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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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    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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    Indoor localization of a mobile robot using sensor fusion : a thesis presented in partial fulfilment of the requirements for the degree of Master of Engineering in Mechatronics with Honours at Massey University, Wellington, New Zealand
    (Massey University, 2011) Zhou, Jason
    Reliable indoor navigation of mobile robots has been a popular research topic in recent years. GPS systems used for outdoor mobile robot navigation can not be used indoor (warehouse, hospital or other buildings) because it requires an unobstructed view of the sky. Therefore a specially designed indoor localization system for mobile robot is needed. This project aims to develop a reliable position and heading angle estimator for real time indoor localization of mobile robots. Two different techniques have been developed and each consisted of three different sensor modules based on infrared sensing, calibrated odometry and calibrated gyroscope. Integration of these three sensor modules is achieved by applying the real time Kalman filter which provides filtered and reliable information of a mobile robot's current location and orientation relative to its environment. Extensive experimental results are provided to demonstrate its improvement over conventional methods like dead reckoning. In addition, a control strategy is developed to control the mobile robot to move along the planned trajectory. The techniques developed in this project have potentials for the application for mobile robots in medical service, health care, surveillances, search and rescue in indoor environments.
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    Tree pruning/inspection robot climbing mechanism design, kinematics study and intelligent control : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Mechatronics at Massey University, Manawatu Campus, New Zealand
    (Massey University, 2018) Gui, Pengfei
    Forestry plays an important role in New Zealand’s economy as its third largest export earner. To achieve New Zealand Wood Council’s export target of $12 billion by 2022 in forest and improve the current situation that is the reduction of wood harvesting area, the unit value and volume of lumber must be increased. Pruning is essential and critical for obtaining high-quality timber during plantation growing. Powerful tools and robotic systems have great potential for sustainable forest management. Up to now, only a few tree-pruning robotic systems are available on the market. Unlike normal robotic manipulators or mobile robots, tree pruning robot has its unique requirements and features. The challenges include climbing pattern control, anti-free falling, and jamming on the tree trunk etc. Through the research on the available pole and tree climbing robots, this thesis presents a novel mechanism of tree climbing robotic system that could serve as a climbing platform for applications in the forest industry like tree pruning, inspection etc. that requires the installation of powerful or heavy tools. The unique features of this robotic system include the passive and active anti-falling mechanisms that prevent the robot falling to the ground under either static or dynamic situations, the capability to vertically or spirally climb up a tree trunk and the flexibility to suit different sizes of tree trunk. Furthermore, for the convenience of tree pruning and the fulfilment of robot anti-jamming feature, the robot platform while the robot climbs up should move up without tilting. An intelligent platform balance control system with real-time sensing integration was developed to overcome the climbing tilting problem. The thesis also presents the detail kinematic and dynamic study, simulation, testing and analysis. A physical testing model of this proposed robotic system was built and tested on a cylindrical rod. The mass of the prototype model is 6.8 Kg and can take 2.1 Kg load moving at the speed of 42 mm/s. The trunk diameter that the robot can climb up ranges from 120 to 160 mm. The experiment results have good matches with the simulations and analysis. This research established a basis for developing wheel-driven tree or pole climbing robots. The design and simulation method, robotic leg mechanism and the control methodologies could be easily applied for other wheeled tree/pole climbing robots. This research has produced 6 publications, two ASME journal papers and 4 IEEE international conference papers that are available on IEEE Xplore. The published content ranges from robotic mechanism design, signal processing, platform balance control, and robot climbing behavior optimization. This research also brought interesting topics for further research such as the integration with artificial intelligent module and mobile robot for remote tree/forest inspection after pruning or for pest control.
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    Mechatronic simulation & exploration of a mechanical context relevant to quadrupedal neuromorphic walking employing Nervous networks for control : a thesis presented in partial fulfilment of the requirements for the degree of Master of Engineering, Mechatronics at Massey University, Albany, New Zealand
    (Massey University, 2008) Read, Matthew
    Neuromorphic engineering is the studv and emulation of neural sensory and control structures found in the natural world. Currently a significant research focus in this field, and indeed, in engineering at large, is the research of robotic walking platforms - an ideal application for artificial neural controllers. To design such neuromorphic controllers, significant knowledge is needed of the robotic context to which they will he applied. The focus of this research is to explore the relationship between the mechanical design of a robot, and its resultant walking proficiency. A neuromorphic controller utilizing Nervous networks was constructed, and embedded into a typical & useful mechatronic context. This consists of a simple walking platform, of a type commonly used in Nervous network research. This robot was used to provide intuition and a reference point for development of a simulation for empirical testing. A physical simulation of the mechanical context was developed, allowing for the exploration of its behaviour, particularly with regard to the type of walking "caused" by the integration of an appropriate Nervous network controller. To evaluate the behavioural fitness of this context in various configurations, empirical simulations were run using the developed simulation, and heuristic results derived to develop optimized parameters for causing walking behaviours in the studied context. Further simulations were then run to evaluation the efficacy of these developed heuristics. From these simulations & explorations, the presence of an identifiable "critical point phenomenon" in the interaction between the robot's legs was demonstrated. This critical point was then used for parameter extraction; further simulation demonstrated that parameters extracted from this critical point provided near-optimal walking behaviour from the robot in a variety of leg topologies. These results provide significant knowledge and intuition for designers of quadrupedal walking platforms, particularly those driven from Nervous network derived neuromorphic controllers. Implementation of these results in such a robotic platform will provide useful new "real world" data, allowing the developed models & heuristics to be further refined.
