Design and validation of a complete haptic system for manipulativetasks (original) (raw)

Whole-hand kinesthetic feedback and haptic perception in dextrous virtual manipulation

IEEE Transactions on Systems, Man, and Cybernetics - Part A: Systems and Humans, 2003

One of the key requirements for a Virtual Reality system is the multimodal, real-time interaction between the human operator and a computer simulated and animated environment. This paper investigates problems related particularly to the haptic interaction between the human operator and a virtual environment. The work presented here focuses on two issues: 1) the synthesis of whole-hand kinesthetic feedback, based on the application of forces (torques) on individual phalanges (joints) of the human hand, and 2) the experimental evaluation of this haptic feedback system, in terms of human haptic perception of virtual physical properties (such as the weight of a virtual manipulated object), using psychophysical methods. The proposed kinesthetic feedback methodology is based on the solution of a generalized force distribution problem for the human hand during virtual manipulation tasks. The solution is computationally efficient and has been experimentally implemented using an exoskeleton force-feedback glove. A series of experiments is reported concerning the perception of weight of manipulated virtual objects and the obtained results demonstrate the feasibility of the concept. Issues related to the use of sensory substitution techniques for the application of haptic feedback on the human hand are also discussed.

Active Manipulation of Users in Haptic-Enabled Virtual Environments

Proceedings of the First International Conference on Ambient Media and Systems, 2008

The main goal of this research is to study the effect of subthreshold forces on human performance in a haptic-enabled virtual reality system. A multi-modal task similar to Fitts is used to study the effects of the sub-threshold forces on user performance. Each user's movement is manipulated using controlled forces such that the user is not aware of the forces. Subjects can see the position of the haptic probe in a virtual environment where they are manipulated using sub-threshold forces. The multi-modal task is used to measure the accuracy of subjects in two experiments. During the experiments, the effects of force intensity and the relative direction of applied forces to the direction of user's hand motion in the presence of visual cues are investigated. A performance index is also introduced that can be used to evaluate human performance in the application of subthreshold forces. A psychophysical method is utilized to ensure that the applied forces on the user's hand are below the force threshold of the human haptic system. Results indicate that user performance is affected by both the intensity and direction of sub-threshold forces even when the users could control their actions through visual feedbacks.

Human-Machine Real-Virtual Haptic Interaction Systems

This paper describes preliminary versions of two human-machine real-virtual haptic interaction systems: a unilateral real-virtual teleoperation system, and a simple bilateral haptic game. Both applications were designed and implemented by computer engineering undergraduate students in collaboration with their teachers. The main objective of this work was to create a basis system that permits to evaluate the effects of force feedback in applications involving interaction between human operators and virtual environments.

Haptic and Visual Feedback for Manipulation Aid in a Virtual Environment

Dynamic Systems and Control

This paper proposes a new method of object manipulation in a Virtual Environment that uses a visual and haptic feedback based manipulation aid. If the displayed position of the object is constrained on a face of another object in the virtual environment, a user can place the virtual object at a precise position as easily as in a real environment. The visual feedback based manipulation aid constrains the motion of the virtual object as if it were moved in a real environment. Furthermore, in simultaneous correspondence with the visual constraints, the haptic feedback based manipulation aid constrains the motion of the user’s hand in the real environment. The proposed method introduces a magnetic metaphor: the user has the sensation of manipulating a virtual object on a rigid surface without using a large and powerful robot arm and the time consuming simulation of detailed physical phenomena. The properties of this manipulation aid based on two kinds of feedback are discussed. Experime...

Haptic interaction with virtual mechanical systems

Abstract1 -In this paper some possible solutions for interaction with virtual mechanical systems are presented. For the purpose of manipulating and interaction with mechanical systems in a realistic manner various haptic devices can be used. To assess the added value of the interaction the authors conducted a series of experiments involving multimodal interaction. Three possible cases and applications are presented: (i) when the user is interacting with a completely virtual mechanical system -for this a desktop virtual reality system was used including a PHANToM® haptic device , (ii) when the user is manipulating one element of the mechanical system in a CAVE-like visualization system using the stringbased SPIDAR haptic device, and (iii) when the user is interacting with one part of a mechanism (the mechanical system being composed by one or more real and virtual elements and joints -using augmented reality techniques and see-through featured head mounted display): a crank linked to a torque controlled electrical motor. The research showed the difficulties when trying to interact with a virtual mechanism using haptic feedback.

Evaluation of a Haptic-Based Interaction System for Virtual Manual Assembly

2009

This paper describes a mixed reality application for the assessment of manual assembly of mechanical systems. The application aims at using low cost technologies and at the same time at offering an effective environment for the assessment of a typical task consisting of assembling two components of a mechanical system. The application is based on the use of a 6-DOF interaction device that is used for positioning an object in space, and a haptic interface that is closer to reality and is used for simulating the insertion of a second component into the first one while feeling a force feedback. The application has been validated by an expert user in order to identify the main usability and performance problems and improve its design.

