽  
Author(s):  
R.E. Ellis ◽  
O.M. Ismaeil ◽  
M.G. Lipsett
Keyword(s):  
High Performance ◽  
Dynamic Range ◽  
Evaluation Criteria ◽  
Haptic Interface ◽  
Human Operator ◽  
Haptic Interfaces ◽  
Environment Design ◽  
Mechanical Constraints ◽  
Computer Controlled ◽  
The Many

SUMMARYA haptic interface is a computer-controlled mechanism designed to detect motion of a human operator without impeding that motion, and to feed back forces from a teleoperated robot or virtual environment. Design of such a device is not trivial, because of the many conflicting constraints the designer must face.As part of our research into haptics, we have developed a prototype planar mechanism. It has low apparent mass and damping, high structural stiffness, high force bandwidth, high force dynamic range, and an absence of mechanical singularities within its workspace. We present an analysis of the human-operator and mechanical constraints that apply to any such device, and propose methods for the evaluation of haptic interfaces. Our evaluation criteria are derived from the original task analysis, and are a first step towards a replicable methodology for comparing the performance of different devices.

Position-Mode Haptic-Based Control of Teleoperated Hydraulic Actuators

2011 ◽  
Author(s):  
Kurosh Zarei-nia ◽  
Nariman Sepehri
Keyword(s):  
Invariant Set ◽  
Haptic Device ◽  
Position Tracking ◽  
Good Position ◽  
View Point ◽  
Hydraulic Actuator ◽  
Control Laws ◽  
Hydraulic Actuators ◽  
Control Scheme ◽  
On Line

A control scheme for teleoperation of hydraulic actuators, using a haptic device, is developed and experimentally evaluated in this paper. In the control laws, the position error between the displacement of the haptic device and the hydraulic actuator movement is used at both master and slave sides to maintain good position tracking at the actuator side while providing a haptic force to the operator. Lyapunov’s stability theory and LaSalle’s invariant set theorems are employed to prove the asymptotic stability of the system. It is shown that beside stability, the system performs well in terms of position tracking of the hydraulic actuator and providing a feel of telepresence to the operator. Proposed controller only needs system’s pressures and displacements that are easy to obtain via on-line measurements. Additionally, the controller does not need any information about the parameters of the system. These characteristics make the controller very attractive from the implementation view point.

Design and Evaluation of Statically Balanced Compliant Mechanisms for Haptic Interfaces

2010 ◽  
Author(s):  
Levi C. Leishman ◽  
Daniel J. Ricks ◽  
Mark B. Colton
Keyword(s):  
Mathematical Model ◽  
Rigid Body ◽  
Virtual Environment ◽  
Compliant Mechanisms ◽  
Haptic Interface ◽  
Design Element ◽  
Haptic Interfaces ◽  
Body Model ◽  
Dynamic Forces ◽  
Rigid Body Model

Compliant mechanisms have the potential to increase the performance of haptic interfaces by reducing the friction and inertia felt by the user. The net result is that the user feels the dynamic forces of the virtual environment, without feeling the dynamics of the haptic interface. This “transparency” typically comes at a cost — compliant mechanisms exhibit a return-to-zero behavior that must be compensated in software. This paper presents a step toward improving the situation by using statically balanced compliant mechanisms (SBCMs), which are compliant devices that do not exhibit the return-to-zero behavior typical with most compliant mechanisms. The design and construction of a prototype haptic device based on SBCMs is presented, along with its mathematical model derived using the pseudo-rigid body model (PRBM) approach. Experimental results indicate that SBCMs effectively eliminate the return-to-zero behavior and are a feasible design element in haptic interfaces.

Design and control of a two-dimensional telerobotic system with a haptic interface

2003 ◽  
Vol 217 (3) ◽  
pp. 169-185
Author(s):  
M-G Her ◽  
M Karkoub ◽  
K-S Hsu
Keyword(s):  
Haptic Interface ◽  
Two Dimensional ◽  
Direct Drive ◽  
Closed Loop System ◽  
Human Arm ◽  
Control Scheme ◽  
Reaction Forces ◽  
And Control ◽  
Theoretical Results ◽  
Good Agreement

A model for a ‘master-slave’ two-dimensional telerobotic dynamic system with a haptic interface device is derived. The telerobotic system consists of a ‘master’ robot, which is a direct-drive robot operated by a human arm, and a ‘slave’ robot, which is an x-y type pallet located at a remote site. When the active handle of the master is moved along an arbitrary trajectory, the remote slave duplicates the motion in a constrained or unconstrained environment. The behaviour of the environment is felt by the operator through the active handle of the master. This is achieved by feeding back the disturbance and reaction forces from the environment and the loads to the active handle. Consequently, the operator gets a feel of the task being performed without being physically at the location of the task. A control scheme is devised for the telerobotic system to establish smooth communication between the master and slave robots. This control scheme integrates the dynamics of the human arm, actuators and the environment in the closed-loop system. It was shown that the experimental and the theoretical results are in good agreement and that the design controller is robust to constrained/unconstrained environments.

