Browsing by Author "Booysen, Tracy"

Now showing 1 - 5 of 5
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    The characterisation of magnetic couplings and the development of a thruster module for an ROV
    (2015) Hope, Timothy Patrick; Nurick, Gerald N; Booysen, Tracy
    This dissertation focuses on the development of thruster modules and the characterisation of magnetic couplings for a Remotely Operated Underwater Vehicle (ROV). The dissertation begins with an introduction to the Seahog ROV developed at the University of Cape Town's Robotics and Agents Research Laboratory (RARL). The history, relevance and features of commercial ROVs are discussed in chapter two to introduce the reader to this form of underwater robotics. After this the dissertation is divided into two separate sections. The first section, chapters three to eight, detail the mechanical and electrical modifications made to an existing, magnetically coupled, thruster module design. The objective of this section was to improve the thruster module in order to achieve performances that are similar to commercially available thrusters. The modifications included changes to the drivetrain, the design of new electronics and motor drivers and a reduction in weight of the module's housing. A fundamental analysis of the thruster module is presented, no Computational Fluid Dynamics (CFD) is provided as the propeller and kort-nozzle designs remained unchanged. Even though the improvements produced a reliable and efficient thruster module a greater understanding of magnetic couplings was required to produce a design that was as lightweight as commercial modules. Therefore the second section of this dissertation, chapters nine to twelve, implement and validate an analytical model to calculate the torque and slip characteristics of magnetic couplings. The dissertation is concluded in chapter thirteen with recommendations that incorporate the knowledge gained in magnetic coupling design with the modifications made to the thruster module to produce a thruster design that is both efficient and light.
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    Design and development of an autonomous duct inspection and mapping robot
    (2008) Booysen, Tracy; Marais, Stephen
    Just a few years ago, the idea of having robots in factories and households was science fiction. But, as robotic technology develops, this is becoming reality. Nowadays, robots not only perform simple household chores, but are used in most production lines and are even employed by the army. Visual inspection robots are very common and are used in many industries, including inspecting the interior of duct systems. Duct systems are in place in almost all large buildings and require ongoing maintenance and cleaning. Systems that are not properly maintained can pose a health risk as dust and mold form and are then blown throughout the building. In some cases, access holes have to be cut to allow access for inspection to occur. A robotic system, small enough to enter a duct through any existing access panel, would be advantageous. An autonomous robot would be even more useful as no operator would be needed thus reducing operating costs. To this end, a robot was developed that could autonomously navigate through a duct system, recoding video images and mapping the internal profile. The development of which is discussed in this thesis, included the design of the robotic platform, the inclusion of appropriate sensors and accompanying circuitry, generation of a simulation to test the control algorithm and implementing embedded software to control the robot. From the testing of the entire system the following conclusions were drawn. The robot as a whole performed well and navigated autonomously through the duct with a success rate of 90%. The system tests were repeatable and the odometry data closely matched the actual paths for straight line travel. The sonar data closely corresponded to the duct walls but was hard to interpret when the odometry and actual paths diverged. These paths diverged from each other due to wheel slip caused as the robot turned. The simulation developed showed that the control algorithm would ensure that the robot recursively inspected any duct system and provided information about the system as a whole. Further work should concentrate on improving the correlation between the odometry path and the actual path, perhaps by adding in a bearing measurement system. Sensors with greater range and accuracy should be implemented and the entire system re-tested. The embedded controller allowed for expansion should additional requirements be needed and was more then adequate for the task.
