IEEE Transactions on Haptics最新文献

Fingertip friction is a key component of tactile perception. In active tactile exploration, friction forces depend on the applied normal force and on the sliding speed chosen. We have investigated whether humans perceive the speed dependence of friction for textured surfaces of materials, which show either increase or decrease of the friction coefficient with speed. Participants perceived the decrease or increase when the relative difference in friction coefficient between fast and slow sliding speed was more than 20 %. The fraction of comparison judgments which were in agreement with the measured difference in friction coefficient did not depend on variations in the applied normal force. The results indicate a perceptual constancy for fingertip friction with respect to self-generated variations of sliding speed and applied normal force.

Ensuring the safety and authenticity of haptic feed2 back is crucial in the domain of surgical operations, particularly in procedures like Natural Orifice Transluminal Endoscopic Surgery (NOTES) and Minimally Invasive Robotic Surgery (MIRS). To enhance the control efficiency of the robotic operating console, we propose a haptic magnetism-based array (HM7 Array). This system employs a solenoid array and a detection stylus to achieve controller localization without the need for additional sensors, while simultaneously generating haptic effects. The device effectively controls the surgical robot's pose through a localization-haptic combined loopback. The entire system is scheduled on a finite state machine (FSM), seamlessly fusing localization and haptic generation. Psychometric evaluations con14 ducted through user studies have demonstrated the device's pre15 cision and accuracy. Teleoperation experimental results further confirm its potential value in surgical treatments and broader medical haptic applications.

To provide deeper immersion for the user in the virtual environments, both force and torque feedbacks are required rather than the mere use of visual and auditory ones. In this paper, we develop a novel propeller-based Ungrounded Handheld Haptic Device (UHHD) that delivers both force and torque feedbacks in one device to help the user experience a realistic sensation of immersion in a three-dimensional (3D) space. The proposed UHHD uses only a pair of propellers and a set of sliders to continuously generate the desired force and torque feedbacks up to 15N and 1N.m in magnitude in less than 370ms, respectively. The produced force and torque feedbacks are oriented in a desired direction using a gimbal mechanism where the propellers are mounted inside in such a way that a simple structure is obtained. These features facilitate the control of the proposed UHHD and enhance its practicality in various applications. To prove the capability of the system, we model it and elaborate on the force and torque analyses. Next, we develop a robust parallel force/position controller to tackle the structured and unstructured uncertainties. Finally, a measurement setup is manufactured to experimentally evaluate the performance of the UHHD and the controller. The implementation of the controller on the developed UHHD prototype shows that a satisfactory control performance is achievable in terms of offering the desired force and torque feedbacks.

Medical palpation is a key skill for clinicians. It is typically trained using animal and synthetic models, which however raise ethical concerns and produce high volumes of consumables. An alternative could be visuo-haptic simulations, despite their training efficacy has not been proved yet. The assessment of palpatory skills requires objective methods, that can be achieved by combining performance metrics with electroencephalography (EEG). The goals of this study were to: (i) develop a visuo-haptic system to train nodule detection, combining a Geomagic Touch haptic device with a visuo-haptic simulation of a skin patch and a nodule, implemented using SOFA framework; (ii) assess whether this system could be used for training and evaluation. To do so, we collected performance and EEG data of 19 subjects performing multiple repetitions of a nodule detection task. Results revealed that participants could be divided in low and high performers; the former applied a greater pressure when looking for the nodule and showed a higher EEG alpha (8.5 - 13 Hz) peak at rest; The latter explored the skin remaining on its surface and were characterized by low alpha power. Furthermore, alpha power positively correlated with error and negatively with palpation depth. Altogether, these results suggest that alpha power might be an indicator of performance, denoting an increase in vigilance, attention, information processing, cognitive processes, and engagement, ultimately affecting strategy and performance. Also, the combination of EEG with performance data can provide an objective measure of the user's palpation ability.

Haptic simulation of needle insertion requires both a needle-tissue interaction model and a method to render the outputs of this model into real-time force feedback for the user. In comparison with interaction models, rendering methods in the literature have seen little development and are either oversimplified or too computationally complex. Therefore, this study introduces the Generalized Tracking Wall (GTW) approach, a haptic rendering method inspired by the proxy approach. It aims to accurately simulate the interaction between a needle tip and soft tissues without the complex calculations of tissue deformations. The essence of the proposed method is that it associates an algorithm based on the energetic analysis of cutting with a contact model capable of simulating viscoelasticity and nonlinearity. This association proved to be a potent tool to faithfully replicate the different phases of needle insertion while adhering to underlying physics. Multi-layered-tissue insertions are also considered. The performance and generecity of the GTW are first evaluated through simulations. Then, the GTW is experimentally compared to empirical methods inspired by the literature.

