Integrating a Grasp Exoskeleton Into a String-Based Interface for Human-Scale Interactions

2008 ◽  
Vol 8 (4) ◽  
Author(s):  
Rasul Fesharakifard ◽  
Maryam Khalili ◽  
Laure Leroy ◽  
Alexis Paljic ◽  
Philippe Fuchs
Keyword(s):  
Virtual Environments ◽  
Degrees Of Freedom ◽  
Force Feedback ◽  
Control Method ◽  
Hybrid Control ◽  
Force Sensor ◽  
Virtual Objects ◽  
Rotary Encoder ◽  
Human Scale ◽  
Novel Design

A grasp exoskeleton actuated by a string-based platform is proposed to provide the force feedback for a user’s hand in human-scale virtual environments. The user of this interface accedes to seven active degrees of freedom in interaction with virtual objects, which comprises three degrees of translation, three degrees of rotation, and one degree of grasping. The exoskeleton has a light and ergonomic structure and provides the grasp gesture for five fingers. The actuation of the exoskeleton is performed by eight strings that are the parallel arms of the platform. Each string is connected to a block of motor, rotary encoder, and force sensor with a novel design to create the necessary force and precision for the interface. A hybrid control method based on the string’s tension measured by the force sensor is developed to resolve the ordinary problems of string-based interface. The blocks could be moved on a cubic frame around the virtual environment. Finally the results of preliminary experimentation of interface are presented to show its practical characteristics. Also the interface is mounted on an automotive model to demonstrate its industrial adaptability.

Force Feedback Glove for Manipulation of Virtual Objects

1993 ◽  
Vol 5 (1) ◽  
pp. 79-84 ◽  
Author(s):  
Haruhisa Kawasaki ◽  
◽  
Takahiro Hayashi
Keyword(s):  
Feedback Control ◽  
Force Feedback ◽  
Joint Angle ◽  
Force Sensor ◽  
Servo Motor ◽  
Force Transmission ◽  
Transmission Characteristics ◽  
Angle Sensor ◽  
Virtual Objects ◽  
The Difference

This paper presents a new force feedback glove for manipulation of virtual objects. The glove is comprised of wire, link, servo motor, force sensor, and joint angle sensor of fingers. These devices are mounted to the back of glove. The object grasping sense is generated by the force feedback control of the servo motor. We show the force transmission characteristics of the glove and the experimental results of recognition of the difference in rigidity of object.

Hybrid Position and Force Control Without Force Sensor

1996 ◽  
Vol 8 (3) ◽  
pp. 226-234
Author(s):  
Kiyoshi Ohishi ◽  
◽  
Masaru Miyazaki ◽  
Masahiro Fujita ◽  
Keyword(s):  
Degrees Of Freedom ◽  
Inverse Dynamics ◽  
Hybrid Control ◽  
Robot Manipulator ◽  
Reaction Force ◽  
Force Sensor ◽  
Force Estimation ◽  
Estimation System ◽  
Dynamics Calculation ◽  
Torque Observer

Generally, hybrid control is realized by sensor signal feedback of position and force. However, some robot manipulators do not have a force sensor due to the environment. Moreover, a precise force sensor is very expensive. In order to overcome these problems, we propose the estimation system of reaction force without using a force sensor. This system consists of the torque observer and the inverse dynamics calculation. Using both this force estimation system and <I>H</I>∞ acceleration controller which is based on <I>H</I>∞ control theory, it takes into account the frequency characteristics of both sensor noise effect and disturbance rejection. The experimental results in this paper illustrate the fine hybrid control of the three tested degrees-of-freedom DD robot manipulator without force sensor.

scholarly journals Haptic Virtual Environments for Blind People: Exploratory Experiments with Two Devices

1999 ◽  
Vol 4 (1) ◽  
pp. 8-17 ◽  
Author(s):  
G Jansson ◽  
H Petrie ◽  
C Colwell ◽  
D. Kornbrot ◽  
J. Fänger ◽  
...  
Keyword(s):  
Virtual Environments ◽  
Virtual World ◽  
Force Feedback ◽  
Virtual Object ◽  
Blind People ◽  
Haptic Devices ◽  
Virtual Objects ◽  
3D Objects

This paper is a fusion of two independent studies investigating related problems concerning the use of haptic virtual environments for blind people: a study in Sweden using a PHANToM 1.5 A and one in the U.K. using an Impulse Engine 3000. In general, the use of such devices is a most interesting option to provide blind people with information about representations of the 3D world, but the restriction at each moment to only one point of contact between observer and virtual object might decrease their effectiveness. The studies investigated the perception of virtual textures, the identification of virtual objects and the perception of their size and angles. Both sighted (blindfolded in one study) and blind people served as participants. It was found (1) that the PHANToM can effectively render textures in the form of sandpapers and simple 3D geometric forms and (2) that the Impulse Engine can effectively render textures consisting of grooved surfaces, as well as 3D objects, properties of which were, however, judged with some over- or underestimation. When blind and sighted participants' performance was compared differences were found that deserves further attention. In general, the haptic devices studied have demonstrated the great potential of force feedback devices in rendering relatively simple environments, in spite of the restricted ways they allow for exploring the virtual world. The results highly motivate further studies of their effectiveness, especially in more complex contexts.

