Publications
36 results found
Liu M, Zhang Y, Fu H, et al., 2023, A seesaw-inspired bistable energy harvester with adjustable potential wells for self-powered internet of train monitoring, Applied Energy, Vol: 337, ISSN: 0306-2619
Energy harvesting provides a potential solution to power distributed sensors for train condition monitoring in a self-sustained manner, but the broadband and random nature of the available vibration energy makes effective energy harvesting very challenging. In this paper, a novel seesaw-inspired bistable energy harvester is developed to facilitate self-powered monitoring of trains and the realization of the Internet of Trains. The seesaw-inspired nonlinear harvester is realized for the first time using the attractive magnetic forces between a moving magnet and two fixed magnets to implement the gravitational force effect in seesaws and the restoring spring forces from limit springs to realize the supporting effect of legs to prevent seesaws from being hitting on the floor. A theoretical model is established to describe the dynamics of the whole systems, and the dynamics of the bistable energy harvester are numerically studied for different structural parameters to explore is potential well adjustability and its impact on energy harvesting performance. Through the numerical analysis, it is identified that different fixed magnet positions and spring lengths correspond to different harvesters’ potential well distribution, operational frequency ranges, and changing the coil positions also affects the output power. The results of the theoretical model are validated by a developed prototype and experimental results. The bistable energy harvester performs well over a wide frequency range of 18–38 Hz. An output power of 7.4 mW was obtained at 38 Hz with a 600 Ω load resistor. Finally, this energy harvester is used to fully power a wireless sensor node with a micro-controller, a Bluetooth module and an accelerometer, showing its capability in realizing self-powered condition monitoring of trains.
Fu H, Jiang J, Hu S, et al., 2023, A multi-stable ultra-low frequency energy harvester using a nonlinear pendulum and piezoelectric transduction for self-powered sensing, MECHANICAL SYSTEMS AND SIGNAL PROCESSING, Vol: 189, ISSN: 0888-3270
Masabi SN, Fu H, Theodossiades S, 2022, A bistable rotary-translational energy harvester from ultra-low-frequency motions for self-powered wireless sensing, JOURNAL OF PHYSICS D-APPLIED PHYSICS, Vol: 56, ISSN: 0022-3727
Lu Z-Q, Zhang F-Y, Fu H-L, et al., 2022, Rotational nonlinear double-beam energy harvesting, SMART MATERIALS AND STRUCTURES, Vol: 31, ISSN: 0964-1726
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- Citations: 26
Rao J, Wang J, Kollmannsberger S, et al., 2021, Point cloud-based elastic reverse time migration for ultrasonic imaging of components with vertical surfaces, MECHANICAL SYSTEMS AND SIGNAL PROCESSING, Vol: 163, ISSN: 0888-3270
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- Citations: 6
Fu H, Mei X, Yurchenko D, et al., 2021, Rotational energy harvesting for self-powered sensing, JOULE, Vol: 5, Pages: 1074-1118, ISSN: 2542-4351
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- Citations: 83
Fu H, Rao J, Harb MS, et al., 2021, Ultrasonic wireless power links for battery-free condition monitoring in metallic enclosures, ULTRASONICS, Vol: 114, ISSN: 0041-624X
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- Citations: 5
Ding K, Zhang Y, Chan FTS, et al., 2021, A cyber-physical production monitoring service system for energy-aware collaborative production monitoring in a smart shop floor, JOURNAL OF CLEANER PRODUCTION, Vol: 297, ISSN: 0959-6526
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- Citations: 7
Masabi SN, Fu H, Theodossiades S, 2021, AN ULTRA-LOW FREQUENCY MAGNET-TETHERED VIBRATION ENERGY HARVESTER FOR SELF-POWERED SENSING, 21st International Conference on Solid-State Sensors, Actuators and Microsystems (Transducers), Publisher: IEEE, Pages: 956-959, ISSN: 2167-0013
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- Citations: 1
Fu H, Zhang Y, Liu M, et al., 2021, A BISTABLE ENERGY HARVESTER FOR SELF-POWERED SENSING IN RAIL TRANSPORT CONDITION MONITORING, 21st International Conference on Solid-State Sensors, Actuators and Microsystems (Transducers), Publisher: IEEE, Pages: 140-143, ISSN: 2167-0013
