A Review of Non-Invasive Haptic Feedback stimulation Techniques for Upper Extremity Prostheses <s> Squeeze Feedback Display <s> Stable grasp is the result of sensorimotor regulation of forces, ensuring sufficient grip force and the integrity of the held object. Grasping with a prosthesis introduces the challenge of finding the appropriate forces given the engineered sensorimotor prosthetic interface. Excessive force leads to unnecessary energy use and possible damage to the object. In contrast, low grip forces lead to slippage. In order for a prosthetic hand to achieve a stable grasp, the haptic information provided to the prosthesis wearer needs to display these two antagonistic grasp metrics (force and slip) in a quantified way. We present the design and evaluation of a wearable single-actuator haptic device that relays multi-modal haptic information, such as grip force and slip speed. Two belts that are activated in a mutually exclusive manner by the rotation direction of a single motor exert normal force and tangential motion on the skin surface, respectively. The wearable haptic device is able to display normal forces as a tap frequency in the range of approximately 1.5–5.0 Hz and slip speed in the range of 50–200 mm/s. Within these values, users are able to identify at least four stimulation levels for each feedback modality, with short-term training. <s> BIB001 </s> A Review of Non-Invasive Haptic Feedback stimulation Techniques for Upper Extremity Prostheses <s> Squeeze Feedback Display <s> In this work we present a novel wearable haptic system based on an elastic fabric which can be moved forward and backward over the user forearm thus simulating a human caress. The system allows to control both the velocity of the “caress-like” movement, by regulating motor velocity, and the “strength of the caress”, by regulating motor positions and hence the force exerted by the fabric on the user forearm. Along with a description of the mechanical design and control of the system, we also report the preliminary results of psycho-physiological assessment tests performed by six healthy participants. Such an assessment is intended as a preliminary characterization of the device capability of eliciting tactually emotional states in humans using different combinations of velocity and caress strength. The emotional state is expressed in terms of arousal and valence. Moreover, the activation of the autonomic nervous system is also evaluated through the analysis of the electrodermal response (EDR). The main results reveal a statistically significant correlation between the perceived arousal level and the “strength of the caress” and between the perceived valence level and the “velocity of the caress”. Moreover, we found that phasic EDR is able to discern between pleasant and unpleasant stimuli. These preliminary results are very encouraging and confirm the effectiveness of this device in conveying emotional-like haptic stimuli in a controllable and wearable fashion. <s> BIB002 </s> A Review of Non-Invasive Haptic Feedback stimulation Techniques for Upper Extremity Prostheses <s> Squeeze Feedback Display <s> The use of haptic display to refer cues sensed electronically from a prosthetic terminal device promises to improve the function of myoelectrically controlled upper limb prostheses. This promise is often evaluated in experiments involving non-amputees, though the availability of additional haptic feedback from an intact hand (auxiliary feedback) may confound attempts to use non-amputees as stand-ins for amputees. In this paper we test the influence of auxiliary haptic feedback on myoelectric control performance by introducing various grasp conditions in a compensatory tracking task. We ask non-amputees to compensate for the motion of a random signal by producing myoelectric control signals with a hard object, soft object, or no object (requiring co-contraction) in their grasp. The error signal is displayed through a squeeze band worn about the upper arm or a visual display. Our results suggest that the main difference between tracking with haptic and visual feedback is low-frequency drift, and that auxiliary feedback does not substantially influence task performance. Despite the drift, our results show that participants are able to respond to cues presented through the squeeze band in the compensatory tracking task. <s> BIB003 </s> A Review of Non-Invasive Haptic Feedback stimulation Techniques for Upper Extremity Prostheses <s> Squeeze Feedback Display <s> In typical movement, humans use a combination of feed-forward and feedback motor control strategies to interact with the world around them. However, when sensory input is impaired or absent, as in the case of various neuropathies or amputation, the ability to perform everyday tasks, like modulating grip force to object weight, can be affected. In this study, we show the results of a preliminary study using a pressure cuff-like force feedback device (CUFF) with the SoftHand Pro (SHP) prosthetic hand. Subjects lifted an object of various weights using their own hand, with the SHP without feedback, and the SHP with force feedback. As expected, significant differences were found between the two SHP conditions and the native hand, but surprisingly not between the SHP conditions. A closer look at the data suggests the feedback may help diminish the overall grip force used during grasping even if it does not alter the grip force modulation to object weight. The lack of significance may be due in part to high intra- and inter-subject variability. Additional training with the CUFF and/or customization of the feedback may enhance the effects and warrants further study. <s> BIB004
The squeeze feedback display is highly portable devices based on using an elastic fabric band to move forward and backward over the user residual part, thus simulating a human caress by means of squeezing it  BIB004 BIB003  BIB002 BIB001 . The main works which associate with this haptic feedback technique are listed in Table 4 . Comparison between the native hand and the prosthetic hand associated with grasping objects and discriminating its size was briefly investigated in  BIB004 , in order to create alternative cutaneous stimulation to the amputees of upper arm mutilation, with high performance and a reliable manner The Clenching Upper-limb Force Feedback device (CUFF) in blending with the Soft Hand Pro (SHP), an anthropomorphic, EMG prosthetic controller are used to grasp and release the objects of different sizes and weights. The researcher validated the inspection truth and concluded that, in general, the real hand uses less force and energy than CUFF and SHF. However, at the same time, the functionality of equipping SHF with the sensing system over the SHF alone has been verified by controlling the prosthetic hand without utilizing the force sensors. Broadly, this type of haptic feedback technology is very effective in conveying sensory information and improving the performance of the myoelectric prosthetic arm in the complete absence of visual vision BIB003  . A novel squeeze feedback wearable device was designed to simulate a human caress BIB002 . The device consists of a rectangular-shaped fabric (60 mm x 160 mm) driven by two rolls, each of roll moved by one DC motor (HITEC digital DC servo motor HS-7954 H with an input voltage of 7.4 V), as shown in Fig. 7 . The rectangular-shaped fabric moves with a sliding motion around the forearm of the subject. The variation of the movement's velocity and the movement's strength give the subject the sensation of the caress-like. The evaluation experiments validated the ability of the haptic device to elicit tactually emotional states in humans. On the other side, the same technique has been used to control the grasping force of the upper limb prosthesis, in order to enable the amputees to apply a suitable grasp strength force on the objects, s to prohibit smashing objects in the palm of the hand and to prevent object slipping BIB001 .