Browsing by Author "Chung, Tien-Kan"

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A magnetic-piezoelectric smart material-structure sensing three axis DC and AC magnetic-fields
(2017-12-01)
Hung, Chiao-Fang
;
Chen, Chin-Chung
;
Yeh, Po-Chen
;
Chen, Po-Wen
;
Chung, Tien-Kan
In this paper, we demonstrate a smart material-structure can sense not only three-axis AC magnetic-fields but also three-axis DC magnetic-fields. Under x-axis and z-axis AC magnetic field ranging from 0.2 to 3.2 gauss, sensing sensitivity of the smart material-structure stimulated at resonant frequency is approximate 8.79 and 2.80 mV/gauss, respectively. In addition, under x-axis and z-axis DC magnetic fields ranging from 2 to 12 gauss, the sensitivity of the smart material-structure is 1.24-1.54 and 1.25-1.41 mV/gauss, respectively. In addition, under x-axis and z-axis DC magnetic fields ranging from 12 to 20 gauss, the sensitivity of the smart material-structure is 5.17-6.2 and 3.97-4.57 mV/gauss, respectively. These experimental results show that the smart material-structure successfully achieves three-axis DC and AC magnetic sensing as we designed. Furthermore, we also compare the results of the AC and DC magnetic-field sensing to investigate discrepancies. Finally, when applying composite magnetic-fields to the smart material-structure, the smart material-structure shows decent outputs as expected (consistent to the sensing principle). In the future, we believe the smart material-structure capable of sensing AC and DC magnetic fields will have more applications than conventional structures capable of sensing only DC or AC magnetic field. Thus, the smart material-structure will be an important design reference for future magnetic-field sensing technologies.
A magnetic-piezoelectric smart material-structure utilizing magnetic force interaction to optimize the sensitivity of current sensing
(2016-01-01)
Yeh, Po-Chen
;
Chung, Tien-Kan
;
Lai, Chen-Hung
;
Wang, Chieh-Min
;
機械工程學系
This paper presents a magnetic-piezoelectric smart material-structure using a novel magnetic-force-interaction approach to optimize the sensitivity of conventional piezoelectric current sensing technologies. The smart material-structure comprises a CuBe-alloy cantilever beam, a piezoelectric PZT sheet clamped to the fixed end of the beam, and an NdFeB permanent magnet mounted on the free end of the beam. When the smart material-structure is placed close to an AC conductor, the magnet on the beam of the smart structure experiences an alternating magnetic attractive and repulsive force produced by the conductor. Thus, the beam vibrates and subsequently generates a strain in the PZT sheet. The strain produces a voltage output because of the piezoelectric effect. The magnetic force interaction is specifically enhanced through the optimization approach (i.e., achieved by using SQUID and machining method to reorient the magnetization to different directions to maximize the magnetic force interaction). After optimizing, the beam\'s vibration amplitude is significantly enlarged and, consequently, the voltage output is substantially increased. The experimental results indicated that the smart material-structure optimized by the proposed approach produced a voltage output of 4.01 V-rms with a sensitivity of 501 m V-rms/A when it was placed close to a conductor with a current of 8 A at 60 Hz. The optimized voltage output and sensitivity of the proposed smart structure were approximately 316 % higher than those (1.27 V-rms with 159 m V-rms/A) of representative piezoelectric-based current sensing technologies presented in other studies. These improvements can significantly enable the development of more self-powered wireless current sensing applications in the future.
