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    Automated 3D weaving continuous natural fibre and optimising harakeke fibre characterisation : a thesis presented in partial fulfilment of the requirements for the degree of Master of Engineering in Mechatronics at Massey University, Albany, New Zealand
    (Massey University, 2019) Lin, Junyi
    This research investigated the design and implementation of a continuous natural fibre filament winding robot for modern artistic and structural architectural design. The idea of a new architectural construction technique based on Arduino integration was inspired by the underwater nesting structure of water spiders. It consists of the motion component, a 3-axis sliding table with limit switches, the construction of the machine, the programming and testing of the resulting microcomputer software through to a robot manufacturing process. This was based on Arduino’s new integrated development environment. In addition, the intelligent programming mode forms the preconceived pattern through winding, producing a model with unique architectural quality, and at the same time, making a structure with superior material efficiency. In terms of hardware design, the first conceptual model focused on using an open-source integrated development environment (IDE) that could be easily configured. Arduino hardware was the primary microcontroller of choice for simplicity and ease of hardware integration and software development. Stepper motor drivers are used to control the three stepper motors to accurately move the fibre feeding mechanism on the sliding table into position. The path of the sliding table is controlled by the controller, and the machine can make forward, backward, wire feed and other movements according to the programmed commands. The developed system automatically weaves and feeds natural fibre into the desired structure. The resulting lightweight natural fibre material forms a model with unique architectural quality. The results show that the model is of great value and significance, and it can be used to make the required structure with the desired natural fibre. Additionally, to establish the feasibility of future work focusing on harakeke fibre development in design and construction, the tensile strength of native New Zealand flax fibre (harakeke fibre) was evaluated with a view for use in these load bearing and architectural design applications. Single filament fibres were selected in batches and tensile tested. The longitudinal strength of specimens was established, and the mechanical properties of the fibres were summarised. Comparison of these attributes with existing data was used to determine if the harakeke fibre can be applied usefully in the construction industry. This research is based on the novel concept of architectural design in the construction industry using 3D weaving with natural fibres, in particular harakeke fibres. To achieve this, several related topics are under investigation, such as the need to design an improved feeding system (including hardware and software control), impregnation of fibre and resin (epoxy and polyester) to make preimpregnated (prepreg) fibre/resin filament, adaptive controlled programme and hardware for the required architecture and structure, and properties testing and characterisation. This project is one of the first attempts to develop an automated robot arm system combined with new material, in this case harakeke fibre, and has made a valuable contribution to this field of research.
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    Pattern recognition-based real-time myoelectric control for anthropomorphic robotic systems : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Mechatronics at Massey University, Manawatū, New Zealand
    (Massey University, 2019) Wang, Jingpeng
    Advanced human-computer interaction (HCI) or human-machine interaction (HMI) aims to help humans interact with computers smartly. Biosignal-based technology is one of the most promising approaches in developing intelligent HCI systems. As a means of convenient and non-invasive biosignal-based intelligent control, myoelectric control identifies human movement intentions from electromyogram (EMG) signals recorded on muscles to realise intelligent control of robotic systems. Although the history of myoelectric control research has been more than half a century, commercial myoelectric-controlled devices are still mostly based on those early threshold-based methods. The emerging pattern recognition-based myoelectric control has remained an active research topic in laboratories because of insufficient reliability and robustness. This research focuses on pattern recognition-based myoelectric control. Up to now, most of effort in pattern recognition-based myoelectric control research has been invested in improving EMG pattern classification accuracy. However, high classification accuracy cannot directly lead to high controllability and usability for EMG-driven systems. This suggests that a complete system that is composed of relevant modules, including EMG acquisition, pattern recognition-based gesture discrimination, output equipment and its controller, is desirable and helpful as a developing and validating platform that is able to closely emulate real-world situations to promote research in myoelectric control. This research aims at investigating feasible and effective EMG signal processing and pattern recognition methods to extract useful information contained in EMG signals to establish an intelligent, compact and economical biosignal-based robotic control system. The research work includes in-depth study on existing pattern