Implementation of a Biometric Interface in Voice Controlled Wheelchairs

In order to assist physically handicapped persons in their movements,we developed an embedded isolated word speech recognition system(ASR)applied to voice control of smart wheelchairs.However,in spite of the existence in the industrial market of several kinds of electric wheelchairs,the problem remains the need to manually control this device by hand via joystick;which limits their use especially by people with severe disabilities.Thus,a significant number of disabled people cannot use a standard electric wheelchair or drive it with difficulty.The proposed solution is to use the voice to control and drive the wheelchair instead of classical joysticks.The intelligent chair is equipped with an obstacle detection system consisting of ultrasonic sensors,a moving navigation algorithm and a speech acquisition and recognition module for voice control embedded in a DSP card.The ASR architecture consists of two main modules.The first one is the speech parameterization module(features extraction)and the second module is the classifier which identifies the speech and generates the control word to motors power unit.The training and recognition phases are based on Hidden Markov Models(HMM),K-means,Baum-Welch and Viterbi algorithms.The database consists of 39 isolated speaker words(13 words pronounced 3 times under different environments and conditions).The simulations are tested under Matlab environment and the real-time implementation is performed by C language with code composer studio embedded in a TMS 320 C6416 DSP kit.The results and experiments obtained gave promising recognition ratio and accuracy around 99%in clean environment.However,the system accuracy decreases considerably in noisy environments,especially for SNR values below 5 dB(in street:78%,in factory:52%).

Basketball Brings Joy to People on Wheelchairs

Though it was early spring in Tibet, with snow still covering the distant mountains and a chill in the air, a group of Tibetans in wheelchairs hardly noticed the cold as they enthusiastically played basketball.

Wanting a Life in Decency!—A Qualitative Study from Experienced Electric Wheelchairs Users’ perspective

Background: The functionality and the safety of the electric wheelchairs were essential for users’ everyday life. Some evidence indicated that the wheelchair Per Se highly influenced users’ occupational life, their personal identity and social life;further, the wheelchair became an extension of the body and more than a technical device. Besides, there was still both environmental and self-efficacy or/and mental health factors obstacles for full social participation. Even so, there was to some extent stigma related to being a wheelchair user. There was a need to reflect users’ perspective on being depended on electric wheelchair. The aim, accordingly, was to describe and to get a deeper insight into electric wheelchairs users’ perspective and experiences of utilizing this device;a qualitative design with an inductive approach was used. Method: Qualitative latent and interpretative content analysis [1] [2] was used after repeated face-to-face semi-structured interviews with three experienced Swedish electric wheelchair users during the autumn 2017. Findings: The findings showed a high degree of dependability of the assistants that supported the users, and of the quality of that working relationship. The findings were formulated, abstracted and interpreted in several steps. It showed one theme of meaning: “Living in a space shifting between potential violation of or respect for human dignity”. Conclusion: The study showed that electric wheelchair users were relatively content with their lives as well as with their devices in turns of mobility and accessibility, but the meaning of their narrations showed a life at constant risk of having the respect of human rights and human respect violated. Besides, the importance of having access to good and high quality devices, good staffing, and environmental support, all in concordance with human rights, the clinical and practical implications of this study narrows down to a question of encountering the other person as a whole and worthy individual.

Enhancing the Efficiency of Voice Controlled Wheelchairs Using NAM for Recognizing Partial Speech in Tamil