Finger Mechanism of a Haptic Glove for Force Feedback in Virtual Environments

2007 ◽  
Author(s):  
Conrad Bullion ◽  
Goktug A. Dazkir ◽  
Hakan Gurocak
Keyword(s):  
Virtual Reality ◽  
Virtual Environments ◽  
Force Feedback ◽  
Bottom Surface ◽  
Force Analysis ◽  
Ongoing Research ◽  
Virtual Objects ◽  
Simulated Environment ◽  
Grasping Forces ◽  
Distributed Forces

In this paper we present details of a finger mechanism designed as part of an ongoing research on a force feedback glove. The glove will be used in virtual reality applications where it will provide force feedback to the user as he grasps virtual objects. Haptic (touch and force) feedback is an essential component to make the simulated environment feel more realistic to the user. The design employs an innovative mechanism that wraps around each finger. Each mechanism is controlled by one cable. By controlling the tension on the cable and the displacement of the cable, we can control the amount of force applied to the user’s finger at any given position of the mechanism. The glove can provide distributed forces at the bottom surface of each finger while reducing the number of actuators and sensors. First kinematic and force analysis of the mechanism along with experimental verifications are presented. Following description of an experiment to determine grasping forces, we conclude with an overview of the next steps in this research.

Educational Force Control Using a Modular 2-DOF Serial Robot Manipulator and Low-Cost 2-DOF Force Sensor

2019 ◽  
Author(s):  
Stephen Mascaro
Keyword(s):  
Force Control ◽  
Degrees Of Freedom ◽  
Hybrid Control ◽  
Robot Manipulator ◽  
Impedance Control ◽  
Low Cost ◽  
Force Sensor ◽  
Physical Contact ◽  
Dynamic Force ◽  
Control Techniques

Abstract This paper describes a modular 2-DOF serial robotic system and accompanying experiments that have been developed to instruct robotics students in the fundamentals of dynamic force control. In prior work, we used this same robot to showcase and compare the performance of a variety of textbook techniques for dynamic motion control (i.e. fast/accurate trajectory tracking using dynamic model-based and robust control techniques). In this paper we now add a low-cost 3D-printed 2-DOF force sensor to this modular robot and demonstrate a variety of force control techniques for use when the robot is in physical contact with the environment. These include stiffness control, impedance control, admittance control, and hybrid position/force control. Each of these various force control schemes can be first simulated and then experimentally implemented using a MATLAB/Simulink real-time interface. The two-degrees of freedom are just enough to demonstrate how the manipulator Jacobian can be used to implement directional impedances in operational space, and to demonstrate how hybrid control can implement position and force control in different axes. This paper will describe the 2-DOF robot system including the custom force sensor, illustrate the various force control methods that can be implemented, and demonstrate sample results from these experiments.

Manipulating Virtual Objects With a Haptic Glove Based on Soft Pneumatic Muscles

2009 ◽  
Author(s):  
Jukka Kuusisto ◽  
Asko Ellman ◽  
Joonas Reunamo ◽  
Joonatan Kuosa
Keyword(s):  
Virtual Environments ◽  
Force Feedback ◽  
Haptic Feedback ◽  
Hand Position ◽  
Position Information ◽  
Data Glove ◽  
Virtual Objects ◽  
University Of Technology ◽  
Pneumatic Muscles ◽  
Magnetic Tracker

In mechanical engineering, hardware mock-ups are increasingly being replaced by virtual models. Virtual environments enable the testing of different designs with considerable savings on time and money. Haptic feedback helps the user in getting a realistic conception about the cabin dimensions and how different controls actually look and feel. The haptic interface must be convenient to use and give realistic feedback on the functioning of the controls. The haptic force-feedback glove “SPM Glove” with soft pneumatic muscles — SPMs for short — on the palm side has been developed at the Department of Mechanics and Design at Tampere University of Technology. The glove provides force feedback to the thumb, index, and middle fingertips. In this paper, the usability of the SPM Glove for grasping, moving, and comparing the size of virtual objects is investigated. For achieving finger position information, the SPM Glove was worn over a data glove. Hand position was tracked with a magnetic tracker. The results indicate that users find manipulating cylindrical objects easier, more comfortable, and more natural with force feedback provided by the SPM Glove than without it. Moreover, all test users managed to arrange three invisible virtual cylinders of different sizes in order of increasing thickness using the SPM Glove.

