CN219359474U - Piezoelectricity electromagnetism hybrid exoskeleton energy harvesting device - Google Patents

Abstract

The utility model belongs to the technical field of power generation, and particularly relates to a piezoelectric electromagnetic hybrid exoskeleton energy harvesting device. Comprises a frame consisting of two frame connecting plates and mounting blocks positioned at two ends and connected with the two frame connecting plates; fixed magnets are arranged on the outer sides of the mounting blocks, piezoelectric cantilever beams are arranged on the upper side or the lower side of the two mounting blocks, fixed magnets are arranged at the tail ends of the two piezoelectric cantilever beams, and four fixed magnets are distributed in a cross shape and coupled to form a fixed magnetic field; still include with the equal interference fit in installation piece both ends, and set up the sleeve pipe in the frame, the inside middle suspension of sleeve pipe just with the homopolar moving magnet that repels of the fixed magnet at installation piece both ends set up, the sleeve pipe overcoat is established the coil. The energy harvester can be applied to energy collection in multiple directions, has wider working frequency band and stronger adaptability, and has better performance for collecting human motion energy.

Description

Piezoelectricity electromagnetism hybrid exoskeleton energy harvesting device

Technical Field

The utility model belongs to the technical field of power generation, and particularly relates to a piezoelectric electromagnetic hybrid exoskeleton energy harvesting device.

Background

The energy supply device is a core for supporting the exoskeleton to operate, and the existing active exoskeleton device mainly depends on an external power supply to achieve the functions of enhancing the human body capacity, adapting to complex environments, performing communication reconnaissance and the like, but the energy supply mode has a series of problems that the power supply is not easy to carry, the battery capacity is limited, the energy utilization rate is low and the like. Therefore, improving the energy utilization rate is one of the exploration directions for improving the endurance of the exoskeleton. Energy harvesting refers to a class of technologies that convert mechanical energy in an environment into electrical energy for reuse. An energy harvester is a device that utilizes energy harvesting technology to recover energy. Most energy harvesters are easily miniaturized and are suitable for installation in an exoskeleton system to power small-sized electronics in the system. The energy harvester can be classified into electromagnetic type, electrostatic type, piezoelectric type, composite type and the like according to the energy recovery modes. The electromagnetic energy harvester has smaller output voltage, and has larger output current but is difficult to realize miniaturization; the piezoelectric energy harvester has the advantages of simple structure, high conversion efficiency and lower total output power. And the compound energy harvester has wider application space due to different compound types.

The existing piezoelectric and electromagnetic energy harvester expands the working frequency band of the energy harvester by introducing a nonlinear structure, adopting a multi-degree-of-freedom structure and the like, but the working frequency of the energy harvester is still higher, and the energy harvester is not suitable for collecting low-frequency human body movement energy with the vibration frequency less than 10 Hz; although research on energy harvester for collecting human body energy at home and abroad has achieved a certain progress and research results, the feasibility of obtaining energy from human body movement is verified, only unidirectional vibration energy can be collected, and the utilization rate of multidirectional vibration energy generated by human body movement is low.

Disclosure of Invention

The utility model aims to provide a piezoelectric electromagnetic hybrid exoskeleton energy harvester for collecting low-frequency human motion energy, which can be applied to energy collection in multiple directions, has wider working frequency band and stronger adaptability, and has better performance for collecting human motion energy.

The technical solution for realizing the purpose of the utility model is as follows: a piezoelectric electromagnetic hybrid exoskeleton energy harvesting device comprises a frame consisting of two frame connecting plates and mounting blocks positioned at two ends and connected with the two frame connecting plates; fixed magnets are arranged on the outer sides of the mounting blocks, piezoelectric cantilever beams are arranged on the upper side or the lower side of the two mounting blocks, fixed magnets are arranged at the tail ends of the two piezoelectric cantilever beams, and four fixed magnets are distributed in a cross shape and coupled to form a fixed magnetic field;

still include with the equal interference fit in installation piece both ends, and set up the sleeve pipe in the frame, the inside middle suspension of sleeve pipe just with the homopolar moving magnet that repels of the fixed magnet at installation piece both ends set up, the sleeve pipe overcoat is established the coil.

Further, the two frame connecting plates are connected with the mounting blocks through bolts.

Further, the two piezoelectric cantilever beams have the same structure, the piezoelectric cantilever beams are formed by bonding piezoelectric sheets and strip-shaped copper sheets serving as copper substrates, one end of each piezoelectric cantilever beam is arranged on the upper surface or the lower surface of the mounting block through bolts and cushion blocks, and the fixed magnet is arranged at the tail end of each piezoelectric cantilever beam through a cylindrical copper sheet below the fixed magnet.