recognition-based methodologies, investigation on effective EMG signal capturing and data processing, EMG-based control system development, and anthropomorphic robotic hand design. The contributions of this research are mainly in following three aspects:  Developed precision electronic surface EMG (sEMG) acquisition methods that are able to collect high quality sEMG signals. The first method was designed in a single-ended signalling manner by using monolithic instrumentation amplifiers to determine and evaluate the analog sEMG signal processing chain architecture and circuit parameters. This method was then evolved into a fully differential analog sEMG detection and collection method that uses common commercial electronic components to implement all analog sEMG amplification and filtering stages in a fully differential way. The proposed fully differential sEMG detection and collection method is capable of offering a higher signal-to-noise ratio in noisy environments than the single-ended method by making full use of inherent common-mode noise rejection capability of balanced signalling. To the best of my knowledge, the literature study has not found similar methods that implement the entire analog sEMG amplification and filtering chain in a fully differential way by using common commercial electronic components.  Investigated and developed a reliable EMG pattern recognition-based real-time gesture discrimination approach. Necessary functional modules for real-time gesture discrimination were identified and implemented using appropriate algorithms. Special attention was paid to the investigation and comparison of representative features and classifiers for improving accuracy and robustness. A novel EMG feature set was proposed to improve the performance of EMG pattern recognition.  Designed an anthropomorphic robotic hand construction methodology for myoelectric control validation on a physical platform similar to in real-world situations. The natural anatomical structure of the human hand was imitated to kinematically model the robotic hand. The proposed robotic hand is a highly underactuated mechanism, featuring 14 degrees of freedom and three degrees of actuation. This research carried out an in-depth investigation into EMG data acquisition and EMG signal pattern recognition. A series of experiments were conducted in EMG signal processing and system development. The final myoelectric-controlled robotic hand system and the system testing confirmed the effectiveness of the proposed methods for surface EMG acquisition and human hand gesture discrimination. To verify and demonstrate the proposed myoelectric control system, real-time tests were conducted onto the anthropomorphic prototype robotic hand. Currently, the system is able to identify five patterns in real time, including hand open, hand close, wrist flexion, wrist extension and the rest state. With more motion patterns added in, this system has the potential to identify more hand movements. The research has generated a few journal and international conference publications.
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    Novel methods to characterise texture changes during food breakdown : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosphy in Food Technology at Massey University, New Zealand
    (Massey University, 2018) Ng, Cui Fang, Grace
    The purpose of the mastication process is to break down food for bolus formation so that it can be swallowed safely. Although light has been shed on the criterion for a swallow safe bolus, quantifying these in terms of the bolus properties is not fully understood. There is a lack of suitable measurement techniques to quantify these identified bolus properties. Thus, the purpose of this work was to develop novel techniques that would be useful in in-vitro studies of food breakdown for the characterisation of bolus properties. A mastication robot (MR) had been previously developed to enable the reproducible mastication of food so that masticatory efficiency and food breakdown dynamics can be assessed quantitatively. To evaluate if the MR could be a controllable and reproducible alternative to subjects for food break down studies, a series of experiments involving the mastication of peanuts using a range of machine parameters was conducted. The bolus particle size distributions were used to characterise the breakdown of the peanuts. There were significant differences in the average particle size of the particles chewed by the different chewing trajectories during the initial chews. The performance of the mastication robot was validated against human subjects (n=5) by comparing the particle size distribution (PSD) of peanut boluses collected from subjects and the MR. Although the MR was unable to achieve similar breakdown capability as that for the human subjects, the MR proved to have good reproducibility in bolus preparation. Two novel techniques were developed to characterise bolus properties. The slip extrusion test was developed to characterise two determinant properties for safe swallowing, the bolus deformation and slippage properties. The test measures the force needed to extrude a bolus through a test bag imitating the swallowing action of a bolus. The multiple pin penetrometer was previously developed to measure the spatial distribution of texture in foods exhibiting heterogenous structures. The forces experienced by each pin is measured independently as they pushed through the food, providing a pressure distribution for each food. This allowed the characterisation of fibrous (non-fracturable) foods in a similar way to PSD analysis, offering a method to characterise boluses that do not form