**5. Typical applications**

Ionic polymer actuators have been expected to be used for some practical applications such as active microcatheters, micropumps, tactile displays, biomimetic microrobots, and so on [42, 43]. First commercial production with ionic EAP was produced by a Japanese company (Eamex Co.) in 2002 ([42] p. 2). They produced a fish robot which has a caudal fin made with ionic EAP. They can control the movement of the caudal fin by electromagnetic induction (wireless control).

because they are heavy (~kg) and large (266 (length) × 129 (width) × 40 mm (thickness) for a 32 Braille characters display). So, we had a motivation to produce an ultra-light and ultra-thin Braille display by using BGAs. The developed prototype Braille display with BGAs is shown in **Figure 10** which has a size of 65 (length) × 30 (width) × 3 mm (thickness) with 6 refreshable Braille characters and the weight is only 5 g. This prototype Braille display was produce by collaborations with ALPS Electric Co., Ltd. Our Braille display was readable for most of visually impaired people but not readable for some visually impaired people who are not used to use Braille display. This is the reason why the dot force is not enough compared to commer-

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Third example is the application for micropipette and micropump. Recently, micropipettes and micropumps have been receiving a lot of attention for the microfluidic point-of-care (POC) diagnostic devices. So, we are willing to test the potential of BGAs as a micropipette. This project has been done by collaborations with Fraunhofer IPA (Stuttgart, Germany) [45]. A BGA (black square film) was set into the printed circuit boards (PCBs) to apply voltages as shown in **Figure 11**. The pipette has a channel tip which has a size of 1 × 1 × 10 mm to suck and release liquid. The BGA showed an up-and-down motion in the PCBs like a diaphragm pump and can dispense *ca*. 10–20 μL liquid. Furthermore, Goya et al. developed a BGA micropipette system equipped with commercially available two- and

**Figure 10.** A photo of prototype braille display with BGAs and an illustration of movement of a braille dot by the

**Figure 11.** A photo of prototype micropipette with BGAs. A black square BGA are set between two PCBs.

bending of BGA.

cial Braille displays. Improving the force and the durability is now in progress.

Here, we introduce three examples of our application trials with IPMC and BGAs.

First sample is the prototype of developed micropump using inner petal-shaped IPMC actuator as shown in **Figure 9**. Micropumps capable of providing an appropriate flow rate and a reasonable back pressure are usually inevitable requirements for a self-contained microfluidic system. Since this is a prototype only, the pump was not made to be very small. The overall size is 70 × 40 × 15 mm (length × width × height). The pump chamber is a 15 mm in diameter, 2 mm in depth. It should be noted that, we only tested inner petal-shaped IPMC actuator with a diameter of 15 mm. The actuator used in this prototype is a Nafion 117-based IPMC actuator. A pair of copper plates as electrodes was used to clamp the two sides of the IPMC actuator, providing the stimulus electrical signal. In order to evaluate the performance of micropump, we carry out the experiment of the flow rate and the back pressure measurement in 1 Hz sine voltage input by changing the voltage amplitude from 0.5 to 3 V by the interval of 0.5 V. The experimental results show that the flow rate from 162 to 1611 μL/min can be obtained by changing the voltage amplitude from 0.5 to 3 V, respectively. And the back pressure on the micropump can be as high as 71 mm-H2O under the condition of 1 Hz and 3 V sine voltage input.

Second example is an ultra-thin and ultra-light refreshable Braille display with BGAs [41, 44]. There are more than 100 million visually impaired people in the world. This means there are a huge number of people who cannot access the internet because most information in the internet are shown with words and photos on the liquid crystal displays of mobile phones, laptop computers, and other tablet tools. Currently, the refreshable Braille displays with inorganic piezoelectric actuators are commercially available but they are not suitable for the mobile use

**Figure 9.** The principle (a) and appearance (b) of the fabricated micropump.

because they are heavy (~kg) and large (266 (length) × 129 (width) × 40 mm (thickness) for a 32 Braille characters display). So, we had a motivation to produce an ultra-light and ultra-thin Braille display by using BGAs. The developed prototype Braille display with BGAs is shown in **Figure 10** which has a size of 65 (length) × 30 (width) × 3 mm (thickness) with 6 refreshable Braille characters and the weight is only 5 g. This prototype Braille display was produce by collaborations with ALPS Electric Co., Ltd. Our Braille display was readable for most of visually impaired people but not readable for some visually impaired people who are not used to use Braille display. This is the reason why the dot force is not enough compared to commercial Braille displays. Improving the force and the durability is now in progress.

Third example is the application for micropipette and micropump. Recently, micropipettes and micropumps have been receiving a lot of attention for the microfluidic point-of-care (POC) diagnostic devices. So, we are willing to test the potential of BGAs as a micropipette. This project has been done by collaborations with Fraunhofer IPA (Stuttgart, Germany) [45]. A BGA (black square film) was set into the printed circuit boards (PCBs) to apply voltages as shown in **Figure 11**. The pipette has a channel tip which has a size of 1 × 1 × 10 mm to suck and release liquid. The BGA showed an up-and-down motion in the PCBs like a diaphragm pump and can dispense *ca*. 10–20 μL liquid. Furthermore, Goya et al. developed a BGA micropipette system equipped with commercially available two- and

**Figure 10.** A photo of prototype braille display with BGAs and an illustration of movement of a braille dot by the bending of BGA.

