Dissertations / Theses on the topic 'Electric powered wheelchairs'

While the active dynamic stability of automobiles has increased over the past 17 years there have been very few similar advances made with electrically powered wheelchairs. This lack of improvement has led to a long standing acceptance of less-than-optimal stability and control of these wheelchairs. Accidents due to loss of stability are well documented. Hence, the healthcare industry has made several efforts for improved control of electric powered wheelchairs (EPWs) to provide enhanced comfort, safety and manoeuvrability at a lower cost. In response, an area of stability control was identified that could benefit from a feedback control system using solid state sensors. To design an effective closed–loop feedback controller with optimal performance to overcome instabilities, an accurate model of wheelchair dynamics needed to be created. Such a model can be employed to test various controllers quickly and repeatedly, without the difficulties of physically setting a wheelchair up for each test. This task was one central goal of this research. A wireless test-bed of a front wheel drive (FWD) wheelchair was also developed to validate a dynamic wheelchair model. It integrates sensors, a data control system, an embedded controller, and the motorised mechanical system. The wireless communication ensures the integrity of sensor data collected and control signals sent. The test-bed developed not only facilitates the development of feedback controllers of motorised wheelchairs, but the collected data can also be used to confirm theories of causes of dynamic instabilities. The prototype test-bed performed the required tasks to satisfaction as defined by the sponsor. Data collected from live tests in which the test-bed followed set patterns, was processed and analysed. The patterns were designed to induce instability. The analysis revealed that an occupied wheelchair is more stable than an unoccupied wheelchair, disproving an initial instability theory proposed in this research. However, a proximal theory explaining over-steer is confirmed. Two models of the FWD test-bed were created. First, a dynamic model inherited from prior research, based on equations of motion was tested and enhanced based on measured data. However, even with alterations to correct parameter values and variables in the equations, a complete model validation was not possible. Second, a kinematic model was created with a factor to compensate for dynamics not normally accounted in kinematic models. The kinematic model was partially validated versus the measured data. Although, still highly accurate, there is room for improvement in this model. Both models contained a sub-system drive motor model, to account for input forces to the FWD wheelchair system model, which is fully validated.

A power assisted wheelchair combines human power, which is delivered by the arms through the pushrims, with electrical motors, which are powered by a battery. Today’s electric power assisted wheelchairs use force sensors to measure the torque exerted on the pushrims by the user. The force sensors in the pushrims are rather expensive and this approach also makes the wheels a little bit clumsy. The objective with this project is to find a new, better and cheaper solution that does not use expensive force sensors in the pushrims. The new power assisted wheelchair will instead only rely on its velocity, which is measured with rotational encoders, as feedback signal and thereby the project name “Torque Sensor Free Power Assisted Wheelchair”.

The project consisted of two main parts; an extensive construction part, where an ordinary joystick controlled motorized wheelchair has been rebuild to the new power assisted wheelchair without torque sensors and a development part, where different torque sensor free controllers has been designed, simulated, programmed and tested.

The project resulted in a torque sensor free power assisted wheelchair, where the final implemented design is a proportional derivative controller, which gives a very good assisting system that is robust and insensitive to measurement noise. The proportional derivative control design gives two adjustable parameters, which can be tuned to fit a certain user; one parameter is used to adjust the amplification of the user’s force and the other one is used to change the lasting time of the propulsion influence.

Since the new assisting control system only relies on the velocity, the torque sensor free power assisted wheelchair will besides giving the user assisting power also give an assistant, which pushes the wheelchair, additional power. This is a big advantage compared to the pushrim activated one, where this benefit for the assistant is not possible.

