Showing papers on "Haptic technology published in 1994"

The PHANToM Haptic Interface: A Device for Probing Virtual Objects

Abstract: 1. Abstract This paper describes the PHANToM haptic interface - a device which measures a user’s finger tip position and exerts a precisely controlled force vector on the finger tip. The device has enabled users to interact with and feel a wide variety of virtual objects and will be used for control of remote manipulators. This paper discusses the design rationale, novel kinematics and mechanics of the PHANToM. A brief description of the programming of basic shape elements and contact interactions is also given.

Factors affecting the Z-Width of a haptic display

Abstract: This paper addresses the performance of force-reflecting interfaces ("haptic displays"). The authors suggest that an important measure of performance is the dynamic range of achievable impedances-"Z-Width"-and that an impedance is achievable if it satisfies a robustness property such as passivity. Several factors affecting Z-Width-sample-and-hold, inherent interface dynamics, displacement sensor quantization, and velocity filtering-are discussed. A set of experiments designed to evaluate these factors is described and experimental results are presented. A striking result is that inherent interface damping exerts an overwhelming influence on Z-Width. >

Human factors for the design of force-reflecting haptic interfaces

Abstract: This paper discusses the design criteria imposed by the capabilities of the human user on the design of force reflecting controllers for hands and arms. A framework of issues regarding human capabilities is presented that maps directly to mechanical design requirements. The state of knowledge for each capability is briefly summarized along with presentation of new experimental measurements. Finally, the implications of the human factors data to haptic interface design are discussed.

Passivity of a class of sampled-data systems: application to haptic interfaces

Abstract: Passivity of systems comprising a continuous time plant and discrete time controller is considered. This topic is motivated by stability considerations arising in the control of robots and force-reflecting human interfaces ("haptic interfaces"). A necessary and sufficient condition for the passivity of a class of sampled-data systems is derived. An example-implementation of a "virtual wall" via a one degree-of-freedom haptic interface-is presented.

Input device including digital force feedback apparatus

Abstract: An input device for an interactive computer simulation or game is disclosed which includes a structure having at least two degrees-of-freedom which is moveable by a digit of a user to transmit input signal to a computer. At least one actuator connected to the moveable structure receives inputs from a computer and applies forces in the at least two degrees-of-freedom to the movable structure and thereby to the digit of the user. The actuator may include an electric motor and any of a variety of force transmission schemes including direct, cable, gear or belt drives. The applied forces are typically based on internal programming within the computer, events occurring in the simulation and movements of and forces applied to the movable structure by the operator. The input device of the invention thereby provides continuous interaction among motion of and forces applied by the movable structure, the events in the simulation and forces applied to and applied by the movable structure to enhance user enjoyment and performance.

The pantograph: a large workspace haptic device for multimodal human computer interaction

Abstract: A multi-modal user interface taking advantage of kinesthesia force display, soundj and graphics, to improve human-computer interaction is described. This design primarily addresses the needs of visually impaired persons working in an office situation, but is presently applied to numerous other instances of human-machine interaction; such as operator workstations in control rooms or cockpits. The main technological item introduced here is the haptic interface itself (nicknamed the “Pantograph”) which measures position and velocity of a manipulated knob and displays forces in two dimensions over a wide frequency range. Programmed mechanical models are used to kinesthetically describe the features of the interface. These models are analogous to iconic representations in conventional graphic interfaces. Users, acting and perceiving through the haptic channel, simultaneously perceive simulated objects through the visual and auditory channels. Further developments are briefly reported.

The dynamics and control of a haptic interface device

Abstract: Haptic interface devices are machines that are controlled by the human arm contact forces. These devices are necessary elements of virtual reality machines. These devices may be programmed to give the human arm the sensation of forces associated with various arbitrary maneuvers. As examples, these devices can give the human the sensation that he/she is maneuvering a mass, or pushing onto a spring or a damper. In general, these devices may be programmed for any trajectory-dependent force. To illustrate and verify the analysis of these machines, a two-degree-of-freedom electrically-powered haptic interface device was designed and built at the Human Engineering Laboratory (HEL) of the University of California-Berkeley. >

Force-feedback data input device

Abstract: A force sensation exhibiting device has a housing which can be grasped by a hand, at least one rotatably or linearly movable motor contained in the housing , an input section where repulsive force informations are input, and control circuit for driving and controlling said motor according to the repulsive force informations, wherein a force sensation is given to said hand by a drive of the motor.

Design and Multi-Objective Optimization of a Linkage for a Haptic Interface

Abstract: A method to carry out the design of linkage for a haptic interface is described. Factors such as size, workspace, intrusion, inertia, response and structural properties are considered in this process. The dependencies of the various criteria are examined and a hierarchical method is applied. The result is a compact device which is easy to manufacture and which fulfills the requirements demanded by its application. Several quantitative measures designed to capture its principal properties are at the heart the process.