discrete particles. The variability in the structure of the boluses was also characterised using the grey level co-occurrence matrix through the image textural features: contrast, energy and homogeneity. Finally, these developed novel techniques were applied to five real foods with varying textures to show how the MR and these techniques may be used to characterise the changes in bolus properties across the mastication stages. Subjects (n=5) were asked to masticate the foods to determine their chewing behaviour and the bolus properties (deformation and slip properties) at swallow point. The chewing parameters from the median subject (subject A) was used to establish the parameters for the mastication robot’s set up for the factorial design of experiments. The developed models from the factorial study were used to optimize the conditions needed for the MR to achieve boluses with similar DR and SR properties as subject A. The five foods were then broken down using the MR configured in this way, and bolus properties were evaluated at various stages of the mastication process through the application of the slip extrusion test, textural mapping using the multiple pin penetrometer, and the back-extrusion test. Factor analysis was applied to the various data collected, which showed that the properties related to the hardness, swallowability and homogeneity attributes were best at describing the changes in the boluses as they were masticated to swallow point. In conclusion, the mastication robot could be used to replicate human chewing trajectories to consistently produce boluses in a controlled trajectory with controlled “simulated saliva” rates throughout the various stages of mastication. Thus, it is relevant as a tool to produce boluses for comparative analysis especially for studies investigating the properties of boluses collected from various stages of the mastication process. In addition, the developed characterisation techniques could be used to track the dynamic changes in the bolus properties for most of the mastication stages from initial chews to the swallow point and beyond that.
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    Design of a three-wheel omni-directional mobile robot base module : a thesis in the partial fulfillment of the requirements for the degree of Master of Engineering in Mechatronics at Massey University, Turitea Campus, Palmerston North, New Zealand
    (Massey University, 2013) Deng, Jinrui
    In this research, the aim is to develop a modular autonomous mobile robot base that has a certain degree of flexibility and cost effectiveness for some indoor mobile robot applications that may have limited maneuverable space. The structure of the mobile robot and the wheel design are the major investigation areas. A modular mobile robot construction that is able to quickly integrate with different wheels and add on sub-systems has been developed for this project. The experiments made on the test model are positive. In this project, the mobile robot is built with omni-directional wheels. The omni-directional wheels make the mobile robot maneuverable in its motions. The shape of the mobile robot, base and number of wheels that are mounted on the mobile robot were decided based on the structure of the omni-directional wheels. Modular design makes the omni-directional mobile robot a very practical application. Most of the parts in the omni-directional mobile robot can be easily replaced and reused. The mobile robot itself is constrained to be one that is inexpensive and simple. This would allow others to replicate its concept and improve on it. The control system can be improved by simply replacing the control circuit board on the mobile robot. The new control system can be easily integrated with the peripheral devices, such as motors and sensors. Moreover, the size of the mobile robot base is adjustable , which makes this base design valuable for those who are interested in the development of omni-directional robot applications but are concerned about the size of the robot.
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    A robotic chewing device for food evaluation : a thesis presented in partial fulfilment of the requirements for the degree of Master of Engineering in Mechatronics at Massey University,
    (Massey University, 2006) Lewis, Darren
    The aim of this masters project was to design and develop a prototype of robotic chewing device. This project was required for use in food evaluation as it can provide standardised chewing. The chewing device was required to follow chewing trajectories of a human and apply the same forces that humans apply during chewing. This was achieved by the use of a robotic system that incorporated a mechanical linkage, supporting software and electronics to control it and therefore ensure correct operation. The mechanical linkage used is based on a four-bar linkage mechanism that can closely approximate human chewing trajectories. The linkage also has the ability to be adjusted to achieve a range of chewing trajectories for different food types. This is due to the fact that humans chew foods with different properties differently. The linkage is driven by a single DC motor that is controlled by a control card and a supervisory software program on a computer. This ensures that chewing is performed at the correct speed in the different phases of the chewing cycle and also provides all the necessary controls for operation of the device. Anatomically correct teeth were also used to help closely match the particle size reduction of the human system, while a food retention device was made to keep the food particles on the teeth while chewing.