A quick-connect wheelchair power add-on unit (PAU) has been developed at the Human Factors Engineering Center of Virginia Tech. The objective of the new invention is to provide an inexpensive, highly portable product which can quickly convert a manual wheelchair into a power-operated wheelchair. This dissertation details the three year research and design effort to develop the new wheelchair PAU. Results are presented from a series of evaluations conducted to identify performance and user-interaction characteristics of the PAU. Interpretation of the results provides a prioritized list of identified design deficiencies along with wheelchair expert and design team suggestions for the next generation of design alterations. The three evaluations conducted with the second generation PAU prototype include a series of wheelchair expert interviews, a PAU performance evaluation, and a usability evaluation which utilized wheelchair operators as subjects. Also included in the dissertation is an explanation of the need for a new PAU, a description of the most recent design iteration, a literature review containing information about the history of wheelchairs, the condition of the current PAU market, and an analysis of wheelchair PAU consumers. The new invention was conceived and patented by Dr. John G. Casali of the Industrial and Systems Engineering (ISE) Department at Virginia Tech. This research was supported jointly by Southwestern Applied Technologies, L. C., of Roanoke, Virginia and Virginia's Center for Innovative Technology in Herndon, Virginia.
Ph. D.

Le fauteuil roulant électrique constitue un moyen efficace permettant de retrouver une certaine mobilité pour de nombreuses personnes dans le monde. Malheureusement, certaines personnes en situation de handicap moteur et atteintes d’une perte de force musculaire peuvent avoir du mal à utiliser un fauteuil roulant électrique à cause de difficultés liées au maniement du joystick, dispositif usuel de pilotage du fauteuil. Cette thèse vise à proposer explorer une alternative au joystick pour des personnes atteintes de maladies neuromusculaires. Le travail de cette thèse s’intéresse plus particulièrement à l’interaction tactile. L’hypothèse est que l’interaction tactile peut offrir un pilotage fiable avec un niveau d’effort physique qui est tolérable par des personnes atteintes de maladies neuromusculaires. Dans cette perspective, nous avons développé une interface sur smartphone de pilotage de fauteuil roulant électrique qui offre de nombreuses possibilités de paramétrage permettant de la personnaliser selon le besoin de la personne. Cette interface a été conçue dans une démarche itérative centrée utilisateur. Dans chaque itération, différentes personnes souffrant d’une perte de mobilité ont pu tester l’interface de pilotage. Leurs retours alimentent les améliorations à apporter à l’interface dans l’itération d’après. Lors de la dernière itération dans le cadre de cette thèse, Une étude a été menée avec des utilisateurs atteints de maladies neuromusculaires au SSR le Brasset, avec l’aide de l’AFM Théléton. Ces participants ont pu s’approprier l’interface tactile et l’utiliser pour piloter leurs fauteuils roulants. Nous avons également comparé les performances de pilotage en utilisant l’interface tactile et le joystick dans différentes tâches quotidiennes (virage, slalom...). Les performances de ces patients avec l’interface tactile sont proches de celles du joystick. Par ailleurs, les remarques récoltées suggèrent que l’interface tactile exige moins d’effort physique que le joystick
The power wheelchair is an effective way to regain mobility for many people around the world. Unfortunately, some people with motor disabilities who also suffer from loss of muscle strength may find it difficult to use a power wheelchair. The reason is that they can experience difficulties related to the handling of a joystick, the standard wheelchair control device. This thesis aims to propose exploring an alternative to the joystick for people with neuromuscular diseases. The work of this thesis is particularly interested in tactile interaction. The hypothesis is that the tactile interaction can offer a reliable control with a level of physical effort which is tolerable by people suffering from neuromuscular diseases. In this perspective, we developed a wheelchair steering interface on smartphone. It offers many configuration possibilities allowing the customization according to the user's needs. This interface was designed in a user-centered, iterative approach. In each iteration, different people suffering from a loss of mobility were able to test the piloting interface. Their feedback feeds into improvements to the interface in the next iteration. During the last iteration as part of this thesis, a study was carried out with users suffering from neuromuscular diseases at the SSR Le Brasset, with the help of the AFM Théléton. These participants were able to take appropriate the use of the touch interface and use it to control their wheelchairs. We also compared the driving performance using the touch interface and the joystick in different daily tasks (cornering, slalom ...). The performance of these patients with the touch interface is close to that of the joystick. In addition, the comments collected suggest that the touch interface requires less physical effort than the joystick

