Thesis (M.E.)--University of Canterbury, 2007. / Typescript (photocopy). Includes bibliographical references (leaves 105-106). Also available via the World Wide Web.

Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1991. / Vita. Abstract. Includes bibliographical references (leaves 163-170). Also available via the Internet.

During major disasters or other emergencies, Urban Search and Rescue (USAR) teams are responsible for extricating casualties safely from collapsed urban structures. The rescue work is dangerous due to possible further collapse, fire, dust or electricity hazards. Sometimes the necessary precautions and checks can last several hours before rescuers are safe to start the search for survivors. Remote controlled rescue robots provide the opportunity to support human rescuers to search the site for trapped casualties while they remain in a safe place. The research reported in this thesis aimed to understand how robot behaviour and interface design can be applied to utilise the benefits of robot autonomy and how to inform future human-robot collaborative systems. The data was analysed in the context of USAR missions when using semi-autonomous remote controlled robot systems. The research focussed on the influence of robot feedback, robot reliability, task complexity, and transparency. The influence of these factors on trust, workload, and performance was examined. The overall goal of the research was to make the life of rescuers safer and enhance their performance to help others in distress. Data obtained from the studies conducted for this thesis showed that semi-autonomous robot reliability is still the most dominant factor influencing trust, workload, and team performance. A robot with explanatory feedback was perceived as more competent, more efficient and less malfunctioning. The explanatory feedback was perceived as a clearer type of communication compared to concise robot feedback. Higher levels of robot transparency were perceived as more trustworthy. However, single items on the trust questionnaire were manipulated and further investigation is necessary. However, neither explanatory feedback from the robot nor robot transparency, increased team performance or mediated workload levels. Task complexity mainly influenced human-robot team performance and the participants’ control allocation strategy. Participants allowed the robot to find more targets and missed more robot errors in the high complexity conditions compared to the low task complexity conditions. Participants found more targets manually in the low complexity tasks. In addition, the research showed that recording the observed robot performance (the performance of the robot that was witnessed by the participant) can help to identify the cause of contradicting results: participants might not have noticed some of the robots mistakes and therefore they were not able to distinguish between the robot reliability levels. Furthermore, the research provided a foundation of knowledge regarding the real world application of USAR in the United Kingdom. This included collecting knowledge via an autoethnographic approach about working processes, command structures, currently used technical equipment, and attitudes of rescuers towards robots. Also, recommendations about robot behaviour and interface design were collected throughout the research. However, recommendations made in the thesis include consideration of the overall outcome (mission performance) and the perceived usefulness of the system in order to support the uptake of the technology in real world applications. In addition, autonomous features might not be appropriate in all USAR applications. When semi-autonomous robot trials were compared to entirely manual operation, only the robot with an average of 97% reliability significantly increased the team performance and reduced the time needed to complete the USAR scenario compared to the manually operated robot. Unfortunately, such high robot success levels do not exist to date. This research has contributed to our understanding of the factors influencing human-robot collaboration in USAR operations, and provided guidance for the next generation of autonomous robots.

Common trends in the vehicle industry are semiautonomous functions and autonomous solutions. This new type of functionality sets high requirements on the knowledge about the state of the vehicle. A precise vehicle speed is important for many functions, and one example is the positioning system which often is reliant on an accurate speed estimation. This thesis investigates how an IMU (Inertial Measurement Unit), consisting of a gyroscope and an accelerometer, can support the vehicle speed estimation from wheel speed sensors. The IMU was for this purpose mounted on a wheelloader. To investigate the speed estimation EKFs (Extended Kalman Filters) with different vehicle and sensor models are implemented. Furthermore all filters are extended to Kalman smoothers. First an analysis of the sensors was performed. The EKFs were then developed and verified using a simulation model developed by Volvo Construction Equipment. The filters were also implemented on the wheel loader and tested on data collected from real world scenarios.