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    Integrated and adaptive traffic signal control for diamond interchange : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Mechatronics Engineering at Massey University, Albany, New Zealand
    (Massey University, 2017) Pham, Cao Van
    New dynamic signal control methods such as fuzzy logic and artificial intelligence developed recently mainly focused on isolated intersection. Adaptive signal control based on fuzzy logic control (FLC) determines the duration and sequence that traffic signal should stay in a certain state, before switching to the next state (Trabia et al. 1999, Pham 2013). The amount of arriving and waiting vehicles are quantized into fuzzy variables and fuzzy rules are used to determine if the duration of the current state should be extended. The fuzzy logic controller showed to be more flexible than fixed controllers and vehicle actuated controllers, allowing traffic to flow more smoothly. The FLC does not possess the ability to handle various uncertainties especially in real world traffic control. Therefore it is not best suited for stochastic nature problems such as traffic signal timing optimization. However, probabilistic logic is the best choice to handle the uncertainties containing both stochastic and fuzzy features (Pappis and Mamdani 1977) Probabilistic fuzzy logic control is developed for the signalised control of a diamond interchange, where the signal phasing, green time extension and ramp metering are decided in response to real time traffic conditions, which aim at improving traffic flows on surface streets and highways. The probabilistic fuzzy logic for diamond interchange (PFLDI) comprises three modules: probabilistic fuzzy phase timing (PFPT) that controls the green time extension process of the current running phase, phase selection (PSL) which decides the next phase based on the pre-setup phase logic by the local transport authority and, probabilistic fuzzy ramp-metering (PFRM) that determines on-ramp metering rate based on traffic conditions of the arterial streets and highways. We used Advanced Interactive Microscopic Simulator for Urban and Non-Urban Network (AIMSUN) software for diamond interchange modeling and performance measure of effectiveness for the PFLDI algorithm. PFLDI was compared with actuated diamond interchange (ADI) control based on ALINEA algorithm and conventional fuzzy logic diamond interchange algorithm (FLDI). Simulation results show that the PFLDI surpasses the traffic actuated and conventional fuzzy models with lower System Total Travel Time, Average Delay and improvements in Downstream Average Speed and Downstream Average Delay. On the other hand, little attention has been given in recent years to the delays experienced by cyclists in urban transport networks. When planning changes to traffic signals or making other network changes, the value of time for cycling trips is rarely considered. The traditional approach to road management has been to only focus on improving the carrying capacity relating to vehicles, with an emphasis on maximising the speed and volume of motorised traffic moving around the network. The problem of cyclist delay has been compounded by the fact that the travel time for cyclists have been lower than those for vehicles, which affects benefit–cost ratios and effectively provides a disincentive to invest in cycling issues compared with other modes. The issue has also been influenced by the way in which traffic signals have been set up and operated. Because the primary stresses on an intersection tend to occur during vehicle (commuter) peaks in the morning and afternoon, intersections tend to be set up and coordinated to allow maximum flow during these peaks. The result is that during off-peak periods there is often spare capacity that is underutilised. Phasing and timings set up for peaks may not provide the optimum benefits during off-peak times. This is particularly important to cyclists during lunch-time peaks, when vehicle volumes are low and cyclist volumes are high. Cyclists can end up waiting long periods of time as a result of poor signal phasing, rather than due to the demands of other road users being placed on the network. The outcome of this study will not only reduce the traffic congestion during peak hours but also improve the cyclists’ safety at a typical diamond interchange.
