scholarly journals Stabilising high energy orbit oscillations by the utilisation of centrifugal effects for rotating-tyre-induced energy harvesting

2018 ◽  
Vol 112 (14) ◽  
pp. 143901 ◽  
Author(s):  
Yunshun Zhang ◽  
Rencheng Zheng ◽  
Kimihiko Nakano ◽  
Matthew P. Cartmell
Keyword(s):  
Energy Harvesting ◽  
High Energy ◽  
Energy Orbit

Investigations of a Stiffness Tunable Nonlinear Vibrational Energy Harvester

2014 ◽  
Vol 14 (08) ◽  
pp. 1440023 ◽  
Author(s):  
Dongxu Su ◽  
Kimihiko Nakano ◽  
Rencheng Zheng ◽  
Matthew P. Cartmell
Keyword(s):  
Energy Harvesting ◽  
Permanent Magnets ◽  
Energy Harvester ◽  
Vibrational Energy ◽  
Duffing Oscillator ◽  
Experimental Tests ◽  
High Energy ◽  
Practical Implementation ◽  
Energy Harvesting Devices ◽  
Energy Orbit

The recent potential benefit of nonlinearity has been applying in order to improve the effectiveness of energy harvesting devices. For instance, at relatively high excitation levels, both low and high-energy responses can coexist for the same parameter combinations in a hardening type Duffing oscillator, and this provides a wider bandwidth and a higher energy harvesting effectiveness under periodic excitations. However, frequency or amplitude sweeps of the excitation must be used in order to reach a desirable high-energy orbit, and this gives a limitation on practical implementation. This paper presents a stiffness tunable nonlinear vibrational energy harvester which contains a moving magnetic end mass attached to a cantilever beam, whose nonlinearity emerges from the interaction forces with two neighboring permanent magnets facing with opposing poles. The motivating hypothesis has been that the jump from the low-energy orbit to the high-energy orbit can be triggered by tuning the stiffness of the system without changing the frequency or the amplitude of the excitation. Theoretical investigations show a methodology for tuning stiffness, and experimental tests have validated that the proposed method can be used to trigger a jump to the desirable state, and hereby this can broaden the bandwidth of the energy harvester.

scholarly journals Stabilisation of the high-energy orbit for a non-linear energy harvester with variable damping

2015 ◽  
Vol 230 (12) ◽  
pp. 2003-2012 ◽  
Author(s):  
Dongxu Su ◽  
Rencheng Zheng ◽  
Kimihiko Nakano ◽  
Matthew P Cartmell
Keyword(s):  
Energy Harvesting ◽  
Energy Harvester ◽  
High Energy ◽  
Low Energy ◽  
Additional Energy ◽  
Non Linear ◽  
In Series ◽  
Improved Performance ◽  
Non Linear Oscillator ◽  
Energy Orbit

The non-linearity of a hardening-type oscillator provides a wider bandwidth and a higher energy harvesting capability under harmonic excitations. Also, both low- and high-energy responses can coexist for the same parameter combinations at relatively high excitation levels. However, if the oscillator’s response happens to coincide with the low-energy orbit then the improved performance achieved by the non-linear oscillator over that of its linear counterpart, could be impaired. This is therefore the main motivation for stabilisation of the high-energy orbit. In the present work, a schematic harvester design is considered consisting of a mass supported by two linear springs connected in series, each with a parallel damper, and a third-order non-linear spring. The equivalent linear stiffness and damping coefficients of the oscillator are derived through variation of the damper element. From this adjustment the variation of the equivalent stiffness generates a corresponding shift in the frequency–amplitude response curve, and this triggers a jump from the low-energy orbit to stabilise the high-energy orbit. This approach has been seen to require little additional energy supply for the adjustment and stabilisation, compared with that needed for direct stiffness tuning by mechanical means. Overall energy saving is of particular importance for energy harvesting applications. Subsequent results from simulation and experimentation confirm that the proposed method can be used to trigger a jump to the desirable state, thereby introducing a beneficial addition to the performance of the non-linear hardening-type energy harvester that improves overall efficiency and broadens the bandwidth.