This thesis extends previous work on navigational aidingof groups of aircraft, primarily intended for the fighter SAAB JAS 39 Gripen,as long as an aircraft gets GPS signals, it is easy to estimate position, but theGPS is relatively easy to jam, rendering alternative methods of positioning necessary.To use internal sensors measuring accelerations and angular velocities is agood replacement on short terms, but gives a drift in positioning over longer timeperiods. To resolve these issues, we review different possibilities to improve navigation performance bycombining measurement data from different aircraft using a consensus filter.We show that the performance canbe improved by using measurements of distance and angles to other aircraft withinthe group in a distributed filter.The filter is implemented in Matlab and evaluated in different scenarios, and this Extended Kalman-Consensus Filter (EKCF) is compared to a previously proposed solution using an Extended Kalman Filter (EKF). / Det här examensarbetet vidareutvecklar en befintlig algorithm för navigeringsstöttningav grupper av flygplan, främst inriktat på SAAB JAS 39 Gripen. Genomatt kombinera mätdata från olika flygplan kommer vi gå igenom hur man kanförbättra prestanda genom applicering av consensusfilter. Så länge ett plan harGPS-signal är positionering enkelt. Dock är den relativt lätt att störa ut, vilketgör alternativa lösningar för positionering nödvändiga. Att använda interna sensorersom mäter accelerationer och vinkelhastigheter fungerar utmärkt på kortsikt, men ger en drift över en längre tidsperiod.För att lösa de här problemen utvärderar vi olika möjligheter att förbättra navigationsprestandangenom att kombinera mätdata från olika flygplan med hjälpav ett consensusfilter. Vi visar att prestandan kan förbättras genom att användadistans- och vinkelmätningar inom gruppen med distribuerade filter. Filtret ärimplementerat i Matlab med olika scenarier och jämför Extended Kalman-ConsensusFilter (EKCF) med den föregående lösningen med ett Extended Kalman Filter (EKF).

This project aims to use the myRIO embedded device with programming development software, LabVIEW, for the education of automatic control in association with the course Control Engineering (Reglerteknik) in Uppsala University.  The myRIO is a portable reconfigurable I/O (RIO) device developed by National Instruments for students to use for designing control, signal processing, robotics, and mechatronics systems. It contains a Xilinx FPGA and a dual-core ARM Cortex-A9 micro-controller that can be programmed with LabVIEW (Laboratory Virtual Instrument Engineering Workbench).  The control system that the project is concerned with is to control a model elevator which, available for the project, is a cabinet driven by a DC motor up and down along two steel poles. It is a representative control system, containing all possible components of a feedback control system, i.e., controlled process, actuator, controller, sensor. The elevator (the controlled process) has three floors with pre-specified heights. The height is determined by an ultrasonic sensor (for feedback). The motor (the actuator) is controlled by a PID (proportional-integral-derivative) controller.  The specifications for the control system implemented are given beforehand, in particular, the parameters related to system performance such as stability, responsiveness and accuracy (or residual error), as well as real time display of operating information.  The motor driver (a H-bridge circuit) for the motor and the circuit for the information have been built. The myRIO is used to implement the PID controller, handle the set point specifying floor number, manage the sensor measurements. The whole elevator control system has been implemented and tested. The test results show that the control system works well and fulfills the given specifications. Further work on improvements for the project is suggested. The myRIO is shown to be an excellent device well suited for the education of control engineering.

The problem of constructing high quality point clouds based on measurements from a moving and rotating single-photon counting lidar is considered in this report. The movement is along a straight rail while the lidar sensor rotates side to side. The point clouds are constructed in three steps, which are all studied in this master’s thesis. First, point clouds are constructed from raw lidar measurements from single sweeps with the lidar. In the second step, the sensor transformation between the point clouds constructed in the first step are obtained in a registration step using iterative closest point (ICP). In the third step the point clouds are combined to a coherent point cloud, using the full measurement. A method using simultaneous localization and mapping (SLAM) is developed for the third step. It is then compared to two other methods, constructing the final point cloud only using the registration, and to utilize odometric information in the combination step. It is also investigated which voxel discretization that should be used when extracting the point clouds. The methods developed are evaluated using experimental data from a prototype photon counting lidar system. The results show that the voxel discretization need to be at least as large as the range quantization in the lidar. No significant difference between using registration and SLAM in the third step is observed, but both methods outperform the odometric method.