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- Citations: 2
Liu H, Fu H, Sun L, et al., 2020, Hybrid energy harvesting technology: From materials, structural design, system integration to applications, Renewable and Sustainable Energy Reviews, Pages: 110473-110473, ISSN: 1364-0321
Fu H, Theodossiades S, Gunn B, et al., 2020, Ultra-low frequency energy harvesting using bi-stability and rotary-translational motion in a magnet-tethered oscillator, NONLINEAR DYNAMICS, Vol: 101, Pages: 2131-2143, ISSN: 0924-090X
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- Citations: 34
Fu H, Song W, Qin Y, et al., 2020, Broadband Vibration Energy Harvesting from Underground Trains for Self-Powered Condition Monitoring, 19th International Conference on Micro and Nanotechnology for Power Generation and Energy Conversion Applications (Power MEMS), Publisher: IEEE
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- Citations: 3
Iuliana T, Fu H, Sharif Khodaei Z, 2019, A convolutional neural network for impact detection and characterization of complex composite structures, Sensors, Vol: 19, ISSN: 1424-8220
This paper reports on a novel metamodel for impact detection, localization and characterization of complex composite structures based on Convolutional Neural Networks (CNN) and passive sensing. Methods to generate appropriate input datasets and network architectures for impact localization and characterization were proposed, investigated and optimized. The ultrasonic waves generated by external impact events and recorded by piezoelectric sensors are transferred to 2D images which are used for impact detection and characterization. The accuracy of the detection was tested on a composite fuselage panel which was shown to be over 94%. In addition, the scalability of this metamodelling technique has been investigated by training the CNN metamodels with the data from part of the stiffened panel and testing the performance on other sections with similar geometry. Impacts were detected with an accuracy of over 95%. Impact energy levels were also successfully categorized while trained at coupon level and applied to sub-components with greater complexity. These results validated the applicability of the proposed CNN-based metamodel to real-life application such as composite aircraft parts.
Fu H, Sharif Khodaei Z, Aliabadi M, 2019, An energy-efficient cyber-physical system for wireless on-board aircraft structural health monitoring, Mechanical Systems and Signal Processing, Vol: 128, Pages: 352-368, ISSN: 0888-3270
In this paper, an energy-efficient cyber-physical system using piezoelectric transducers (PZTs) and wireless sensor networks (WSN) is proposed, designed and experimentally validated for on-board aircraft structural health monitoring (SHM). A WSN is exploited to coordinate damage detection using PZTs distributed on the whole aircraft. An active sensing methodology is adopted for PZTs to evaluate the structural integrity in a pitch-catch manner. The system configuration and operation principle are discussed in the first place. Then, the detailed hardware design was introduced. The proposed system is not only characterized as low-power, high-compactness and wireless, but also capable of processing actuating-sensing signals at megahertz, generating actuating signals with great flexibility, handling multiple actuating-sensing channels with marginal crosstalk. The design was implemented on a 4-layer printed circuit board (8 × 6.5 cm) and evaluated on a large-scale composite fuselage. A 5 MHz sampling rate for actuating and 1.8 MHz for sensing (8 channels) were realized, and the accuracy was validated by comparing the results with those from an oscilloscope. The crosstalk issue caused by actuation on sensing channels is properly addressed using a 2-stage attenuation method. An ultra-low current (81.7 μA) was measured when no detection was required; the average current was 0.45 mA with a detection rate of twice per hour, which means the system can continuously work for up to 12.6 months for 2 AA batteries. Eventually, an example of damage detection is provided, showing the capability of such a system in SHM.