In this paper, we have presented an effective method for recognizing partial speech with the help of Non Audible Murmur (NAM) microphone which is robust against noise. NAM is a kind of soft murmur that is so weak that even people nearby the speaker cannot hear it. We can recognize this NAM from the mastoid of humans. It can be detected only with the help of a special type of microphone termed as NAM microphone. We can use this approach for impaired people who can hear sound but can speak only partial words (semi-mute) or incomplete words. We can record and recognize partial speech using NAM microphone. This approach can be used to solve problems for paralysed people who use voice controlled wheelchair which helps them to move around without the help of others. The present voice controlled wheelchair systems can recognize only fully spoken words and can’t recognise words spoken by semi-mute or partially speech impaired people. Further it uses normal microphone which hassevere degradation and external noise influence when used for recognizing partial speech inputs from impaired people. To overcome this problem, we can use NAM microphone along with Tamil Speech Recognition Engine (TSRE) to improve the accuracy of the results. The proposed method was designed and implemented in a wheelchair like model using Arduino microcontroller kit. Experimental results have shown that 80% accuracy can be obtained in this method and also proved that recognizing partially spoken words using NAM microphone was much efficient compared to the normal microphone.

Efficient Body-Transfer Wheelchair for Assisting Functionally Impaired People

Functionally impaired people always have difficulty accomplishing activities of daily living.In this regard,tasks including toileting and bathing have a higher prevalence rate of injuries and greater risk of falling.In this study,a body-transfer wheelchair was developed to assist people in transferring from bed to wheelchair for bathing,and toileting.The bodytransfer wheelchair is a semi-automatic wheelchair that has features such as a controlled leg and backrest,linkage commode slot,and height adjustment.The wheelchair consists of a seat and a main frame that can be detached to enable bathtub transfer.This mechanism lets the user stay on the seat while being transferred into the bathtub without any risk of falling.A linkage mechanism was developed as a part of the seat for ease of toileting.Kinematic and force analysis was conducted to calculate the force required for each actuator.It has been proved by the experimental results that the wheelchair can securely and comfortably transfer a patient from the bed to the toilet or bathtub.A survey has been conducted to evaluate the wheelchair prototype design idea.Two focus groups were chosen:one comprised of functionally impaired people,and the other comprised of caregivers.The results of the survey show that 60%of both functionally impaired people and caregivers would like to use the body-transfer wheelchair for toileting and bathing purpose.Additionally,on average 65%of both focus groups find it convenient to operate the body-transfer wheelchair independently.

Review on Development of Pressure Injury Prevention Fabric

Pressure injury is a common postoperative complication of wheelchair users. It has a high incidence rate and can induce sepsis and even death. The fabrics that touch patients’ skin directly have a profound impact on their skin surfaces. This review summarizes the research in the last five years on the relationship between pressure injuries and fabrics. Following the preferred reporting items for systematic reviews and meta-analyses(PRISMA) statement, a systematic literature search is conducted in nine databases, including SCI(Web of Science), IEEE, ASTM, Taylor & Francis, ProQuest, Wiley, SpringerLink, PubMed and SAGE. The research objects, experimental equipment and survey results are investigated in this review, in which twenty-four different textiles and seven different test methodologies are involved. The test methodologies include five kinds of performance tests and two kinds of observational studies. Two studies showed that the particular fabric was helpful to reduce the pressure on the skin surface, and twelve studies revealed that the multi-layer fabric with good air permeability, heat dissipation and moisture dissipation was helpful to prevent pressure injury. This review confirms the correlation between the fabric properties and the occurrence of postoperative pressure injury in wheelchair users. Further experiments are needed to reasonably integrate the fabric characteristics of pressure injury prevention into the mass-produced pressure injury prevention clothes for wheelchair users.

Hand rim wheelchair training: Effects of intensity and duration on physical capacity

The purpose of this study was to compare the effects of intensity and duration of training on physical capacity in a 7 weeks hand rim wheelchair training in able-bodied men. Thirty-six able-bodied men participated in three groups: a 30% heart rate reserve (HRR) 70 min training group (N = 14), a 70% HRR 30 minutes training group (N = 13) and a 30% HRR 30 minutes training group (N = 9). All groups trained 3 times per week for 7 weeks on a treadmill. Pre and post tests on a wheelchair ergometer comprised a submaximal test at 20% and 40% of the estimated peak power output, in which submaximal heart rate, oxygen uptake and mechanical efficiency were determined. In maximal exercise tests, maximal isometric strength, sprint power, peak power output and peak oxygen uptake were measured. No significant differences were found between the training groups on submaximal and maximal parameters. It can be concluded that, in persons new to wheelchair use, seven weeks of wheelchair endurance training at an intensity of 30% HRR for 30 minutes is as effective as a training at a higher intensity (70% HRR) or with a longer duration (70 min).