Design and implementation of haptic interactions

Ph.D. Thesis of Naci Zafer, 2000 , 2000

This thesis addresses current haptic display technology where the user interacts with a virtual environment by means of specialized interface devices. The user manipulates computer generated virtual objects and is able to feel the sense of touch through haptic feedback. The objective of this work is to design high performance haptic interactions by developing multi-purpose virtual tools and new control schemes to implement a PUMA 560 robotic manipulator as the haptic interface device. This study focuses on engineering applications where the interaction is with computer generated physical models of dynamic systems and mechanisms. Thus, the research presented in this dissertation focuses on introducing and using new modeling techniques in designing haptic interactions. The interactions are modeled by coupling the motions of the virtual tool with those of the PUMA 560 robotic manipulator. Kane’s method is introduced to model dynamics of virtual tools. The resulting model is used to develop an approach to dynamic simulation for use in interacting haptic display, which includes multibody systems switching constraints. Multibody dynamics of a virtual simulator, a dumbbell, is developed and the advantages of the Kane’s method in handling the non-holonomic constraints are presented. Experimental data is also collected to show various contact configurations. A two-degree of freedom virtual manipulator is modeled to feel the surface of a taurus shape. An optimal position controller is designed to achieve stable interactions. The controller is designed to achieve kinematic coupling between the virtual manipulator and the haptic display device to impose motion constraints and the virtual interactions. Stability of the haptic interface is also studied and proved using Lyapunov’s direct method. Experimental data in various positions of the robotic manipulator is obtained to justify theoretical results. A shift mechanism is then implemented on the taurus shape, thus the motions of the robotic manipulator is further constrained. The difficulties in handling the motion constraints are discussed and an alternative approach is presented. The work presented in this dissertation uses both kinematic and dynamic based virtual manipulators as virtual simulators to address problems associated in both free and constrained motions. Implementation of both haptic display simulations in an experimental interaction system allows for the evaluation of the performance of the haptic interaction. Both implementations are general enough to allow researchers with any six degree-of-freedom robot to apply the approaches and continue in this area of research. The results are expected to improve on the current haptic display technology by a new type of optimal position controller and better algorithms to handle both holonomic and nonholonomic constraints.

A Dynamic Virtual Environment for Haptic Interaction

We present a rigid-body simulation for multi-contact haptic interaction. The simulation is designed to make use of modern multiprocessor machines and the framework for this is discussed. An existing haptic rendering algorithm is extended to: facilitate simple implementation on a number of object types, enable the use of arbitrary objects as haptic cursors and allow multiple object contacts on the same haptic cursor. We also justify the use of hard-constraint based methods for rigid-body dynamics and discuss our implementation.

Segmentation of Bimanual Virtual Object Manipulation Tasks Using Multifinger Haptic Interfaces

IEEE Transactions on Instrumentation and Measurement, 2000

ABSTRACT This paper describes data processing using a haptic interface for virtual object grasping tasks. The haptic interface known as MasterFinger-2 (MF-2) is used. This haptic device enables the simulation of object manipulation using the thumb and index finger, which are inserted within thimbles located at the far end of the haptic interface. The experiments were conducted using a setup that provides the operator with two MF-2s. This setup enables bimanual virtual object manipulation. The haptic device provides data about the angular position of all joints and data from four contact sensors located within the thimbles. The values obtained from the angular positions of the joints enable a calculation of the position and orientation of the thimbles, whereas the values obtained from the contact sensors are used to formulate an approximate calculation of the user's force during object manipulation. This information regarding forces enables the segmentation of manipulation tasks and is essentially based on the rising edges produced by the contact sensor signals. After performing task segmentation, the state of the task in progress is detected. This facilitates improvements in user interaction because restrictions can be established in the relationships between the objects that change dynamically depending on the stage of manipulation. This information allows for an improvement in the realism of the simulation because the forces reflected take into account how the relationships between objects vary over the course of the task. Task segmentation is also used to ascertain objects' physical properties. These features are then used to simulate virtual objects with the same properties.

Analysis and Design of a Haptic Control System: Virtual Reality Approach

The International Journal of Advanced Manufacturing Technology, 2002

In this paper, the analysis and design of telerobotics based on the haptic virtual reality (VR) approach for simulating the clay cutting system is proposed. The main components of the approach include a user interface, networking, simulation, and a robot control scheme. The telerobotics for the clay cutting system and the environment is simulated by a haptic virtual system that enables operators to feel the actual force feedback from the virtual environment just as they would from the real environment. The haptic virtual system integrates the dynamics of the cutting tool and the virtual environment whereas the handle actuator consists of the dynamics of the handle and the operator on the physical side. The control scheme employs a dynamical controller which is designed considering both the force and position that the operator imposes on the handle and feedforward to the cutting tool, and the environmental force imposed on the cutting tool and the feedback to the handle. The stability robustness of the closed-loop system is analysed based on the Nyquist stability criterion. It is shown that the proposed control scheme guarantees global stability of the system, with the output of the cutting tool approaching that of the handle when the ratios of the position and the force are selected correctly. Experiments in the virtual environment on cutting a virtual clay system are used to validate the theoretical developments.