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    A chewing robot based on parallel mechanism-- analysis and design : a thesis presented in partial fulfilment of the requirements for the degree of Master of Engineering in Mechatronics at Massey University
    (Massey University, 2006) Pap, József-Sebastian
    Masticatory efficiency, dependent on number and condition of the teeth, length of time spent in chewing a bolus and the force exerted when chewing, influences an individual with the selection of food and therefore nutritionally diet. A characterisation of the masticatory efficiency could be possible with a chewing robot that simulates human chewing behaviours in a mechanically controllable way (Pap et al. 2005; Xu et al. 2005). This thesis describes such a chewing robot, developed from a biological basis in terms of jaw structure and muscles of mastication according to published articles. A six degrees of freedom parallel mechanism is proposed with the mandible as a moving platform, the skull as a fixed platform, and six actuators representing the main masticatory muscle groups, temporalis, masseter, and lateral pterygoid on the left and right side. Extensive simulations of inverse kinematics (i.e., generating muscular actuations with implementing recorded human trajectories) were conducted in SolidWorks and COSMOS/Motion to validate two mathematical models of the robot and to analyse kinematic properties. The research showed that selection of appropriate actuation systems, to achieve mandible movement space, velocity, acceleration, and chewing force, was the key challenge in successfully developing a chewing robot. Two custom designed actuation systems, for the six actuators, were developed and built. In the first approach, the muscle groups were presented as linear actuators, positioned so as to reproduce the resultant lines of action of the human muscles. However, with this design concept the spatial requirements specified from the human masticatory system made the physical building of the model impossible. The second approach used a crank mechanism based actuator. This concept did not allow a perfectly linear actuator movement that copied the muscle line of action. However, it was possible to fulfil the spatial requirements set by the human system and to allow reproduction of human chewing behaviours in relation to kinematic requirements and chewing force. The design, manufacture and testing of the entire chewing robot with crank actuators was then carried out. This included the implementation of realistic denture morphology, a mechanical jaw and the framework design for the whole system. In conclusion, this thesis research has developed successfully a mathematical and a physical robotic model. Future work on the control and sensing of the robot and design of a food retention system are required in order to fully functionalise the device.
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    Kinematics, motion control and force estimation of a chewing robot of 6RSS parallel mechanism : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Engineering at Massey University, Palmerston North, New Zealand
    (Massey University, 2011) Torrance, Jonathan David
    Parallel robots have been found in many applications where the work requirements are beyond the capabilities of serial robots. Mouth movements during the chewing of foods are ideally suited to the parallel robot due to relatively high force together with 6 degree of freedom (DOF) motion all occurring in a small workspace. The Massey Robotic Jaw (MRJ) is a life sized mastication robot of 6RSS parallel mechanism designed with human physiology in mind, and to be capable of recreating the movements and forces of human mastication. The MRJ consists of a movable mandible attached to a fixed 'skull' through 6RSS crank mechanisms enabling six degree of freedom motion. In order to perform targeted movements of the MRJ, inverse kinematics of mechanism are solved. Target movements of the lower jaw can then be translated to six individual movements of each actuator. The synchronised motion of all six actuators is implemented using appropriate motion control to create the desired motion at the lower jaw. Motion control in context of the MRJ involves position control during the non-occluding phases of the mastication cycle. The kinematic and dynamic models of a generic 6RSS robot are discussed and are then simplified considering the special features of a practical chewing robot and the requirements of controller design. The issue of dynamic position and force control of a chewing robot with a 6RSS mechanism is addressed. An impedance control scheme is proposed to achieve the position and force control of the robot. A detailed description on the steps to implement the controller is also presented. The application of the 6RSS parallel chewing robot to food chewing experiments was described. The force vector applied on the active molar was calculated from the measured torques applied on the six actuators using an analysis of forces through the linkage mechanism. A series of experiments were carried out using model and real foods. The work shows promise for application of the robot to characterise food texture, however a number of future developments are required. To make the robot more human-like, a tongue, cheek and mouth chamber need to be included. Furthermore, accurate force sensing and position sensing of the mandible in Cartesian space is suggested as a means to validate the impendence control method proposed and to verify the force measurement strategy implemented in chapter 6.