A multi-modal mouse with tactile and force feedback

Abstract: We have developed a mouse with tactile and force feedback Tactile information is provided to the operator by a small pin which projects slightly through the mouse button when pulsed Force information is provided by an electromagnet inside the mouse in conjunction with an iron mouse pad Tactile and force feedback are controlled by software linked to the visual information of targets on the visual display In an empirical evaluation using a target selection task, the addition of tactile and force feedback shortened the response time and widened the effective area of targets Design issues for interactive systems are discussed

Electrotactile haptic display on the fingertips: preliminary results

Abstract: Electrical stimulation of the sense of touch may be used to display pictorial information to blind computer users via a fingertip-scanned (haptic) touch tablet containing embedded electrodes. This might be particularly useful to users of systems with graphical user interfaces, or with drawing and layout software. Electrotactile (electrocutaneous) stimulation on the fingertip, however, differs substantially from that on other body locations. We discuss the implications of designing a practical graphics haptic display by addressing the high-resistance and variable nature of the fingertip electrode-skin interface. >

Networked spidar: A networked virtual environment with visual, auditory, and haptic interactions

Abstract: This research aims at the realization of a networked virtual environment for the design of three-dimensional 3-D objects. Based on an analysis of an ordinary collaborative design, we illustrate that a collaborative work space consists of a dialog space and an object space. In the dialog space, a participant interacts with partners, and in the object space with an object. The participants enter the dialog space and the object space in turn, appropriately. In addition, collaborative design of 3-D objects is carried out with multimodal interactions: visual, auditory, and haptic. A networked virtual environment must support these interactions without contradiction in either time or space. In this paper, we propose a networked virtual environment for a pair of participants to satisfy the conditions described above. To implement the networked system, we take into account the necessity of visual, auditory, and haptic interactions, the need for participants to switch between the dialog space and the object space quickly and appropriately, and human ergonomics on the functional space of hands and eyes. An experiment on hand-over task was done to investigate the effect of the networked haptic device with the proposed system. Object layout tasks, such as toy block layout, office furniture layout, city building layout, etc., can be performed by using this environment.

Improved efficiency through I- and E-feedback

Abstract: It has been argued by Engel and Haakma (1993, Expectations and feedback in user-system communication, International Journal of Man-Machine Studies, 39, 427-452) that for user-system communication to become more efficient, machine interfaces should present both early layered I-feedback on the current partial message interpretation as well as layered expectations (E-feedback) concerning the message components still to be communicated. As a clear example of our claim, this paper describes an experimental trackball device that provides the user with the less common E-feedback in addition to the conventional layered I-feedback in the form of the momentary cursor position on the screen and the kinetic forces from the ball. In particular, the machine expresses its expectation concerning the goal position of the cursor by exerting an extra force to the trackball.Two optical sensors and two servo motors are used in the described trackball device with contextual force feedback. One combination of position sensor and servo motor handles the cursor position and tactile feedback along the x -axis, the other combination controls that along the y-axis. By supplying supportive force feedback as a function of the current display contents and the momentary cursor position, the user's movements are guided towards the cursor target position expected by the machine. The force feedback diminishes the visual processing load of the user and combines increased ease of use with robustness of manipulation.Experiments with a laboratory version of this new device have shown that the force feedback significantly enhances speed and accuracy of pointing and dragging, while the effort needed to master the trackball is minimal compared with that for the conventional trackball without force feedback.

Touch with a mouse-a mouse type interface device with tactile and force display

Abstract: A mouse was modified to add tactile and force display via a solenoid driving a small pin and an electromagnet. In a target selection task experiment, the addition of tactile and force information feedback reduced target selection times, as compared to using a conventional mouse. A more pronounced effect was observed on the clicking time. In order to compare different sensory modalities, an experiment is conducted using a target selection task under five different sensory feedback conditions ("normal", auditory, colour, tactile, and combined one). Significant differences were found in the clicking times. The modified mouse was also used in a test of virtual texture. >

Reversible Deficit in Haptic Delay Tasks from Cooling Prefrontal Cortex

Abstract: The main purpose of this study was to explore the role of dorsolateral prefrontal cortex in skilled and sequential haptic performance. Monkeys were trained to perform a delayed matching-to-sample task that required the memorization of three-dimensional objects perceived either by palpation (haptically) or by sight. At the start of a trial the animal was allowed to touch or view an object, the sample; after a period of delay, during which the object remained out of touch and out of sight, the animal was presented with two side-by-side objects--one of them the sample--for either tactile or visual recognition, and the choice of the sample (correct match) was rewarded. Three variants of the task were used: (1) visual sample, haptic match; (2) haptic sample, visual match; and (3) haptic sample, haptic match. The temporary bilateral cooling of dorsolateral prefrontal cortex to 15 degrees C induced a reversible deficit in performance of all three tasks. Cooling to the same degree a portion of posterior parietal cortex of equivalent size did not significantly alter either performance or reaction time. These findings indicate that the functional integrity of the dorsolateral prefrontal cortex is important for performance of sequential behavior dependent on haptic skill. Further, the results suggest that the role of this cortex in active memory, already well documented for spatially and nonspatially defined visual information, extends also to tactile information and associated motor acts.