This study addresses the challenges of Programming by Demonstration (PbD) in the context of collaborative robots, focusing on the need to provide additional degrees of programming without hindering the user's ability to demonstrate trajectories. PbD enables an intuitive programming of robots through demonstrations, allowing non-expert users to teach robot skills without coding. The two main PbD modalities, observational and kinesthetic, have limitations when it comes to programming the diverse functionalities offered by modern collaborative robots. To overcome these limitations, the study proposes the use of a wearable human-robot interface based on surface Electromyography (sEMG) to measure the forearm's muscle co-contraction level, enabling additional programming inputs through hand stiffening level modulations without interfering with voluntary movements. Vibrotactile feedback enhances the operator's understanding of the additional programming inputs during PbD tasks. The proposed approach is demonstrated through experiments involving a collaborative robot performing an industrial wiring task. The results showcase the effectiveness and intuitiveness of the interface, allowing simultaneous programming of robot compliance and gripper grasping. The framework, applicable to both teleoperation and kinesthetic teaching, demonstrated effectively in an industrial wiring task with a 100% success rate over the group of subjects. Furthermore, the presence of vibortactile feedback showed an average decrease of programming errors of 33%, and statistical analyses confirmed the subjects' ability to correctly modulate co-contraction levels. This innovative framework augments programming by demonstration by integrating neuromuscular interfacing and introducing structured programming logics, providing an intuitive human-robot interaction for programming both gripper and compliance in teleoperation and kinesthetic teaching.

The experience of time and space in subjective perception is closely connected. The Kappa effect refers to the phenomenon where the perceived duration of the time interval between stimuli is influenced by the spatial distance between them. In this study, we aimed to explore the Kappa effect from a psychophysical perspective. We investigated participants' perception of temporal duration in the sub-second range by delivering visual and tactile inputs through wearable devices placed on both the palm and the forearm. We compared the impact of unimodal sensory stimulation, involving either visual or tactile stimuli, with different bimodal stimulation conditions. Our results revealed that the illusory effect on inter-stimulus duration perception can be observed in both unimodal conditions, although the distortions were significantly more pronounced in vision. In the multimodal stimulation condition, where visual stimuli were presented at non-equidistant spatial locations, the integration of tactile input did not reduce the Kappa effect, regardless of the spatial location of the tactile stimuli. However, when the visual stimuli were equidistant in space, regardless of the spatial location of the tactile stimuli, the Kappa effect disappeared. These results can shed light on the effect played by multimodality on the perception of space and time.

Wearable vibrotactile devices seem now mature for entering the daily lives and practices of more and more users. However, vibrotactile perception can greatly differ between individuals, in terms of psychophysics and physiology, not to mention higher levels (cognitive or affective for example). Broadly-distributed and affordable vibrotactile devices hence must be adapted to each user's own perception, first of all by delivering intensity levels that are in the perceptible range of the user. This implies determining the user's own thresholds of perception, and then adapting the devices' output levels. Classical methods for the estimation of thresholds elicit too long procedures, and little is known about the reliability of other methods in the vibrotactile domain. This article focuses on two alternative methods for the estimation of amplitude thresholds in the vibrotactile modality ("increasing-intensity" and "decreasing-intensity" methods), and compares their estimations to the estimations from a staircase method. Both rapid methods result in much shorter test durations, and are found less stressful and tiring than the classic method, while showing threshold estimations that are never found to differ by more than 1.5 JND from the estimations by the classic method.

There is a growing interest in using the tactile modality as a compensation or sensory augmentation tool in various fields. The Multichannel Vibrotactile Glove was designed to meet the needs of these diverse disciplines and overcome the limitations of current sound-to-touch technologies. Using 12 independent haptic exciters on each finger's back and on the palm, the device can convey acoustic information to cutaneous vibrotactile receptors with precise control of the location, frequency, timing, and intensity. A staircase method was used to model vibration detection thresholds at six frequencies (100, 200, 250, 500, 800, 1000 Hertz) for each actuator position (All, Thumb, Index, Major, Middle, Pinky, Palm) and both hands (Right, Left). No between hand difference was observed and all finger actuators provided consistent thresholds, except for the Palm which exhibited higher thresholds. Spatial summation effects were observed when all actuators were activated simultaneously. Detection thresholds significantly increased at 100 Hertz and above 500 Hertz. These findings confirm that the system provides uniform stimulation across hands and actuators. Overall, the Multichannel Vibrotactile Glove provides the freedom to send various acoustic features to individual actuators, providing a versatile tool for research and a potential technology to substitute, compensate, or extend sensory perception.

We introduce minimal passive physical realizations of series (damped) elastic actuation (S(D)EA) under closed-loop control to determine the effect of different plant parameters and controller gains on the closed-loop performance of the system and to establish an intuitive understanding of the passivity bounds. Furthermore, we explicitly derive the feasibility conditions for these passive physical equivalents and compare them to the necessary and sufficient conditions for the passivity of S(D)EA under velocity-sourced impedance control (VSIC) to establish their relationship. Through the passive physical equivalents, we rigorously compare the effect of different plant dynamics (e.g., SEA and SDEA) on the system performance. We demonstrate that passive physical equivalents make the effect of controller gains explicit and establish a natural means for effective impedance analysis. We also show that passive physical equivalents promote co-design thinking by enforcing simultaneous and unbiased consideration of (possibly negative) controller gains and plant parameters. We demonstrate the usefulness of negative controller gains when coupled with properly designed plant dynamics. Finally, we provide experimental validations of our theoretical passivity results and comprehensive characterizations of the haptic rendering performance of S(D)EA under VSIC.