Publications
390 results found
Chen X, Kiziroglou ME, Yeatman EM, 2022, Linear displacement and force characterisation of a 3D-printed flexure-based delta actuator, Smart Materials and Structures, Vol: 31, Pages: 1-9, ISSN: 0964-1726
Piezoelectric beams provide a fast, high-force and scalable actuation mechanism that could offer precise motion control to medical microdevices including invasive micromanipulators, catheters and diagnosis tools. Their small displacement range can be addressed by motion amplification mechanisms. In this paper, a piezoelectric-actuated delta-robot actuator is proposed for probe-based confocal laser endomicroscopy (pCLE) microsystems. A prototype is designed and fabricated using three-dimensional (3D) polymer compound printing for a multi-flexure compliant motion amplifier and commercial piezoelectric beams. The flexure material is optimised for maximum linear output motion. The overall robot length is 76 mm and its maximum lateral dimension is 32 mm, with 10 g overall mass, including three piezoelectric beams. An axial motion control range of 0.70 mm and a maximum axial force of 20 mN are demonstrated, at 140 V actuation voltage. The proposed actuator architecture is promising for controlling lens, fibre and micromanipulator components for medical microrobotic applications.
Holmes AS, Kiziroglou ME, Yang SKE, et al., 2022, Minimally invasive online water monitor, IEEE Internet of Things Journal, Vol: 9, Pages: 14325-14335, ISSN: 2327-4662
Sensor installation on water infrastructure is challenging due to requirements for service interruption, specialised personnel, regulations and reliability as well as the resultant high costs. Here, a minimally invasive installation method is introduced based on hot-tapping and immersion of a sensor probe. A modular architecture is developed that enables the use of interchangeable multi-sensor probes, non-specialist installation and servicing, low-power operation and configurable sensing and connectivity. A prototype implementation with a temperature, pressure, conductivity and flow multi-sensor probe is presented and tested on an evaluation rig. This paper demonstrates simple installation, reliable and accurate sensing capability as well as remote data acquisition. The demonstrated minimally invasive multi-sensor probes provide an opportunity for the deployment of water quality sensors that typically require immersion such as pH and spectroscopic composition analysis. This design allows dynamic deployment on existing water infrastructure with expandable sensing capability and minimal interruption, which can be key to addressing important sensing parameters such as optimal sensor network density and topology.
Wales DJ, Keshavarz M, Howe C, et al., 2022, 3D Printability Assessment of Poly(octamethylene maleate (anhydride) citrate) and Poly(ethylene glycol) Diacrylate Copolymers for Biomedical Applications, ACS APPLIED POLYMER MATERIALS, Vol: 4, Pages: 5457-5470, ISSN: 2637-6105
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- Citations: 2
Cursi F, Bai W, Yeatman EM, et al., 2022, Model learning with backlash compensation for a tendon-driven surgical Robot, IEEE Robotics and Automation Letters, Vol: 7, Pages: 7958-7965, ISSN: 2377-3766
Robots for minimally invasive surgery are becoming more and more complex, due to miniaturization and flexibility requirements. The vast majority of surgical robots are tendon-driven and this, along with the complex design, causes high nonlinearities in the system which are difficult to model analytically. In this work we analyse how incorporating a backlash model and compensation can improve model learning and control. We combine a backlash compensation technique and a Feedforward Artificial Neural Network (ANN) with differential relationships to learn the kinematics at position and velocity level of highly articulated tendon-driven robots. Experimental results show that the proposed backlash compensation is effective in reducing nonlinearities in the system, that compensating for backlash improves model learning and control, and that our proposed ANN outperforms traditional ANN in terms of path tracking accuracy.