**Figure 11.** A photo of prototype micropipette with BGAs. A black square BGA are set between two PCBs.

**Figure 9.** The principle (a) and appearance (b) of the fabricated micropump.

**5. Typical applications**

(wireless control).

50 Actuators

and 3 V sine voltage input.

Ionic polymer actuators have been expected to be used for some practical applications such as active microcatheters, micropumps, tactile displays, biomimetic microrobots, and so on [42, 43]. First commercial production with ionic EAP was produced by a Japanese company (Eamex Co.) in 2002 ([42] p. 2). They produced a fish robot which has a caudal fin made with ionic EAP. They can control the movement of the caudal fin by electromagnetic induction

First sample is the prototype of developed micropump using inner petal-shaped IPMC actuator as shown in **Figure 9**. Micropumps capable of providing an appropriate flow rate and a reasonable back pressure are usually inevitable requirements for a self-contained microfluidic system. Since this is a prototype only, the pump was not made to be very small. The overall size is 70 × 40 × 15 mm (length × width × height). The pump chamber is a 15 mm in diameter, 2 mm in depth. It should be noted that, we only tested inner petal-shaped IPMC actuator with a diameter of 15 mm. The actuator used in this prototype is a Nafion 117-based IPMC actuator. A pair of copper plates as electrodes was used to clamp the two sides of the IPMC actuator, providing the stimulus electrical signal. In order to evaluate the performance of micropump, we carry out the experiment of the flow rate and the back pressure measurement in 1 Hz sine voltage input by changing the voltage amplitude from 0.5 to 3 V by the interval of 0.5 V. The experimental results show that the flow rate from 162 to 1611 μL/min can be obtained by changing the voltage amplitude from 0.5 to 3 V, respectively. And the back pressure on the micropump can be as high as 71 mm-H2O under the condition of 1 Hz

Second example is an ultra-thin and ultra-light refreshable Braille display with BGAs [41, 44]. There are more than 100 million visually impaired people in the world. This means there are a huge number of people who cannot access the internet because most information in the internet are shown with words and photos on the liquid crystal displays of mobile phones, laptop computers, and other tablet tools. Currently, the refreshable Braille displays with inorganic piezoelectric actuators are commercially available but they are not suitable for the mobile use

Here, we introduce three examples of our application trials with IPMC and BGAs.

three-way solenoid valves [46]. In this system, the three-way valve and a particular twoway valve are open during the BGA shows upward motion (during sucking water). They were successful to dispense *ca*. 20 μL water droplet within 2% of relative standard deviation. We hope that our BGAs will be practically appreciable for some medical and medical welfare devices in the near future.

**References**

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#### **6. Conclusions**

Ionic polymer actuator is a class of functional polymers that has great potential for application in soft robotics and micro-devices. In this chapter, two representative ionic polymer actuators are introduced: IPMC and BGA. Some fundamental characteristics and properties of the ionic polymer actuator have been clarified, and some recent applications in the micro pump, braille display and micropipette of IPMC and BGA as soft actuators have been presented.

#### **Acknowledgements**

This work is supported by the National Natural Science Foundation of China (NO.51505369 and 91748124), Jiangsu Key Laboratory of Special Robot Technology (NO. 2017B21114), and the Fundamental Research Funds for the Central Universities, P.R. China. The authors gratefully acknowledge the supports. The author T. S. thank to Sendai R&D center of Alps Electric Co. Ltd., Keio University (Prof. Nakano) and University of Tokyo (Prof. Someya) for their collaborations in the Braille project (the grant from Ministry of Health, Labor and Welfare of Japan in 2009 FY and 2010 FY).

#### **Note**

The authors contributed equally to this work.

#### **Author details**

Yanjie Wang<sup>1</sup> \* and Takushi Sugino2

\*Address all correspondence to: yjwang@hhu.edu.cn

1 School of Mechanical and Electrical Engineering, HoHai University, Changzhou, China

2 Inorganic Functional Materials Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Ikeda, Osaka, Japan

## **References**

three-way solenoid valves [46]. In this system, the three-way valve and a particular twoway valve are open during the BGA shows upward motion (during sucking water). They were successful to dispense *ca*. 20 μL water droplet within 2% of relative standard deviation. We hope that our BGAs will be practically appreciable for some medical and medical

Ionic polymer actuator is a class of functional polymers that has great potential for application in soft robotics and micro-devices. In this chapter, two representative ionic polymer actuators are introduced: IPMC and BGA. Some fundamental characteristics and properties of the ionic polymer actuator have been clarified, and some recent applications in the micro pump, braille display and micropipette of IPMC and BGA as soft actuators have

This work is supported by the National Natural Science Foundation of China (NO.51505369 and 91748124), Jiangsu Key Laboratory of Special Robot Technology (NO. 2017B21114), and the Fundamental Research Funds for the Central Universities, P.R. China. The authors gratefully acknowledge the supports. The author T. S. thank to Sendai R&D center of Alps Electric Co. Ltd., Keio University (Prof. Nakano) and University of Tokyo (Prof. Someya) for their collaborations in the Braille project (the grant from Ministry of Health, Labor and Welfare of

1 School of Mechanical and Electrical Engineering, HoHai University, Changzhou, China

2 Inorganic Functional Materials Research Institute, National Institute of Advanced

welfare devices in the near future.