Further, the thickness ratio of the piezoelectric ceramic sheet to the base copper sheet is 0.5-0.7.

Further, the initial distance between the fixed magnets at the tail ends of the two piezoelectric cantilevers meets the requirement that the elastic restoring force of the piezoelectric cantilevers is equal to the attractive force between the magnets when the two magnets attract each other, so that the piezoelectric cantilevers can get rid of magnetic vibration, and the movable magnets can continue to reciprocate.

Further, it is fitted in the exoskeleton.

Further, the device is assembled in the exoskeleton knee joint.

Further, the electric energy storage device also comprises a rectifying circuit, wherein the rear ends of the two piezoelectric cantilever beams are connected into the rectifying circuit through leads, the coils are connected into the rectifying circuit, and electric energy is stored or power is supplied to the exoskeleton through the rectifying circuit.

Further, the rectifying circuit comprises a full wave Quan Qiaozi circuit, a voltage regulating sub-circuit and a buffer sub-circuit;

the full-wave Quan Qiaozi circuit is used for realizing the change of alternating current and direct current, and comprises four rectifier diodes which are directly connected with the energy harvesting device;

the voltage regulating sub-circuit is directly connected with the load, and periodically extracts the energy on the equivalent capacitor in the piezoelectric ceramic by controlling the switching time of the switching device;

the buffer sub-circuit is positioned between the full-wave full-bridge sub-circuit and the voltage regulating sub-circuit and mainly comprises a capacitor and a diode, and the energy is buffered and accumulated by controlling the charge and discharge of the capacitor.

Further, the full-wave full-bridge sub-circuit includes: the four rectifying diodes are connected in parallel after being connected in series;

the voltage regulating sub-circuit comprises a filter capacitor, an inductor, a diode and a control switch; the inductor is connected with the filter capacitor in parallel with the load, a diode is connected between the inductor and the filter capacitor, and the control switch is connected with the voltage regulating sub-circuit and the upper circuit:

the buffer sub-circuit comprises three diodes, two capacitors and a current limiting resistor; a series combination of one diode and one capacitor is connected in parallel with a series combination of the other group of capacitors and diodes; and a diode and a current limiting resistor which are connected in series are connected between the two groups.

The energy in two directions from the knee joint is respectively recovered by a piezoelectric and electromagnetic hybrid energy harvesting mode, and the quality of the energy harvester is reduced by an electromagnetic and piezoelectric coupling mode. The vibration frequency of the piezoelectric cantilever beam is reduced by adding a mode with fast mass so as to adapt to human body movement and obtain the optimal working frequency band. The energy harvester structure parameters are optimized to improve the energy harvester energy efficiency, and the finishing circuit of the energy harvester is improved to obtain higher output power. The circuit output is separated from the energy harvester input in time to avoid the impact of external load on the energy harvester efficiency.

Compared with the prior art, the utility model has the remarkable advantages that:

1. the utility model discloses a piezoelectric electromagnetic hybrid exoskeleton energy harvesting device, which is characterized in that two magnets are respectively arranged on a piezoelectric cantilever beam on the basis of a piezoelectric leaf spring damping mass model, and when a cylindrical magnet in a sleeve moves, the two magnets are coupled with the magnet at the tail end of the piezoelectric cantilever beam through magnetic force, so that the piezoelectric cantilever beam is deformed, and electric energy is generated by the piezoelectric cantilever beam. Through the magnetic force action between the center magnet and the end magnet of the piezoelectric cantilever beam, the excitation of the center magnet with low frequency is converted into the high-frequency vibration of the piezoelectric cantilever beam, so that the piezoelectric cantilever beam is suitable for the low-frequency motion of the knee of a human body, and the energy harvesting efficiency is improved. Meanwhile, the magnets are adopted to replace part of the mass blocks, so that the mass is reduced and the energy density is improved.

2. The utility model discloses a piezoelectric electromagnetic hybrid exoskeleton energy harvesting device, which is capable of recycling energy in both the vertical direction and the advancing direction during walking. The piezoelectric part mainly captures energy in the vertical direction, and the electromagnetic part mainly captures energy in the advancing direction of the human body.

3. The piezoelectric electromagnetic hybrid exoskeleton energy harvesting device disclosed by the utility model can be connected with a rectifying circuit, and can output alternating current into direct current, so that the piezoelectric electromagnetic hybrid exoskeleton energy harvesting device can meet the power supply requirements of most electronic elements in an exoskeleton.