A magnetic-piezoelectric smart material-structure utilizing magnetic force interaction to optimize the sensitivity of current sensing
(2016-01)
Yeh, Po-Chen
;
Chung, Tien-Kan
;
Lai, Chen-Hung
;
Wang, Chieh-Min
;
機械工程學系
This paper presents a magnetic-piezoelectric smart material-structure using a novel magnetic-force-interaction approach to optimize the sensitivity of conventional piezoelectric current sensing technologies. The smart material-structure comprises a CuBe-alloy cantilever beam, a piezoelectric PZT sheet clamped to the fixed end of the beam, and an NdFeB permanent magnet mounted on the free end of the beam. When the smart material-structure is placed close to an AC conductor, the magnet on the beam of the smart structure experiences an alternating magnetic attractive and repulsive force produced by the conductor. Thus, the beam vibrates and subsequently generates a strain in the PZT sheet. The strain produces a voltage output because of the piezoelectric effect. The magnetic force interaction is specifically enhanced through the optimization approach (i.e., achieved by using SQUID and machining method to reorient the magnetization to different directions to maximize the magnetic force interaction). After optimizing, the beam\'s vibration amplitude is significantly enlarged and, consequently, the voltage output is substantially increased. The experimental results indicated that the smart material-structure optimized by the proposed approach produced a voltage output of 4.01 V-rms with a sensitivity of 501 m V-rms/A when it was placed close to a conductor with a current of 8 A at 60 Hz. The optimized voltage output and sensitivity of the proposed smart structure were approximately 316 % higher than those (1.27 V-rms with 159 m V-rms/A) of representative piezoelectric-based current sensing technologies presented in other studies. These improvements can significantly enable the development of more self-powered wireless current sensing applications in the future.
A MAGNETIC/MECHANICAL APPROACH FOR OPTIMIZING A MINIATURE SELF-POWERED CURRENT SENSOR
(2014-01-01)
Chung, Tien-Kan
;
Yeh, Po-Chen
;
Wang, Chieh-Min
;
機械工程學系
;
Department of Mechanical Engineering
In this paper, we demonstrate a magnetic/mechanical approach for optimizing a miniature self-powered current sensor. The sensor consists of a piezoelectric PZT sheet, Cu Be cantilever beam, NdFeB magnet, and mechanical clamp. When the sensor is placed nearby an AC-current carrying wire from a breaker, the magnet fixed on the beam of the sensor experiences an alternative magnetic attractive and repulsive force produced by an AC magnetic field generated by the wire. Due to the alternative magnetic attractive and repulsive force, the magnet fixed on the beam is oscillated. The oscillating beam deforms the PZT sheet and subsequently produces strain in the PZT sheet. Due to the piezoelectric effect, the strain is converted to a voltage response. Through the optimized approach, the voltage output of the sensor is increased from 1.27 volts to 4.01 volts when the sensor is used to detect an AC current-carrying wire of 8 ampere at 60 Hz.
A Magnetic/Piezoelectric-Based Thermal Energy Harvester
(2013)
Chung, Tien-Kan
;
Shukla, Ujjwal
;
Tseng, Chia-Yuan
;
Chen, Chin-Chung
;
Wang, Chieh-Min
In this paper, we demonstrate a non-contact magnetic/piezoelectric-based thermal energy harvester utilizing an optimized thermal-convection mechanism to enhance the heat transfer in the energy harvesting/converting process in order to increase the power output. The harvester consists of a CuBe spring, Gadolinium soft magnet, NdFeB hard magnets, frame, and piezoelectric PZT cantilever beams. According to the configuration, the energy harvesting/converting process under a temperature-difference is cyclic. Thus, the piezoelectric beams continuously oscillate and subsequently produce voltage responses due to the piezoelectric effect. The maximum voltage response of the harvester under a temperature-difference of 25 degrees C is 16.6 mV with a cycling frequency of 0.58 Hz. In addition, we compare the testing result of the harvester utilizing the new thermal-convection mechanism reported in this paper and using previous thermal-convection mechanism reported elsewhere. According to the comparison, the results show the harvester utilizing the new thermal-convection mechanism has a higher cycling frequency resulting in a higher power output than the previous mechanism.
A MICRO KINETIC ENERGY HARVESTER DEMONSTRATING ENERGY HARVESTING FROM 3-D MECHANICAL MOTION AND POWER INCREASING THROUGH MAGNETIC-BASED FREQUENCY RECTIFICATION
(2012)
Chung, Tien-Kan
;
Wang, Chieh-Min
;
Tseng, Chia-Yuan
;
Liu, Tzu-Wei
;
Yeh, Po-Chen
In this paper, we report a micro 3-D kinetic energy harvester demonstrating an energy conversion from environmental mechanical-energy (3-D mechanical motion) to electrical energy (voltage output). In addition to energy harvesting/conversion from 3-D motion, we demonstrate a non-contact frequency-up rectification approach which converts an incoming lower vibration frequency to a higher frequency in order to increase the power output of the harvester.