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    Design of a man-wearable control station for a robotic rescue system
    (2015) Fong, Wai K; Ginsberg, Samuel; Booysen, Tracy
    This report details the design, development, and testing of a man-wearable operator control station for the use of a low-cost robotic system in Urban Search and Rescue (USAR). The complete system, dubbed the "Scarab", is the 1st generation developed and built in the Robotics and Agents Research Laboratory (RARL) at the University of Cape Town (UCT), and was a joint effort between three MSc students. Robots have found a place in USAR as replaceable units which can be deployed into dangerous and confined voids in the place of humans. As such, they have been utilized in a large variety of disaster environments including ground, aerial, and underwater scenarios, and have been gathering research momentum since their first documented deployment in the rescue operations surrounding the 9/11 terrorist attacks. However one issue is their cost as they are not economical solutions, making them less viable for inclusion into a rescue mission as well as negatively affecting the operator‟s decisions in order to prioritise the safety of the unit. Another concern is their difficulty of transport, which becomes dependent on the size and portability of the robot. As such, the Scarab system was conceived to provide a deployable robotic platform which was lowcost, with a budget goal of US $ 500. To address the transportability concerns, it aimed to be portable and light-weight; being able to be thrown through a window by a single hand and withstanding a drop height of 3 m. It includes an internal sensor payload which incorporates an array of sensors and electronics, including temperature monitors and two cameras to provide both a normal and IR video feed. Two LED spotlights are used for navigation, and a microphone and buzzer is included for interaction with any discovered survivors. The operator station acts as the user interface between the operator and the robotic platform. It aimed to be as intuitive as possible, providing quick deployment and minimalizing the training time required for its operation. To further enhance the Scarab system‟s portability, it was designed to be a manwearable system, allowing the operator to carry the robotic platform on their back. It also acts as a charging station, supplying power to the robotic platform‟s on-board charging circuitry. The control station‟s mechanical chassis serves as the man-wearable component of the system, with the functionality being achieved by integration onto a tactical vest. This allows the operator to take the complete system on and off as a single unit without assistance, and uses two mounting brackets to dock the robotic platform. Key areas focussed upon during design were the weight and accessibility of the system, as well as providing a rugged housing for the internal electronics. All parts were manufactured in the UCT Mechanical Engineering workshop.
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    Design of the communication, power management and interchangeable sensor payload system for an inspection-class robotic platform
    (2015) Knox, Greig; Ginsberg, Samuel; Booysen, Tracy
    With the "golden day" being the first 24 hours after an urban disaster, after which the survival rate of victims decreases dramatically, there is a requirement for a low-cost first-response robotic platform. UCT robotics is developing a platform to fulfil this requirement, with the Scarab (Figure 0-1) - a low-cost, man-packable, throwable inspection-class robotic platform with interchangeable payloads. The system was designed to create a 1:1 human-to-robot ratio which improves the efficiency of rescue operations. Once the operator has reached the inspection void, the Scarab is thrown in where the sensor stimulus from the inspection environment is communicated, via wireless communications, from the payload back to the operator station. The interchangeable payload allows the sensor configuration to be tailored to the needs of the disaster, while reducing the cost of the platform. The design of the battery and battery management system, communications and interchangeable sensor payload for this platform are described in this report.
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    SCARAB : development of a rugged, low cost, inspection-class robotic platform
    (2015) Mathew, Thomas J; Cloete, Trevor; Booysen, Tracy
    This dissertation details the design and development of a prototype of a new robotic platform designed to carry a variety of sensors into environments that are too dangerous or confined for human workers, and forms part of a series of three concurrent M.Sc(Eng) dissertations which will integrate into a complete system. Ultimately this platform will be controlled and transported by the man-wearable harness and control station developed by W.K. Fong, and will gather data using the sensor payloads designed by G. Knox. Each dissertation, however, has independently quantifiable goals and results. An important application area for such a system is Urban Search and Rescue (USAR): the field of work concerned with the discovery, extrication, and treatment of survivors trapped in collapsed structures. These typically occur as a result of terrorist attacks, natural disasters, or engineering failure. Human workers, often assisted by dogs, are trained in this work but the danger of the working environments make USAR a key area where the use of robotic assistance can make a massive difference in helping to save lives - both those of rescuees and rescuers. A body of existing work, both in the commercial and academic spheres, has been done in this regard, and as a result there is much to be learned from the experiences of others. The history of robot-assisted USAR work, as well as the existing robots available, is surveyed and critically analysed. Significant challenges are noted: existing systems frequently lack sufficient mobility, are too large, difficult to transport and deploy, difficult to use, and very costly. Their cost has affected the prevalence of their use both as a barrier to acquisition but also during their use; robot operators frequently have their decisions constrained by the financial risk of losing or damaging a robot. Accordingly, it is proposed to develop a small, rugged, low-cost inspection-class robot that can be quickly and easily deployed in a variety of scenarios. This development work is covered in three sections; the mechanical and industrial design of the platform, its design, manufacture and assembly are considered first. This is followed by a description of the electrical and electronic systems needed to power and control the robot as it conducts inspections in challenging terrain. To protect the robot from damage in this terrain, impact-absorbing wheels are developed. The test-driven iterative design approach followed, as well as the equipment and methods used therein, constitute a large portion of this dissertation and are detailed in their own chapter which can be read as a sub-project within the main project. The finished prototype is tested against the developed specifications, and from these results conclusions are drawn and recommendations for future work made.