On the Ability of Humans to Haptically Identify and Discriminate Real and Simulated Objects

2005 ◽  
Vol 14 (3) ◽  
pp. 366-376 ◽  
Author(s):  
Marcia K. O'Malley ◽  
Michael Goldfarb
Keyword(s):  
Human Subjects ◽  
Haptic Device ◽  
Haptic Interface ◽  
Maximum Force ◽  
Size Discrimination ◽  
Force Output ◽  
Simulated Environments ◽  
Real Objects ◽  
Simulation Results ◽  
Haptic Simulation

The ability of human subjects to identify and discriminate between different-sized real objects was compared with their ability to identify and discriminate between different-sized simulated objects generated by a haptic interface. This comparison was additionally performed for cases of limited force and limited stiffness output from the haptic device, which in effect decrease the fidelity of the haptic simulation. Results indicate that performance of size-identification tasks with haptic-interface hardware capable of a minimum of 3 N of maximum force output can approach performance in real environments, but falls short when virtual surface stiffness is limited. For size-discrimination tasks, performance in simulated environments was consistently lower than performance in a comparable real environment. Interestingly, significant variations in the fidelity of the haptic simulation do not appear to significantly alter the ability of a subject to identify or discriminate between the types of simulated objects described herein.

Communication Method of Time Synchronization and Strength Using Haptic Interface

2014 ◽  
Vol 26 (6) ◽  
pp. 772-779
Author(s):  
Takashi Asakawa ◽  
◽  
Noriyuki Kawarazaki ◽  
Keyword(s):  
Real Time ◽  
Visually Impaired ◽  
Time Synchronization ◽  
Haptic Device ◽  
Haptic Interface ◽  
Acceleration Sensor ◽  
Vibration Strength ◽  
Music Lessons ◽  
Communication Method ◽  
Radio Signals

<div class=""abs_img""><img src=""[disp_template_path]/JRM/abst-image/00260006/10.jpg"" width=""300"" />Electric music baton system</div> We are developing an electronic baton system as an alternative haptic interface to facilitate music lessons for the visually impaired. This system incorporates an acceleration sensor in the baton, transmits data to a player via radio signals, and acts as a haptic interface by generating vibrations. In this paper, we experimentally evaluate responses to the stimulus of the visual and the tactile senses in order to verify that a haptic interface can substitute for vision in scenarios that involve real-time tasks, such as music lessons. In the first experiment, we verify that clue motions are important for both the visual and a tactile senses. Next, we test the new method of communicating strength. Thismethod uses not vibration strength but oscillating time for vibrations of the haptic device. The results of the experiment confirm that the technique is effective. </span>

Virtual Reality in Orthopedic Surgeons Training

2015 ◽  
Vol 638 ◽  
pp. 344-351 ◽  
Author(s):  
Diana Popescu ◽  
Robert Iacob ◽  
Dan Laptoiu
Keyword(s):  
Virtual Reality ◽  
Surgical Techniques ◽  
Haptic Device ◽  
General Context ◽  
Good Correspondence ◽  
Virtual Training ◽  
Surgical Simulators ◽  
Orthopedic Surgeons ◽  
Immersion Experience ◽  
High Level

Nowadays the use of Virtual Reality (VR) based surgical simulators or training environments is becoming more and more spread in the medical world. These are usually dedicated to the development and improvement of novice trainees’ skills by helping them to learn different surgical techniques, to use proper instrumentation or to practice surgical protocols, but also in the training of expert surgeons for conserving their skills, for planning or rehearsing new, complicated or rare procedures. In this general context of interest, our paper aims at answering the following questions: What are the main requirements for a haptic device in order to be successfully used in the virtual training of orthopedic surgeons? What requirements are mandatory to be included in an orthopedic surgery haptic-based training application for providing a realistic user’s experience? These are legitimate questions considering that surgical education can really benefit the advantages offered by such virtual simulators only if they can satisfy a list of requirements among which high level of immersion and interactivity, realistic 3D virtual models and constraints of anatomical structures, good correspondence between real and simulated cases (i.e. a natural ‘behavior’ and ‘feeling’ of simulated anatomy). The focus of the literature review presented in this paper will be on orthopedic VR simulators for drilling, sawing and fixing implants screws, pins and plates, with an emphasize on devices’ characteristics and applications features. This study enrolls in the trend of improving user’s immersion experience at a cost as low as possible, representing the basis on which an innovative and affordable haptic device and an application for training basic orthopedic surgical skills are proposed for development in further research.

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