A Miniature Magnetic-Force-Based Three-Axis AC Magnetic Sensor with Piezoelectric/Vibrational Energy-Harvesting Functions
(2017-02-01)
Hung, Chiao-Fang
;
Yeh, Po-Chen
;
Chung, Tien-Kan
;
機械工程學系
;
國際半導體學院
In this paper, we demonstrate a miniature magnetic-force-based, three-axis, AC magnetic sensor with piezoelectric/vibrational energy-harvesting functions. For magnetic sensing, the sensor employs a magnetic-mechanical-piezoelectric configuration (which uses magnetic force and torque, a compact, single, mechanical mechanism, and the piezoelectric effect) to convert x-axis and y-axis in-plane and z-axis magnetic fields into piezoelectric voltage outputs. Under the x-axis magnetic field (sine-wave, 100 Hz, 0.2-3.2 gauss) and the z-axis magnetic field (sine-wave, 142 Hz, 0.2-3.2 gauss), the voltage output with the sensitivity of the sensor are 1.13-26.15 mV with 8.79 mV/gauss and 1.31-8.92 mV with 2.63 mV/gauss, respectively. In addition, through this configuration, the sensor can harness ambient vibrational energy, i.e., possessing piezoelectric/vibrational energy-harvesting functions. Under x-axis vibration (sine-wave, 100 Hz, 3.5 g) and z-axis vibration (sine-wave, 142 Hz, 3.8 g), the root-mean-square voltage output with power output of the sensor is 439 mV with 0.333 mu W and 138 mV with 0.051 mu W, respectively. These results show that the sensor, using this configuration, successfully achieves three-axis magnetic field sensing and three-axis vibration energy-harvesting. Due to these features, the three-axis AC magnetic sensor could be an important design reference in order to develop future three-axis AC magnetic sensors, which possess energy-harvesting functions, for practical industrial applications, such as intelligent vehicle/traffic monitoring, processes monitoring, security systems, and so on.
A Miniature Magnetic-Piezoelectric Thermal Energy Harvester
(2015-07-01)
Chen, Chin-Chung
;
Chung, Tien-Kan
;
Tseng, Chia-Yuan
;
Hung, Chiao-Fang
;
Yeh, Po-Chen
In this paper, we report a miniature thermal energy harvester with a novel magnetic-piezoelectric design. The harvester consists of a soft magnetic Gd cantilever beam, a piezoelectric lead zirconate titanate sheet, an NdFeB hard magnet, silicon clamps, and a silicon frame. In this design, the harvester is driven by a temperature difference between a cold side and room temperature ambient air, unlike other magnetic-piezoelectric thermal energy harvesters that are driven by a temperature difference between a cold side and a hot side or between two hot sides. Experimental results show that with a temperature difference of 20 degrees C (cold side: 6.7 degrees C, hot side: 26.7 degrees C), the harvester produces a maximum peak-to-peak voltage of 37 mV and a root mean square voltage of 1.98 mV. The estimated maximum instantaneous power density and average power density is 21.7 nW/cm(3) and 62.9 pW/cm(3), respectively. Moreover, the total volume of our harvester (length x width x height: 6 x 3.5 x 3 mm) is 217 times lower than that of previous experimental harvesters and 38 times smaller than that of previous theoretical-modeled harvesters. Therefore, our harvester is the smallest machined magnetic-piezoelectric thermal energy harvester designed to date. These features enable our harvester to be more easily implemented and integrated with micro wireless sensors and thereby increase more self-powered wireless-sensing applications.