**6. Conclusions**

52 Actuators

been presented.

**Note**

**Author details**

Yanjie Wang<sup>1</sup>

**Acknowledgements**

Japan in 2009 FY and 2010 FY).

The authors contributed equally to this work.

\* and Takushi Sugino2

\*Address all correspondence to: yjwang@hhu.edu.cn

Industrial Science and Technology (AIST), Ikeda, Osaka, Japan


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**Chapter 4**

**Provisional chapter**

**Development of Resonators with Reversible**

**Development of Resonators with Reversible** 

**and Energy Harvesters**

**and Energy Harvesters**

Jerzy Kaleta, Rafał Mech and

Jerzy Kaleta, Rafał Mech and

http://dx.doi.org/10.5772/intechopen.78572

Additional information is available at the end of the chapter

Additional information is available at the end of the chapter

Przemysław Wiewiórski

Przemysław Wiewiórski

**Abstract**

transmission system.

harvesting, harvesters

**Magnetostrictive Effect for Applications as Actuators**

**Magnetostrictive Effect for Applications as Actuators** 

This chapter presents the methodology of designing and testing wideband actuators and energy harvesters which can be treated as one device called a mechanical resonator. In order to obtain described effects, the magnetostriction phenomenon was used. This effect enables the construction of resonators in selected frequency bands, including the ultrasonic range. Cores made of giant magnetostrictive materials (GMM) were used for the construction. Considerable attention was given to composite cores to reduce the weight of pure Terfenol-D. The influence of the volume fraction of Terfenol-D powder, the size of its grains, and the direction of polarization on the value of magnetostriction in a wide frequency band were investigated. The magnetostriction of composite cores and solid Terfenol-D samples was also compared. The structure and the use of magnetostrictive cores containing a combination of NdFeB magnets and pure Terfenol-D are also presented. An important issue was also the development of our own methodology of magnetostriction testing, including the use of fiber optic sensors (Fiber Bragg Grating sensors, FBGs), Hall's sensors, and the original measuring system for magnetic field visualization (Magscanner). The chapter also discusses several own designs of actuators and energy harvesters, including shock harvester, resonant harvester, and energy

**Keywords:** magnetomechanical cross-effect, smart magnetic materials,

magnetostriction, Terfenol-D, magnetostrictive actuators, frequency response, energy

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

© 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use,

distribution, and reproduction in any medium, provided the original work is properly cited.

DOI: 10.5772/intechopen.78572


#### **Development of Resonators with Reversible Magnetostrictive Effect for Applications as Actuators and Energy Harvesters Development of Resonators with Reversible Magnetostrictive Effect for Applications as Actuators and Energy Harvesters**

DOI: 10.5772/intechopen.78572

Jerzy Kaleta, Rafał Mech and Przemysław Wiewiórski Jerzy Kaleta, Rafał Mech and Przemysław Wiewiórski

Additional information is available at the end of the chapter Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/intechopen.78572

#### **Abstract**

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[43] Carpi F, Smela E, editors. Biomedical Applications of Electroactive Polymer Actuators.

[44] Takahashi I, Takatsuka T, Abe M. Application of nano-carbon actuator to braille display. In: Asaka K, Okuzaki H, editors. Soft Actuators: Materials, Modeling, Applications, and Future Perspectives. Springer Japan: Springer; 2014. pp. 371-384. DOI: 10.1007/978-4-

[45] Addinall R. Sugino T, Neuhaus R, Kosidlo U, Tonner F, Glanz C, Kolaric I, Bauerhansl T, Asaka K. Integration of CNT-based actuators for bio-medical applications-example printed circuit board CNT actuator pipette. In: Proceedings of 2014 IEEE/ASME international conference on advanced intelligent mechatronics (AIM); 8-11 July 2014; Besacon.