Cursi F, Bai W, Li W, et al., 2022, Augmented neural network for full robot kinematic modelling in SE(3), IEEE Robotics and Automation Letters, Vol: 7, Pages: 7140-7147, ISSN: 2377-3766
Due to the increasing complexity of robotic structures, modelling robots is becoming more and more challenging, and analytical models are very difficult to build. Machine learning approaches have shown great capabilities in learning complex mapping and have widely been used in robot model learning and control. Generally, the inverse kinematics is directly learned, yet, learning the forward kinematics is simpler and allows computing exploiting the optimality of the controllers. Nevertheless, the learning method has no knowledge about the differential relationship between the position and velocity mappings. Currently, few works have targeted learning full robot poses considering both position and orientation. In this letter, we present a novel feedforward Artificial Neural network (ANN) architecture to learn full robot pose in SE(3) incorporating differential relationships in the learning process. Simulation and real world experiments show the capabilities of the proposed network to properly model the robot pose and its advantages over standard ANN.
Arteaga JM, Mitcheson PD, Yeatman EM, 2022, Development of a fast-charging platform for buried sensors using high frequency IPT for agricultural applications, 2022 IEEE Applied Power Electronics Conference and Exposition (APEC), Publisher: IEEE, Pages: 1116-1121
This paper describes the methodology and experimental results for wireless power delivery to a soil-sensors power and data distribution unit from an unmanned aerial vehicle (UAV), using a high frequency inductive power transfer (HF-IPT) link. The configuration features, at the transmit side, a lightweight single-turn air-core coil driven by a 13.56 MHz Class EF inverter mounted on a Matrice 100 drone by DJI, and at the receive side, a two-turn PCB coil with a voltage-tipler Class D rectifier, an off-the-shelf 42 V battery charger and a supercapacitors module for energy storage. The experiments were conducted with a coil-to-coil gap of 250 mm, which corresponds to a coupling factor lower than 5%. In the experiments, a 10 F, 42 V supercapacitors module was charged in eleven minutes with an energy efficiency of 34% from the 80 V DC source that feeds the inverter on the drone to the supercapacitor-based energy storage unit in the sensor module. At higher power (50 W) the HF-IPT system was able to achieve a 68% DC-DC efficiency with a coupling factor of 3.5%. The work reported in this paper is part of a multiple-discipline project which looks to enable the optimal usage of water in agriculture with broader sensing techniques and more frequent sensing cycles.
Kiziroglou ME, Wright SW, Yeatman EM, 2022, Power supply based on inductive harvesting from structural currents, IEEE Internet of Things Journal, Vol: 9, ISSN: 2327-4662
Monitoring infrastructure offers functional optimisation, lower maintenance cost, security, stability and data analysis benefits. Sensor nodes require some level of energy autonomy for reliable and cost-effective operation, and energy harvesting methods have been developed in the last two decades for this purpose. Here, a power supply that collects, stores and delivers regulated power from the stray magnetic field of currentcarrying structures is presented. In cm-scale structures the skin effect concentrates current at edges at frequencies even below 1 kHz. A coil-core inductive transducer is designed. A fluxfunnelling soft magnetic core shape is used, multiplying power density by the square of funnelling ratio. A power management circuit combining reactance cancellation, voltage doubling, rectification, super-capacitor storage and switched inductor voltage boosting and regulation is introduced. The power supply is characterised in house and on a full-size industrial setup, demonstrating a power reception density of 0.36 mW/cm3, 0.54 mW/cm3 and 0.73 mW/cm3 from a 25 A RMS structural current at 360 Hz, 500 Hz and 800 Hz respectively, corresponding to the frequency range of aircraft currents. The regulated output is tested under various loads and cold starting is demonstrated. The introduced method may enable power autonomy to wireless sensors deployed in current-carrying infrastructure.
Gil Rosa B, Akingbade OE, Guo X, et al., 2022, Multiplexed immunosensors for point-of-care diagnostic applications, Biosensors and Bioelectronics, Vol: 203, ISSN: 0956-5663
Accurate, reliable, and cost-effective immunosensors are clinically important for the early diagnosis and monitoring of progressive diseases, and multiplexed sensing is a promising strategy for the next generation of diagnostics. This strategy allows for the simultaneous detection and quantification of multiple biomarkers with significantly enhanced reproducibility and reliability, whilst requiring smaller sample volumes, fewer materials, and shorter average analysis time for individual biomarkers than individual tests. In this opinionated review, we compare different techniques for the development of multiplexed immunosensors. We review the state-of-the-art approaches in the field of multiplexed immunosensors using electrical, electrochemical, and optical methods. The barriers that prevent translating this sensing strategy into clinics are outlined together with the potential solutions. We also share our vision on how multiplexed immunosensors will continue their evolution in the coming years.