Further musings on the psychophysics of presence

Abstract: This is an extension of the author's earlier paper (1992) which considered alternative meanings and significance of "presence", the experience of "being there", commonly called "telepresence" in the case of remote control or teleoperation, and called "virtual presence" in the case of computer-generated simulation. In both cases presence can include feedback to the human senses of vision, hearing and haptics, both kinesthetic and cutaneous. Presence is discussed here in terms of alternative subjective meanings, operational measurements, and meaningful experimental comparisons. Three practical approaches to measurement of presence are discussed, including elicitation of "natural" neuromuscular or vocal responses, single or multidimensional subjective scaling, and ability to discriminate the real and immediate environment from that which is recorded transmitted or synthesized, under varying levels of constraint. The author also opines on the stimulus magnitude, space and time attributes of human interactions with a tele- or virtual environment. >

Haptic object recognition with a dextrous hand based on volumetric shape representations

Abstract: A haptic object recognition methodology suitable for application with a multifingered robot hand is presented. The methodology exploits the peculiar features of robot hands such as their distributed sensoriality and parallel kinematics for fast acquisition of contact data, and is based on volumetric representation models for efficient dynamic integration of the perceived information. Experimental results demonstrate the effectiveness and applicability of the methodology to non-trivial examples. >

A new micro-teleoperation system employing a hand-held force-feedback pencil

Abstract: This paper describes a new micro-teleoperation system that is inherently suitable for micro-object handling since it mitigates several drawbacks associated with human interface devices. The system uses an upward-facing CRT display monitor mounted beneath a table. An operator performs micro-tasks in a sitting posture at the table while looking down at the monitor with a touch sensor screen situated between the operator's arms. To execute these tasks, microscope-observed images of the target objects are utilized in conjunction with the touch sensor screen and a specially designed, pencil-shaped master manipulator having a force-feedback function. The system incorporates the following characteristic features: (1) Intuitive teleoperation is possible because coincidence of the operating and monitoring point is provided. (2) The pencil-shaped master manipulator enables sensitive bilateral micro teleoperation because of its light weight and small inertia for movement, and (3) With the side of the right hand fixed in a pen-holder grip, the operator uses the master manipulator to generate commands with a wide dynamic range of force feedback, i.e., the operator can simultaneously feel force feedback during operation from both pressure/slip sensory receptors on the fingertips and sensory receptors which detects stretching of the finger muscles. The stated features are proved experimentally by the constructed micro teleoperation prototype system. >

Virtual environments for aerospace training

Abstract: Virtual Environments (VEs) have the potential to significantly enhance the training of NASA astronauts and ground-based personnel for a variety of activities. At the same time this technology offers significant cost savings and increased training throughput. Issues being explored include the use of VEs to replicate features of microgravity environments that are not available in ground-based simulators, the degree of fidelity needed for effective training, the addition of haptic (tactile, force, temperature) feedback to VEs, and the feasibility of using VEs on orbit for "just-in-time training" and mission planning. The results of the use of virtual environments for training the Hubble Space Telescope Repair and Maintenance Mission flight team is discussed. In addition, progress on the development of shared virtual environments for training is presented. >

Interacting with virtual environments using augmented virtual tools

Abstract: Once donned, a virtual reality headset totally immerses its user in the virtualenvironment. Gone are the keyboard and monitor, gone are the normal means forcommunicating with the computer system. Users either must remove the headset,perform the needed interaction, and then replace the headset, or they must use headand body movements to provide input and the headset to see the output.Removing and replacing the headset each time a user wishes to interact with the

Visual-haptic relations in a two-dimensional size-matching task.

Abstract: Visual and haptic perceptions of the two-dimensional size of square stimuli were compared using cross-modal, intramodal, and bimodal matching tasks. In a repeated-measures factorial design, 12 women participated in five matching tasks involving various combinations of vision and haptic touch; five sizes of standard squares were matched with a comparison range of 10 squares during each task. Analysis showed that, for stimuli with side lengths of .75 in. and smaller, matching accuracy was superior when vision was used during the matching task regardless of the modality used during inspection. When haptic touch was used in the matching task, accuracy was better when vision had been used during inspection than when it bad not. These results were consistent with those of previous studies comparing size perception by vision and other forms of touch. The over-all relationship between matched size and inspected size was best accounted for by a third-order polynomial function.

