An asynchronous wheelchair control by hybrid EEG–EOG brain–computer interface

Wheelchair control requires multiple degrees of freedom and fast intention detection, which makes electroencephalography (EEG)-based wheelchair control a big challenge. In our previous study, we have achieved direction (turning left and right) and speed (acceleration and deceleration) control of a wheelchair using a hybrid brain–computer interface (BCI) combining motor imagery and P300 potentials. In this paper, we proposed hybrid EEG-EOG BCI, which combines motor imagery, P300 potentials, and eye blinking to implement forward, backward, and stop control of a wheelchair. By performing relevant activities, users (e.g., those with amyotrophic lateral sclerosis and locked-in syndrome) can navigate the wheelchair with seven steering behaviors. Experimental results on four healthy subjects not only demonstrate the efficiency and robustness of our brain-controlled wheelchair system but also indicate that all the four subjects could control the wheelchair spontaneously and efficiently without any other assistance (e.g., an automatic navigation system).     

Robust Brain-computer Interface for virtual Keyboard (RoBIK): Project results

Brain-Computer Interface (BCI) is a technology that translates the brain electrical activity into a command for a device such as a robotic arm, a wheelchair or a spelling device. BCIs have long been described as an assistive technology for severely disabled patients because they completely bypass the need for muscular activity. The clinical reality is however dramatically different and most patients who use BCIs today are doing so as part of constraining clinical trials. To achieve the technological transfer from bench to bedside, BCI must gain ease of use and robustness of both measure (electroencephalography [EEG]) and interface (signal processing and applications). The Robust Brain-computer Interface for virtual Keyboard (RoBIK) project aimed at the development of a BCI system for communication that could be used on a daily basis by patients without the help of a trained team of researchers. To guide further developments clinicians first assessed patients’ needs. The prototype subsequently developed consisted in a 14 felt-pad electrodes EEG headset sampling at 256 Hz by an electronic component capable of transmitting signals wirelessly. The application was a virtual keyboard generating a novel stimulation paradigm to elicit P300 Evoked Related Potentials (ERPs) for communication. Raw EEG signals were treated with OpenViBE open-source software including novel signal processing and stimulation techniques.     

Gifa V. 4: A complete package for NMR data set processing

Summary The Gifa program is designed for processing, displaying and analysing 1D, 2D and 3D NMR data sets. It has been constructed in a modular fashion, based on three independent modules: a set of commands that perform all the basic processing operations such as apodisation functions, a complete set of Fourier Transforms, phasing and baseline correction, peak-picking and line fitting, linear prediction and maximum entropy processing; a set of command language primitives that permit the execution of complex macro commands; and a set of graphic commands that permit to build a complete graphic user interface, allowing the user to interact easily with the program. We have tried to create a versatile program that can be easily extended according to the user's requirements and that is adapted to a novice as well as an experienced user. The program runs on any UNIX computer, with or without graphic display, in interactive or batch mode.     

Human-Machine Interface for the Control of Multi-Function Systems Based on Electrocutaneous Menu: Application to Multi-Grasp Prosthetic Hands

Modern assistive devices are very sophisticated systems with multiple degrees of freedom. However, an effective and user-friendly control of these systems is still an open problem since conventional human-machine interfaces (HMI) cannot easily accommodate the system’s complexity. In HMIs, the user is responsible for generating unique patterns of command signals directly triggering the device functions. This approach can be difficult to implement when there are many functions (necessitating many command patterns) and/or the user has a considerable impairment (limited number of available signal sources). In this study, we propose a novel concept for a general-purpose HMI where the controller and the user communicate bidirectionally to select the desired function. The system first presents possible choices to the user via electro-tactile stimulation; the user then acknowledges the desired choice by generating a single command signal. Therefore, the proposed approach simplifies the user communication interface (one signal to generate), decoding (one signal to recognize), and allows selecting from a number of options. To demonstrate the new concept the method was used in one particular application, namely, to implement the control of all the relevant functions in a state of the art commercial prosthetic hand without using any myoelectric channels. We performed experiments in healthy subjects and with one amputee to test the feasibility of the novel approach. The results showed that the performance of the novel HMI concept was comparable or, for some outcome measures, better than the classic myoelectric interfaces. The presented approach has a general applicability and the obtained results point out that it could be used to operate various assistive systems (e.g., prosthesis vs. wheelchair), or it could be integrated into other control schemes (e.g., myoelectric control, brain-machine interfaces) in order to improve the usability of existing low-bandwidth HMIs.     

Intelligent Touchscreen Joystick for Controlling Electric Wheelchair

Background

The objective of this research was to design, implement, use and evaluate a human-machine touch interface for driving an electric wheelchair. This new interface allows control of the electric wheelchair with touch screen smartphone technologies (android, IOS or Windows phone). In addition, an intelligent calibration algorithm, based on the neural network (NN), is implemented in this interface to overcome manoeuvring problems, namely the inability to move correctly in one or more directions.