Study on Characteristics of the Wheelchair-User Combination

To summarize the characteristics of wheelchair-user combination, this paper studied wheelchairs, wheelchair users, nursing staffs and interaction relationship between them. Firstly, the findings of some research on wheelchairs and wheelchair users were investigated, and the studies in four aspects of wheelchairs and their accessories, wheelchair users, wheelchairs and wheelchair users (man-machine system), and skills training for the performance of wheelchair were reviewed. Then “wheelchair-user combination” was put forward based on the relationship between wheelchairs and wheelchair users in real life, and the “wheelchair-user combination” was divided into “WUs-Ws system” and “WUs-Ws-NSs system” according to whether the nursing staffs were needed. Finally, this paper analytically studied the characteristics of wheelchair users, characteristics in use of wheelchair and characteristics of nursing staffs, as well as put forward the characteristics of the wheelchair-user combination.

Measurement of the Wheelchair-Operating Time Spent by Stroke Patients Using a New Triaxial Accelerometer System

Purpose: We investigated the validity of a triaxial accelerometer system for measuring the time spent lying down, sitting, standing, walking, and operating a wheelchair by control subjects and stroke patients in a convalescence ward. Methods: Physical activities were measured using a new triaxial accelerometer system (A-MES;Activity Monitoring and Evaluation System) that consists of two sensors, a station, and analytical software used with a personal computer. In Experiment 1, the times that the healthy subjects (n = 12) spent operating a wheelchair, lying down, sitting, standing, and walking were measured both by the A-MES and by videotaping (video time). In Experiment 2, the amounts of time spent by the stroke patients not able to walk without support (n = 30) as they were lying down, sitting, standing, walking, and operating a wheelchair were measured by the A-MES. Results: The time spent operating a wheelchair measured with the A-MES was significantly correlated with the video time in the healthy subjects. The stroke patients’ average times (minutes) of total, operating a wheelchair, lying down, sitting, standing, and walking were 601.0 ± 18.1, 57.1 ± 28.8, 265.0 ± 86.3, 263.3 ± 60.6, 7.8 ± 7.0, and 7.7 ± 6.0, respectively. Conclusions: The A-MES accurately evaluated the stroke patients’ time spent operating a wheelchair. The stroke patients’ mean time spent operating a wheelchair over the course of one day was 57.1 ± 28.8 min in a Center for Rehabilitation.

Mechanics analysis of a wheelchair robot with wheel-track coupling mechanism

A barrier-free wheelchair robot with a mechanism coupled by wheel and track is presen- ted in this paper. Using the wheelchair, the lower limb disabled persons could be more relaxed to take part in outdoor activities whether on flat ground or stairs and obstacles in the city. The wheel- track coupling mechanism is designed and the stability of the bodywork of the wheelchair robot on the stairs is analyzed. In order to obtain the stability of wheelchair robot when it climbs obstacles, centroid projection method is applied to analyze the static stability, stability margin is proposed to provide the stability under some dynamic forces, and the push rod rotation angle in terms of the guaranteed stability margin is given. Finally, the dynamic model of the wheelchair robot based on Lagrange equation is established, which can be a theoretical foundation for the wheelchair control system design.

Electric Wheelchair Control System Using Brain-Computer Interface Based on Alpha-Wave Blocking

A brain-computer interface(BCI)-based electric wheelchair control system was developed, which enables the users to move the wheelchair forward or backward, and turn left or right without any pre-learning. This control system makes use of the amplitude enhancement of alpha-wave blocking in electroencephalogram(EEG) when eyes close for more than 1 s to constitute a BCI for the switch control of wheelchair movements. The system was formed by BCI control panel, data acquisition, signal processing unit and interface control circuit. Eight volunteers participated in the wheelchair control experiments according to the preset routes. The experimental results show that the mean success control rate of all the subjects was 81.3%, with the highest reaching 93.7%. When one subject's triggering time was 2.8 s, i.e., the flashing time of each cycle light was 2.8 s, the average information transfer rate was 8.10 bit/min, with the highest reaching 12.54 bit/min.