scholarly journals Combining sustainable stochastic resonance with high-energy orbit oscillation to broaden rotational bandwidth of energy harvesting from tire

AIP Advances ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 015011
Author(s):  
Yunshun Zhang ◽  
Yingfeng Cai ◽  
Xiaopeng Teng ◽  
Rencheng Zheng ◽  
Kimihiko Nakano
Keyword(s):  
Energy Harvesting ◽  
Stochastic Resonance ◽  
High Energy ◽  
Energy Orbit

A bistable piezoelectric oscillator with an elastic magnifier for energy harvesting enhancement

2016 ◽  
Vol 28 (3) ◽  
pp. 392-407 ◽  
Author(s):  
Guang-Qing Wang ◽  
Wei-Hsin Liao
Keyword(s):  
Energy Harvesting ◽  
Effective Means ◽  
High Energy ◽  
Open Circuit ◽  
Lumped Parameter Model ◽  
Vibration Level ◽  
Restoring Force ◽  
Output Displacement ◽  
Piezoelectric Harvester ◽  
Energy Orbit

Bistable oscillator has been recognized as an effective means by which to improve the linear resonant energy harvesting performance for its unique double-well restoring force potential. As oscillating in a high-energy orbit, the oscillator should be located at a distance from one stable to the other with a much higher velocity or acceleration. However, the vibration level in environment would be too low to provide the oscillator with a larger velocity to overcome the potential well barrier. This article is focused on the enhancement of a bistable piezoelectric oscillator with an elastic magnifier for high-energy orbit harvesting. The elastic magnifier positioned between the bistable piezoelectric oscillator and the base is to amplify the base vibration level in order to provide the bistable piezoelectric harvester with large movement. A 2-degree-of-freedom nonlinear lumped-parameter model of the bistable piezoelectric harvester with an elastic magnifier (bistable piezoelectric harvester + elastic magnifier) is derived to exhibit the large-amplitude periodic oscillation behaviors. With the comparison of the electromechanical responses obtained from theory and experiment, the results show that the output displacement, tip velocity, and harvesting voltage under open-circuit condition of the bistable piezoelectric harvester + elastic magnifier configuration are 15 mm, 1500 mm s−1, and 13 V, respectively, while those of the only bistable piezoelectric harvester configuration are 1 mm, 120 mm s−1, and 2 V under the excitation level of 8.69 m s−2 and frequency of 16 Hz. It is verified that the bistable piezoelectric harvester with an elastic magnifier can generate larger output performance than that of the bistable piezoelectric harvester without elastic magnifier at several excitation frequencies and levels.

scholarly journals High-energy Orbit Sliding Mode Control for Nonlinear Energy Harvesting

2021 ◽  
Author(s):  
Ying Zhang ◽  
Changshun Ding ◽  
Jie Wang ◽  
Junyi Cao
Keyword(s):  
Energy Harvesting ◽  
Sliding Mode Control ◽  
Health Monitoring ◽  
Control Method ◽  
Sliding Mode ◽  
High Energy ◽  
Restoring Force ◽  
Mode Control ◽  
Solution Region ◽  
Energy Orbit

Abstract Vibration energy harvesting has extensive application prospects in many significant occasions, such as mechanical structure health monitoring, vehicle tire pressure monitoring, IoT devices and human health monitoring. The nonlinearity is an effective method to improve the energy harvesting efficiency where there are low- and high-energy orbits in the multi-solution region of the system. The harvested power will be increased significantly when the system is guided from the low-energy orbit to the high-energy orbit. However, previous research mainly focuses on the theoretical and numerical investigation of controlling strategy, but the feasibility of control methods has not been verified experimentally. This paper proposes a high-energy sliding mode control method through rotatable magnets actuated by micro-motor. The electromechanical model of mono-stable and bi-stable systems with the identified nonlinear restoring force is established to design a sliding mode control algorithm for enhancing the energy harvesting performance. Simulation and experiment results demonstrate that the rotatable magnets with sliding mode control have a positive influence on reaching the high-energy orbit for both mono-stable and bi-stable systems within the multi-solution region. Moreover, the rotatable magnets method with a sliding mode control actuates the small magnets in the system for a short time with little consumption of energy. This research has provided a practical application of high-energy orbit control for improvement of the energy harvesting.