[46] Goya K, Fuchiwaki Y, Tanaka M, Addinall R, Ooie T, Sugino T, Asaka K. A micropipette system based on low driving voltage carbon nanotube actuator. Microsystem

Technologies. 2017;**23**:2657-2661. DOI: 10.1007/s00542-016-2943-y

West Sussex: Wiley; 2009. 476 p. DOI: 10.1002/9780470744697

431-54767-9.ch27

56 Actuators

France: IEEE; 2014. p. 1436-1441

This chapter presents the methodology of designing and testing wideband actuators and energy harvesters which can be treated as one device called a mechanical resonator. In order to obtain described effects, the magnetostriction phenomenon was used. This effect enables the construction of resonators in selected frequency bands, including the ultrasonic range. Cores made of giant magnetostrictive materials (GMM) were used for the construction. Considerable attention was given to composite cores to reduce the weight of pure Terfenol-D. The influence of the volume fraction of Terfenol-D powder, the size of its grains, and the direction of polarization on the value of magnetostriction in a wide frequency band were investigated. The magnetostriction of composite cores and solid Terfenol-D samples was also compared. The structure and the use of magnetostrictive cores containing a combination of NdFeB magnets and pure Terfenol-D are also presented. An important issue was also the development of our own methodology of magnetostriction testing, including the use of fiber optic sensors (Fiber Bragg Grating sensors, FBGs), Hall's sensors, and the original measuring system for magnetic field visualization (Magscanner). The chapter also discusses several own designs of actuators and energy harvesters, including shock harvester, resonant harvester, and energy transmission system.

**Keywords:** magnetomechanical cross-effect, smart magnetic materials, magnetostriction, Terfenol-D, magnetostrictive actuators, frequency response, energy harvesting, harvesters

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

#### **1. Introduction**

Materials called/classified as smart materials (SM) have already formed a large group of new construction materials. The phenomenon of smart materials is based on the fact that their main properties, expressed as a physical unit (i.e., mechanical field), depend on some other unit (i.e., magnetic, electric or temperature field). Therefore, in the description and application of these materials, cross effects are the crucial factor. A significant group of SM is materials that present their main application characteristics based on magnetic stimulation (smart magnetic materials, SMM). The following materials should be mentioned as the representatives of the group: magnetorheological, giant magnetostrictive and magnetoresistive, magnetocaloric, shape memory magnetically activated, etc. It means that the diverse properties of SMM including, for example, viscosity, shape, stiffness, temperature, electric resistance, color—can be modified with use of magnetic stimulation. In this chapter, the possibilities of using one of SMM groups, namely giant magnetostrictive materials (GMM), are presented.

unique properties, the material allows the conversion of magnetic field energy into mechanical energy, using a magnetostriction effect. The effect is reversible and allows the conversion of mechanical energy into magnetic energy using the Villari effect. Therefore, Terfenol-D is widely used in a variety of applications such as construction of actuators [3–5], sensors [6],

Development of Resonators with Reversible Magnetostrictive Effect for Applications…

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59

Unfortunately, despite their numerous advantages, solid materials also have significant drawbacks, among which the most important ones are as follows: the presence of strong eddy currents as a result of cyclic loading at high frequency of work [8], and low tensile strength. In order to eliminate these drawbacks, researchers are trying to produce new materials, such

The Department of Mechanics, Materials Science and Engineering has been associated with the area of magnetic SM since the early 1990s. The first research related to this type of materials was mainly related to liquids, especially magnetorheological fluids. However, in subsequent years, this interest became more and more widespread, and as a result, a few years later, a great deal of attention was also paid to other materials, including the so-called giant magnetostriction. As it was mentioned before, Terfenol-D is a representative of such materials. The first work related to the research on this material allowed the design and manufacturing of the actuator whose core was the solid Terfenol-D. **Figure 1** shows one of the earliest

magnetostrictive actuators called "singing table" which was designed by the authors.

Although the actuator presented in **Figure 1** was used mainly as a demonstration object, it allowed to show how the magnetostriction phenomenon works in an accessible way. Based on this first construction, the actuator construction was improved and modified in such a way that it could serve as an executive element in a prototype research stand. A new type of actuator made it possible to damp the vibrations of the construction with the use of counter vibration. Thanks to this, the vibrating wave of the opposite phase was adjusted to the natural

**Figure 1.** Vibration exciter system (singing table) as the first step taken by the authors' team to magnetostrictive tech-

as polymer composites containing powdered Terfenol-D [9–14].

and so-called energy harvesters [7].

**2.1. Actuators based on Terfenol-D**

nology [15].

The following subjects are described in this chapter:


#### **2. Magnetostrictive mechanical resonators and their applications**

The main goal described in this chapter is to develop a methodology for designing and testing broadband resonators. This methodology should offer a better understanding of both actuators and energy harvesters, including those working alternately as one device. One of the most important issues to solve is obtaining mechanical resonance in a wide frequency band, which would allow the use of resonators in any mechanical construction.

It turned out that one of the materials exhibiting the so-called giant magnetostriction effect is Terfenol-D [1, 2], which might be very useful in solving this particular issue. Thanks to its unique properties, the material allows the conversion of magnetic field energy into mechanical energy, using a magnetostriction effect. The effect is reversible and allows the conversion of mechanical energy into magnetic energy using the Villari effect. Therefore, Terfenol-D is widely used in a variety of applications such as construction of actuators [3–5], sensors [6], and so-called energy harvesters [7].

Unfortunately, despite their numerous advantages, solid materials also have significant drawbacks, among which the most important ones are as follows: the presence of strong eddy currents as a result of cyclic loading at high frequency of work [8], and low tensile strength. In order to eliminate these drawbacks, researchers are trying to produce new materials, such as polymer composites containing powdered Terfenol-D [9–14].