ARMEN: Assistive robotics to maintain elderly people in natural environment

This document presents the research project ARMEN aiming at the conception of an assistive robot very simple to use and providing advanced functions to help maintaining disabled or elderly people at home. The document presents the robot SAM and the functions of navigation, of emotion detection from speech, of image understanding, the knowledge representation and the avatar conceived for the supervision of the robot in an intuitive way. The document presents the results of the technical evaluations made showing the interest and potential of these functions for practical applications. The document presents the clinic evaluations that will take place soon to validate the development made with elderly and handicapped people in a therapeutic setting. The protocol used for these evaluations is described before the presentation of conclusions evoking the perspective of the project.     

HFs/ergonomics of assistive technology

An assistive device is designed to accommodate the special needs of disability that can help people with physical, mental or cognitive challenges go through their day-to-day activities with less difficulty. An assistive device usually provide alternatives to functional limitations imposed by the client's disorder, and thereby minimising rehabilitation costs. It is therefore important to know about how assistive technology will function in all the possible aspects of such disabilities and impairements. When designing a technical device, particularly in conjunction with the target user group, ergonomic issues are therefore important to find out the extent to which an assistive device is convenient or not, and to check the quality performance of assistive technology. Since the question of the match or mismatch of an assistive device and a disabled person requires much attention, it is therefore suggested that paying attention on how an assistive device be ergonomically designed and developed is important. Ergonomic applications are to be applied for increasing motivation of prospective customers through innovative performance of AT. The authors believe that there are opportunities in ergonomic applications to manufacture an assistive device as unique, cost saving, and allows less exertation and reduces energy consumption when it is used. Hence this paper highlights human factors and/or ergonomics consideration in the process of design and development of assistive devices synchronising with gerontechnological research and development aiming to emphasise user's requirement.     

When mental fatigue maybe characterized by Event Related Potential (P300) during virtual wheelchair navigation

The goal of this study is to investigate the influence of mental fatigue on the event related potential P300 features (maximum pick, minimum amplitude, latency and period) during virtual wheelchair navigation. For this purpose, an experimental environment was set up based on customizable environmental parameters (luminosity, number of obstacles and obstacles velocities). A correlation study between P300 and fatigue ratings was conducted. Finally, the best correlated features supplied three classification algorithms which are MLP (Multi Layer Perceptron), Linear Discriminate Analysis and Support Vector Machine. The results showed that the maximum feature over visual and temporal regions as well as period feature over frontal, fronto-central and visual regions were correlated with mental fatigue levels. In the other hand, minimum amplitude and latency features didn’t show any correlation. Among classification techniques, MLP showed the best performance although the differences between classification techniques are minimal. Those findings can help us in order to design suitable mental fatigue based wheelchair control.     

MODEM: a multi-agent hierarchical structure to model the human motor control system

In this study, based on behavioral and neurophysiological facts, a new hierarchical multi-agent architecture is proposed to model the human motor control system. Performance of the proposed structure is investigated by simulating the control of sit to stand movement. To develop the model, concepts of mixture of experts, modular structure, and some aspects of equilibrium point hypothesis were brought together. We have called this architecture MODularized Experts Model (MODEM). Human motor system is modeled at the joint torque level and the role of the muscles has been embedded in the function of the joint compliance characteristics. The input to the motor system, i.e., the central command, is the reciprocal command. At the lower level, there are several experts to generate the central command to control the task according to the details of the movement. The number of experts depends on the task to be performed. At the higher level, a “gate selector” block selects the suitable subordinate expert considering the context of the task. Each expert consists of a main controller and a predictor as well as several auxiliary modules. The main controller of an expert learns to control the performance of a given task by generating appropriate central commands under given conditions and/or constraints. The auxiliary modules of this expert learn to scrutinize the generated central command by the main controller. Auxiliary modules increase their intervention to correct the central command if the movement error is increased due to an external disturbance. Each auxiliary module acts autonomously and can be interpreted as an agent. Each agent is responsible for one joint and, therefore, the number of the agents of each expert is equal to the number of joints. Our results indicate that this architecture is robust against external disturbances, signal-dependent noise in sensory information, and changes in the environment. We also discuss the neurophysiological and behavioral basis of the proposed model (MODEM).     

