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Independent mobility is critical to quality of life for people of all ages, and impaired mobility leaves one with both physical and mental disadvantages. Unfortunately, there are some individuals unable to operate an electric wheelchair due to physical, perceptual, or cognitive deficits. The prime objective of this research was to develop a prototype system which can provide mobility assistant to individuals who would otherwise find it difficult or impossible to operate a power wheelchair. To accomplish this goal, a prototype system consisting of several components including an embedded microcontroller and multiple sensors has been designed which can be added to a standard power wheelchair and make it smart. The control system algorithm designed for this prototype model is based on the fuzzy logic control theory and its main purpose is to augment the user ability to navigate the wheelchair and will provide a safe and comfortable journey to the user.

In social situations, people who use a powered wheelchair must divide their attention between navigating the chair and conversing with people. As a solution that maintains a good conversation distance between the wheelchair and the accompanying person, a wheelchair control system was introduced to provide automated side-by-side following by wirelessly tethering the wheelchair to the person. This thesis designed, developed, and evaluated a wireless tethering system using ultrasonic sensors. Two ping sensors and three piezoelectric ultrasonic transducers were used to identify the accompanying person and determine their pose. A trajectory algorithm determined the person’s direction of motion and a drive control algorithm determined the wheelchair’s required direction by maintaining a comfortable conversation distance between the person and the wheelchair user. A plug-and-play prototype was developed using commercially available components and the firmware was implemented using an open-source platform. The prototype developed in this thesis was mounted to a Permobil F3 Corpus powered wheelchair with a modified Eightfold Technologies SmartChair Remote, which controlled the wheelchair direction. Results demonstrated that the system can navigate a wheelchair beside an accompanying person and maintain a comfortable conversation distance, which is advantageous for users who require hands-free wheelchair control during social activities.

<p>I detta examensarbete har ett system för navigering och styrning av ett autonomt fordon implementerats. Syftet med detta arbete är att vidareutveckla fordonet som ska användas vid utvärdering av banplaneringsalgoritmer och studier av andra autonomifunktioner. Med hjälp av olika sensormodeller och sensorkonfigurationer går det även att utvärdera olika strategier för navigering. Arbetet har utförts utgående från en given plattform där fordonet endast använder sig av enkla ultraljudssensorer samt pulsgivare på hjulen för att mäta förflyttningar. Fordonet kan även autonomt navigera samt följa en enklare given bana i en känd omgivning. Systemet använder ett partikelfilter för att skatta fordonets tillstånd med hjälp av modeller för fordon och sensorer.</p><p>Arbetet är en fortsättning på projektet Collision Avoidance för autonomt fordon som genomfördes vid Linköpings universitet våren 2005.</p> / <p>In this thesis a system for navigation and control of an autonomous ground vehicle has been implemented. The purpose of this thesis is to further develop the vehicle that is to be used in studies and evaluations of path planning algorithms as well as studies of other autonomy functions. With different sensor configurations and sensor models it is also possible to evaluate different strategies for navigation. The work has been performed using a given platform which measures the vehicle’s movement using only simple ultrasonic sensors and pulse encoders. The vehicle is able to navigate autonomously and follow a simple path in a known environment. The state estimation is performed using a particle filter.</p><p>The work is a continuation of a previous project, Collision Avoidance för autonomt fordon, at Linköpings University in the spring of 2005.</p>