A Miniature Mechanical-Piezoelectric-Configured Three-Axis Vibrational Energy Harvester
(2015-10-01)
Hung, Chiao-Fang
;
Chung, Tien-Kan
;
Yeh, Po-Chen
;
Chen, Chin-Chung
;
Wang, Chieh-Min
In this paper, we demonstrate a novel robust miniature three-axis vibrational energy-harvester using a mechanical-piezoelectric configuration. Using the configuration, the harvester employs Newton\'s law of inertia and the piezoelectric effect to convert either the x-axis or y-axis in-plane and z-axis out-of-plane ambient vibrations into piezoelectric voltage-responses. Under the x-axis vibration (sine-wave, 75 Hz, 3.5 g), our modeled, finite-element analyzed/simulated, and experimental root mean square voltage-response with power-outputs of the harvester (stimulated in resonant with the optimum load) is 525.36 mV with 0.477 mu W, 516.51 mV with 0.461 mu W, and 548 mV with 0.519 mu W, respectively. Under the z-axis vibration (sine-wave, 95 Hz, 3.8 g), the modeled, finite-element analyzed/simulated, and experimental root mean square voltage-response with power-output of the harvester (stimulated in resonant with the optimum load) is 157.35 mV with 0.066 mu W, 170.25 mV with 0.0772 mu W, and 168 mV with 0.075 mu W, respectively. These show that not only both of our modeling and finite-element analysis/simulation can successfully predict the experimental results, but also our harvester is capable of harnessing three-axial ambient vibrations. Moreover, through the piezoelectric lead-zirconate-titanate-connected-in-series approach, the voltage and power outputs are increased. According to these achievements, we believe that our harvester would be an important design reference in industry for future development of microfabrication-based (MEMS-based) three-axial piezoelectric energy harvesters and accelerometers.
A MINIATURE THREE-AXIS PIEZOELECTRIC ENERGY HARVESTER
(2014-01-01)
Hung, Chiao-Fang
;
Wang, Chieh-Min
;
Lin, Shin-Hung
;
Chung, Tien-Kan
;
機械工程學系
In this paper, we demonstrate a novel miniature three-axis piezoelectric energy harvester. The energy harvester consists of four piezoelectric lead zirconate titanate cantilever beams, connector, proof mass, and mechanic frame. Through the connector, a special configuration with a well-constrained mechanism of the energy harvester is achieved. Due to the configuration/mechanism of the energy harvester, the Newton\'s law of inertia and piezoelectric effect are utilized to convert the in-plane (either x-axis or y-axis) and out-of-plane (z-axis) environmental vibrations into voltage responses. This achieves energy harnessing from 3-axial environmental vibration.
A NOVEL ELECTROMAGNETIC TARGETING SYSTEM USING ROTATING MAGNETIC-FLUX CONCENTRATION METHOD FOR NAVIGATING ENDOBRONCHOSCOPY
(2018-01-01)
Chen, Chin-Chung
;
Lin, Ching-Kai
;
Cheng, Yun-Chien
;
Chang, Chen-Wei
;
Tsai, Sung-Lin
In this paper, we proposed a novel electromagnetic targeting system using rotating magnetic-flux concentration method for navigating endo-bronchoscope. This system consists of a magnetic-flux emitting coil, a magnetic-flux receiving electromagnets-array, a 2D model of bronchial tree, the magnetic-flux concentrator embedded on brush-guiding tube which was connected to the guide sheath. When the concentrator in the 2D bronchial tree passes through the air gap between the emitting coil and the receiving electromagnets array, the concentrator concentrates the magnetic flux between the coil and the array. The concentrated magnetic flux is subsequently received by the receiving electromagnets-array and thus stable voltage output is produced. Furthermore, when the concentrator is rotated, the concentration of the magnetic flux is periodically changed and thereby the voltage output is periodically changed. By analyzing the voltage changes, the location of the concentrator (as well as guide tube and sheath) is targeted. According to the experimental results, the system successfully targets the location of the guide sheath in the 2D model of bronchial tree.