Bacha SC, Bai W, Wang Z, et al., 2022, Deep Reinforcement Learning-Based Control Framework for Multilateral Telesurgery, IEEE TRANSACTIONS ON MEDICAL ROBOTICS AND BIONICS, Vol: 4, Pages: 352-355
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- Citations: 6
Bai W, Cursi F, Guo X, et al., 2022, Task-Based LSTM Kinematic Modeling for a Tendon-Driven Flexible Surgical Robot, IEEE TRANSACTIONS ON MEDICAL ROBOTICS AND BIONICS, Vol: 4, Pages: 339-342
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- Citations: 4
Cursi F, Bai W, Yeatman EM, et al., 2022, GlobDesOpt: a global optimization framework for optimal robot manipulator design, IEEE Access, Vol: 10, Pages: 5012-5023, ISSN: 2169-3536
Robot design is a major component in robotics, as it allows building robots capable of performing properly in given tasks. However, designing a robot with multiple types of parameters and constraints and defining an optimization function analytically for the robot design problem may be intractable or even impossible. Therefore black-box optimization approaches are generally preferred. In this work we propose GlobDesOpt, a simple-to-use open-source optimization framework for robot design based on global optimization methods. The framework allows selecting various design parameters and optimizing for both single and dual-arm robots. The functionalities of the framework are shown here to optimally design a dual-arm surgical robot, comparing the different two optimization strategies.
Bai W, Wang Z, Cao Q, et al., 2022, Anthropomorphic dual-arm coordinated control for a single-port surgical robot based on dual-step optimization, IEEE Transactions on Medical Robotics and Bionics, Vol: 4, Pages: 72-84, ISSN: 2576-3202
Effective teleoperation of the small-scale and highly-integrated robots for single-port surgery (SPS) imposes unique control and human-robot interaction challenges. Traditional isometric teleoperation schemes mainly focus on end-to-end trajectory mapping, which is problematic when applied to SPS robotic control, especially for dual-arm coordinated operation. Inspired by the human arm configuration in boxing maneuvers, an optimized anthropomorphic coordinated control strategy based on a dual-step optimization approach is proposed. Theoretical derivation and solvability of the problem are addressed, and the effectiveness of the method is further demonstrated in detailed simulation and in-vitro experiments. The proposed control strategy has been shown to perform dexterous SPS bimanual manipulation more effectively, involving less instrument-interference and is free from singularities, thereby improving the safety and efficiency of SPS operations.
Vyas K, Yeatman E, Dasgupta R, 2022, Rapid digital histology of urothelial carcinoma using line-scan confocal laser endomicroscopy
We present a high-speed line-scan confocal laser endomicroscope, which enables digital histopathology of freshly excised un-fixed bladder tissue specimens in real-time.
Sanchez J, Arteaga JM, Pucci N, et al., 2022, Misalignment Parameterization of a 13.56 MHz Inductive Power Transfer System for in-situ Soil Sensing, Pages: 278-281
This paper discusses the measurement and characterization of the coil-to-coil misalignment in a 13.56 MHz inductive power transfer (IPT) system using variables that are either measurable on the wireless power transmitter alone (inverter current) or in conjunction with the receiver's Bluetooth module (rectifier voltage). A two- axis gantry transported the receiver on a plane 22 cm below the transmitter to perform these tests. The results from these tests demonstrate that the lateral coil-to-coil misalignment of this IPT system can be parameterized over the range of 0 to 30 cm with an average error of less than 2 cm. At peak alignment, this error decreases power transmission efficiency by less than 0.2%.