Unified approach for teleoperation of virtual and real environment for skill based teleoperation

Abstract: This paper proposes an alternative control scheme for a teleoperation system which consists of a master arm, a slave arm and a virtual environment. For a given task, the operator manipulates a virtual environment and executes the task, a skill for the task is extracted through the manipulation, and the skill is transferred to the remote site to execute the task in real. First, the authors consider the design of a control algorithm for a master arm manipulating the virtual environment so that the system has a given dynamics for the operator and the environment. Then the authors consider the design of a control algorithm for the master-slave system manipulating the real environment so that the system has the same dynamics given to the manipulator of the virtual environment. By designing a control scheme, with which the master arm with a real environment and the master arm with a virtual environment have the same dynamics, the skill extracted from the operation of the virtual environment would be applied to the real task using the slave arm. The proposed control system is applied to an experimental master-slave manipulator and experimental results illustrate the effectiveness of the system. >

Haptic computer input device eg for virtual reality

Abstract: Typically for use in Virtual Reality computer software applications, the invention provides a hand-held haptic computer input device comprising a body (1) grippable in the palm of the hand of a user and a front panel (4) contactable by the fingers of the user at points A, B, C, D. The outer membrane of panel (4) is resiliently flexible and at each of points A to D covers a respective pressure transducer actuator fabricated from a resiliently flexible or elastomeric material. Each actuator is arranged so as at least in part to be flexed or compressed relative to the body (1) by pressure applied by the appropriate digit of the user. The arrangement provides that deformation of an actuator by movement of the appropriate digit and the resultant electrical transducer output are both generally in proportion to the magnitude of the pressure applied.

Perceptual Dependence for Shape and Texture during Haptic Processing

Abstract: Perceptual dependence—the existence of perceptual interactions between the component dimensions of the same stimulus—was investigated for shape and texture during haptic processing. The haptic system combines tactual and kinesthetic information. Previous research has demonstrated that haptic exploration influences the extent to which object properties are integrated. Conditions designed to promote and impede the integration of shape and texture were compared. Perceptual independence was assessed by the use of a speeded-classification paradigm and quantitative tests developed by Ashby and Maddox. Results indicate that shape and texture are perceptually dependent for both conditions. Hand-movement analyses show simultaneous exploration for both dimensions. The tendency to process dimensions dependently is discussed in terms of a limited-capacity model of haptic-information processing.

Dynamic control gain and tactile feedback in the capture of cursor movements

Abstract: Recent research at IPO involving a trackball with force feedback has demonstrated that tactile feedback can enhance the acquisition of targets in graphical user interfaces in terms of movement times and errors. The present study seeks to explore the degree to which being able to feel a target in contrast with changes in the display/control gain, over the target, influences movement performance. Tactile feedback over a target is felt as a pulling force towards the centre of a target, with counterforces applied when moving out of the centre. Changes in the target gain can create a cursor-catching effect by requiring more movement of the control device to enter than to leave the centre of the target. Results of an experiment indicated that target acquisition performance was generally higher in the tactile feedback condition, followed by target gain feedback, in comparison with no-target gain feedback. User interface design issues are discussed in respect to gain and tactile feedback.

Quantitative measurement of haptic perception

Abstract: Development and evaluation of teleoperators and haptic virtual environment technologies require objective quantitative measures of haptic quality. In this paper a theoretical framework and experimental procedures are introduced for quantitative assessment of haptic perception. Human haptic perception of objects is distorted and uncertain as well. Perceptual distortion is defined to be a systematic bias of perception with respect to an objective standard. Perceptual uncertainty is defined to be a measure of statistical distribution of percepts. A set of mathematical tools is presented to quantify perceptual distortion and uncertainty. Two experiments are presented which apply these tools to investigate the fundamental structure of human haptic perception. >

Master-slave system with force feedback based on dynamics of virtual model

Abstract: A master-slave system can extend manipulating and sensing capabilities of a human operator to a remote environment. But the master-slave system has two serious problems: one is the mechanically large impedance of the system; the other is the mechanical complexity of the slave for complex remote tasks. These two problems reduce the efficiency of the system. If the slave has local intelligence, it can help the human operator by using its good points like fast calculation and large memory. The authors suggest that the slave is a dextrous hand with many degrees of freedom able to manipulate an object of known shape. It is further suggested that the dimensions of the remote work space be shared by the human operator and the slave. The effect of the large impedance of the system can be reduced in a virtual model, a physical model constructed in a computer with physical parameters as if it were in the real world. A method to determine the damping parameter dynamically for the virtual model is proposed. Experimental results show that this virtual model is better than the virtual model with fixed damping.