A Novel Guiding Device for Distal Locking of Intramedullary Nails
(2012)
Lee, Meng-Shiue
;
Wu, Sung-Yueh
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Wong, Tze-Hong
;
Hsu, Wensyang
;
Chung, Tien-Kan
This paper presents the prototype of a new remote guiding device to find the accurate screw hole position for drilling and direction for locking in intramedullary nailing surgery. The device consists of three magnetic pins and an electrical conductive board. The three symmetrically placed magnetic pins can rotate freely and point to the permanent magnet inside the nail. The drilling position and screwing direction can be obtained by moving the device with those magnetic pins to align with the magnet in the nail. The alignment condition is indicated by a LED. When the device is not aligned with the magnet in the nail properly, either in position or direction, the pins then will contact with the board to trigger a light-emitting diode for alarming.
A NOVEL MECHANICAL-MECHANISM ENHANCED THERMOMAGNETIC TWEEZER DEMONSTRATING GRIPPING OF FERROMAGNETIC AND NON-FERROMAGNETIC OBJECTS
(2016)
Wang, Hsin-Min
;
Chung, Tien-Kan
;
Chen, Chin-Chung
;
Cheng, Chih-Cheng
;
Lin, Chu-Yi
In this article, we demonstrate a mechanical-mechanism enhanced thermomagnetic tweezer. The tweezer which utilizes a thermal-magnetic-mechanical converting consists of two cross jointed Al arms, two Gd sheets, two NdFeB hard magnets, two thermoelectric generators (TEGs), and a ball bearing set. When comparing conventional thermomagnetic grippers, our thermomagnetic tweezer can grip either ferromagnetic or non-ferromagnetic objects and avoid producing temperature-influence to the gripped objects. Experimental results show that we can control TEGs to generate a temperature difference to operate the tweezer to grip small ferromagnetic objects (such as NdFeB hard magnet) and other non-ferromagnetic objects (such as PMMA bulk). The maximum gripping force produced by the tweezer operated by applying the DC current of 1.3 A with the voltage of 0.85 V is 0.59 newton. The corresponding gripping and releasing duration is 7.9 seconds and 8.1 seconds, respectively. According to these results, our tweezer would produce more practical objects-gripping applications.
A Novel MEMS DC Magnetic Sensor Using Thermomagnetic-Piezoelectric Materials with a Coil-Less Reset Approach
(2018-01-01)
Chen, Chin-Chung
;
Chen, I-Lun
;
Duan, Hao
;
Chung, Tien-Kan
;
機械工程學系
We report a novel MEMS DC magnetic sensor using thermomagnetic-piezoelectric materials with a coil-less magnetization-reset approach. The magnetic sensor consists of a silicon MEMS diaphragm, a piezoelectric PZT thin film, and a thermomagnetic Gadolinium (Gd) sheet. Due to the Gd's thermomagnetic property, the sensor at low temperature (for instant, 9 degrees C.; below its Curie temperature which is in room temperature range) can sense ambient DC magnetic fields. Without using on-chip coils, the sensor can be easily reset by heating the sensor higher than its Curie temperature (for example, 45 degrees C. According to experimental results, the sensor successfully senses DC magnetic field from 2 to 100 Gauss and is 45 degrees C. When comparing to conventional NEMS, MEMS, and AMR magnetic sensors (i.e., using magnetic materials requiring on-chip magnetization-reset coils which occupy huge chip footprint), our sensor with the coil-less reset approach can significantly reduce the sensor footprint.