#### **2.1. Actuators based on Terfenol-D**

**1. Introduction**

58 Actuators

Materials called/classified as smart materials (SM) have already formed a large group of new construction materials. The phenomenon of smart materials is based on the fact that their main properties, expressed as a physical unit (i.e., mechanical field), depend on some other unit (i.e., magnetic, electric or temperature field). Therefore, in the description and application of these materials, cross effects are the crucial factor. A significant group of SM is materials that present their main application characteristics based on magnetic stimulation (smart magnetic materials, SMM). The following materials should be mentioned as the representatives of the group: magnetorheological, giant magnetostrictive and magnetoresistive, magnetocaloric, shape memory magnetically activated, etc. It means that the diverse properties of SMM including, for example, viscosity, shape, stiffness, temperature, electric resistance, color—can be modified with use of magnetic stimulation. In this chapter, the possibilities of using one of

• Development of the concept of GMM actuators in terms of applications as a vibration

• Application of the inverse magnetostriction effect (called Villari-effect) for energy harvest-

• Preparation methods of composite magnetostrictive rods: GMM composite (GMMc): as

• Application of fiber Bragg gratings (FBG) technique in online measurement of the magne-

• Testing method of resonators cores using impact as energy harvesting power sources for

• Construction of high-power actuator with a real-time PID magnetostrictive regulator to

The main goal described in this chapter is to develop a methodology for designing and testing broadband resonators. This methodology should offer a better understanding of both actuators and energy harvesters, including those working alternately as one device. One of the most important issues to solve is obtaining mechanical resonance in a wide frequency band,

It turned out that one of the materials exhibiting the so-called giant magnetostriction effect is Terfenol-D [1, 2], which might be very useful in solving this particular issue. Thanks to its

**2. Magnetostrictive mechanical resonators and their applications**

which would allow the use of resonators in any mechanical construction.

SMM groups, namely giant magnetostrictive materials (GMM), are presented.

The following subjects are described in this chapter:

tostriction level in strong magnetic field environment

the standard microcontroller dedicated to wireless nodes

exciter or active vibration damper.

ing devices

magnetic active cores

compensate self-thermal effect

The Department of Mechanics, Materials Science and Engineering has been associated with the area of magnetic SM since the early 1990s. The first research related to this type of materials was mainly related to liquids, especially magnetorheological fluids. However, in subsequent years, this interest became more and more widespread, and as a result, a few years later, a great deal of attention was also paid to other materials, including the so-called giant magnetostriction. As it was mentioned before, Terfenol-D is a representative of such materials. The first work related to the research on this material allowed the design and manufacturing of the actuator whose core was the solid Terfenol-D. **Figure 1** shows one of the earliest magnetostrictive actuators called "singing table" which was designed by the authors.

Although the actuator presented in **Figure 1** was used mainly as a demonstration object, it allowed to show how the magnetostriction phenomenon works in an accessible way. Based on this first construction, the actuator construction was improved and modified in such a way that it could serve as an executive element in a prototype research stand. A new type of actuator made it possible to damp the vibrations of the construction with the use of counter vibration. Thanks to this, the vibrating wave of the opposite phase was adjusted to the natural

**Figure 1.** Vibration exciter system (singing table) as the first step taken by the authors' team to magnetostrictive technology [15].

vibrations of the structure, which caused the damping of vibrations and ensured the stability of the entire structure. **Figure 2** presents the second type of a Terfenol-D-based actuator dedicated for dumping mechanical vibrations in a low-frequency band (50–1000 Hz) [15].

energy recovering devices' (harvesters) development belongs to the field of alternative and

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Taking into account the physical phenomena occurring during the energy exchange process, the construction and principles of work, and environmental conditions in a specified working area, harvesters (as sources with different electrical characteristics) can be divided into three

• AC voltage harvesters (e.g., harvesters based on the Faraday effect or so called piezoelectric

In order to be able to design electrical circuits for harvesters, the knowledge of their working characteristics is mandatory. Only the ones based on the thermoelectric or photovoltaic effect can generate DC voltage. Those which regain energy from vibrations, magnetostrictive, piezoelectric or based on the Faraday effect are the sources of AC voltage. The scope of research related to energy harvesting conducted by the authors of the chapter is shown in **Figure 3**.

Harvesters supplied with energy from impacts [16] are a completely different type of devices. Electric energy generation lasts only for a very short period of time when it comes to the impulse power supply although its current amplitude is extremely high. Harvesters "supplied" with a mechanical shock generate various voltage outputs. However, they are considered devices characterized by strong current impulse and additional frequencies generated in

• DC voltage harvesters (e.g., harvesters based on the thermoelectric effect),

• Shock harvesters (e.g., harvesters with a magnetostrictive core).

