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In this paper, we present the design of a new fMRI compatible haptic interface with 3DOFs, based on electrical DC actuation, for the study of brain mechanisms of human motor control. In order to evaluate the validity of the proposed solution, we performed some preliminary experiments with a single degree of freedom device to test the compatibility with the fMRI environment. The 1DOF design was extended...
Pneumatic control has been used for armature control of robots with pneumatic air muscles achieving accurate position control of the piston actuator with inexpensive solenoid valves. We describe a pneumatic fuzzy controller associated with a pulse width modulation conversion scheme in a novel haptic device within a colonoscopy simulation system. A rubber bladder was used to simulate forces experienced...
Providing force and torque feedback in every degree of freedom of a haptic device can be complex and costly, often prohibitively so. Consequently, devices that reduce the number of actuators such as SensAble's PHANTOM Omni, a 6-degree-of-freedom (DOF) positioning, 3-degree-of-freedom force feedback haptic device, have gained popularity. While these devices have been widely accepted, no previous study...
The main result of this paper is a new model based on homotopy switching between intrinsically distinct controllers that encompass most behaviors encountered in dyadic haptic collaborative tasks. The basic idea is to switch continuously between two distinct extreme behaviors (leader and follower) for each individual, which creates an implicit bilateral coupling within the dyad. The physical collaborative...
We describe a wearable haptic feedback device that imparts rotational skin stretch to provide feedback regarding movement of a virtual object. Applications for this device include feedback of motion for physical therapy or rehabilitation exercises or proprioceptive feedback for amputees. The device uses a small piezoelectric motor for a combination of low weight, moderate torques and rotation without...
We consider the following problem in haptics: information update from the virtual world is slow w.r.t. the local servo-loop rate of the haptic device, and the information transmission/update between the haptic device and the virtual world is of variable rate and/or asynchronous. For this, we propose a novel control framework, that, by relying on our recently proposed passive set-position modulation...
This paper reports on two experiments we conducted to look at how to design effective linear and circular apparent-motion displays. Using a two-tactor array on the upper arm, the first study found that a time interval of greater than 400 ms before repeating the directional sequence is required for subjects to achieve 95 % proficiency of direction identification over a range of duration of stimulus...
In this paper we present a method for generating accurate haptic force models to describe the feel of physical devices. The models are generated by fitting polynomial hypersurfaces to experimentally measured motion and force data obtained by actuating physical devices. The methods are demonstrated by modeling the complex force-deflection profile of a nonlinear mass-spring-damper system. Initial results...
The force-update-rate requirements of transparent rendering of virtual environments are in conflict with the computational cost required for computing complex interactions between deforming objects. In this paper we introduce a novel method for satisfying high force update rates with deformable objects, yet retaining the visual quality of complex deformations and interactions. The objects that are...
In this paper, we discuss a method for presenting virtual objects to multiple fingers on both hands using multiple single-point haptic devices operating over a network. We evaluated the effect of the number of fingers used on ability to recognize shapes using this system. The experimental results suggest that the number of contact points do not sufficiently improve the ability to recognize shapes,...
This paper presents an energy bounding approach (EBA) to enhance directional transparency while guaranteeing stability for multiple degree-of-freedom (DOF) haptic interaction. It was observed that the passivity condition for multiple ports may lead to some oscillations in some coordinate directions even though total energy is positive. The passivity condition, therefore, needs to be applied to each...
Several causes of instabilities in the interaction of users with actively controlled haptic devices, notably sampling effects, sensor quantization, and hardware nonlinearities, have been identified and analyzed in prior work. However, certain instabilities may occur that cannot be attributed to these hardware limitations. The problem becomes acute when rendering passive virtual environments which...
In this paper we discuss dielectric elastomer actuators (DEA) as one of the most promising technologies in electroactive polymers (EAP). For tactile display applications a large number of actuator elements is essential. The multilayer technology presented here offers the possibility to build up independent actuators and arrays at a high density within one substrate. The functional principle of these...
In this paper, a new parallel link mechanism ldquoDELTA-4rdquo is developed as a new haptic device within a high quality force display capability and operability. DELTA-4 realizes 3 DOF of translational motions by a new redundant parallel link mechanism. The name of the mechanism DELTA-4 is derived from a conventional parallel link mechanism ldquoDELTArdquo, because there are several common points...
In robotic applications tactile sensor systems serve the purpose of localizing a contact point and measuring contact forces. We have investigated the applicability of a sensorial device commonly used in cursor navigation technology for tactile sensing in robotics. We show the potential of this sensor for active haptic exploration. More specifically, we present experiments and results which demonstrate...
This paper reports the detection threshold of human hairy skin with the use of a direct vibrotactile stimulus to the hair on human hairy skin. We designed an experimental method to quantify the psychological effect and developed a stimulation instrument to directly stimulate the hair. This vibrotactile stimulation was provided from the tip of tweezers which traveled horizontally against the human...
This paper presents a small and lightweight tactile display system and describes its capabilities with respect to spatial and temporal tactile feedback. Each tactile display module is comprised of a 4times4 piezoelectric ultrasonic actuator array with a spatial resolution of 1.5 mm and a temporal resolution of 20 Hz. The objective of this research is to build a small and lightweight tactile display...
As an approach to real-time simulation of haptic interaction with deformable objects, we proposed a record-reproduction method called dasiaimpulse response deformation modelpsila (IRDM), in which the deformation of an object shape is computed by convolving temporal sequence of interaction force with a pre-computed response of model to impulse force. Although, IRDM has an advantage that its computation...
The purpose of these experiments was to investigate the minimum duration of haptic memory representations. The term haptic memory can be defined as the ability to retain impressions of haptically acquired information after the original stimulus is absent. Participants repeatedly picked up objects of various masses. The time interval between the final practice lift of each object and a test lift was...
We discuss the theory, design, and performance of a flat-panel tactile display capable of controlling shear force on a finger. In previous research a TPaD variable friction device was presented. It modulates friction by using vertical ultrasonic vibrations to form a squeeze film of air between the finger and the horizontal glass surface. In this research, a TPaD is oscillated in the horizontal plane...
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