Submitted by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2018-09-17T17:22:44Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertacao_impressao.pdf: 2956113 bytes, checksum: e6a4b36626de2a1892da7e9ffd7ac14a (MD5)
Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2018-09-17T17:22:55Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertacao_impressao.pdf: 2956113 bytes, checksum: e6a4b36626de2a1892da7e9ffd7ac14a (MD5)
Made available in DSpace on 2018-09-17T17:22:55Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertacao_impressao.pdf: 2956113 bytes, checksum: e6a4b36626de2a1892da7e9ffd7ac14a (MD5) Previous issue date: 2018-08-10
CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
Currently, diverse existing training environments help new users of electric powered wheelchairs (EPW) learn how to drive, acquaint and improve their abilities with these assistive devices. Several authors are developing such environments, and most of them use virtually simulated wheelchairs. Despite the similarities between virtual and real wheelchairs, it is easier to drive the real device because representation of the wheelchair physical behavior is still a problem for virtual simulated environments. Concerning the driving methods, most of them are based on a joystick, which does not give the opportunity for users to test, practice and acquaint themselves with new technologies, such as driving through eye movements. This work implements and tests a more realistic approach for a training environment dedicated to new users of EPW. The proposed system is based on a real EPW controlled by teleoperation, and it is flexible enough to attend to multiple driving methods. An architecture that allows a user to send command messages to control a real EPW through the Internet was implemented to validate the system. The implemented driving methods were conventional joystick, eye-tracker and a generic human-machine interface. For the system’s evaluation, scenarios were created considering the implemented driving methods, and also scenarios considering a long distance teleoperation. The experimental results suggest that new users can practice safely using a real EPW through the Internet, even in a situation with a communication delay of 130.2 ms (average). Furthermore, the proposed system showed potential for attending new EPW users with different types of disabilities and to be a low-cost approach that could be applied in developing countries.
Atualmente, diversos ambientes de treinamento existentes ajudam novos usuários de cadeira de rodas motorizada (CRM) a aprender a comandar, se familiarizar e aprimorar suas habilidades. Vários autores estão desenvolvendo esses ambientes, e a maioria deles está usando CRM virtualmente simulada. Apesar das semelhanças entre a CRM virtual e a real, observouse que é mais fácil comandar o dispositivo real. Isso ocorre porque nesses ambientes virtuais, a representação do comportamento físico da CRM ainda é um problema. Outro aspecto observado, foi a respeito dos métodos de condução, onde a maioria dos trabalhos utiliza apenas o joystick. Porém, esse método não oferece a oportunidade a usuários com deficiência severa de aprender a comandar a partir de novas tecnologias, como por exemplo, o rastreamento ocular. Para superar essas dificuldades, este trabalho propõe, implementa e valida uma abordagem mais realista, a qual é baseada em treinamento por teleoperação e por múltiplos métodos de condução. Foi implementada uma arquitetura que permite ao usuário enviar comandos remotamente para comandar uma CRM real a longas distâncias. Os métodos de condução implementados foram por joystick, eye-tracker e por meio de uma interface humanomáquina genérica. Para a avaliação do sistema, foram criados cenários considerando diferentes configurações. Os resultados experimentais sugerem que novos usuários podem praticar com segurança utilizando uma CRM real através da Internet, mesmo em uma situação com delay de 130,2 ms (média). O sistema proposto mostrou potencial em atender novos usuários de CRM com diferentes tipos de deficiência, bem como de ser uma abordagem de baixo custo com possibilidade de ser aplicada em países em desenvolvimento.

