In recent years, wearability has become a new fundamental requirement for an effective and lightweight design of human-robot interfaces. Among the different application fields, robotic teleoperation represents the ideal scenario that can largely benefit from wearability to reduce constraints to the human workspace (acting as a master) and enable an intuitive and simplified information exchange within the teleoperator system. This effective simplification is particularly important if we consider the interaction with synergy-inspired robotic devices, i.e., those that are endowed with a reduced number of control inputs and sensors, with the goal of simplifying control and communication among humans and robots. In this article, we present an integrated approach for augmented teleoperation where wearable hand/arm pose undersensing and haptic feedback devices are combined with teleimpedance (TI) techniques for the simplified yet effective position and stiffness control of a synergy-inspired robotic manipulator in real time. The slave robot consists of a KUKA lightweight robotic arm equipped with the Pisa/IIT SoftHand, both controlled in impedance to perform a drilling task-an illustrative example of a dynamic task with environmental constraints. The experimental results from ten healthy subjects suggest that the proposed integrated interface enables the master to appropriately regulate the stiffness and pose of the robotic hand-arm system through the perception of interaction forces and vision, contributing to successful and intuitive executions of the remote task. The achieved performance is presented in comparison to the reduced versions of the integrated system, in which either TI control or wearable feedback is excluded.

Despite the importance of softness, there is no evidence of wearable haptic systems able to deliver controllable softness cues. Here, we present the Wearable Fabric Yielding Display (W-FYD), a fabric-based display for multi-cue delivery that can be worn on a user's finger and enables, for the first time, both active and passive softness exploration. It can also induce a sliding effect under the finger-pad. A given stiffness profile can be obtained by modulating the stretching state of the fabric through two motors. Furthermore, a lifting mechanism allows to put the fabric in contact with the user's finger-pad, to enable passive softness rendering. In this paper, we describe the architecture of W-FYD, and a thorough characterization of its stiffness workspace, frequency response, and softness rendering capabilities. We also computed device Just Noticeable Difference in both active and passive exploratory conditions, for linear and non-linear stiffness rendering as well as for sliding direction perception. The effect of device weight was also considered. Furthermore, performance of participants and their subjective quantitative evaluation in detecting sliding direction and softness discrimination tasks are reported. Finally, applications of W-FYD in tactile augmented reality for open palpation are discussed, opening interesting perspectives in many fields of human-machine interaction.

Myoelectric-artificial limbs can significantly advance the state of the art in prosthetics, since they can be used to control mechatronic devices through muscular activity in a way that mimics how the subjects used to activate their muscles before limb loss. However, surveys indicate that dissatisfaction with the functionality of terminal devices underlies the widespread abandonment of prostheses. We believe that one key factor to improve acceptability of prosthetic devices is to attain human-likeness of prosthesis movements, a goal which is being pursued by research on social and human-robot interactions. Therefore, to reduce early abandonment of terminal devices, we propose that controllers should be designed such as to ensure effective task accomplishment in a natural fashion. In this work, we have analyzed and compared the performance of three types of myoelectric controller algorithms based on surface electromyography to control an under-actuated and multi-degrees of freedom prosthetic hand, the SoftHand Pro. The goal of the present study was to identify the myoelectric algorithm that best mimics the native hand movements. As a preliminary step, we first quantified the repeatability of the SoftHand Pro finger movements and identified the electromyographic recording sites for able-bodied individuals with the highest signal-to-noise ratio from two pairs of muscles, i.e. flexor digitorum superficialis/extensor digitorum communis, and flexor carpi radialis/extensor carpi ulnaris. Able-bodied volunteers were then asked to execute reach-to-grasp movements, while electromyography signals were recorded from flexor digitorum superficialis/extensor digitorum communis as this was identified as the muscle pair characterized by high signal-to-noise ratio and intuitive control. Subsequently, we tested three myoelectric controllers that mapped electromyography signals to position of the SoftHand Pro. We found that a differential electromyography-to-position mapping ensured the highest coherence with hand movements. Our results represent a first step towards a more effective and intuitive control of myoelectric hand prostheses.

Palpation is an essential step of several open surgical procedures for locating arteries by arterial pulse detection. In this context, surgical simulation would ideally provide realistic haptic sensations to the operator. This paper presents a proof of concept implementation of tactile augmented reality for open-surgery training. The system is based on the integration of a wearable tactile device into an augmented physical simulator which allows the real time tracking of artery reproductions and the user finger and provides pulse feedback during palpation. Preliminary qualitative test showed a general consensus among surgeons regarding the realism of the arterial pulse feedback and the usefulness of tactile augmented reality in open-surgery simulators.

Integrating tactile feedback for lump localization in Robot-assisted Minimally Invasive Surgery (RMIS) represents an open research issue, which is still far to be solved. Main reasons for this are related e.g. to the need for a transparent connection with the teleoperating console, and an intuitive decoding of the delivered information. In this article, we focus on the specific case of RMIS treatment of uterine leiomyomas or fibroids, where little has been done in haptics to improve the outcomes of robotics-enabled palpation tasks. In this article, we propose the usage of a wearable haptic interface for softness rendering as a lump display. The device was integrated in a teleoperation architecture that simulates a robot-assisted surgical palpation task of leiomyomas. This article moved from an ex-vivo sample characterization of uterine tissues to show the effectiveness of our interface in conveying meaningful softness information. We extensively tested our system with gynecologic surgeons in palpation tasks with silicone specimens, which replicated the characteristics of uterine tissues with embedded leyomiomas. Results show that our system enables a softness-based discrimination of the embedded fibroids comparable to the one that physicians would achieve using directly their fingers in palpation tasks. Furthermore, the feedback provided by the haptic interface was perceived as comfortable, intuitive, and highly useful for fibroid localization.

Despite technological advancements, upper limb prostheses still face high abandonment/rejection rates due to limitations in control interfaces and the absence of force/tactile feedback. Improving these aspects is crucial for enhancing user acceptance and optimizing functional performance. This pilot study, therefore, aims to understand which sensory feedback in combination with a soft robotic prosthetic hand could provide advantages for amputees, including performing everyday tasks. Tactile cues provided are contact information, grasping force, degree of hand opening, and combinations of this information. To transfer such feedback, different wearable systems are used, based on either vibrotactile or force stimulation in a non-invasive modality matching approach. Five volunteers with a trans-radial amputation controlling the new prosthetic hand SoftHand Pro performed a study protocol including everyday tasks. The results indicate the preference of amputees for a single, i.e. non-combined, feedback modality. The choice of appropriate haptic feedback seems to be subject and task-specific. Furthermore, in alignment with the participants' feedback, force feedback, with adequate granularity and clarity, could potentially be the most valuable feedback among those presented. Finally, the study suggests that prosthetic solutions should be preferred where amputees are able to choose their feedback system.