The Design of Wheelchair Lifting Mechanism and Control System

In order to achieve a wheelchair lift function, this paper designs a tri-scissors mechanism. Through the so-called H-type transmission and L-type swing rod, the three scissors mechanisms lift in the same rate with only one liner motor while ensuring the stability of the lift. Finite element analysis in ANSYS is performed to verify the material strength. The control system with Sunplus SCM achieves the voice control of wheelchair walking and lifting.

Navigation system for a smart wheelchair

Recent results on the development of a navigation system for a smart wheelchair are presented in this paper. In order to reduce the development cost, a modular solution is designed by using commercial and low cost devices. The functionalities of the tracking control system are described. Experimental results of the proposed assistive system are also presented and discussed.

IP Mobility Issues for a Mobile Tele-Robotic System-NEPWAK

The network-centric applied research team (N-CART) is continuing its work on an ambitious project known as the network-enabled powered wheelchair adaptor kit (NEPWAK). It introduces techniques for modifying and using powered wheelchairs as mobile platforms enabling communication and remote control. The wheelchair is equipped with a laptop computer, a CCD camera and a wireless network interface card (NIC) for 802.11b Internet access. The laptop acts as a server allowing network clients to gain access through a custom control interface on the chair. The remote controlling client receives a video and audio feed from the chair and sends control signals for maneuvering. While traveling, the chair is able to change its network association from one access point (AP) to another within the same subnet-the process is known as handoff. However, there is no inter-network handoff mechanism presently available in IP networks. This restricts the mobility of the wheelchair to within the coverage area of the subnet APs. This paper shows that the Internet engineering task force’s (IETF) network layer mobility protocol—Mobile IP suffers from large handoff latencies that can hinder communication between the client and the wheelchair during handoff. Mobile IP alone is not a sufficient solution for a mobile telebotic system such as NEPWAK. An interesting solution to the handoff latency problem comes from the Fast-handover protocol described in Section 4.4 with simulation results in Section 6.2.

Development of Voice Control Algorithm for Robotic Wheelchair Using MIN and LSTM Models

In this work,we developed and implemented a voice control algorithm to steer smart robotic wheelchairs(SRW)using the neural network technique.This technique used a network in network(NIN)and long shortterm memory(LSTM)structure integrated with a built-in voice recognition algorithm.An Android Smartphone application was designed and configured with the proposed method.A Wi-Fi hotspot was used to connect the software and hardware components of the system in an offline mode.To operate and guide SRW,the design technique proposed employing five voice commands(yes,no,left,right,no,and stop)via the Raspberry Pi and DC motors.Ten native Arabic speakers trained and validated an English speech corpus to determine the method’s overall effectiveness.The design method of SRW was evaluated in both indoor and outdoor environments in order to determine its time response and performance.The results showed that the accuracy rate for the system reached 98.2%for the five-voice commends in classifying voices accurately.Another interesting finding from the real-time test was that the root-mean-square deviation(RMSD)for indoor/outdoor maneuvering nodes was 2.2∗10–5(for latitude),while that for longitude coordinates was a whopping 2.4∗10–5(for latitude).

A navigation method based on POMDP for smart wheelchair in uncertain environments

A navigation method based on the partially observable markov decision process （POMDP） for smart wheelchairs in uncertain environments is presented in this paper. The design key factors for the navigation system of a smart wheelchair are discussed. A kinematics model of the smart wheelchair is given, and the model and principle of POMDP are introduced. In order to respond in uncertain local environments, a novel navigation methodology based on POMDP using the sensors perception and the user＇s joystick input is presented. The state space, the action set, the observations and the sensor fusion of the navigation method are given in detail, and the optimal policy of the POMDP model is proposed. Experimental results demonstrate the feasibility of this navigation method. Analysis is also conducted to investigate performance evaluation, advantages of the approach and potential generalization of this paper.