Wheelchair-mounted integrated control systems for multiply handicapped people

Integrated control systems allow disabled people access to multiple functions from a single input device (for example a set of switches). Multiply handicapped users are thereby able to switch efficiently between wheelchair control, communication, computer access and control of their environment, without third-party help. Integrated systems have been developed for multiply handicapped children and adults in the Barnsley area. The design philosophy has concentrated upon utilizing, wherever possible, commercially available assistance devices and remotely controlling these via logic-based integrated control systems tailored to the needs and abilities of the individual client. This approach presents few problems as the inputs to commercially available devices are often based on simple switch control. The systems already supplied have proved, after an initial training period, to be easy to operate and have led to a considerable improvement in quality of life for the users. Computer-based, wheelchair-mounted integrated systems are now being developed. A prototype system currently emulates the logic-based controllers described above, employing the screen to display information on the current status of the system. Future development will move toward a more flexible system which will be able to read a variety of input signals and control a large number of outputs. The system will also have the facility to utilize software-based communications, keyboard emulation and environmental control packages as well as business and education software. Such a system could be easily set up, via software, for use by any disabled person.     

Floor anchorage load and safety space for adult wheelchair users during a crash

Over the last 20 years in France as well as generally in Europe and also in North America, the integration of disabled people into society has become a more and more pressing issue. Work is in progress to increase the safety level of wheelchair occupants up to becoming equivalent to that of able-bodied road vehicles occupants. Present world practices are that wheelchair occupants who are unable to transfer to a vehicle seat for transportation remain in their wheelchair, which is secured to the vehicle floor using tie downs, and the occupant is restrained in the wheelchair. The aim of this paper was to perform a series of crash tests to make sure that the current standards are suitable to identify possible failures in safety in the restraint systems intended for wheelchair users. To date, there is no specific regulatory criterion related to floor anchorage for wheelchairs in vehicles during a crash. At a 48 km/h crash test, loads reached 30 kN on rear anchorage, and 13 kN on shoulder belt. Also the kinematics analysis of the wheelchair user during impact pointed out dimension of his safety space.     

A Preliminary Study of the Noninvasive Remote Control System for Rat Bio-Robot

<正> A system is described here that can noninvasively control the navigation of freely behaving rat via ultrasonic,epidermaland LED photic stimulators on the back.The system receives commands from a remote host computer to deliver specifiedelectrical stimulations to the hearing,pain and visual senses of the rat respectively.The results demonstrate that the three stimuliwork in groups for the rat navigation.We can control the rat to proceed and make right and left turns with great efficiency.Thisexperiment verified that the rat was able to reach a setting destination in the way of cable with the help of a person through theappropriate coordination of the three stimulators.The telemetry video camera mounted on the head of the rat also achieveddistant image acquisition and helped to adjust its navigation path over a distance of 300 m.In a word,the non-invasive motioncontrol navigation system is a good,stable and reliable bio-robot.     

Preferred elbow position in confined wheelchair configuration

High mechanical load leads to pain and damage in the upper extremities of wheelchair users. Wheelchair users suffer a limited range of motion of the upper extremities due to the confining wheelchair configuration. This is a key factor affecting the efficiency of wheelchair propulsion and upper extremity loading. With a view toward further understanding the interaction between the user and wheelchair, this study identifies the accessible workspace of the elbow under conventional wheelchair design and identifies the actual location and range of motion of the elbow during wheelchair propulsion. An eight-camera motion analysis system recorded the kinematics of 14 non-experienced wheelchair users. Users under standardized conservative wheelchair-sitting position moved their right elbow as widely as possible at five different wheel angles while elbow positions were recorded, thereby establishing the maximum possible elbow workspace. Actual positions of the right elbow were recorded during wheelchair propulsion. The arc angles of the elbow workspace range from 68.8° to 83.4° and are located at the lateral and posterior quadrant of the circle on which the elbow trajectories located. Reachable workspace is smaller when the hand holds the hand rim at a larger wheel angle. The preferred positions for propulsion are located approximately 2/3's of the way through the total workspace. The obtained data will be useful for improved wheelchair design and biomechanical modeling of the wheelchair/user system.     

A new dynamic model of the wheelchair propulsion on straight and curvilinear level-ground paths

Independent-roller ergometers (IREs) are commonly used to simulate the behaviour of a wheelchair propelled in a straight line. They cannot, however, simulate curvilinear propulsion. To this effect, a motorised wheelchair ergometer could be used, provided that a dynamic model of the wheelchair–user system propelled on straight and curvilinear paths (WSC) is available. In this article, we present such a WSC model, its parameter identification procedure and its prediction error. Ten healthy subjects propelled an instrumented wheelchair through a controlled path. Both IRE and WSC models estimated the rear wheels' velocities based on the users' propulsive moments. On curvilinear paths, the outward wheel shows root mean square (RMS) errors of 13% in an IRE vs 8% in a WSC. The inward wheel shows RMS errors of 21% in an IRE vs 11% in a WSC. Differences between both models are highly significant (p < 0.001). A wheelchair ergometer based on this new WSC model will be more accurate than a roller ergometer when simulating wheelchair propulsion in tight environments, where many turns are necessary.     