A Novel Miniature Thermomagnetic Energy Harvester
(2014)
Chen, Chin-Chung
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Chung, Tien-Kan
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Cheng, Chi-Cheng
;
Tseng, Chia-Yuan
;
機械工程學系
Nowadays, thermal-energy-harvesting is an important research topic for powering wireless sensors. Among numerous thermal-energy-harvesting approaches, some researchers demonstrated novel thermomagnetic-energy harvesters to convert a thermal-energy from an ambient temperature-difference to an electrical-output to power the sensors. However, the harvesters are too bulky to be integrated with the sensors embedded in tiny mechanical-structures for some structural-health-monitoring applications. Therefore, miniaturized harvesters are needed. Hence, we demonstrate a miniature thermomagnetic-energy harvester. The harvester consists of CuBe-beams, PZT-piezoelectric-sheet, Gd-soft-magnet, NdFeB-hard-magnet, and mechanical-frame. The piezoelectric-sheet and soft-magnet is bounded at fixed-end and free-end of the beams, respectively. The mechanical-frame assembles the beams and hard-magnet. The lengthxwidthxthickness of the harvester is 2.5cmx1.7cmx1.5cm. According to this, our harvester is 20-times smaller than the other harvesters. In the initial-state of the energy-harvesting, the beams\' free-end is near the cold-side. Thus, the soft-magnet is cooled lower than its curie temperature (Tc) and consequently changed from paramagnetic to ferromagnetic. Therefore, a magnetic-attractive force is produced between the soft-magnet and hard-magnet. Consequently, the beams/soft-magnet are down-pulled toward the hard-magnet fixed on the hot-side. The soft-magnet closing to the hot-side is heated higher than its Tc and subsequently changed to paramagnetic. Consequently, the magnetic-force is eliminated thus the beams are rebounded to the initial-state. Hence, when the harvester is under a temperature-difference, the beams\' pulling-down/back process is cyclic. Due to the piezoelectric effect, the piezoelectric-sheet fixed on the beams continuously produces voltage-response. Under the temperature-difference of 29 C, the voltage-response of the harvester is 30.4 mV with an oscillating-frequency of 0.098 Hz.
A NOVEL NANOELECTROMAGNETIC SYSTEM USING MULTIFERROIC/MAGNETOELECTRIC NI-NANO-CHEVRON/PMN-PT HETEROSTRUCTURE TO DEMONSTRATE AN ELECTRIC -FIELD -CONTROLLED PERMANENT MAGNETIC SINGLE -DOMAIN TRANSFORMATION
(2018-01-01)
Cheng, Chih-Cheng
;
Lin, Shin-Hung
;
Chen, Yu-Jen
;
Wang, Hsin-Min
;
Chu, Hou-Jen
In this paper, we report a novel nanoelectromagnetic system using multiferroic/magnetoelectric Ni-nanochevron/PMN-PT heterostructure to demonstrate an electric field -controlled permanent magnetic single-domain transformation. The heterostructure consists of a magnetostrictive Ni-nano-chevron, Pt top and bottom electrodes, and a piezoelectric PMN-PT substrate. In initial state (as demagnetized), the magnetization of the magnetic single domain is stably along the long axis of the nano-chevron. A magnetic field of 3000 Oe (along 45 degree of nano-chevron) is applied to magnetize the Ni-nano-chevron from stable single domain to metastable two-domains. After this, an electric field of 0.8MV/m is applied to the PMN-PT substrate to produce the converse magnetoelectric effect to transform the two-domains. After the electric field is removed, the two-domains are further transformed back to the single-domain. Finally, when comparing the domains before and after applying our approach, approximately 50 % of single-domains are successfully and permanently switched (i.e., magnetization-direction is permanently rotated 180 degrees).
A NOVEL SELF-POWERED PIEZOELECTRIC THREE-AXIS MEMS MAGNETIC SENSOR
(2017-01-01)
Yeh, Po-Chen
;
Duan, Hao
;
Chung, Tien-Kan
;
機械工程學系
;
國際半導體學院
This paper demonstrates a self-powered piezoelectric three-axis MEMS magnetic sensor. The sensor consists of a silicon diaphragm, a PZT thin film with Pt top and bottom electrodes, and two patterned Ni thick films. When three-axial magnetic fields are applied to the sensor, alternating magnetic forces/torques are induced in two Ni films and consequently corresponding deformation/bending are produced in the diaphragm structure. The deformation/bending of the diaphragm generate the strains in the PZT thin film and thus produce corresponding different piezoelectric voltage responses. The testing results show the sensor successfully senses three-axial magnetic fields and has a decent linearity in the range of 5-70 Gauss.
