An AI-Based Model for Texture Classification from Vibrational Feedback: Towards Development of Self-Adapting Sensory Robotic Prosthesis

This paper presents a novel method of tuning vibration parameters to elicit specific perceptions of texture using vibration artefacts detected in EMG signals. Though often used for prosthetic control, sensory feedback modalities like vibration can be used to convey proprioceptive or sensory information. Literature has shown that the presence of sensory feedback in prosthesis can improve embodiment and control of prosthetic devices. However, it is not widely adopted in daily prosthesis use, due in large part to the daily change in perception and interpretation of the sensory modality. This results in daily parameter adjustments so that sensory perception can be maintained over time. A method therefore needs to be established to maintain perception generated by modalities like vibrations. This paper investigates modulating the vibration parameters based on how the vibrations dissipate in the surrounding tissue from the stimuli. This is with the aim of correlating dissipation of vibration to specific perceptions of texture. Participants were asked to control vibration motor parameters to elicit the perception of three different grades of sandpaper, provided to them for reference. Once the vibration parameters were chosen a CNN algorithm identified and categorized the artefact features along equidistantly spaced EMG electrodes. Participants were asked to repeat this experiment on three separate days and on the fourth was asked to complete a texture identification task. The task involved identifying the texture of the sandpaper based on their previously chosen parameters and compared the results to tuning against an AI-based algorithm using the dissipation of the vibration artefacts

Reusable Flexible Concentric Electrodes Coated With a Conductive Graphene Ink for Electrotactile Stimulation

Electrotactile stimulation is a highly promising technique for providing sensory feedback information for prosthetics. To this aim, disposable electrodes which are predominantly used result in a high environmental and financial cost when used over a long period of time. In addition, disposable electrodes are limited in their size and configurations. This paper presents an alternative approach based on a 3D printed reusable flexible concentric electrode coated with a conductive graphene ink. Here, we have characterized the electrode and demonstrated its effective performance in electrotactile stimulation and sensory feedback for robotic prosthetic hands

Using Vibration Motors to Create Tactile Apparent Movement for Transradial Prosthetic Sensory Feedback

It has been reported in the literature that sensory information is a valuable and desired form of feedback for prosthetic users. Communication of how the arm moves can reduce cognitive load, reduce the need for visual attention and help the user predict the initial grasping force. In this paper, a new method of communicating movement sensations is presented through the application of tactile apparent movement. By overlapping vibration created by arrays of linear resonant actuators, a stroking movement can be felt on the user\u27s arm. The results show potential for a low cost and light weight system that can communicate stimulations for up to three degrees of actuation in a prosthetic

A hybrid haptic stimulation prosthetic wearable device to recover the missing sensation of the upper limb amputees

A hybrid haptic feedback stimulation system that is capable in sensing the contact pressure, the surface texture, and the temperature, simultaneously, was designed for a prosthetic hand to provide a tactile sensation to amputation patients. In addition, the haptic system was developed to enable the prosthetic’s users to implement withdrawal reflexes due to the thermal noxious stimulus in a quick manner. The re-sensation is achieved by non-invasively stimulating the skin of the patients’ residual limbs, based on the type and the level of tactile signals provided by the sensory system of the prostheses. Accordingly, three stages of design and development were performed to satisfy the research methodology. A vibrotactile prosthetic device, which is designed for the detection of contact pressure and surface texture in upper extremity, represents. While, the design of a novel wearable hybrid pressure-vibration haptic feedback stimulation device for conveying the tactile information regarding the contact pressure between the prosthetic hand and the grasped objects represents the second methodology stage. Lastly, the third stage was achieved by designing a novel hybrid pressure-vibration-temperature feedback stimulation system to provide a huge information regarding the prostheses environment to the users without brain confusing or requiring long pre-training. The main contribution of this work is the development and evaluation of the first step of a novel approach for a lightweight, 7 Degrees-Of-Freedom (DOF) tactile prosthetic arm to perform an effective as well as fast object manipulation and grasping. Furthermore, this study investigates the ability to convey the tactile information about the contact pressure, surface texture, and object temperature to the amputees with high identification accuracy by mean of using the designed hybrid pressure-vibration-temperature feedback wearable device. An evaluation of sensation and response has been conducted on forty healthy volunteers to evaluate the ability of the haptic system to stimulate the human nervous system. The results in term of Stimulus Identification Rate (SIR) show that all the volunteers were correctly able to discriminate the sensation of touch, start of touch, end of touch, and grasping objects. While 94%, 96%, 97%, and 95.24% of the entire stimuli were successfully identified by the volunteers during the experiments of slippage, pressure level, surface texture, and temperature, respectively. The position tracking controller system was designed to synchronize the movements of the volunteers’ elbow joints and the prosthetic’s elbow joint to record the withdrawal reflexes. The results verified the ability of the haptic system to excite the human brain at the abnormal noxious stimulus and enable the volunteers to perform a quick withdrawal reflex within 0.32 sec. The test results and the volunteers' response established evidence that amputees are able to recover their sense of the contact pressure, the surface texture, and the object temperature as well as to perform thermal withdrawal reflexes using the solution developed in this work