Servo systems play an important role in industrial automation. A servo system denotes a closed loop controlled system capable of tracking required demands. One way of achieving high performance servo drive systems is to apply the closed loop control of an a.c. permanent magnet synchronous machine (PMSM). PMSM is a type of machine which rotates once three-phase a.c. voltages are supplied. The usage of permanent magnet materials contributes to the high efficiency of PMSM, and makes it a popular type of machine in industrial applications. However, the interaction between the permanent magnets and the machine stator would generate torque ripple and consequently unsmooth speed. Therefore, torque ripple of PMSM need to be considered carefully in the control of such servo systems. An innovative control scheme combining an enhanced high bandwidth deadbeat current controller and a fractional delay variable frequency angle-based repetitive controller, is developed in this work in order to minimize torque ripple. For the purpose of accurately modelling the cogging torque and flux harmonics in PMSM, a lookup table embedded PMSM model is also proposed. It has been validated by both simulative and experimental tests that the proposed control scheme is able to reduce torque ripple in a PMSM drive system effectively for a wide range of frequencies, and even during transients, which has never been achieved according to the author's knowledge. The proposed method is not only adaptive to variable frequencies, but also adaptive to the variations of electrical and mechanical parameters in normal operating conditions.

An experimental investigation has been conducted in a low-speed wind tunnel at the University of Nottingham to study the flow separation control capability of a wall-normal plasma jet by DBD plasma actuator over a NACA 0012 aerofoil. As an active flow separation control technique, DBD plasma actuators could be applied when required to manipulate a flow. They are surface-mounted and require no moving parts, ducts, holes or cavities, so no profile drag penalty will be caused. Moreover, they are fast responding since they are purely electrical devices and could be operated at a higher frequency relative to other flow control techniques. DBD plasma actuators are easy to manufacture, low in weight, low energy consuming and can be easily fitted to aerofoils. Therefore, they are ideal tools to control the flow separation around aerofoil. Up to date, wall plasma jet was used to add momentum to flow directly so that flow becomes more energetic and capable of withstanding adverse pressure gradient. In this study, a wall-normal plasma jet by steady actuation of plasma actuator was investigated and PIV results show that it has the capability of controlling the separation around aerofoil at post-stall angles of attack. The wall-normal jet is bent towards freestream direction and some small-scale vortical structures are created due to the interaction between the wall-normal plasma jet and freestream. These vortical structures could promote mixing and transport high-momentum fluids into the boundary layer, which affects the flow above the suction surface significantly. Moreover, unsteady actuation of plasma actuator was also utilised to control the flow separation around aerofoil. It was found that it has a stronger ability to control flow separation even at a much lower energy consumption than steady actuation of plasma actuator. PIV measurements demonstrate that separated flow could be reattached at post-stall angle of attack of 14° with only 10% of the energy consumption by steady actuation. Flow is well organized and a series of large-scale vortices are created with periodic activation of plasma actuator, these vortices enhance entrainment and the outwards transport of fluids from aerofoil surface leads to a favourable pressure gradient, resulting in a control of flow separation.

The present work is concerned with the advancement of the knowledge of structural optimization in engineering design while focusing on efficient and easy to use ways of setting-up the required automated processes as well as the problems arising from it. Three industry examples are considered. In the first example a software tool that serves as a hands-on decision guidance for many occurring design situations for structured wall PE pipes is developed. In order to avoid licensing fees only public domain software or in-house code are used. It offers the efficient and automated simulation of the ringstiffness test as well as the most common pipe installation scenarios. In addition, an optimization feature is implemented for the design of optimum pipe profiles with regards to the ringstiffness test. In the second example a framework for the optimum design of carbon fibre mountain bike frames is developed. An extensively parameterized and automated simulation model is created that allows for varying tube shapes, paths and laminate ply thicknesses as well as joint locations. For improved efficiency a decomposition approach has been employed that decomposes the original optimization problem into a size optimization sub problem and a shape optimization top level problem. The former is solved by the built-in optimization tool in OptiStruct and the latter by means of surrogate based optimization where each experiment in the DoE is a full size optimization. The third example is concerned with the optimum design of a blade for a novel vertical axis wind turbine. A design approach similar to those with horizontal axes is chosen. The altered design requirements are accounted for by creating a parameterized simulation model and performing size optimization runs for 32 models with different material settings and shear web locations where the model creation process has been automated.