4. Compared with a conventional battery, the piezoelectric electromagnetic hybrid exoskeleton energy harvesting device disclosed by the utility model captures the negative work of knee joints in the walking process of a human body through the piezoelectric effect and electromagnetic induction principle and supplies power for a microelectronic device in the exoskeleton, so that the piezoelectric electromagnetic hybrid exoskeleton energy harvesting device has the advantages of no pollution, no need of replacement, high energy density, high reliability and light weight.

5. The utility model discloses a piezoelectric electromagnetic hybrid exoskeleton energy harvesting device, which is designed to have applicability to other parts with energy harvesting value such as ankle and wrist, and further adjust structural parameters of an energy harvester along with the change of the parts.

Drawings

Fig. 1 is a schematic diagram of the internal structure of a piezoelectric electromagnetic hybrid exoskeleton energy harvester.

Fig. 2 is a schematic diagram of a piezoelectric electromagnetic hybrid exoskeleton energy harvester as a whole.

Fig. 3 is a rectifier circuit diagram of a piezoelectric electromagnetic hybrid exoskeleton energy harvester.

Reference numerals illustrate:

1-frame, 2-sleeve, 3-M3 nut, 4-M3 bolt, 5-washer, 6-fixed magnet I, 7-fixed magnet II, 8-fixed magnet III, 9-fixed magnet IV, 10-cylindrical copper sheet I, 11-cylindrical copper sheet II, 12-piezoelectric sheet I, 13-piezoelectric sheet II, 14-strip copper sheet I, 15-strip copper sheet II, 16-enameled wire coil, 17-movable magnet, 18-frame connecting plate and 19-cushion.

Detailed Description

The utility model is described in further detail below with reference to the accompanying drawings.

The technical means and effects adopted to further explain the intended purpose of the present utility model are so that the advantages and features of the present utility model can be more easily understood by those skilled in the art, and the detailed description of the specific embodiments, structural features and effects of the present utility model will be described below with reference to the accompanying drawings and examples.

Referring to fig. 1, 2 and 3, the utility model discloses a piezoelectric electromagnetic hybrid exoskeleton energy harvesting device, which consists of a frame 1, a sleeve 2, an M3 nut 3, an M3 bolt 4, a gasket 5, a fixed magnet I6, a fixed magnet II 7, a fixed magnet III 8, a fixed magnet IV 9, a cylindrical copper sheet I10, a cylindrical copper sheet II 11, a piezoelectric sheet I12, a piezoelectric sheet II 13, a strip copper sheet I14, a strip copper sheet II 15, an enameled wire coil 16, a movable magnet 17, a frame connecting plate 18 and a cushion block 19.

The piezoelectric energy harvesting part comprises a sleeve 2, a fixed magnet I6, a fixed magnet II 7, a cylindrical copper sheet I10, a cylindrical copper sheet II 11, a piezoelectric sheet I12, a piezoelectric sheet II 13, a strip-shaped copper sheet I14, a strip-shaped copper sheet II 15, a frame connecting plate 18 and a cushion block 19.

The electromagnetic energy harvesting part comprises a fixed magnet I6, a fixed magnet II 7, a fixed magnet III 8, a fixed magnet IV 9, an enameled wire coil 16 and a movable magnet 17 of the sleeve 2.

The piezoelectric energy harvesting part and the electromagnetic energy harvesting part comprise a fixed magnet I6 and a fixed magnet II 7 of the sleeve 2.

The two ends of the sleeve 2 are connected with the frame 1 in an interference fit mode, so that the adjustment of the magnet in the sleeve is facilitated. The two side frames 1 are fixed and conveniently detached by two frame connecting plates 18 in a bolt connection mode. A cushion block 19 is added between the piezoelectric cantilever beam and the other side of the frame 1 and is fixed in a bolt connection mode so as to facilitate the adjustment of the height of the cantilever beam. Fixed magnets III 8 and IV 9 are fixed at two ends of the frame 1. The cylindrical copper sheet I10, the fixed magnet I6, the cylindrical copper sheet II 12 and the fixed magnet II 7 are respectively arranged at the tail ends of the two piezoelectric cantilever beams and used as mass blocks, so that the coordination frequency of the piezoelectric vibrator is reduced, the piezoelectric cantilever beam is suitable for the low-frequency movement of the knee of a human body, and the energy harvesting efficiency is improved. Four fixed magnets are respectively distributed at the left end and the right end of the sleeve and the tail end of the cantilever beam, and the four fixed magnets are in cross-shaped distribution and coupled to form a fixed magnetic field. A cylindrical magnet 17 is arranged in the middle of the sleeve and is repulsed with fixed magnets and fixed magnets at two ends of the sleeve, the cylindrical magnet is positioned in the sleeve, and an enamelled coil 16 is sleeved outside the sleeve and used for outputting induction current. The rear end of the piezoelectric cantilever beam is connected with a lead, and the lead and the coil are connected into a rectifying circuit together.