The use of a commercial powered wheelchair during daily activities by people with motor limitations provides autonomy, increasing quality of life. For people with more severe restrictions, specifically reduced handling, the use of the powered wheelchair may be compromised as they cannot control the joystick with the required ability. This work is intended to give these people the ability to drive comfortably and safely their electric wheelchair. This proposal for adapting a commercial powered wheelchair has essentially two main objectives. The first one is to allow people who cannot drive a conventional powered wheelchair because they have muscle weakness in their upper limbs to do so. So, and to facilitate the wheelchair navigation, three modes of operation are proposed. Therefore, the adapted wheelchair controller must able translate the new impulses provided by the joystick, depending of the user abilities, in direction commands. Driving the powered wheelchair continuously can quickly become a stressor. Thus, the second goal is to ensure that during the powered wheelchair driving, its user always remains in a calm state, avoiding harming their well-being and their health. It is thus proposed to insert a system for monitoring the emotional state of the wheelchair user. The primary purpose of this system is to alert its user when he reached critical emotional levels, which makes it impossible to continue driving safely. In this situation the wheelchair controller becomes responsible for the wheelchair command. The implementation of the stress detection system was based in the galvanic skin response and heart rate sensors. With the acquired information, it was defined the user’s emotional profile and evaluated several algorithms classification to predict new emotional states. This system was tested by two users groups. The first group consisted of drivers driving cars and the second group consisted of tetraplegic people driving their powered wheelchair. For people without disabilities, it was confirmed through biometric signals that each person reacts differently to the same situations. This difference is most striking in the response of skin conductivity. For tetraplegic people, we concluded and confirmed, that the sympathetic nervous system response cannot be measured by galvanic skin response. Several classification algorithms were trained for stress detection in realtime. For each user, the best classifying model was found. We conclude that the best models vary from person to person and also depend on the number and type of predictors used. This work results from the collaboration of the University of Aveiro and the Centro de Reabilitação e Medicina da Região Centro - Rovisco Pais.
O uso de uma cadeira de rodas elétrica durante as atividades do quotidiano por pessoas com limitações motoras proporciona autonomia, aumentando qualidade de vida. No caso de pessoas com limitações mais severas, nomeadamente com manipulação reduzida, a utilização da cadeira de rodas elétricas pode estar comprometida, pois não conseguem controlar o joystick com a destreza necessária. Este trabalho pretende proporcionar a essas pessoas a possibilidade de conduzir a sua cadeira de rodas elétrica de uma forma confortável e segura. Esta proposta de adaptação de uma cadeira de rodas elétrica tem essencialmente dois grandes objetivos. O primeiro é permitir a pessoas que não conseguem conduzir uma cadeira de rodas elétrica convencional por sofrerem de fraqueza muscular nos membros superiores, o comecem a fazer. Assim, para facilitar a condução da cadeira, propõem-se três modos de operação. Além disso, o controlador da cadeira adptada vai ter que ter a capacidade de interpretar os novos impulsos dados no joystick, que dependem das capacidades de manipulação de cada utilizador, em comandos de direção. A condução da cadeira de forma consecutiva pode-se tornar rapidamente um fator de stress. Assim, o segundo objetivo ´e garantir que, enquanto a pessoa conduz a cadeira se mantenha sempre num estado calmo, evitando prejudicar o seu bem-estar e consecutivamente, a sua saúde. E assim proposto a integração de um sistema de monitorização do seu estado emocional durante a condução da cadeira. Este sistema tem como principal objetivo alertar o utilizador que este atingiu níveis emocionais críticos que inviabilizam a continuação da condução em segurança. Nesta situação, quem passa a ficar responsável pelo comando da cadeira é o próprio controlador da cadeira. A implementação do sistema baseou-se no uso de sensores de resposta galvânica e de batimento cardíaco. Com a informação adquirida por estes sensores, definiu-se o conceito de perfil emocional do utilizador e foram avaliados algoritmos de classificação de stress capazes de prever diferentes estados emocionais. Este sistema foi testado por dois grupos de utilizadores. O primeiro grupo foi composto por condutores a conduzirem automóveis e o segundo grupo foi composto por pessoas tetraplégicas, a conduzirem as cadeiras de rodas elétrica pessoais. Para pessoas sem deficiência confirmou-se, através dos sinais biométricos, que cada pessoa reage de forma diferente perante as mesmas situações. Esta diferença é mais flagrante na resposta da condutividade da pele. No que diz às pessoas tetraplégicas, confirmou-se que a resposta do sistema nervoso simpático não pode ser medida através da resposta galvânica da pele. Para a implementação da deteção de stress em tempo real foram usados diversos algoritmos de classificação. Para cada utilizador, foi encontrado o melhor modelo de classificação. Conclui-se que os melhores modelos variam de pessoa para pessoa e que também dependem do número e tipo de preditores utilizados. Este trabalho resulta da colaboração entre a Universidade de Aveiro e o Centro de Medicina de Reabilitação da Região Centro - Rovisco Pais.
Programa Doutoral em Engenharia Eletrotécnica