Children in wheelchairs.

Three hundred and seventy-five families replied to a questionnaire about the use of their disabled children''s wheelchairs. Many problems were found, such as difficulty in folding the chair and placing it in the car boot and difficulty in using pulbic transport. These families need adequate guidance to anticipate and deal with the problems. Provision of a wheelchair does not solve the mobility problems. The parents are faced with the task of transporting both the disabled child and the wheelchair whenever they want to use their own car or public transport. Ease of folding and lightness are important criteria for wheelchairs carried by cars. Parents need careful guidance about selecting suitable cars and also need to be shown how to lift the chairs without endangering their backs. Such advice should be provided by every wheelchair clinic and assessment and rehabilitation certre.     

Datac: A multipurpose biological data analysis program based on a mathematical interpreter

The use of a mathematical command interpreter combined with the structural facility of the C-language allowed us to design a data treatment program having considerable flexibility and being able to handle any types of data (electrophysiological, biochemical and theoretical data). Ensembles of data are treated by the interpreter as if they were simple variables so that an elaborate computation can be performed on the spot by simply writing the appropriate equation on the terminal. These facilities combined with the ability of editing macrocommands at run time provide the user with data treatment possibilities that extends far beyond the possibilities actually implemented in the program. The originality of this program is that the user can easily implement the commands he most often needs, writing them in a language that most scientists will know, algebra.     

Surface EMG pattern recognition for real-time control of a wrist exoskeleton

Background  

Surface electromyography (sEMG) signals have been used in numerous studies for the classification of hand gestures and movements and successfully implemented in the position control of different prosthetic hands for amputees. sEMG could also potentially be used for controlling wearable devices which could assist persons with reduced muscle mass, such as those suffering from sarcopenia. While using sEMG for position control, estimation of the intended torque of the user could also provide sufficient information for an effective force control of the hand prosthesis or assistive device. This paper presents the use of pattern recognition to estimate the torque applied by a human wrist and its real-time implementation to control a novel two degree of freedom wrist exoskeleton prototype (WEP), which was specifically developed for this work.     

Motor Imagery for Severely Motor-Impaired Patients: Evidence for Brain-Computer Interfacing as Superior Control Solution

Brain-Computer Interfaces (BCIs) strive to decode brain signals into control commands for severely handicapped people with no means of muscular control. These potential users of noninvasive BCIs display a large range of physical and mental conditions. Prior studies have shown the general applicability of BCI with patients, with the conflict of either using many training sessions or studying only moderately restricted patients. We present a BCI system designed to establish external control for severely motor-impaired patients within a very short time. Within only six experimental sessions, three out of four patients were able to gain significant control over the BCI, which was based on motor imagery or attempted execution. For the most affected patient, we found evidence that the BCI could outperform the best assistive technology (AT) of the patient in terms of control accuracy, reaction time and information transfer rate. We credit this success to the applied user-centered design approach and to a highly flexible technical setup. State-of-the art machine learning methods allowed the exploitation and combination of multiple relevant features contained in the EEG, which rapidly enabled the patients to gain substantial BCI control. Thus, we could show the feasibility of a flexible and tailorable BCI application in severely disabled users. This can be considered a significant success for two reasons: Firstly, the results were obtained within a short period of time, matching the tight clinical requirements. Secondly, the participating patients showed, compared to most other studies, very severe communication deficits. They were dependent on everyday use of AT and two patients were in a locked-in state. For the most affected patient a reliable communication was rarely possible with existing AT.     

Generation of variants of a motor act in a modular and hierarchical motor network

BACKGROUND: Most motor systems can generate a variety of behaviors, including categorically different behaviors and variants of a single motor act within the same behavioral category. Previous work indicated that many pattern-generating interneuronal networks may have a modular organization and that distinct categories of behaviors can be generated through flexible combinations of a small number of modules or building blocks. However, it is unclear whether and how a small number of modules could possibly generate a large number of variants of one behavior. RESULTS: We show that the modular feeding motor network of Aplysia mediates variations in protraction duration in biting-like programs. Two descending commands are active during biting behavior and trigger biting-like responses in a semiintact preparation. In the isolated CNS, when activated alone, the two commands produce biting-like programs of either long or short protraction duration by acting specifically on two modules that have opposite effects on protraction duration. More importantly, when coactivated at different frequencies, the two commands produce biting programs with an intermediate protraction duration. CONCLUSIONS: It was previously hypothesized that behavioral variants may be produced by combining different activity levels of multiple descending commands. Our data provide direct evidence for such a scheme and show how it is implemented in a modularly organized network. Thus, within a modular and hierarchical architecture, in addition to generating different categories of behavior, a small number of modules also efficiently implements variants of a single behavior.