I detta examensarbete har ett system för navigering och styrning av ett autonomt fordon implementerats. Syftet med detta arbete är att vidareutveckla fordonet som ska användas vid utvärdering av banplaneringsalgoritmer och studier av andra autonomifunktioner. Med hjälp av olika sensormodeller och sensorkonfigurationer går det även att utvärdera olika strategier för navigering. Arbetet har utförts utgående från en given plattform där fordonet endast använder sig av enkla ultraljudssensorer samt pulsgivare på hjulen för att mäta förflyttningar. Fordonet kan även autonomt navigera samt följa en enklare given bana i en känd omgivning. Systemet använder ett partikelfilter för att skatta fordonets tillstånd med hjälp av modeller för fordon och sensorer. Arbetet är en fortsättning på projektet Collision Avoidance för autonomt fordon som genomfördes vid Linköpings universitet våren 2005. / In this thesis a system for navigation and control of an autonomous ground vehicle has been implemented. The purpose of this thesis is to further develop the vehicle that is to be used in studies and evaluations of path planning algorithms as well as studies of other autonomy functions. With different sensor configurations and sensor models it is also possible to evaluate different strategies for navigation. The work has been performed using a given platform which measures the vehicle’s movement using only simple ultrasonic sensors and pulse encoders. The vehicle is able to navigate autonomously and follow a simple path in a known environment. The state estimation is performed using a particle filter. The work is a continuation of a previous project, Collision Avoidance för autonomt fordon, at Linköpings University in the spring of 2005.

An automated prototype variable rate (VR) sprayer was developed for control of eight individual nozzles on a 6.1 m sprayer boom for spot-application (SA) of agrochemicals in wild blueberry fields. The VR control system consisted of eight ultrasonic sensors and four cameras mounted on a separate boom in front of the ATV, flow controller, VR controller, ruggedized computer, flow valve and solenoid valves. Custom software was capable of processing the images to detect weeds or plants in real-time and automatically send a signal to the VR controller for SA at the correct target. The performance of VR sprayer for SA on weeds (herbicide) and foliage (fungicide) was evaluated in commercial wild blueberry fields. Based on the results of this study, the VR sprayer was reliable, efficient and accurate enough for SA of agrochemicals. The average volume of chemical saved with SA was 70 % herbicide and 30 % fungicide.

no / Real-time diagnostics of ceramic powder injection molding using a commercial micromolding machine was performed using ultrasound. Miniature ultrasonic sensors were integrated onto the mold insert. Melt front, solidification, temperature variation and part detachment of the feedstock inside the mold cavity were observed. It has been demonstrated that ultrasonic velocity in feedstock inside the mold cavity, the ultrasonic contact duration during which the part and mold are in contact, and holding pressure can be used to assist with optimization of injection and cooling parameters to minimize energy consumption and maximize process efficiency.Real-time diagnostics of ceramic powder injection molding using a commercial micromolding machine was performed using ultrasound. Miniature ultrasonic sensors were integrated onto the mold insert. Melt front, solidification, temperature variation and part detachment of the feedstock inside the mold cavity were observed. It has been demonstrated that ultrasonic velocity in feedstock inside the mold cavity, the ultrasonic contact duration during which the part and mold are in contact, and holding pressure can be used to assist with optimization of injection and cooling parameters to minimize energy consumption and maximize process efficiency.