Fu H, Yeatman E, 2019, Rotational energy harvesting using bi-stability and frequency up-conversion for low-power sensing applications: Theoretical modelling and experimental validation., Mechanical Systems and Signal Processing, Vol: 125, Pages: 229-244, ISSN: 0888-3270
Abstract Kinetic energy harvesting has drawn great attention in the past decade, but low-frequency and broadband operation is still a big issue which impedes this technology to be widely deployed in low-power Internet of Things applications. In this paper, theoretical modelling and experimental validation of a rotational harvester with bi-stability and frequency up-conversion is presented for harnessing low-frequency kinetic energy with a wide bandwidth. Piezoelectric transduction was adopted to convert the rotational kinetic energy into electricity. Distributed-parameter modelling was employed for analyzing the electromechanical dynamics of the bistable piezoelectric beam. Bistable and frequency up-converting behaviours were considered in the theoretical model by introducing two external input magnetic forces. Different oscillating modes were analyzed, showing the variation of power generation capability under different modes, and the advantage of operating in the periodic double-well mode. From the potential well study, we got a conclusion that for the same input magnetic force, periodic double-well mode is capable of achieving a larger vibration amplitude compared to a harvester without bi-stability. Asymmetric potential well shapes were investigated. This asymmetric shape provides a way to stabilize the initiation position of the beam for each plucking cycle, and eventually to stabilized the output. Key design factors to control the oscillating modes were studied, providing a guideline for future design. An experimental study was conducted to verify the theoretical results. A close match was achieved. This bistable harvester demonstrated a significant improvement (up to 2 × ) compared to a harvester without bi-stability over a wide bandwidth (from 1 to 11 Hz) at low frequencies, when operating in the periodic double-well mode. This paper presents a detailed theoretical model and in-depth analysis of a bistable frequency up-converting harvester, providing a
Fu H, Zhou S, Yeatman E, 2019, Exploring coupled electromechanical non-linearities for broadband energy harvesting from low-frequency rotational sources, Smart Materials and Structures, Vol: 28, ISSN: 0964-1726
This paper presents a methodology to effectively harness low-frequency broadband rotational energy using coupled electromechanical non-linearities. This design integrates bi-stability and a synchronized switch harvesting on inductor (SSHI) circuit into a frequency up-converting harvester. The bistable behaviour enables improved output power due to the increased vibration amplitude under the same input plucking force. The SSHI circuit exhibits enhanced conversion capability, contributing higher electrical damping which is ideal for frequency up-converting harvesters to alleviate output fluctuation at high frequencies. To study the coupled non-linear dynamics from both the mechanical (bi-stability) and electrical (SSHI) sides, a system-level theoretical model is, for the first time, established and numerically solved using Matlab/Simulink. System behaviours, which would not be able to obtain using circuit simulation methods, are studied for different operating frequencies and load resistances. To validate the theoretical analysis, this harvester was implemented and tested experimentally. A close match was obtained. From the experimental results, an enhanced output power (up to 525%), over a broad frequency range, was realized, compared to that of a harvester with neither bi-stability nor SSHI circuits.