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    The design and construction of an anthropomorphic humanoid service robot : a thesis presented in partial fulfilment of the requirements for the degree of Master of Engineering in Mechatronics at Massey University, Palmerston North, New Zealand
    (Massey University, 2011) Barlow, Peter William Edward
    This thesis presents the research, mechanical design and construction of the lower half of a biped robot. In the long run this work will be developed further to build a service robot to perform repetitive (and often dangerous) tasks and to help disabled people to carry out everyday tasks. The aim of this research project is to develop a humanoid with the agility of a ‘high end’ robot but on a very low budget in comparison. In order to achieve this, several unique mechanical attributes have been proposed and implemented such as dual push rod actuated joint articulation. This technique produces a larger joint torque and reduces leg inertia allowing for the implementation of WCK serial controlled servo modules for actuation. To further increase human-like similarities a toe joint is implemented. This gives the humanoid the ability to stride more elegantly, increase speed control, and reduce energy used for each step. All the parts of this robot have been manufactured from scratch and most have been CNC machined. Solidworks is used as a 3D modelling package to produce a simulated version of the humanoid to determine dimensions and dynamics before construction takes place. SolidCAM is a computer aided machining package which was used to specify machining paths to produce G-Code. An additional 4th axis was added to the CNC machine solely for the purpose of this project as many parts were too intricate and complex for the standard 3 axis machine. A biped humanoid requires several types of sensors for balancing. High accuracy and resolution is of paramount importance for the successful control of the humanoid. Various force sensors are reviewed and their advantages and disadvantages are discussed. Gyroscopes and attitude heading reference systems (AHRS) are investigated and tests are performed on all units to obtain operational characteristics and accuracy. Visual Basic.net has been used for developing software for controlling and monitoring all sensors and actuator modules. Essentially a humanoid platform has been developed with appropriate software allowing for the next stage of development, the development of the gait control algorithms.
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    Autonomous agents in a dynamic collaborative environment : a thesis presented in partial fulfilment of the requirements for the degree of PhD in Engineering at Massey University, Palmerston North, New Zealand
    (Massey University, 2008) Sen Gupta, Gourab
    The proliferation of robots in industry and every day human life is gaining momentum. After the initial few decades of employment of robots in the industry, especially the automotive assembly plants, robots are now entering the home and offices. From being pick-and-place manipulators, robots are slowly being transformed in shape and form to be more anthropomorphic. The wheeled robots are however here to stay for the foreseeable future until such time as artificial muscles, and efficient means to control them, are well developed. The next phase of development of robots will be for the service industry. Robots will cooperate with each other to accomplish collaborative tasks to aid human life. They will also collaborate with human beings to assist them in doing tasks such as lifting loads and moving objects. At the same time, with the advancement of hardware, robots are becoming very fast and are capable of being programmed with more intelligence. Coupled with this is the availability of sophisticated sensors with which the robots can perceive the real world around them. Combinations of these factors have created many challenging areas of research. Several factors affect the performance of robots in a dynamic collaborative environment. The research presented in this thesis has identified the major contributing factors, namely fast vision processing, behaviour programming, predictive movement and interception control, and precise motion control, that collectively have influence on the performance of robots which are engaged in a collaborative effort to accomplish a task. Several novel techniques have been proposed in this thesis to enhance the collective performance of collaborating robots. In many systems, vision is used as one of the sensory inputs for the robot’s perception of the environment. This thesis describes a new colour space and the use of discrete look-up-tables (LUT) for very fast and robust colour segmentation and real-time identification of objects in the robot’s work space. A distributed camera system and a stereo vision using a single camera are reported. Advanced filtering has been applied to the vision data for predictive identification of the position and orientation of moving robots and targets, and for anticipatory interception control. Collaborative tasks are generally complex and robots need to be capable of exhibiting sophisticated behaviours. This thesis has detailed the use of State Transition Based Control (STBC) methodology to build a hierarchy of complex behaviour. Behaviour of robots in a robot soccer game and features such as role selection and obstacle avoidance have been built using STBC. A novel methodology for advanced control of fast robots is detailed. The algorithm uses a combination of Triangular Targeting Algorithm (TTA) and Proximity Positioning Algorithm (PPA) to position a robot behind an object aligned with a target. Various forms of velocity profiling have been proposed and validated with substantial test results. The thesis ends by looking at future scenarios where robots and human beings will coexist and work together to do many collaborative tasks. Anthropomorphic robots will be more prevalent in future and teleoperation will gain momentum. Throughout the thesis, the engineering applicability of proposed algorithms and architectures have been emphasised by testing on real robots.