As shown in fig. 3, the rectifying circuit is composed of three parts. The four rectifying diodes are directly connected with the energy harvester to form a full-wave full-bridge rectifying circuit, and the full-wave full-bridge rectifying circuit is a first part of the rectifying circuit and is responsible for realizing the change of alternating current and direct current. The part directly connected with the load is a voltage regulating sub-circuit, and the energy on the equivalent capacitance inside the piezoelectric ceramic is periodically extracted by controlling the switching time of the switching device, so that the conversion efficiency of the interface circuit is improved. The part of the circuit formed by the capacitor and the diode realizes the buffer accumulation of energy by controlling the charge and discharge of the capacitor.

The piezoelectric electromagnetic hybrid exoskeleton energy harvesting device is used for converting knee energy into electric energy for storage when a human body walks or runs, and can supply power to a microelectronic device, and the working method is as follows: during walking, the knee joint mainly plays a role in buffering in the movement process and absorbs the kinetic energy change caused by acceleration mutation. And this energy will act on the energy harvester in an acceleration excited manner. The energy harvesting device is excited by acceleration to capture energy according to the piezoelectric effect and the electromagnetic induction principle, and then a rectifying circuit performs rectifying and voltage reduction and other treatments to finally supply power to the microelectronic device. The specific working method comprises the following steps: is arranged outside the human body when the knee joint is horizontally placed. When a person walks or runs, the acceleration change generated in the vertical direction of the knee joint can cause the piezoelectric cantilever Liang Youding magnet I6, the cylindrical copper sheet I10, the piezoelectric sheet I12 and the strip-shaped copper sheet I14 to form vibration deformation in the vertical direction. According to the piezoelectric effect, when the piezoelectric cantilever beam deviates from the equilibrium position, charges are accumulated on the upper and lower surfaces, and a potential difference is generated. Along with the vibration, the potential difference on the two sides of the piezoelectric cantilever beam is continuously changed to form an alternating voltage source, and the potential difference is output through a lead at the tail end of the piezoelectric cantilever beam. When the knee is excited by acceleration from the advancing direction of the human body, the moving magnet 17 in the sleeve 2 moves in the advancing direction of the human body. Since the coupling magnetic field formed by the fixed magnet is relatively stationary, the movement of the moving magnet 17 changes the distribution of the total coupling magnetic field. Thereby generating an induced current in the coil. The movement of the moving magnet 17 within the sleeve 2 is also represented by a reciprocating movement in the direction of movement of the human body, so that an alternating current will be generated within the coil. The electromagnetic and piezoelectric portions capture energy from two directions, respectively, and then sink into the rectifying circuit. Since the operating environment of the microelectronics in the exoskeleton is mostly direct current, and the energy harvesting is an alternating current point, rectifiers are required.

The rectifying circuit is improved on the basis of the traditional synchronous charge extraction circuit, and a buffer circuit is added in addition to a full-wave full-bridge rectifying and voltage regulating sub-circuit part. The four rectifying diodes mainly complete direct current conversion, and the output current flow directions of the energy harvester are unified due to unidirectional conductivity of the diodes. When the output voltage of the energy harvester is increased, the D1 and the D4 are conducted by the buffer part, one part of current generated by the piezoelectric ceramic supplies power to the load at the rear stage through the voltage regulating sub-circuit, the other part of current flows through the D1 and the D6 to charge the C1 and the C2, the R1 plays a role in current, the C1 and the C2 are connected in series at the moment, and when the peak voltage is reached, the sum of the voltages at the two ends of the C1 and the C2 is the peak voltage. When the voltage is gradually reduced, the sum of the voltages at the two ends of the C1 and the C2 is higher than the rectified voltage, so that the D6 is cut off, the C1 and the C2 are not charged at the moment, the current generated by the piezoelectric ceramic only supplies power to a load through the rectifier diode and the voltage regulating sub-circuit, when the voltage at the two ends of the piezoelectric ceramic is reduced to half of the peak value, the voltage generated by the piezoelectric ceramic is equal to the voltage at the two ends of the C1 and the C2, no voltage difference exists at the two ends of the D1 and the D4, the rectifier diode is cut off and is conducted, and the C1 and the C2 are connected in parallel to supply power to a rear-stage load through the voltage regulating sub-circuit at the moment. The tank circuit repeats the above process to further power the microelectronic device.