碩士
大葉大學
車輛工程學系碩士班
96
Due to the aging of our society, the electric powered wheelchairs become more and more needed. However, the electric powered wheelchairs on the market currently are bulky, heavy, and costly. The present thesis focuses on the feasibility of converting a self-propelled wheelchair into a lightweight electric powered wheelchair by adding a hub motor to one of its rear wheels. The commercial code ADAMS was used to predict the motion of the wheelchair and a lightweight electric powered wheelchair was fabricated to perform the road test. The results show that the outcomes of simulations and road tests are in good agreement and this lightweight electric powered wheelchair is feasible and deserves further development and commercialization

碩士
南台科技大學
電機工程系
98
This thesis is mainly based on the technology of SoPC (System on a Programmable Chip) which can embedded a Nios II soft core in an FPGA (Field Programmable Gate Array), to implement a motion control IC for electric wheelchair. This electric wheelchair herein is run by two DC rim motors and a fuzzy controller is applied in speed loop of motor drive to cope with the uncertainly and external load problems. The motion control IC has two modules. One is Nios II processor IP (Intelligent properties) which is used to perform the function of motion trajectory and the data communication with control panel and generation of differential speed command; and the other is an application IP which is utilized to execute the function of PWM (Pulse width modulation) generation, QEP (Quadrature encoder pulse) signal detection, fuzzy controller scheme and speed loop controller, trapezoidal speed command generator. Therefore, a fully digital motion controller for electric wheelchair can be realized within one FPGA chip. Finally, an experimental system, which is composed of the DE2 (Cyclone II EP2C35F672C6) with FPGA basis, two inverters, one control panel, and one platform for electric wheelchair, is set up to prove the efficiency and correctness of the proposed motion control IC.

碩士
國立臺灣大學
機械工程學系
85
This research develops an electrical differential for electrical wheelchairs with two motors instead of mechanical differential. The steering function is achieved by the control of differential speed between two motors, whose comm- ands are generated by a simplified differential formula. A digital full- bridge PWM (Pulse Width Modulation) motor driver and a single board controller with the PI control law is designed and implemented with the motorized wheelchair. The performance of the electrical wheelchair is tested successfully with simu- lations and experiments.

碩士
臺灣大學
機械工程學研究所
98
In recent years, fuel cell vehicles are becoming the most focus technology in the electric vehicles. Considering the fuel economy, the combination of fuel cells and secondary batteries is most widely used. The classical hybrid fuel cell powertrains could be classified into two types: series and parallel. The default application of this research is the electric wheelchair powered by rim motors. The limitation for energy storage system in the electric wheelchair is more critical than in general electric vehicles. The size and weight should be reasonable reduced with keeping enough drive ability. But the classical hybrid fuel cell powertrains could not satisfy the request. Also, the power management might cause the large variation of fuel cell output power and the decrease of the cycle life of batteries. In this research, a novel hybrid fuel cell powertrain and power management strategies were designed to improve this drawback and reduced the size and weight of fuel cells and batteries with reasonable size by load power and driving cycle analysis. The proposed and classical fuel cell powertrain were simulated with Matalb SimPowerSystems and compared simulation results to evaluate the improvements. From simulation results, the power requirement of fuel cells in proposed hybrid fuel cell powertrain is smaller than in classical fuel cell powertrain. The output power of fuel cells is nearly constant, so the size of fuel cells could be reasonably reduced and easy to control in future. Furthermore, the charging times of secondary batteries were also reduced 96%~98% compared with classical fuel cell powertrains.