A operação de veículos autônomos necessita de meios para evitar colisões quando obstáculos não conhecidos previamente são interpostos em sua trajetória. Algoritmos para executar o desvio e sensores apropriados para a detecção destes obstáculos são essenciais para a operação destes veículos. Esta dissertação apresenta estudos sobre quatro algoritmos de desvio de obstáculos e tecnologia de três tipos de sensores aplicáveis à operação de veículos autônomos. Após os estudos teóricos, um dos algoritmos foi testado para a comprovação da aplicabilidade ao veículo de teste. A etapa experimental foi a realização de um programa, escrito em linguagem de programação Java, que aplicou o algoritmo Inseto 2 para o desvio de obstáculos em uma plataforma robótica (Robodeck) com o uso de sensores ultrassônicos embarcados na referida plataforma. Os experimentos foram conduzidos em ambiente fechado (indoor), bidimensional e horizontal (plano), fazendo o Robodeck executar uma trajetória. Para os testes, obstáculos foram colocados para simular situações variadas e avaliar a eficácia do algoritmo nestas configurações de caminho. O algoritmo executou o desvio dos obstáculos com sucesso e, quando havia solução para a trajetória, ela foi encontrada. Quando não havia solução, o algoritmo detectou esta situação e parou o veículo. / The operation of autonomous vehicles need means to avoid collisions when unforeseen obstacles are posed in its trajectory. Algorithms to perform the deviation and suitable sensors for detecting these obstacles are essential for the operation of such vehicles. This dissertation presents studies on four obstacle avoidance algorithms and technology of three types of sensors applicable to the operation of autonomous vehicles. After the theoretical studies, one of the algorithms has been tested for evidence of applicability to the test vehicle. The experimental phase was the implementation of a program written in Java programming language, which applied the Insect 2 algorithm for obstacle avoidance in a robotic platform (Robodeck) using ultrasonic sensors embedded in the platform. The experiments were conducted in a closed environment (indoor), two-dimensional and flat, making Robodeck perform a trajectory. For testing, obstacles were placed to simulate various situations and evaluating the algorithm efficacy for these path configurations. The algorithm successfully performed the deviation of obstacles and, when there was a solution to the trajectory, it was found. When there was no solution, the algorithm has detected this situation and stopped the vehicle.

A operação de veículos autônomos necessita de meios para evitar colisões quando obstáculos não conhecidos previamente são interpostos em sua trajetória. Algoritmos para executar o desvio e sensores apropriados para a detecção destes obstáculos são essenciais para a operação destes veículos. Esta dissertação apresenta estudos sobre quatro algoritmos de desvio de obstáculos e tecnologia de três tipos de sensores aplicáveis à operação de veículos autônomos. Após os estudos teóricos, um dos algoritmos foi testado para a comprovação da aplicabilidade ao veículo de teste. A etapa experimental foi a realização de um programa, escrito em linguagem de programação Java, que aplicou o algoritmo Inseto 2 para o desvio de obstáculos em uma plataforma robótica (Robodeck) com o uso de sensores ultrassônicos embarcados na referida plataforma. Os experimentos foram conduzidos em ambiente fechado (indoor), bidimensional e horizontal (plano), fazendo o Robodeck executar uma trajetória. Para os testes, obstáculos foram colocados para simular situações variadas e avaliar a eficácia do algoritmo nestas configurações de caminho. O algoritmo executou o desvio dos obstáculos com sucesso e, quando havia solução para a trajetória, ela foi encontrada. Quando não havia solução, o algoritmo detectou esta situação e parou o veículo. / The operation of autonomous vehicles need means to avoid collisions when unforeseen obstacles are posed in its trajectory. Algorithms to perform the deviation and suitable sensors for detecting these obstacles are essential for the operation of such vehicles. This dissertation presents studies on four obstacle avoidance algorithms and technology of three types of sensors applicable to the operation of autonomous vehicles. After the theoretical studies, one of the algorithms has been tested for evidence of applicability to the test vehicle. The experimental phase was the implementation of a program written in Java programming language, which applied the Insect 2 algorithm for obstacle avoidance in a robotic platform (Robodeck) using ultrasonic sensors embedded in the platform. The experiments were conducted in a closed environment (indoor), two-dimensional and flat, making Robodeck perform a trajectory. For testing, obstacles were placed to simulate various situations and evaluating the algorithm efficacy for these path configurations. The algorithm successfully performed the deviation of obstacles and, when there was a solution to the trajectory, it was found. When there was no solution, the algorithm has detected this situation and stopped the vehicle.

The goal of this paper is to suggest suitable senzoric subsystem of mobile robot. There are being analyzed robotic kits of different manufacturers. Their advantages and disadvantages in the theoretical way are being explained in this part and also their opportunities of use in the practical way. In the following parts the work is focused on senzoric subsystems of other manufacturers and again are desribed their advantages and disadvantages. On the last part there is shown own concept of senzoric subsystem. HW and SW implementation is described and there are shown testing data of the conception.