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

Combining Local and Global Features in Automatic Affect Recognition from Body Posture and Gait

There has been a growing interest in machine-based recognition of emotions from body gait and posture, and its combination with other modalities. Applications such as human computer interaction, social robotics, and security have been the driving force behind such trend. The majority of the previous work in automatic affect perception deploys only either local features or global features. Whilst a combination of both types of features are deployed in applications such as object recognition and facial recognition, the literature does not reveal any study in affect recognition from body language using combined global and local features. In this thesis, such gap is addressed by examining how deploying a combination of local and global features can improve the recognition rate in automatic classification of emotions using gait and posture. The motion data used in the study comprising kinematic parameters associated with the gait and posture of a number of actors expressing a set of emotions, were recorded electronically using an inertia motion capture system. A combination of local and global features proposed by Kapur et al. and Zacharatos et al., respectively, were used in the classification process using WEKA classification system. Additional global features of shape flow and shaping, horizontal and vertical symmetry were added to the combination feature set to increase the performance of the classifier. The results obtained in the analysis demonstrate that deploying a combination of local and global features leads to a more robust and reliable method for automatic affect recognition from body language as it improves accuracy across a range of classifiers. This research also demonstrates that the inclusion of the additional features, which represent additional Laban Movement Analysis components, increases the maximum classification accuracy from 88.5% to 92.3%. Achieving better automatic affect recognition rates can lead to increased application of the approach, improved usefulness and reliability of such systems

Providing Non-Invasive Sensory Feedback for Transradial Prosthetic Hand Users

Currently there is a large rejection rate and dissatisfaction with prosthetic hands. One primary reason for the rejection of the prosthetic hands is that there is no or negligibly small feedback or tactile sensation from the prosthetic hand to the user, making the prosthetic device less functional. This lack of feedback requires significant reliance on visual information from the user in order to do basic gestures and daily activities, and therefore, can lead to significant cognitive effort. In addition to reducing the need for visual attention, sensory feedback has been shown to increase embodiment and reduce the occurrence of phantom limb pain

Applying Mechanical Pressure and Skin Stretch Simultaneously for Sensory Feedback in Prosthetic Hands

An effective method of communicating sensory feedback for prosthetics is presented using a combination of mechanical pressure and skin stretch, resulting in a mixture of normal and shear force being applied to the human arm. Stimulations were induced on the subject\u27s forearm by three mechanical cranks, each attached to their own servo motor. Three different crank orientations were tested, each producing a different skin stretch direction, with the results showing that shear force/tangential skin stretch applied longitudinally to the forearm was perceived more easily as it produced the best recognition rate. With minimal training, eighteen able-bodied test subjects were able to recognise six different grips with an accuracy of up to 88%, and achieved an accuracy of 80% when recognising the six grips at two different pressure levels. This sensory feedback mechanism shows potential for a simple, easy to learn stimulation device that could help improve users control and embodiment of their prosthetic device that requires three separate feedback channels

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 Review of Non-Invasive Sensory Feedback Methods for Transradial Prosthetic Hands

Any implant or prosthesis replacing a function or functions of an organ or group of organs should be biologically and sensorily integrated with the human body in order to increase their acceptance with their user. If this replacement is for a human hand, which is an important interface between humans and their environment, the acceptance issue and developing sensory-motor embodiment will be more challenging. Despite progress in prosthesis technologies, 50-60 & #x0025; of hand amputees wear a prosthetic device. One primary reason for the rejection of the prosthetic hands is that there is no or negligibly small feedback or tactile sensation from the hand to the user, making the hands less functional. In fact, the loss of a hand means interrupting the closed-loop sensory feedback between the brain (motor control) and the hand (sensory feedback through the nerves). The lack of feedback requires significant cognitive efforts from the user in order to do basic gestures and daily activities. To this aim, recently, there has been significant development in the provision of sensory feedback from transradial prosthetic hands, to enable the user take part in the control loop and improve user embodiment. Sensory feedback to the hand users can be provided via invasive and noninvasive methods. The latter includes the use of temperature, vibration, mechanical pressure and skin stretching, electrotactile stimulation, phantom limb stimulation, audio feedback, and augmented reality. This paper provides a comprehensive review of the non-invasive methods, performs their critical evaluation, and presents challenges and opportunities associated with the non-invasive sensory feedback methods

Automatic Affect Perception Based on Body Gait and Posture: A Survey

There has been a growing interest in machine-based recognition of emotions from body gait and its combination with other modalities. In order to highlight the major trends and state of the art in this area, the literature dealing with machine-based human emotion perception through gait and posture is explored. Initially the effectiveness of human intellect and intuition in perceiving emotions in a range of cultures is examined. Subsequently, major studies in machine-based affect recognition are reviewed and their performance is compared. The survey concludes by critically analysing some of the issues raised in affect recognition using gait and posture, and identifying gaps in the current understanding in this area

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

A survey on what Australians with upper limb difference want in a prosthesis: justification for using soft robotics and additive manufacturing for customized prosthetic hands

Purpose: Upper limb prostheses are part of a rapidly changing market place. Despite development in device design, surveys report low levels of uptake and dissatisfaction with current prosthetic design. In this study, we present the results of a survey conducted with people with upper limb difference in Australia on their use of current prostheses and preferences in a prosthetic in order to inform future prosthetic hand design. Methods: An online survey was conducted on upper limb amputees, with 27 respondents that completed the survey. The survey was a mixture of open-ended questions, ranking design features and quantitative questions on problems experienced and desired attributes of future prosthesis designs. Results: Common key issues and concerns were isolated in the survey related to the weight, manipulation and dexterity, aesthetics, sensory feedback and financial cost; each of which could be addressed by additive manufacturing and soft robotics techniques. Conclusions: The adaptability of additive manufacturing and soft robotics to the highlighted concerns of participants shows that further research into these techniques is a feasible method to improve patient satisfaction and acceptance in prosthetic hands.Implications for rehabilitation Even with recent developments and advances in prosthetic design, the needs and desires of prosthetic users are not being met with current products. The desires and needs of those with upper limb difference are diverse. Using additive manufacturing to produce prosthetics allows for mass customization of prosthetics to meet these diverse needs while reducing costs. A soft robotic approach to prosthetics can help meet the desires of reducing weight and costs, while maintaining functionality