碩士
國立臺灣大學
電機工程學研究所
87
A power-assisted pedaling wheelchair using functional electrical stimulation (FES) was proposed in this research to offer prolonged mobility for paralyzed patients and to achieve rehabilitation purposes. To design suitable stimulation patterns, an FES pedaling model was proposed in the thesis. The pedaling model was composed of a muscular subsystem and a skeletal subsystem. The muscular subsystem accepts stimulation input and generates force output according to the experimentally obtained isometric recruitment curve. The generated forces then produce moments to drive the skeletal subsystem and result in a pedaling movement. The stimulation timing was designed in connection to the activation timing of normal subjects’ electromyography (EMG). Stimulation patterns were suggested based on acquired EMG activation timing, and stimulated pedaling experiments were conducted to verify such patterns. The muscular model helped to establish a closed-loop FES pedaling control and simulation structure. The isometric quadriceps recruitment of one able-bodied subject was measured to reveal the dynamic range of muscle recruitment with pulse amplitude modulation. The measurements were taken on stimulated right quadriceps by a Cybex NORMTM torque meter. The results indicated able-bodied subjects had a maximum knee joint torque around 40 Ft-Lbs, which saturated at 90 mA of stimulation. The quadriceps and hamstrings surface EMG’s of three able-bodied subjects pedaling at 40, 50, and 60 RPM were analyzed. A consistent advancing trend of activation was seen when pedaling rate increased. With respect to individual maximum flexion (MF) positions, the activation ranges of three subjects were consistently matched. Two stimulation durations were suggested by averaging the durations of quadriceps activation at 40 and 60 RPM. Same pedaling experiments were repeated under three load levels. Delays in quadriceps activation and advances in hamstrings’ were seen while load increased. The amplitudes of integrated EMG (iEMG) increased along with both pedaling rates and loads. A closed-loop stimulated pedaling experiment was conducted with two able-bodied patients. Both suggested quadriceps stimulation ranges were implemented in reference to individual subject’s maximum flexion positions. A proportional and integral (PI) controller was adopted to achieve constant pedaling rate. Results indicated the suggested stimulation patterns achieved constant rate pedaling. A comparison of the stimulation efficiency between the two suggested patterns was reported. The results showed that the 40-RPM pattern was more efficient when pedaling at 40 RPM. Similarly, the 60-RPM pattern was more efficient when pedaling at 60 RPM. The experiment results also offered required activation timing information in the FES pedaling model simulation.

碩士
國立成功大學
電機工程學系
104
There are a lot of mature mobile assistive devices for increasing amount of elderlies and people with disabilities. But for highly disabled people, these mobile assistive devices have relatively high threshold for them. For those patients with the lack of ability, neither traditional joystick-controlling wheelchairs nor wheelchairs with sound control can’t offer a suitable environment for highly disabled people. As a result, this decrease the chance for outside activities and interactions with families for them, so caregivers are highly relied for them. So, a system combining image object tracking and the LiDAR obstacle avoidance is proposed. This system can be used in household environment to enhance the condition of interacting with families. Also, it is suitable for going outside with a smart electrical power wheelchair away from the home. In this research, a system composed of embedded systems, an Android Tablet, a Light Detection and Ranging, and cameras with 180 degree fisheye lens is constructed. This system is suitable for image-tracking small tracked cars and can be migrated on the electrical power wheelchairs for outside activities. Using cameras with 180 degree fisheye lens can increase the field of view, and it’s helpful for people with high disabilities and low sensitivities. This project use a tablet PC which is available everywhere as the user interface, the Android APP on it display the whole required information while driving. For the division of work, two embedded system microcontrollers are responsible for different tasks respectively. The Raspberry Pi is in charge of image processing with a large amount of data calculation. On the other hand, the STM32F4-Discovery discovery kit execute the data transmission to the tablet PC through Bluetooth, LiDAR data receiving, and the motor control. UART is used to communicate between two microcontrollers. This research uses the Continuously Adaptive Mean-Shift as the method of image object tracking. CAMShift has good efficiency and precision, and it widely used in image tracking. By doing Mean-Shift continuously and adaptively, it calculates out the best position according to the target color feature and its histogram. The motor control algorithm have been aimed at in wheelchair researches over the past years, and there are few wheelchair systems in connection to image recognition. This research adds the LiDAR sensor which is popular in the field of self-driving car to achieve the purpose of interacting safely. Via the mode selected by users on the Android APP, it can be divided in the object tracking mode and the manually control mode. The object tracking mode tracks the objects with a certain color according to the color users choose. The results returned from the Raspberry Pi are passed to the STM32F4-Discovery discovery kit and then move the small tracked car toward the target and maintain the safety distance. The experimental results shows that the positions CAMShift calculated are projected to actual position from camera image position through the calibration transform of fisheye lens camera. It successfully targets the best position of objects with specific color. By the assistance of LiDAR, the distance of safety is considered to reach the stability and the driving safety. This research combines the techniques of self-driving, and the integrated science assistive system consisting of low power and low-cost sensors and embedded systems is designed. This system can be used in household communication and also be expanded to electrical power wheelchair to do social activities. The enhanced interaction with families and caregivers is expected.