**Figure 3.** Structure of evaluating energy harvesting methods.

renewable energy.

groups:

patches),

#### **2.2. Reversible effect actuators selected for energy harvesting**

Energy harvesting (EH), in primary sources known also as power harvesting or energy scavenging, is a set of methods allowing to generate electrical energy using surrounding sources, such as mechanical, thermal, solar and electromagnetic energy, salinity gradients, etc., for example, [7]. Generally, the goal is using sources commonly available in the environment (so called background energy) which are undesirable and usually are suppressed (e.g., noise, impact and mechanical vibration of devices and constructions, electromagnetic smog, frictional and combustion heat as well as heat obtained as a result of electric current flow and engine cooling) or commonly available (solar light, wave energy, salinity differences, biochemical processes in, e.g., plants) and also related to human biology (motion, body heat, etc.). Currently, it is assumed that EH can be an effective source of "cost-free" (apart from installation costs) power supply for low power devices (e.g., electronic devices, sensor systems). It is assumed that in the future vast harvester networks will also be used as large power energy sources.

Magnetostrictive harvesters and actuators are constructed using physical cross effects based on magneto-mechanical phenomena. It is assumed that even in terms of low power and efficiency (albo: in the case of low power and efficiency techniques) they can be a valuable source of power supply. In low-power techniques, it is assumed that harvesters work as typical power supplies that are connected by a wire to a microprocessor subsystem (μC) which after supplying power sends data wirelessly to a unit receiving and processing information according to its operation algorithm (program code).

The principle of EH is to create a new concept of voltage generators which will use cross effects including the magneto-mechanic one. The assumption is that even though EH using the magneto-mechanical effect can provide only small powers or efficiencies, they can become valuable sources of energy. Special attention has been paid to this issue for the last few years in the biggest research institutes all over the world, especially in the USA and quickly developing Asian countries. The energy harvesting concept together with the development of

**Figure 2.** View of actuator as a part of the active dumping vibration system of calibrated mechanical beam [15].

energy recovering devices' (harvesters) development belongs to the field of alternative and renewable energy.

Taking into account the physical phenomena occurring during the energy exchange process, the construction and principles of work, and environmental conditions in a specified working area, harvesters (as sources with different electrical characteristics) can be divided into three groups:


vibrations of the structure, which caused the damping of vibrations and ensured the stability of the entire structure. **Figure 2** presents the second type of a Terfenol-D-based actuator dedicated for dumping mechanical vibrations in a low-frequency band (50–1000 Hz) [15].

Energy harvesting (EH), in primary sources known also as power harvesting or energy scavenging, is a set of methods allowing to generate electrical energy using surrounding sources, such as mechanical, thermal, solar and electromagnetic energy, salinity gradients, etc., for example, [7]. Generally, the goal is using sources commonly available in the environment (so called background energy) which are undesirable and usually are suppressed (e.g., noise, impact and mechanical vibration of devices and constructions, electromagnetic smog, frictional and combustion heat as well as heat obtained as a result of electric current flow and engine cooling) or commonly available (solar light, wave energy, salinity differences, biochemical processes in, e.g., plants) and also related to human biology (motion, body heat, etc.). Currently, it is assumed that EH can be an effective source of "cost-free" (apart from installation costs) power supply for low power devices (e.g., electronic devices, sensor systems). It is assumed that in the future vast harvester networks will also be used as large power

Magnetostrictive harvesters and actuators are constructed using physical cross effects based on magneto-mechanical phenomena. It is assumed that even in terms of low power and efficiency (albo: in the case of low power and efficiency techniques) they can be a valuable source of power supply. In low-power techniques, it is assumed that harvesters work as typical power supplies that are connected by a wire to a microprocessor subsystem (μC) which after supplying power sends data wirelessly to a unit receiving and processing information

The principle of EH is to create a new concept of voltage generators which will use cross effects including the magneto-mechanic one. The assumption is that even though EH using the magneto-mechanical effect can provide only small powers or efficiencies, they can become valuable sources of energy. Special attention has been paid to this issue for the last few years in the biggest research institutes all over the world, especially in the USA and quickly developing Asian countries. The energy harvesting concept together with the development of

**Figure 2.** View of actuator as a part of the active dumping vibration system of calibrated mechanical beam [15].

**2.2. Reversible effect actuators selected for energy harvesting**

according to its operation algorithm (program code).

energy sources.

60 Actuators

In order to be able to design electrical circuits for harvesters, the knowledge of their working characteristics is mandatory. Only the ones based on the thermoelectric or photovoltaic effect can generate DC voltage. Those which regain energy from vibrations, magnetostrictive, piezoelectric or based on the Faraday effect are the sources of AC voltage. The scope of research related to energy harvesting conducted by the authors of the chapter is shown in **Figure 3**.

Harvesters supplied with energy from impacts [16] are a completely different type of devices. Electric energy generation lasts only for a very short period of time when it comes to the impulse power supply although its current amplitude is extremely high. Harvesters "supplied" with a mechanical shock generate various voltage outputs. However, they are considered devices characterized by strong current impulse and additional frequencies generated in

**Figure 3.** Structure of evaluating energy harvesting methods.

the signal which occur as a result of resonance in the core-coil system. In this chapter, a new method of electrical current generation due to the demagnetization of neodymium magnets in the circuits with magnetostrictive core is also presented.