Sun L, Huang Y, Wang Z, et al., 2022, Dual Quaternion Based Finite-Time Tracking Control for Mechatronic Systems with Actuation Allocation
This paper investigates the tracking control performance regulation and actuation allocation of mechatronic systems subject to coupling motions. In particular, the kinematic and dynamic model is described by dual quaternion, which captures the coupling effect between translation and rotation movements. Considering external disturbances and system uncertainties, a non-singular fast terminal sliding controller is then developed to ensure finite-time tracking performance. In addition, the unwinding problem caused by the redundancy of dual quaternion is addressed with the help of a novel attitude error function. Furthermore, an improved simplex method is designed for distributing the developed control commands to proper actuators. Numerical simulations demonstrate the effectiveness with respect to disturbance suppression, fast tracking, high accuracy, and finite-time stability of the proposed method.
Bautista-Salinas D, Abdelaziz MEMK, Temelkuran B, et al., 2022, Towards a Functional Atraumatic Self-Shaping Cochlear Implant, MACROMOLECULAR MATERIALS AND ENGINEERING, Vol: 307, ISSN: 1438-7492
Rosa BMG, Lo B, Yeatman E, 2022, Prototype smartwatch device for prolonged physiological monitoring in remote environments, IEEE-EMBS International Conference on Wearable and Implantable Body Sensor Networks (BSN) / 18th IEEE-EMBS International Conference on Biomedical and Health Informatics (BHI), Publisher: IEEE, ISSN: 2376-8886
Cursi F, Bai W, Yeatman EM, et al., 2022, Adaptive Kinematic Model Learning for Macro-Micro Surgical Manipulator Control, 7th IEEE International Conference on Advanced Robotics and Mechatronics, Publisher: IEEE, Pages: 494-501
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- Citations: 1
Zhou X, Bai W, Ren Y, et al., 2022, An LSTM-based Bilateral Active Estimation Model for Robotic Teleoperation with Varying Time Delay, 7th IEEE International Conference on Advanced Robotics and Mechatronics, Publisher: IEEE, Pages: 725-730
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- Citations: 2
Moorthy V, Kassanos P, Burdet E, et al., 2022, Stencil Printing of Low-Cost Carbon-Based Stretchable Strain Sensors, IEEE Sensors Conference, Publisher: IEEE, ISSN: 1930-0395
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- Citations: 1
Sanchez J, Arteaga JM, Zeisiger C, et al., 2022, Integration of a High Frequency Inductive Power Transfer System to Energize Agricultural Sensors Through Soil, Wireless Power Week (WPW), Publisher: IEEE, Pages: 366-371
Yang S, Kiziroglou M, Yeatman E, et al., 2021, Passive acoustic transducer as a fluid flow sensor, IEEE Sensors Conference, Publisher: IEEE, Pages: 1-4
Autonomy and minimal disruption are key desirable features for sensors to be deployed in medical, industrial, vehicle and infrastructure monitoring systems. Using a passive structure to transduce the quantity of interest into an acoustic or electromagnetic wave could offer an attractive solution for remote sensing, lifting the requirements of installing active materials, electronics, and power sources in remote, inaccessible, sensitive, or harsh environment locations. Here, we report a simple cavity and ball structure that transduces fluid flow through a pipe into an acoustic signal. A microphone on the outside wall of the pipe records the intensity and arrival rate of the sound pulses generated by collisions between the ball and the cavity walls. Using this approach external measurement of flow is demonstrated with adequate repeatability before any acoustic signal processing. This result is expected to open the way to the implementation of passive, remotely readable sensors for fluid flow and other fluid properties of interest.
Huang Z, Wang Z, Bai W, et al., 2021, A novel training and collaboration integrated framework for human-agent teleoperation., Sensors (Basel, Switzerland), Vol: 21, Pages: 1-15, ISSN: 1424-8220
Human operators have the trend of increasing physical and mental workloads when performing teleoperation tasks in uncertain and dynamic environments. In addition, their performances are influenced by subjective factors, potentially leading to operational errors or task failure. Although agent-based methods offer a promising solution to the above problems, the human experience and intelligence are necessary for teleoperation scenarios. In this paper, a truncated quantile critics reinforcement learning-based integrated framework is proposed for human-agent teleoperation that encompasses training, assessment and agent-based arbitration. The proposed framework allows for an expert training agent, a bilateral training and cooperation process to realize the co-optimization of agent and human. It can provide efficient and quantifiable training feedback. Experiments have been conducted to train subjects with the developed algorithm. The performances of human-human and human-agent cooperation modes are also compared. The results have shown that subjects can complete the tasks of reaching and picking and placing with the assistance of an agent in a shorter operational time, with a higher success rate and less workload than human-human cooperation.