Decoupling Control of Three Degrees of Freedom Hybrid Magnetic Bearing Based on LS-SVM

2014 ◽  
Vol 529 ◽  
pp. 534-538
Author(s):  
Yuan Yuan Li ◽  
Huang Qiu Zhu
Keyword(s):  
Degrees Of Freedom ◽  
Control Method ◽  
Hybrid Control ◽  
Original System ◽  
Magnetic Bearing ◽  
Inverse System ◽  
Least Square ◽  
Decoupling Control ◽  
Support Vector ◽  
Three Degrees Of Freedom

In the paper, the decoupling control method based on least square support vector machine (LS-SVM) inverse system is proposed, and adopting the method realizes decoupling control of an AC-DC three degrees of freedom hybrid magnetic bearing (AC-DC-3DOF-HMB). Aimed at the complicated multivariate nonlinear, strong coupling system of the AC-DC-3DOF-HMB, the reversibility of original system was analyzed, by the ability of least square support vector machines (LS-SVM) in universal approximation and identification fitting to get inverse model of AC-DC three degrees of freedom hybrid magnetic bearing. Then according to the basic principle of inverse system method, the inverse system was connected with the original system. So the complex nonlinear multivariable system is decoupled into three independent pseudo-linear system. The simulation results show that the system was decoupled; the hybrid control method has good dynamic and static performance, verify the feasibility of the proposed control method.

scholarly journals Hybrid Impedance-Admittance Control for Upper Limb Exoskeleton Using Electromyography

2020 ◽  
Vol 10 (20) ◽  
pp. 7146
Author(s):  
Lucas D. L. da Silva ◽  
Thiago F. Pereira ◽  
Valderi R. Q. Leithardt ◽  
Laio O. Seman ◽  
Cesar A. Zeferino
Keyword(s):  
Upper Limb ◽  
Degrees Of Freedom ◽  
Control Method ◽  
Hybrid Control ◽  
Impedance Control ◽  
Robotic Arm ◽  
Average Error ◽  
Acceptable Error ◽  
Upper Limb Exoskeleton ◽  
Input Signals

Exoskeletons are wearable mobile robots that combine various technologies to enable limb movement with greater strength and endurance, being used in several application areas, such as industry and medicine. In this context, this paper presents the development of a hybrid control method for exoskeletons, combining admission and impedance control based on electromyographic input signals. A proof of concept of a robotic arm with two degrees of freedom, mimicking the functions of a human’s upper limb, was built to evaluate the proposed control system. Through tests that measured the discrepancy between the angles of the human joint and the joint of the exoskeleton, it was possible to determine that the system remained within an acceptable error range. The average error is lower than 4.3%, and the robotic arm manages to mimic the movements of the upper limbs of a human in real-time.

scholarly journals Prototyping and Design for Assembly Analysis Using Multimodal Virtual Environments

1995 ◽  
Author(s):  
Rakesh Gupta ◽  
David Zeltzer
Keyword(s):  
Virtual Environments ◽  
Virtual Environment ◽  
Force Feedback ◽  
Human Subjects ◽  
3D Models ◽  
Design Tool ◽  
Design For Assembly ◽  
Manual Assembly ◽  
Virtual Objects ◽  
Assembly Analysis

Abstract This work investigates whether estimates of ease of part handling and part insertion can be provided by multimodal simulation using virtual environment (VE) technology, rather than by using conventional table-based methods such as Boothroyd and Dewhurst Charts. To do this, a unified physically based model has been developed for modeling dynamic interactions among virtual objects and haptic interactions between the human designer and the virtual objects. This model is augmented with auditory events in a multimodal VE system called the “Virtual Environment for Design for Assembly” (VEDA). Currently these models are 2D in order to preserve interactive update rates, but we expect that these results will be generalizable to 3d models. VEDA has been used to evaluate the feasibility and advantages of using multimodal virtual environments as a design tool for manual assembly. The designer sees a visual representation of the objects and can interactively sense and manipulate virtual objects through haptic interface devices with force feedback. He/She can feel these objects and hear sounds when there are collisions among the objects. Objects can be interactively grasped and assembled with other parts of the assembly to prototype new designs and perform Design for Assembly analysis. Experiments have been conducted with human subjects to investigate whether Multimodal Virtual Environments are able to replicate experiments linking increases in assembly time with increase in task difficulty. In particular, the effect of clearance, friction, chamfers and distance of travel on handling and insertion time have been compared in real and virtual environments for peg-in-hole assembly task. In addition, the effects of degrading/removing the different modes (visual, auditory and haptic) on different phases of manual assembly have been examined.

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