Fu H, Sharif Khodaei Z, Aliabadi M, 2019, A bio-inspired host-parasite structure for broadband vibration energy harvesting from low-frequency random sources, Applied Physics Letters, Vol: 114, ISSN: 0003-6951
Energy harvesting for low-power sensing has drawn great attention, but still faces challenges in harnessing broadband random motions. Inspired by the parasitic relationship in plants, a host-parasite vibration harvester is designed to scavenge random low-frequency vibrations by incorporating bi-stability and frequency up-conversion within such a design. A hosting beam is formed in a buckled condition by clamping it at both ends and applying an axial compression load. Two parasitic piezoelectric beams are fixed at the center of the hosting beam and plucked at the free ends by two plectra on the hosting beam, while it oscillates in an inter-well mode. The low-frequency hosting beam oscillation is converted to high-frequency parasitic beam's vibration at resonance due to the plucking effect, allowing the harvester to convert the broadband low-frequency motion into electricity effectively. The electromechanical dynamics are modeled and the design is validated experimentally. The harvester is capable of harnessing low-frequency random vibration (0.0018 g2/Hz @ 5–400 Hz) over a wide bandwidth. More than 1 mJ energy was collected over 100 s under this pseudorandom vibration.Energy harvesting has been recognized as one of the key enablers for self-powered sensing applications in the era of Internet of things.1–4 However, enhancing the energy harvesting effectiveness requires significant efforts, especially for different energy sources under various conditions, such as low-frequency human motion,5,6 random aircraft vibrations7 or ocean waves.8 Harnessing a random, broadband and low-frequency kinetic energy is one of the key challenges, and different mechanisms have been developed to enhance the conversion performance.Nonlinear dynamics are one major consideration to enhance the operation bandwidth.9–11 Different harvesters have been developed with monostable,12–14 bistable15–17 and multistable behaviors.18–20 The aim is to al
Fu H, Sharif Khodaei Z, Aliabadi MH, 2019, An energy efficient wireless module for on-board aircraft impact detection, Nondestructive Characterization and Monitoring of Advanced Materials, Aerospace, Civil Infrastructure, and Transportation XIII, Publisher: Society of Photo-optical Instrumentation Engineers, ISSN: 0277-786X
An innovative wireless passive system for impact detection on large-scale composite airframe structures is presented. The wireless system is designed to operate with a sensor network for onboard of aircraft for structural health monitoring, of composite airframe. The wireless systems efficient design allows for low power consumption, wireless communication capability, system robustness and large sensing area. The system is evaluated on a large-scale stiffened composite fuselage under different operational conditions. It is demonstrated that it is possible to detect impact events with different impact energy levels and impact locations over a large monitoring area. This work provides a potential solution for aircraft on-board structural health monitoring with no human intervention. This sensing system can be also adapted to other Internet of Things and structural health monitoring applications.
Fu H, Sharif Khodaei Z, Aliabadi MH, 2019, An event-triggered energy-efficient wireless structural health monitoring system for impact detection in composite airframes, IEEE Internet of Things Journal, Vol: 6, Pages: 1183-1192, ISSN: 2327-4662
In this paper, a low-power high-response wireless structural health monitoring system (WSHMS) is designed, implemented and experimentally evaluated for impact detection in composite airframes. Due to the rare, random and transitory nature of impacts, an event-triggered mechanism is adopted for allowing the system to exhibit low power consumption when no impact occurs and high performance when triggered. System responsiveness, robustness and energy efficiency are considered and modelled. Based on system requirements and functions, several modules are designed, including filtering, impact detecting, local processing and wireless communicating modules. The system was implemented on a printed circuit board. The response time is about 12 us with an average current lower than 1 mA when the impact activity is lower than 0.1%. The system exhibits high robustness to ambient vibration noises and is also capable of accurately and responsively capturing multiple sensing input channels (up to 24 channels). This work presents a low-latency energy-aware WSHMS for impact detection of composite structures. It can be adapted to monitor of other rare, random and ephemeral events in many Internet of Things applications.
Fu H, Khodaei ZS, Aliabadi MHF, 2019, BROADBAND ENERGY HARVESTING USING BI-STABILITY AND FREQUENCY UP-CONVERSION FOR SELF-POWERED SENSING IN INTERNET OF THINGS, 20th International Conference on Solid-State Sensors, Actuators and Microsystems and Eurosensors XXXIII (TRANSDUCERS and EUROSENSORS), Publisher: IEEE, Pages: 354-357
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- Citations: 2
Fu H, Yeatman E, 2018, Comparison and scaling effects of rotational micro‐generators using electromagnetic and piezoelectric transduction, Energy Technology, Vol: 6, ISSN: 2194-4296
Rotational energy is widely distributed or easily acquirable from other energy sources (fluid flow, machine operation or human motion) in many industrial and domestic scenarios. At small scales, power generation from such rotational ambient sources can enable many autonomous and self‐reliant sensing applications. In this paper, three typical types of micro‐generators (energy harvesters), namely electromagnetic (EMREHs), piezoelectric resonant (PRREHs) and piezoelectric non‐resonant rotational energy harvesters (PNRREHs) are discussed and compared in terms of device dimensions and operation frequencies. Theoretical models are established for each type to calculate maximum achievable output power as a function of device dimension and operating frequency. Using these theoretical models, scaling laws are established for each type to estimate the achievable output. The EMREHs have a strong scaling effect both on device dimension (as L5) and on operating frequency (as ω2), whereas the PNRREHs are less so (L2.5ω0.5). PRREHs have a narrow band‐width as resonant harvesters, and are ideal for cases where the excitation frequency is constant. This study provides a guideline for selection and design of rotational energy harvesters (REHs) when the device dimension and operating frequency are defined. The proposed scaling laws offer a convenient method to estimate the harvester performance for different dimensions and operating frequencies.