Chen X, Kiziroglou ME, Yeatman EM, 2021, Evaluation platform for MEMS-actuated 3D-printed compliant structures, 2021 IEEE 20th International Conference on Micro and Nanotechnology for Power Generation and Energy Conversion Applications (PowerMEMS), Publisher: IEEE, Pages: 188-191
This paper presents experimental results on an evaluation platform for MEMS-actuated compliant structures. A combination of 3 dimensional (3D) flexure design, 3D printing of polymers with controlled stiffness is employed. A modular system design approach allows the interchange and combination of different actuation cantilevers, flexures and structure designs implemented as standalone test parts with minimal assembly requirements. The performance evaluation method includes synchronised electrical excitation and optical displacement measurements, allowing characterisation of motion amplification, dynamic response as well as actuating power transfer. As a demonstrator, a single lever compliant structure was designed, fabricated and tested on the platform to investigate how geometry and material stiffness affect performance. The experimental results reveal that significant improvement of amplification ratio and absolute phase lag can be achieved by selecting a flexure height and material composition suitable for a given application. This method of combined experimental evaluation and custom 3D design and printing is promising for optimising the design of compliant structures for MEMS sensors, actuators and energy transducers with amplified or translated motion capability.
Pandiyan AYS, Kiziroglou ME, Yeatman EM, 2021, Complex impedance matching for far-field acoustic wireless power transfer, 2021 IEEE 20th International Conference on Micro and Nanotechnology for Power Generation and Energy Conversion Applications (PowerMEMS), Publisher: IEEE, Pages: 44-47
In this study, different load matching techniques are analysed to identify the optimum method to deliver power to the receiver for acoustic wireless power transfer systems. Complex impedance matching of the system’s transducers provides an advantage to drive the transmitter off-resonance for cases where there is a resonance mismatch between the transducers due to make, defect or ambient conditions. By studying the effect of impedance matching for different frequencies near the resonance frequency, similar power levels can be achieved for a wider bandwidth of frequencies using complex impedance matching. Thus, increased power can be delivered to the receiver by controlling the frequency of the transmitter, which can be exploited for beam steering along the propagation axis when standing waves are prominent between the transducers. A summary of the power experimentally extracted for the different loading techniques presented in this paper demonstrates a 4 kHz increase in system bandwidth and 140% more power can be delivered by tuning both transducers with complex impedance matching.
Wright SW, Kiziroglou ME, Yeatman EM, 2021, Magnetic flux guidance using H structures for miniature transducers, 2021 IEEE 20th International Conference on Micro and Nanotechnology for Power Generation and Energy Conversion Applications (PowerMEMS), Publisher: IEEE, Pages: 156-159
Limited magnetic flux has been a significant restriction in the applicability of scaled-down inductive energy, sensing and actuating devices. Magnetic flux concentration could potentially address this challenge by offering higher flux density B and thereby higher transduction power density, sensitivity and force in the small scale. In this paper, a study of flux concentration from a flux path perspective is presented. Numerical simulations show that high permeability cylindrical cores can achieve a flux concentration ratio in the scale of their aspect ratio, as they gather flux from their reachable vicinity. Flux guiding structures such as H-shapes can concentrate the flux incident to their surface and guide it through a small cross-section, achieving a higher concentration ratio. In an experimental study, a flux concentration factor of 6 is reported using a single 5 mm diameter, 20 mm high cylinder, and an additional increase factor of 4.3 from the addition of 70 mm × 12 mm × 2 mm flanges. A total B amplification ratio of 26 is demonstrated. As an application demonstrator, this approach is employed in an inductive energy harvester yielding 11.4 mW average power output (0.3 mW/g) from a 0.12 mT RMS, 800 Hz field.