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    Multiple configuration shell-core structured robotic manipulator with interchangeable mechatronic joints : a thesis presented in partial fulfilment of the requirements for the degree of Masters of Engineering in Mechatronics at Massey University, Turitea Campus, Palmerston North, New Zealand
    (Massey University, 2017) Janse van Vuuren, Jacques J P
    With the increase of robotic technology utilised throughout industry, the need for skilled labour in this area has increased also. As a result, education dealing with robotics has grown at both the high-school and tertiary educational level. Despite the range of pedagogical robots currently on the market, there seems to be a low variety of these systems specifically related to the types of robotic manipulator arms popular for industrial applications. Furthermore, a fixed-arm system is limited to only serve as an educational supplement for that specific configuration and therefore cannot demonstrate more than one of the numerous industrial-type robotic arms. The Shell-Core structured robotic manipulator concept has been proposed to improve the quality and variety of available pedagogical robotic arm systems on the market. This is achieved by the reconfigurable nature of the concept, which incorporates shell and core structural units to make the construction of at least 5 mainstream industrial arms possible. The platform will be suitable, but not limited to use within the educational robotics industry at high-school and higher educational levels and may appeal to hobbyists. Later dubbed SMILE (Smart Manipulator with Interchangeable Links and Effectors), the system utilises core units to provide either rotational or linear actuation in a single plane. A variety of shell units are then implemented as the body of the robotic arm, serving as appropriate offsets to achieve the required configuration. A prototype consisting of a limited number of ‘building blocks’ was developed for proof-of-concept, found capable of achieving several of the proposed configurations. The outcome of this research is encouraging, with a Massey patent search confirming the unique features of the proposed concept. The prototype system is an economic, easy to implement, plug and play, and multiple-configuration robotic manipulator, suitable for various applications.
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    Omni-directional mobile platform for the transportation of heavy objects : a thesis presented in partial fulfilment of the requirements for the degree of Masters in Engineering at Massey University, Palmerston North, New Zealand
    (Massey University, 2011) Thomas, Ryan
    As the cost of work related injuries continues to rise, it becomes more economically viable to employ robotic help in the workplace. This thesis details the development of a robotic platform for the purposes of aiding in the transportation of heavy objects, specifically hospital beds. Because in most workplaces space is at a premium, it is important for any device to be highly manoeuvrable. As anthropomorphic robots are not at a stage of providing this kind of service, a wheeled platform is the most cost effective option. To maximise the manoeuvrability of such a platform an omni-directional approach is advantageous. Existing commercial products have been investigated and found to be lacking true omni-directional capabilities. These platforms also rely on lifting the beds, usually with large forklift like mechanisms that encumber bed attachment in small room. Mecanum wheels have been used to achieve omni-directional movement for this platform. For Mecanum wheels to function correctly all four wheels must be individually powered and must maintain contact with the ground at all times. To achieve this, various suspension systems have been looked at with the most suitable being chosen. Various methods of speed feedback have been investigated and a sensorless method has been compared to a traditional quadrature encoder. Motor drivers/controllers are necessary to enable the precise control of the motors which is essential for the omni-directional capabilities. Commercial drivers have been investigated but found to be inadequate for the purposes of this project. Therefore a motor driver has been developed, built and tested including the sensorless speed feedback system. The directional user input is handled by a joystick which is interpreted by a microcontroller. This microcontroller controls all the aspects of the platform including the motor drivers, LCD screen, an inclination sensor and another microcontroller for any possible add-on equipment. The add-on equipment for this project is a bed attachment device. A headboard gripping system provides the most robust, compact and flexible system for bed attachment. A combined microcontroller and motor driver arrangement has been designed for the gripper. The gripper and the platform have been combined with a human interface and the system has been tested as a whole. The system has been fully tested in the lab and is awaiting clearance for field trials.
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    Optimal robust control systems design and analysis by state space approaches : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy, Technology, at Massey University
    (Massey University, 1995) Wei, Hao
    This thesis provides a fundamental investigation of robust control, both the issues of robust controller design and robustness analysis of control systems are addressed. The techniques presented evolve from time domain descriptions of linear systems and employ state space approaches. A comprehensive review of the field is given and several significant advances are presented. These include some new design and analysis techniques and some new perspectives on existing techniques. The thesis is fundamental in nature, systematically developing and criticising algorithms and methodologies. Some numerical examples are employed to illustrate the results. Robust control addresses problems caused by discrepancies between nominal system models used for conventional controller design and analysis, and actual 'real' systems. Much of the classical work in the field assumed no knowledge of possible (or even probable) uncertainties and considered system tolerance to some general, imprecise classes of discrepancy. This tended to lead to conservative designs which degraded system performance to an unnecessary extent. The modern trend is to provide a 'precise' prediction of possible (probable) uncertainties, described by an uncertainty model. This aims to avoid the consideration of unfeasible discrepancies which often caused the conservatism and will tend to minimise performance degradation. However, tolerance to further (hopefully small) unpredicted uncertainties should still be considered as such residual discrepancies will always exist. This modern trend is supported in this thesis and one of the main potential benefits of the new methodologies will be less conservative designs. The principle contributions include: systematic methods for the design of cost-optimal robust controllers for both full state feedback and output feedback systems. These explicitly consider a nominal system model and an admissible domain of uncertainties and also provide some inherent robustness to residual uncertainties. Furthermore, a new method for the analysis of the robustness of given full state feedback controllers is presented. For an admissible domain of uncertainty of given structure, the maximal magnitude is determined such that stability and performance criteria are upheld.