Haptic technology

About: Haptic technology is a research topic. Over the lifetime, 18818 publications have been published within this topic receiving 306713 citations. The topic is also known as: haptics & haptic media.

Imposing motion constraints to a force reflecting telerobot through real-time simulation of a virtual mechanism

Abstract: In a teleoperation system, assistance can be given to the operator by constraining the telerobot position to remain within a restricted subspace of its workspace. A new approach to motion constraint is presented in this paper. The control law is established simulating a virtual ideal mechanism acting as a jig, and connected to the master and slave arms via springs and dampers. Using this approach, it is possible to impose any (sufficiently smooth) motion constraint to the system, including non-linear constraints (complex surfaces) involving coupling between translations and rotations. Physical equivalence ensures that the controller is passive. Experimental results obtained with a 6-DOF teleoperation system are given. Other applications of the virtual mechanism concept include hybrid position-force control and haptic interfaces.

The "Bubble" technique: interacting with large virtual environments using haptic devices with limited workspace

Abstract: The "Bubble" technique is a novel interaction technique to interact with large virtual environments (VE) using a haptic device with a limited workspace. It is based on a hybrid position/rate control which enables both accurate interaction and coarse positioning in a large VE. The haptic workspace is displayed visually using a semi-transparent sphere (looking like a bubble) that surrounds the manipulated cursor. When the cursor is located inside the bubble, its motion is position-controlled. When the cursor is outside, it is rate-controlled. The user may also "feel" the inner surface of the bubble, since the spherical workspace is "haptically" displayed by applying an elastic force-feedback when crossing the surface of the bubble.

Psychophysical characterization and testbed validation of a wearable vibrotactile glove for telemanipulation

Abstract: This paper describes and evaluates a high-fidelity, low-cost haptic interface for teleoperation. The interface is a wearable vibrotactile glove containing miniature voice coils that provides continuous, proportional force information to the user's fingertips. In psychophysical experiments, correlated variations in the frequency and amplitude of the stimulators extended the user's perceptual response range compared to varying amplitude or frequency alone. In an adaptive, force-limited, pick-and-place manipulation task, the interface allowed users to control the grip forces more effectively than no feedback or binary feedback, which produced equivalent performance. A sorting experiment established that proportional tactile feedback enhances the user's ability to discriminate the relative properties of objects, such as weight. We conclude that correlated amplitude and frequency signals, simulating force in a remote environment, substantially improve teleoperation.

A haptic wristwatch for eyes-free interactions

Abstract: We present a haptic wristwatch prototype that makes it possible to acquire information from a companion mobile device through simple eyes-free gestures. The wristwatch we have built uses a custom-made piezoelectric actuator combined with sensors to create a natural, inconspicuous, gesture-based interface. Feedback is returned to the user in the form of haptic stimuli that are delivered to the wrist. We evaluated the capabilities and limitations of our prototype through two user experiments. One experiment verified that the apparatus could be used as a tactile notification mechanism. The other experiment assessed the feasibility of using a cover-and-hold gesture on the wristwatch to obtain numerical data tactually. Results from the numerosity experiment and feedback from participants prompted us to redesign the cover-and-hold gesture to provide users with additional control over the interaction. We qualitatively evaluated the redesigned interaction by handing the prototype to users so that they could use it in a realistic work environment. Taken together, results from the experiments and the validation process indicate that a wrist accessory can be effectively used to perform discreet, closed-loop, eyes-free interactions with a mobile device.

Spanning large workspaces using small haptic devices

Abstract: Exploring large virtual environments using a small haptic device with limited-workspace capabilities is a challenging task because the user very quickly reaches the borders of the physical workspace of the device. In the case of a computer mouse, this problem is solved by lifting the device off the table and repositioning it at a different location. With most ground-based haptic devices such indexing procedure is not possible and requires the use of an additional switch to decouple the device from the cursor and allow the user to relocate the end-effector at the center of the physical workspace. Below certain physical workspace dimensions such indexing methods become cumbersome to the operator and therefore different control paradigms are required. This paper presents a new approach referred to as workspace drift control which progressively relocates the physical workspace of the device mapped inside the virtual environment towards the area of interest of the operator without disturbing his or her perception of the environment. This technique uses the fact that people are greatly influenced by what they perceive visually and often do not notice small deviations of their hand unless that small deviation has a corresponding visual component.