Fu H, Hami Seno A, Sharif Khodaei Z, et al., 2018, Design of a wireless passive sensing system for impact detection of aerospace composite structures, 2018 5th IEEE International Workshop on Metrology for AeroSpace (MetroAeroSpace), Publisher: IEEE, Pages: 585-589, ISSN: 2575-7490
In this paper, the design and implementation of a novel on-board wireless passive sensing system for impact detection of composite airframe is presented for the first time. Several modules, including filtering, impact detection, local processing and wireless transmission are designed and evaluated for detecting rare, random and transitory impact events. An event-triggered mechanism with high responsiveness is adopted to reduce the system power dissipation and to maintain the detection effectiveness. This design allows the system to be adaptive, energy-efficient and highly responsive to impacts. The whole system was implemented in an experimental study, and the effectiveness was evaluated and illustrated. The system was woken up by impact events in around 12 µs, and the impact data were recorded at 200 kHz (up to 5.33 MHz). This work provides a guideline for low-power, high-responsiveness passive on-board sensing system design. This system can also be adapted to other sensing applications in aerospace engineering.
Fu H, Yeatman EM, 2018, Effective piezoelectric energy harvesting using beam plucking and a synchronized switch harvesting circuit, Smart Materials and Structures, Vol: 27, Pages: 084003-084003, ISSN: 0964-1726
Fu H, Chen G, Bai N, 2018, Electrode coverage optimization for piezoelectric energy harvesting from tip excitation, Sensors, Vol: 18, ISSN: 1424-2818
Piezoelectric energy harvesting using cantilever-type structures has been extensively investigated due to its potential application in providing power supplies for wireless sensor networks, but the low output power has been a bottleneck for its further commercialization. To improve the power conversion capability, a piezoelectric beam with different electrode coverage ratios is studied theoretically and experimentally in this paper. A distributed-parameter theoretical model is established for a bimorph piezoelectric beam with the consideration of the electrode coverage area. The impact of the electrode coverage on the capacitance, the output power and the optimal load resistance are analyzed, showing that the piezoelectric beam has the best performance with an electrode coverage of 66.1%. An experimental study was then carried out to validate the theoretical results using a piezoelectric beam fabricated with segmented electrodes. The experimental results fit well with the theoretical model. A 12% improvement on the Root-Mean-Square (RMS) output power was achieved with the optimized electrode converge ratio (66.1%). This work provides a simple approach to utilizing piezoelectric beams in a more efficient way.
Fu H, Yeatman EM, 2017, A methodology for low-speed broadband rotational energy harvesting using piezoelectric transduction and frequency up-conversion, Energy, Vol: 125, Pages: 152-161, ISSN: 0360-5442
Energy harvesting from vibration for low-power electronics has been investigated intensively in recent years, but rotational energy harvesting is less investigated and still has some challenges. In this paper, a methodology for low-speed rotational energy harvesting using piezoelectric transduction and frequency up-conversion is analysed. The system consists of a piezoelectric cantilever beam with a tip magnet and a rotating magnet on a revolving host. The angular kinetic energy of the host is transferred to the vibration energy of the piezoelectric beam via magnetic coupling between the magnets. Frequency up-conversion is achieved by magnetic plucking, converting low frequency rotation into high frequency vibration of the piezoelectric beam. A distributed-parameter theoretical model is presented to analyse the electromechanical behaviour of the rotational energy harvester. Different configurations and design parameters were investigated to improve the output power of the device. Experimental studies were conducted to validate the theoretical estimation. The results illustrate that the proposed method is a feasible solution to collecting low-speed rotational energy from ambient hosts, such as vehicle tires, micro-turbines and wristwatches.