碩士
國立臺灣大學
機械工程學研究所
99
This thesis proposes control and integration of a fuel-cell powered wheelchair. The study was carried out in three steps: the fuel-cell control, power management, and system integration. First, we apply multivariable robust control strategies to a 500W proton exchange membrane fuel cell (PEMFC) system, which has inputs of air and hydrogen and outputs of stack voltage, to provide steady electrical power. Second, we design a serial power-train for the electric wheelchair. The power system consists of the 500W PEMFC, two 6.9Ah LiFePO4 battery sets, and two 300W electric motors. The motors are directly driven by the battery sets in order to avoid damaging the PEMFC by rapidly varying loads. And the battery sets are charged by the PEMFC when their capacities drop to a certain level. From the experimental results, the power management system is successful in providing uninterrupted electricity to the wheelchair. Lastly, we apply a motor control card and a joystick to regulate the motions of the wheelchair motors. Then we integrate the aforementioned sub-systems and demonstrate the effectiveness of the system by experiments.

碩士
國立成功大學
電機工程學系
103
People with quadriplegia usually have less chance to go out because of the lost of mobility. Although there are a lot of commercial products providing different input methods such as joystick, brain wave, eye control and sound control to manipulate the electrical power wheelchair, none of them can fit their needs because of three main difficulties. First, in order to use the wheelchair for long time, the input device should be very comfortable. Moreover, high stability and safety of control system are absolutely required. Last, they have a huge blind spot during controlling the wheelchair because their vision is constraint by the lost of body mobility. The goal of this research is to overcome the second difficulties by applying neural network control, Lidar obstacle avoidance, multi-camera real-time blind spot image display and remote monitoring functions to the system. In this research, we made a Smart Electrical Power Wheelchair (SEPW) system with embedded systems, Android tablet. Also, Lidar, Wifi, Bluetooth and encoder modules are also equipped to the wheelchair. In order to modify the system to fit different demands, we modularize the system and separate it to two parts – the main system and additional functions. The main system part is including the electrical power wheelchair, Android tablet and STM32F4 Discovery controller. The user can use the well-developed Morse code controller to input command to the Android tablet. The command will be transmitted to the controller through Bluetooth. Then, the wheelchair executes the corresponding movement. In order to control the wheelchair, PID control method was applied to the previous research. However, due to the lack of adaptive ability, the PID parameter should be re-configured manually according to different user or environment. As a result, the neural network is applied and implement on STM32F4-Discovery to identify the system features and auto-configure the PID parameter, improving the adaptive ability of SEPW system. Additional functions are obstacle avoidance, blind spot real-time image display and remote monitoring. These functions can be added to the main system according the different demands. The XV-11 Lidar sensor is applied to do obstacle avoidance. This sensor can perform 360 degree obstacle scanning and return the distance of obstacle in each degree. However, there are some errors caused by the motion or sensor. Kalman filter is applied to cancel these errors. After cancel the error, an obstacle avoidance algorithm presented in [2] was applied to navigate the wheelchair when approaching obstacles. Moreover, the number of Lidar can be increased depend on user’s demand. In order to display real-time image of blind spot, a Rapberry Pi connected with two USB cameras is installed to the wheelchair. The USB cameras can capture the image from left and right. Through Wifi, the images can be displayed on the corresponding position in the use interface of Android tablet. Similarly, more Rapberry Pi can be installed to the wheelchair to display more blind spot image. Last, the remote monitoring function is used to send warning message and real-time image to their family when the system detects the unusual motion pattern. This function is implement on the Android tablet and PC environment through internet socket programming. The result shows that the PID parameter of the controller can approach optimal number when the neural network controller is trained after 2 commands. The wheelchair is move on the ceramic tile. The desire speed is set to 10 encoder pulses in 20ms. The input command is going for 2000 encoder pulse. The error between two wheels is lower than 20 pulse no matter the wheelchair is without load, moving on the ground or person sit on it. Real-time image of blind spot can be display with 19.8 frame per second when the image resolution is 160x120. Remote image monitor can reach 15.38 fps when Android tablet can receive adequate 3G signal and the PC with 20Mbps fiber Internet. With this SEPW project, people with severe disabilities can control the SEPW safely, stably and comfortably. The remote monitor function also help the caregiver decrease anxious and worry.