A NOVEL THERMOMAGNETIC ROTATIONAL-ACTUATOR
(2016)
Cheng, Chih-Cheng
;
Chung, Tien-Kan
;
Chen, Chin-Chung
;
Wang, Hsin-Min
;
機械工程學系
In this article, we demonstrate a novel thermomagnetic rotational-actuator. The actuator consists of thermomagnetic material Gadolinium sheets, thermoelectric generators, a rotary aluminum cantilever beam with NdFeB hard magnets fixed on the free-end of the beam, a stainless steel bearing, and a mechanical frame. As conventional magnetic rotational actuators are controlled by using electromagnetic-induction based magnetic-force interaction produced by electromagnets or coils, our actuator is controlled by using a heating-induced magnetic force interaction produced by the thermomagnetic generators. Experimental results show that our actuator is successfully rotated by a controlled sequence of temperature difference generated by the TEGs.
A Novel Thermomagnetic-Actuated Gripper With a Piezoelectric-Pyroelectric Sensing Readout of Gripping States and Forces
(2017-10-01)
Chen, Chin-Chung
;
Chung, Tien-Kan
;
Lin, Chu-Yi
;
機械工程學系
;
國際半導體學院
In this paper, we reported a thermomagnetic-actuated gripper with a piezoelectric-pyroelectric sensing readout of gripping states and forces. The gripper consists of two CuBe cantilever beams, a Gd sheet, NdFeB hard magnets, a thermoelectric generator (TEG), a piezoelectric-pyroelectric PZT sheet, and a polymer-polymethyl methacrylate base. When TEG cools the Gd sheet lower than its Curie temperature, the magnetic attraction between the Gd sheet and the NdFeB magnets is produced due to the thermomagnetic property of the Gd sheet. Subsequently, the magnetic attractive force deflects two beams until beams contact to each other. Thus, the gripper can grasp a small object. Furthermore, when the gripper is operated to grasp the object, the piezoelectric-pyroelectric PZT sheet of the gripper produces voltage response. Through analyzing the voltage response, the gripping state is detected and subsequently the gripping force is obtained. After gripping, a negative dc current is applied to TEG to heat the Gd sheet higher than Gd's Curie temperature. Due to this, the magnetic attractive force is reduced and eventually eliminated. Consequently, the beams are separated due to their spring-back force. Thus, the gripper releases the object. The experimental results show that the gripper can be sequentially operated to grasp and release the object. Furthermore, as the current applied to the TEG is increased, the gripping force is increased. The maximum gripping force of the gripper is 0.69 N when a dc current of 0.7 A is applied. Moreover, when comparing conventional magnetic-field-actuated magnetic grippers, our gripper can be individually operated by applied currents, detect the gripping state, and sense the gripping force.
A Novel Three-Axial Magnetic-Piezoelectric MEMS AC Magnetic Field Sensor
(2019-10-01)
Yeh, Po-Chen
;
Duan, Hao
;
Chung, Tien-Kan
;
機械工程學系
;
國際半導體學院
We report a novel three-axial magnetic-piezoelectric microelectromechanical systems (MEMS) magnetic field sensor. The sensor mainly consists of two sensing elements. Each of the sensing elements consists of a magnetic Ni thick film, a Pt/Ti top electrode, a piezoelectric lead zirconate titanate (PZT) thin film, a Pt/Ti bottom electrode, a SiO2 insulation layer, and a moveable Si MEMS diaphragm. When the sensor is subjected to an AC magnetic field oscillating at 7.5 kHz, a magnetic force interaction between the magnetic field and Ni thick film is produced. Subsequently, the force deforms and deflects the diaphragms as well as the PZT thin film deposited on the diaphragms. The deformation and deflection produce corresponding voltage outputs due to the piezoelectric effect. By analyzing the voltage outputs through our criterion, we can obtain details of the unknown magnetic fields to which the sensor is subjected. This achieves sensing of three-axial magnetic fields. The experimental results show that the sensor is able to sense three-axial magnetic fields ranging from 1 to 20 Oe, with X-axial, Y-axial, and Z-axial sensitivities of 0.156 mV(rms)/Oe, 0.156 mV(rms)/Oe, and 0.035 mV(rms)/Oe, respectively, for sensing element A and 0.033 mV(rms)/Oe, 0.044 mV(rms)/Oe, and 0.130 mV(rms)/Oe, respectively, for sensing element B.