Currently, a particular type of generators is harvesters from the explosive-driven ferromagnetic generators (EDFMG) group. They generate the electromagnetic wave that occurs due to the instant demagnetization of a magnet caused by a mechanical shock which results from an explosion or another strong force impulse. In this moment, the magnet loses its magnetic properties, generating a strong impulse magnetic field in its surroundings. During the impact, even the total destruction of a magnet is possible; however, the amount of energy that is generated on a coil is huge and it is sufficient to charge high-voltage capacitors with a substantial amount of electric energy.

The new concept of the harvester was developed based on the idea of a ferromagnetic generator (FMG) in which strong magneto-mechanical phenomena occur, including the demagnetization of strong neodymium NdFeB magnets in order to generate electric current due to a mechanical shock. One of the construction priorities was to standardize particular sizes and parts, so every single element of the harvester could be easily exchanged and disassembled. **Figure 4** presents the parts of the harvester.

It has to be remembered that the estimated efficiency value of the transformation between the mechanical shock, which occurs during the demagnetization of the neodymium magnets, and the electric current is about 0.2%. That is why, the main challenge is to improve power transformation. The so-called pulse power supply harvester constructions are shown in **Figure 5**.

#### **2.3. Use of actuator-harvester circuits to power up wireless network system**

Harvesters which in their principle of work use cross effects are more frequently based on magneto-mechanical phenomena. It is assumed that even in the case of low power and efficiency; they can be a valuable source of power supply.

A multinode harvesting structure can be used in structural health monitoring (SHM) applications to recover electric power from wasted energy generated mostly from vibrations. Magnetic harvesters might also be used as a power source in SHM systems which monitor large mechanical structures. Our latest system presents this solution. It uses 14 MEMS sensors with designated 14 degrees of freedom (DOF) (3D accelerometer, 3D gyroscope, 3D magnetometer, barometric pressure sensor, microphone, temperature T, humidity R, light intensity). The structure of the system is shown in **Figure 6**. The software designed by the authors allows to monitor the parameters provided by 14 sensors via a webpage or in a service mode. The software is designed to support such systems as an ADIS16488 module and other components of the most precise IMU (Analog Devices iMEMS 2016). In order to process the data received from the 14 DOF sensors, which includes not only measuring the certain physical value but also monitoring the level of recovered energy, proper microprocessors had to be chosen (an important factor here is power consumption).

**Figure 6.** The structure of a wireless harvesting system with a 14 DOF block [17].

**Figure 5.** View of solid-state harvesters based on GMMc diameter of φ=5 mm (left) and φ=10 mm rod (right) for tactical

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grade versions of 10 W devices.

**Figure 7** shows three typical sources of low-frequency energy harvesting: mechanical shock wave (**Figure 7A**), low-frequency mechanical resonance (**Figure 7B**) and energy transmission through ultrasonic resonant vibrations (**Figure 7C**). A properly selected conditioning circuit provides the harvesting system with useful current and voltage capabilities. The creation of a wireless node to measure certain physical quantities and to monitor the level of recovered energy requires the selection of an appropriate hardware platform, such as a microprocessor and a wireless transmission system. The use of SM in wireless power transmission turned out

**Figure 4.** View of a shock harvester with description of its elements [16].

Development of Resonators with Reversible Magnetostrictive Effect for Applications… http://dx.doi.org/10.5772/intechopen.78572 63

**Figure 5.** View of solid-state harvesters based on GMMc diameter of φ=5 mm (left) and φ=10 mm rod (right) for tactical grade versions of 10 W devices.

**Figure 6.** The structure of a wireless harvesting system with a 14 DOF block [17].

the signal which occur as a result of resonance in the core-coil system. In this chapter, a new method of electrical current generation due to the demagnetization of neodymium magnets

Currently, a particular type of generators is harvesters from the explosive-driven ferromagnetic generators (EDFMG) group. They generate the electromagnetic wave that occurs due to the instant demagnetization of a magnet caused by a mechanical shock which results from an explosion or another strong force impulse. In this moment, the magnet loses its magnetic properties, generating a strong impulse magnetic field in its surroundings. During the impact, even the total destruction of a magnet is possible; however, the amount of energy that is generated on a coil is huge and it is sufficient to charge high-voltage capacitors with a substantial amount of electric energy. The new concept of the harvester was developed based on the idea of a ferromagnetic generator (FMG) in which strong magneto-mechanical phenomena occur, including the demagnetization of strong neodymium NdFeB magnets in order to generate electric current due to a mechanical shock. One of the construction priorities was to standardize particular sizes and parts, so every single element of the harvester could be easily exchanged and disassembled.

It has to be remembered that the estimated efficiency value of the transformation between the mechanical shock, which occurs during the demagnetization of the neodymium magnets, and the electric current is about 0.2%. That is why, the main challenge is to improve power transformation. The so-called pulse power supply harvester constructions are shown in **Figure 5**.