Shi M, Yeatman EM, 2021, A comparative review of artificial muscles for microsystem applications, Microsystems and Nanoengineering, Vol: 7, Pages: 1-19, ISSN: 2055-7434
Artificial muscles are capable of generating actuation in microsystems with outstanding compliance. Recent years have witnessed a growing academic interest in artificial muscles and their application in many areas, such as soft robotics and biomedical devices. This paper aims to provide a comparative review of recent advances in artificial muscle based on various operating mechanisms. The advantages and limitations of each operating mechanism are analyzed and compared. According to the unique application requirements and electrical and mechanical properties of the muscle types, we suggest suitable artificial muscle mechanisms for specific microsystem applications. Finally, we discuss potential strategies for energy delivery, conversion, and storage to promote the energy autonomy of microrobotic systems at a system level.
Kiziroglou ME, Yeatman EM, 2021, Micromechanics for energy generation, Journal of Micromechanics and Microengineering, Vol: 31, Pages: 1-18, ISSN: 0960-1317
The emergence and evolution of energy micro-generators during the last two decades has delivered a wealth of energy harvesting powering solutions, with the capability of exploiting a wide range of motion types, from impulse and low frequency irregular human motion, to broadband vibrations and ultrasonic waves. It has also created a wide background of engineering energy microsytems, including fabrication methods, system concepts and optimal functionality. This overview presents a simple description of the main transduction mechanisms employed, namely the piezoelectric, electrostatic, electromagnetic and triboelectric harvesting concepts. A separate discussion of the mechanical structures used as motion translators is presented, including the employment of a proof mass, cantilever beams, the role of resonance, unimorph structures and linear/rotational motion translators. At the mechanical-to-electrical interface, the concepts of impedance matching, pre-biasing and synchronised switching are summarised. The separate treatment of these three components of energy microgenerators allows the selection and combination of different operating concepts, their co-design towards overall system level optimisation, but also towards the generalisation of specific approaches, and the emergence of new functional concepts. Industrial adoption of energy micro-generators as autonomous power sources requires functionality beyond the narrow environmental conditions typically required by the current state-of-art. In this direction, the evolution of broadband electromechanical oscillators and the combination of environmental harvesting with power transfer operating schemes could unlock a widespread use of micro-generation in microsystems such as micro-sensors and micro-actuators.
Becker T, Borjesson V, Cetinkaya O, et al., 2021, Energy harvesting for a green internet of things, PSMA
The ubiquitous nature of energy autonomous microsystems, which are easy to install and simple toconnect to a network, make them attractive in the rapidly growing Internet of Things (IoT) ecosystem.The growing energy consumption of the IoT infrastructure is becoming more and more visible. Energyharvesting describes the conversion of ambient into electrical energy, enabling green power suppliesof IoT key components, such as autonomous sensor nodes.Energy harvesting methods and devices have reached a credible state-of-art, but only a few devices arecommercially available and off-the-shelf harvester solutions often require extensive adaption to theenvisaged application. A synopsis of typical energy sources, state-of-the-art materials, and transducertechnologies for efficient energy conversion, as well as energy storage devices and power managementsolutions, depicts a wide range of successful research results. Developing power supplies for actualusage reveals their strong dependence on application-specific installation requirements, powerdemands, and environmental conditions.The industrial challenges for a massive spread of autonomous sensor systems are manifold anddiverse. Reliability issues, obsolescence management, and supply chains need to be analyzed forcommercial use in critical applications. The current gap between use-case scenarios and innovativeproduct development is analyzed from the perspective of the user. The white paper then identifies thekey advantages of energy autonomy in environmental, reliability, sustainability, and financial terms.Energy harvesting could lead to a lower CO2 footprint of future IoT devices by adoptingenvironmentally friendly materials and reducing cabling and battery usage. Further research anddevelopment are needed to achieve technology readiness levels acceptable for the industry. This whitepaper derives a future research and innovation strategy for industry-ready green microscale IoTdevices, providing useful information to the sta
Shi M, Holmes AS, Yeatman EM, 2021, NONLINEAR WIND ENERGY HARVESTING BASED ON MECHANICAL SYNCHRONOUS SWITCH HARVESTING ON INDUCTOR, 21st International Conference on Solid-State Sensors, Actuators and Microsystems (Transducers), Publisher: IEEE, Pages: 964-967, ISSN: 2167-0013
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