While the foregoing is directed to embodiments of the present utility model, other and further embodiments of the utility model may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.

Claims (10)

1. The piezoelectric electromagnetic hybrid exoskeleton energy harvesting device is characterized by comprising a frame consisting of two frame connecting plates and mounting blocks positioned at two ends and connected with the two frame connecting plates; fixed magnets are arranged on the outer sides of the mounting blocks, piezoelectric cantilever beams are arranged on the upper side or the lower side of the two mounting blocks, fixed magnets are arranged at the tail ends of the two piezoelectric cantilever beams, and four fixed magnets are distributed in a cross shape and coupled to form a fixed magnetic field;

still include with the equal interference fit in installation piece both ends, and set up the sleeve pipe in the frame, the inside middle suspension of sleeve pipe just with the homopolar moving magnet that repels of the fixed magnet at installation piece both ends set up, the sleeve pipe overcoat is established the coil.

2. The exoskeleton energy harvesting device of claim 1, wherein the two frame connection plates and the mounting block are bolted together.

3. The exoskeleton energy harvesting device of claim 2, wherein the two piezoelectric cantilevers have the same structure, the piezoelectric cantilevers are formed by bonding a piezoelectric sheet and a strip-shaped copper sheet serving as a copper substrate, one end of each piezoelectric cantilever is arranged on the upper surface or the lower surface of the mounting block through bolts and cushion blocks, and the fixed magnet is arranged at the tail end of each piezoelectric cantilever through a cylindrical copper sheet below each fixed magnet.

4. The exoskeleton energy harvesting device of claim 3, wherein the ratio of the thickness of the piezoelectric ceramic sheet to the thickness of the base copper sheet is between 0.5 and 0.7.

5. The exoskeleton energy harvesting device of claim 4, wherein the initial spacing of the fixed magnets at the ends of the two piezoelectric cantilevers is such that the elastic restoring force of the piezoelectric cantilevers is equal to the attractive force between the magnets when the two magnets are attracted to each other, such that the piezoelectric cantilevers are free of magnetic vibrations and the moving magnets continue to reciprocate.

6. The exoskeleton energy harvesting device of claim 5, wherein the device is mounted in an exoskeleton.

7. The exoskeleton energy harvesting device of claim 6, wherein the device is mounted in an exoskeleton knee joint.

8. The exoskeleton energy harvesting device of claim 7, further comprising a rectifying circuit, wherein the rear ends of the two piezoelectric cantilevers are connected to the rectifying circuit via wires, and the coil is connected to the rectifying circuit, and wherein the rectifying circuit stores electrical energy or supplies power to the exoskeleton.

9. The exoskeleton energy harvesting device of claim 8, wherein the rectifying circuit comprises a full wave Quan Qiaozi circuit, a voltage regulator sub-circuit, and a buffer sub-circuit;

the full-wave Quan Qiaozi circuit is used for realizing the change of alternating current and direct current, and comprises four rectifier diodes which are directly connected with the energy harvesting device;

the voltage regulating sub-circuit is directly connected with the load, and periodically extracts the energy on the equivalent capacitor in the piezoelectric ceramic by controlling the switching time of the switching device;

the buffer sub-circuit is positioned between the full-wave full-bridge sub-circuit and the voltage regulating sub-circuit and mainly comprises a capacitor and a diode, and the energy is buffered and accumulated by controlling the charge and discharge of the capacitor.

10. The exoskeleton energy harvesting device of claim 9, wherein the full-wave full-bridge sub-circuit comprises: the four rectifying diodes are connected in parallel after being connected in series;

the voltage regulating sub-circuit comprises a filter capacitor, an inductor, a diode and a control switch; the inductor is connected with the filter capacitor in parallel with the load, a diode is connected between the inductor and the filter capacitor, and the control switch is connected with the voltage regulating sub-circuit and the upper circuit:

the buffer sub-circuit comprises three diodes, two capacitors and a current limiting resistor; a series combination of one diode and one capacitor is connected in parallel with a series combination of the other group of capacitors and diodes; and a diode and a current limiting resistor which are connected in series are connected between the two groups.