Harvesters which in their principle of work use cross effects are more frequently based on magneto-mechanical phenomena. It is assumed that even in the case of low power and effi-

**2.3. Use of actuator-harvester circuits to power up wireless network system**

in the circuits with magnetostrictive core is also presented.

62 Actuators

**Figure 4** presents the parts of the harvester.

ciency; they can be a valuable source of power supply.

**Figure 4.** View of a shock harvester with description of its elements [16].

A multinode harvesting structure can be used in structural health monitoring (SHM) applications to recover electric power from wasted energy generated mostly from vibrations. Magnetic harvesters might also be used as a power source in SHM systems which monitor large mechanical structures. Our latest system presents this solution. It uses 14 MEMS sensors with designated 14 degrees of freedom (DOF) (3D accelerometer, 3D gyroscope, 3D magnetometer, barometric pressure sensor, microphone, temperature T, humidity R, light intensity). The structure of the system is shown in **Figure 6**. The software designed by the authors allows to monitor the parameters provided by 14 sensors via a webpage or in a service mode. The software is designed to support such systems as an ADIS16488 module and other components of the most precise IMU (Analog Devices iMEMS 2016). In order to process the data received from the 14 DOF sensors, which includes not only measuring the certain physical value but also monitoring the level of recovered energy, proper microprocessors had to be chosen (an important factor here is power consumption).

**Figure 7** shows three typical sources of low-frequency energy harvesting: mechanical shock wave (**Figure 7A**), low-frequency mechanical resonance (**Figure 7B**) and energy transmission through ultrasonic resonant vibrations (**Figure 7C**). A properly selected conditioning circuit provides the harvesting system with useful current and voltage capabilities. The creation of a wireless node to measure certain physical quantities and to monitor the level of recovered energy requires the selection of an appropriate hardware platform, such as a microprocessor and a wireless transmission system. The use of SM in wireless power transmission turned out

After matching the sensor-microprocessor configuration with a suitable energy harvester, the whole packets, together with a wireless communication system, were placed in the nodes. Due to the fact that every node is equipped with the same wireless communication system, different types of sensors can be easily substituted or put together by the user, thanks to the

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A properly selected conditioning circuit provides the harvesting system with a certain current and voltage output. The creation of a wireless node to measure certain physical quantities and to monitor the level of recovered energy requires the selection of an appropriate hardware

Bearing in mind the justifiability of limiting the use of solid Terfenol-D in the construction of magnetostrictive resonators, two solutions are presented below, namely the use of a GMM composite core and—in Chapter 4—a core consisting of a neodymium magnet and

Referring to price of Terfenol-D which is a relatively expensive material, a device which would not require this material would be adequately cheaper. The brittleness of pure Terfenol-D can

A prospective application area for Terfenol-D, which is a typical representative of the GMM group, is (electric) energy harvesting from, for example, mechanical vibration systems [18, 19]. However, some of the applications of this material are restricted due to eddy current loss at a high frequency. In addition, it has some drawbacks, such as intrinsic brittleness accompanied by maximizing the fraction of the brittle, Laves phase. The magnetostrictive composite materials have been developed as an alternative way to overcome both the eddy current loss and

The main advantages of magnetostrictive composites based on a nonmagnetic polymer matrix

• reduction of solid Terfenol-D's drawbacks (eddy currents at higher operating frequencies and its brittleness limiting its use under, for example, tensile stress [1, 20], whereby its

• new potential applications in, for example, (SHM) composite materials and structures (tag-

Therefore, the main goal of this research was to investigate the magnetostriction of a fieldstructural composite with Terfenol-D particles. The composite should replace the solid Terfenol-D rods in an actuator or a damper. It was decided to closely examine the effect of the

platform, such as a microprocessor and a wireless transmission system.

**3. The idea of the composite rod in the wideband actuator and** 

dedicated software shown in **Figure 8**.

**3.1. The preparation of GMM composite**

be replaced with a composite material [7].

and containing Terfenol-D powder particles are as follows:

application range is significantly extended,

intrinsic brittleness since 1990.

ging) [21].

**energy harvester**

Terfenol-D.

**Figure 7.** Energy harvesting sources and their power requirements: (A) mechanical impact, (B) low-frequency mechanical resonance and (C) energy transmission by ultrasonic vibration [17].

**Figure 8.** Prototyping of multi-DOF wireless sensors platform: Main communication station and Multi-DOF software [17].

to be effective. For this purpose, Smart Ultrasonic Resonant Power System (SURPS), a system for simultaneous power and data transmission, was developed. It ensured transmission through various media (solid, liquid) and with various transmitter-receiver configurations [17].

After matching the sensor-microprocessor configuration with a suitable energy harvester, the whole packets, together with a wireless communication system, were placed in the nodes. Due to the fact that every node is equipped with the same wireless communication system, different types of sensors can be easily substituted or put together by the user, thanks to the dedicated software shown in **Figure 8**.

A properly selected conditioning circuit provides the harvesting system with a certain current and voltage output. The creation of a wireless node to measure certain physical quantities and to monitor the level of recovered energy requires the selection of an appropriate hardware platform, such as a microprocessor and a wireless transmission system.