scholarly journals Recent applications of high energy and spatial resolution STEM-EELS to energy harvesting materials

2016 ◽  
pp. 942-943
Author(s):  
Quentin Ramasse ◽  
Alpesh Shukla ◽  
Fredrik Hage ◽  
Demie Kepaptsoglou ◽  
Feridoon Azough ◽  
...  
Keyword(s):  
Energy Harvesting ◽  
Spatial Resolution ◽  
High Energy

Dielectric Elastomer Energy Harvesting and its Application to Human Walking

2011 ◽  
Author(s):  
Heather Lai ◽  
Chin An Tan ◽  
Yong Xu
Keyword(s):  
Energy Harvesting ◽  
Knee Joint ◽  
Mechanical Energy ◽  
Electrical Energy ◽  
High Energy ◽  
Dielectric Elastomer ◽  
Metabolic Energy ◽  
High Energy Density ◽  
Human Walking ◽  
Wide Range

Human walking requires sophisticated coordination of muscles, tendons, and ligaments working together to provide a constantly changing combination of force, stiffness and damping. In particular, the human knee joint acts as a variable damper, dissipating greater amounts of energy when the knee undergoes large rotational displacements during walking, running or hopping. Typically, this damping results from the dissipation, or loss, of metabolic energy. It has been proven to be possible however; to collect this otherwise wasted energy through the use of electromechanical transducers of several different types which convert mechanical energy to electrical energy. When properly controlled, this type of device not only provides desirable structural damping effects, but the energy generated can be stored for use in a wide range of applications. A novel approach to an energy harvesting knee joint damper is presented using a dielectric elastomer (DE) smart material based electromechanical transducer. Dielectric elastomers are extremely elastic materials with high electrical permittivity which operate based on electrostatic effects. By placing compliant electrodes on either side of a dielectric elastomer film, a specialized capacitor is created, which couples mechanical and electrical energy using induced electrostatic stresses. Dielectric elastomer energy harvesting devices not only have a high energy density, but the material properties are similar to that of human tissue, making it highly suitable for wearable applications. A theoretical framework for dielectric elastomer energy harvesting is presented along with a mapping of the active phases of the energy harvesting to the appropriate phases of the walking stride. Experimental results demonstrating the energy harvesting capability of a DE generator undergoing strains similar to those experienced during walking are provided for the purpose of verifying the theoretical results. The work presented here can be applied to devices for use in rehabilitation of patients with muscular dysfunction and transfemoral prosthesis as well as energy generation for able-bodied wearers.

Flexoelectric Energy Harvesting Using Circular Thin Membranes

2020 ◽  
Vol 87 (9) ◽  
Author(s):  
Zhaoqi Li ◽  
Qian Deng ◽  
Shengping Shen
Keyword(s):  
Energy Harvesting ◽  
Energy Harvester ◽  
Energy Conversion Efficiency ◽  
High Energy ◽  
Circular Membrane ◽  
Governing Equations ◽  
Energy Harvesters ◽  
Thin Membranes ◽  
High Energy Conversion Efficiency ◽  
Working Frequency

Abstract In this work, we propose a circular membrane-based flexoelectric energy harvester. Different from previously reported nanobeams based flexoelectric energy harvesters, for the flexoelectric membrane, the polarization direction around its center is opposite in sign to that far away from the center. To avoid the cancelation of the electric output, electrodes coated to upper and lower surfaces of the flexoelectric membrane are respectively divided into two parts according to the sign of bending curvatures. Based on Hamilton’s principle and Ohm’s law, we obtain governing equations for the circular membrane-based flexoelectric energy harvester. A generalized assumed-modes method is employed for solving the system, so that the performance of the flexoelectric energy harvester can be studied in detail. We analyze the effects of the thickness h, radius r0, and their ratio on the energy harvesting performance. Specifically, we show that, by selecting appropriate h and r0, it is possible to design an energy harvester with both high energy conversion efficiency and low working frequency. At last, through numerical simulations, we further study the optimization ratio for which the electrodes should be divided.

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