Fu H, Yeatman EM, 2017, BROADBAND ROTATIONAL ENERGY HARVESTING USING BISTABLE MECHANISM AND FREQUENCY UP-CONVERSION, 30th IEEE International Conference on Micro Electro Mechanical Systems (MEMS), Publisher: IEEE, Pages: 853-856, ISSN: 1084-6999
This paper presents the electromechanical dynamics of a broadband rotational piezoelectric energy harvester using bi-stability and frequency up-conversion. Bi-stability is achieved by the repulsive force between the tip magnet on a piezoelectric cantilever and a fixed magnet above the tip magnet. Frequency up-conversion is realized by the plucking force generated between the tip magnet and a rotating driving magnet below the tip magnet. A numerical model based on the distributed-parameter model was built in Matlab/Simulink. The power extraction capability of different modes of oscillation was analyzed theoretically. The keys to maintain harvester operation in high energy orbit (inter-well vibration) were investigated. The rotational piezoelectric energy harvester was implemented experimentally, showing a significant improvement in output power over a wide bandwidth compared to a harvester without bi-stability.
Fu H, Yeatman EM, 2016, Broadband Rotational Energy Harvesting with Non-linear Oscillator and Piezoelectric Transduction, 16th International Conference on Micro and Nanotechnology for Power Generation and Energy Conversion Applications (PowerMEMS 2016), Publisher: IOP Publishing, ISSN: 1742-6588
Rotational energy is widely distributed in many industrial and domestic applications, such as ventilation systems, moving vehicles and miniature turbines. This paper reports the design and implementation of a bi-stable rotational energy harvester with wide bandwidth and low operating frequency. The rotational energy is converted into electricity by magnetic plucking of a piezoelectric cantilever using a driving magnet mounted on a rotating host. The bistable condition is achieved by introducing a fixed magnet above the tip magnet at the cantilever's free end. The repulsive magnetic force between the magnets creates two equilibrium positions for the piezoelectric beam. The harvester is designed to operate in the high energy orbit (interwell vibration mode) to extract more energy from the rotational energy source. Harvesters with and without bistability are compared experimentally, showing the difference of power extraction on both the output power and bandwidth. The method proposed in this paper provides a simple and efficient way to extract rotational energy from the ambient environment.
Fu H, Cao K, Xu R, et al., 2016, Footstep energy harvesting using heel strike-induced airflow for human activity sensing, 13th IEEE International Conference on Wearable and Implantable Body Sensor Networks (BSN), Publisher: IEEE, Pages: 124-129, ISSN: 2376-8886
Body sensor networks are increasingly popular in healthcare, sports, military and security. However, the power supply from conventional batteries is a key bottleneck for the development of body condition monitoring. Energy harvesting from human motion to power wearable or implantable devices is a promising alternative. This paper presents an airflow energy harvester to harness human motion energy from footsteps. An air bladder-turbine energy harvester is designed to convert the footstep motion into electrical energy. The bladders are embedded in shoes to induce airflow from foot-strikes. The turbine is employed to generate electrical energy from airflow. The design parameters of the turbine rotor, including the blade number and the inner diameter of the blades (the diameter of the turbine shaft), were optimized using the computational fluid dynamics (CFD) method. A prototype was developed and tested with footsteps from a 65 kg person. The peak output power of the harvester was first measured for different resistive loads and showed a maximum value of 90.6 mW with a 30.4 Ω load. The harvested energy was then regulated and stored in a power management circuit. 14.8 mJ was stored in the circuit from 165 footsteps, which means 90 μJ was obtained per footstep. The regulated energy was finally used to fully power a fitness tracker which consists of a pedometer and a Bluetooth module. 7.38 mJ was consumed by the tracker per Bluetooth configuration and data transmission. The tracker operated normally with the harvester working continuously.
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