碩士
國立成功大學
電機工程學系
104
Lots of people with severe physical disabilities could not go outside for a long time due to the loss of mobility. There are many different kinds of commercial electrical power wheelchair on the market which provides different input methods that the users with disabilities could control the wheelchair with some method like joystick, brain wave control or sound control. But, none of them match the demands of the user with severe physical disabilities. The difficulties would occur when they operate the wheelchair and need to be overcome. One is the input method of the wheelchair, another is the safety and comfort of the wheelchair, and the other is the blind spot caused by the vision constraint due to the lack of body mobility. Several researches for the difficulties have been proposed, the most important is the safety of the wheelchair and the user. The goal of this researches is to increase the safety of the wheelchair by improving the control system with fuzzy neural network control. The study is based on the researches of seniors in the past and propose a control system based on fuzzy neural network to make the system of wheelchair better. The system of interactive electrical power wheelchair in the study include the electrical power wheelchair, the embedded system, an Android tablet and the components of the wheelchair. The system is based on well-developed Morse code controller, which the users with disabilities could input command to the tablet with. The App on the tablet would transfer the command to the control unit of the wheelchair to operate the wheelchair such as displacement adjustments of the wheelchair and wheelchair moving. On the system architecture, the system is modularized to match the different demands of the user. Moreover, open source real-time operating system for embedded system is applied as the OS of the control unit STM32F4-Discovery, which make the control system work efficiently, smoothly and stably. More details about the electrical power wheelchair system would be introduced in Chapter 2. The control system of this study outputs the corresponding control signals of the target speed based on the dynamic model of the wheelchair. And, fuzzy neural network control would output the compensating control signals with the algorithms proposed according to the error every 20ms. The dynamic model of the wheelchair could be obtained from the data of the experiments, and the better dynamic model could be obtained by iterative experiments. The fuzzy neural network control system applied to the research is based on Lyapunov stability theorem. The tuning methods of fuzzy neural network is guaranteed to make the system stable. With the dynamic model of the wheelchair, the relation between the speed and the control signals would be known. The simulations of the outputs of the control signals are performed with the different error and conditions according to the relation mentioned above and fuzzy neural network controller. Practical tests are also performed. The experiments show the wheelchair could move straightly and work stably with different load on the tile ground. The target speed is set to about 3 km/hr, after the wheelchair moving forward for 5 seconds and 3 meters only with the load of the wheelchair, the error is 0.063%. And, when the wheelchair moves forward in the same conditions with the load of the wheelchair and 60kg-weight, the error is 1.34%. The case tests are performed which the users with severe physical disabilities control the wheelchair on their own with their own switch. The tests include displacement adjustments of the wheelchair and the moving test in all directions The study is based on the researches of seniors. The concept of modularization is retained and the unnecessary components are removed. The study applies the dynamic model of the wheelchair and fuzzy neural network control to the control system to improve the stability and the safety. With the control system proposed, people with severe physical disabilities could input the command with the Morse code controller and their switches to operate the electrical power wheelchair safely and stably. This makes people with severe physical disabilities be able to and be glad to go outdoors.