Influence of Wheelchair Cushions Fabricated by Therapists on Stability, Comfort, and Functionality

“Ease of comfort” and “functionality” are important factors that have been cited to improve wheelchair seating. The ability to maintain balance and posture while seated in a wheelchair improves stability, comfort, and functionality and is a prerequisite for daily activities. In this study, the authors used a sitting position measuring device to scientifically verify differences in sitting posture, comfort, and functionality depending on the presence or absence of cushions and the type of cushion in elderly individuals who used wheelchairs. Results suggested that a cushion fabricated by a therapist was more useful than a commercially available air cushion. While a commercially available air cushion was the most suitable, the therapist’s self-made cushion could be expected to demonstrate the same or better applicability than an air cushion.

Clothing Needs for Wheelchair Users: A Systematic Literature Review

The aim of this study was to identify the clothing needs of wheelchair users using relevant literatures in a global scale and to design a method to classify the clothing needs into a unified system, in order to generate a map of wheelchair users’ clothing needs with the information from multiple resources. The paper reviewed the previous studies about clothing needs and preference of wheelchair users. A three-tier screening was designed to extract main findings from the relevant literature. Content analysis and statistical analysis were used to integrate the information and identify implications. Information was categorized to represent the attributes of the clothing needs. The paper provides comprehensive insights about the specific barriers and abstract demands about the clothing needs of wheelchair users regarding their preference for apparel products. Eight essential attributes relating to the clothing needs of wheelchair users were identified: functional needs, fit attribute fabric and fiber, safety issue, aesthetic needs, expressive needs, quality of life, and extrinsic attributes. The attributes were classified into two general domains, reflecting the physical challenges and psychological desires of wheelchair users.

Office Furniture Design for Wheelchair User

There are an estimated 1.19 million wheelchair users in Spain. People use wheelchairs for a variety of reasons, the most common one is paralysis from spinal cord injuries. Current estimates indicate there are around 504,000 people alive in Spain with spinal cord injuries. Among other reasons for using wheelchairs are： fatigue from multiple sclerosis, muscle weakness from muscular dystrophy, lower limb spasticity from cerebral palsy, and missing limbs due to amputation. People who use wheelchairs may encounter a variety of obstacles at their workstations depending on their limitations. Some possible accommodations could be adjustable height desk or table for a person who cannot work comfortably at an existing desk, accessible filing system or office supplies, and frequently used materials on most accessible shelves or drawers for a person who cannot reach upper and lower shelves and drawers. This paper presents the graphical design of a workstation for wheelchair users, in this case, technical, anthropometric, ergonomic, aesthetics and scientists aspects have been analyzed. The design of composite structure conduct to explicit safety constraints applied to office furniture requirements kept continuously current and updated as part of innovation. Finally, results are showed in a three-dimensional model.

Mean Threshold and ARNN Algorithms for Identification of Eye Commands in an EEG-Controlled Wheelchair

This paper represented Autoregressive Neural Network (ARNN) and meant threshold methods for recognizing eye movements for control of an electrical wheelchair using EEG technology. The eye movements such as eyes open, eyes blinks, glancing left and glancing right related to a few areas of human brain were investigated. A Hamming low pass filter was applied to remove noise and artifacts of the eye signals and to extract the frequency range of the measured signals. An autoregressive model was employed to produce coefficients containing features of the EEG eye signals. The coefficients obtained were inserted the input layer of a neural network model to classify the eye activities. In addition, a mean threshold algorithm was employed for classifying eye movements. Two methods were compared to find the better one for applying in the wheelchair control to follow users to reach the desired direction. Experimental results of controlling the wheelchair in the indoor environment illustrated the effectiveness of the proposed approaches.