A percussion-type fruit texture nondestructive testing device based on pneumatic and electromagnetic combination

Abstract

The present invention discloses a percussion-type fruit texture nondestructive detection device based on pneumatic and electromagnetic combination. The two ends of the bellows support are respectively connected to the connecting plate and the bellows, the pneumatic joint is connected to the bellows support, the bottom end of the support spring is connected to the bottom end of the bellows support, the top end of the support spring is fixedly connected to the bottom end of the impactor outer shell cover, and the two ends of the impactor outer shell are respectively connected to the impactor outer shell cover and the bottom of the bellows; the insulating sleeve is installed inside the impactor outer shell, and there is a hollow area for placing the electromagnetic coil between the insulating sleeve and the inner side wall of the impactor outer shell, the iron core is arranged inside the insulating sleeve, and the sliding column is movably connected inside the iron core; two annular magnets are connected to the two ends of the sliding column through a magnetic ring base; the sensor is nested in the sensor base, and the flexible percussion head is fixedly connected to the bottom of the sensor base. The present invention can be used for fruit texture detection, realize fruit quality grading and standardization, improve supply chain efficiency, and increase fruit added value.

Description

Technical Field

[0001] The invention belongs to the field of agricultural machinery, and in particular relates to a percussion-type fruit texture nondestructive detection device based on pneumatic and electromagnetic combination. Background Art

[0002] my country is one of the world's largest fruit producers and consumers. In 2021, my country's fruit production was 300 million tons, and the per capita consumption was 175.27 kilograms. In recent years, with the continuous improvement of the living standards of the Chinese people, consumers' attention to their own health needs and the pursuit of quality life have brought greater market space for high-quality fruits. In 2021, the proportion of imported fruit consumption in my country rose to 2.51%, and the proportion of imported fruit consumption continued to increase. The fruit industry covers multiple links, including production, harvesting, sorting, packaging, transportation, storage and processing. Among them, the post-harvest sorting link of fruits sorts and grades fruits by evaluating the weight, size, appearance quality and internal quality of fruits, which plays a key role in ensuring the quality of fruits, extending the shelf life and improving market competitiveness. The texture of fruits is one of the important indicators for evaluating their internal quality and taste, and it is also an indirect measurement of maturity and freshness. The texture detection of post-harvest fruits can be used to guide fruit harvesting, sorting, transportation, storage and sales. Through texture testing, fruits can be classified into different grades or specifications to meet the market demand for fruits of different textures. It can also help identify possible soft, rotten, spoiled or overripe fruits to ensure that the fruits provided to consumers are of excellent quality.

[0003] There are few devices for post-harvest fruit texture detection at home and abroad. These detection systems are mainly composed of excitation devices, detection sensors and signal processing modules. By adopting different excitation methods and excitation devices, fruits can show free or forced vibration forms. Among them, the commonly used devices for free vibration are ball pendulums, instrument hammers, wooden sticks and compressed air. Different excitation devices often bring different detection accuracy and affect the integrity of the fruit. In addition, the response signal of the fruit will also be affected by the detection method and sensor. Among them, the commonly used sensors are microphone sensors, acceleration sensors, piezoelectric sensors and laser displacement sensors. In general, the existing fruit texture detection devices and methods have problems such as low detection autonomy, limited detection accuracy, unstable repeatability, limited scope of application and easy to cause fruit damage.

[0004] The patent with announcement number US5372030 proposes a laser air blowing instrument and method for detecting fruit texture. The instrument delivers a stream of pressurized air to the stationary fruit and uses a laser displacement sensor to record the resulting surface deformation. Subsequently, a texture prediction model is established based on the relationship between the maximum surface deformation and the fruit puncture hardness. However, the device is limited to the detection of soft-textured fruits. The detection accuracy is greatly affected by environmental vibration factors, and the repeatability of the detection results is unstable. It is not suitable for online sorting production lines. The patent with announcement number US6539781B1 proposes a device and method for measuring fruit hardness. The device knocks the fruit through electromagnetically driven slug movement, two signal sensors detect fruit vibration, and predicts the maturity of the fruit through model analysis. The device uses a combined signal sensor for detection to increase the reliability of fruit hardness detection, but it is easily affected by the shape and size of the fruit. The adjustment of the knocking force and knocking stroke is not flexible enough, which can easily cause fruit damage. Patent No. EP0981744 B1 proposes a fruit and vegetable quality assessment device, which pneumatically controls the expansion of a bellows until the nose piece contacts the fruit, and the internal impactor strikes the fruit under the action of inertia, and the piezoelectric sensor detects the vibration signal and generates an output pulse. The device uses pneumatic drive to solve the problem of fruit damage, but the knock detection of the internal impactor depends on the movement of the bellows, which has a random factor. In addition, the device uses a passive sensor with low detection sensitivity and limited measurement range. Summary of the invention

[0005] In order to solve the problems existing in the background technology, the purpose of the present invention is to provide a percussion-type fruit texture non-destructive detection device based on pneumatic and electromagnetic combination.

[0006] The technical solution adopted by the present invention is as follows:

[0007] The device includes a retractable bellows motion unit, an impactor motion unit and an impactor outer cover unit; the impactor outer cover unit is installed inside the bellows motion unit, a flexible striking head in the impactor motion unit is installed inside the impactor outer cover unit movably up and down, the bellows motion unit is connected to an external air pump, and the air pump is used to change the length of the bellows motion unit; the impactor motion unit is used to strike the fruit to be detected, and a sensor is arranged in the impactor motion unit, and the sensor is used to detect the texture of the fruit.

[0008] The bellows motion unit includes a connecting plate, a pneumatic joint, a bellows support and a retractable bellows; the top of the bellows support is fixedly connected to the connecting plate, the pneumatic joint is connected to the top of the bellows support, and the top of the bellows is sleeved on the outer wall of the bottom of the bellows support; the pneumatic joint is externally connected to an air pump, and the air pump is used to apply vacuum or pressurized air to the bellows support, thereby changing the telescopic length of the bellows.

[0009] The impactor outer cover unit comprises an impactor outer shell, a support spring and an impactor outer shell cover; the support spring and the impactor outer shell cover are both located inside the bellows support, the bottom end of the support spring is connected to the inner side wall of the bottom end of the bellows support, and the top end of the support spring is fixedly connected to the bottom end of the impactor outer shell cover; the top end of the impactor outer shell is fixedly connected to the inner side wall of the bottom end of the impactor outer shell cover, and the bottom end of the impactor outer shell is sealed and connected to the bottom of the bellows;

[0010] By changing the internal air pressure of the bellows, the position of the bottom end of the bellows is changed, so that the bottom end of the bellows drives the impactor outer shell and the impactor outer shell cover to move up and down synchronously.

[0011] The impactor motion unit comprises an upper magnetic ring base, a sliding column, an upper annular magnet, an iron core, a lower annular magnet, a sensor, a flexible knocking head, a sensor base, a lower magnetic ring base, an insulating sleeve and an electromagnetic coil; the insulating sleeve is installed at the upper end of the inner part of the impactor outer shell, and there is a hollow area for placing the electromagnetic coil between the insulating sleeve and the inner side wall of the impactor outer shell, the iron core is fixedly connected to the inner side wall of the insulating sleeve, and the sliding column is movably arranged inside the iron core; the upper magnetic ring base and the lower magnetic ring base are respectively connected to the upper and lower ends of the sliding column, and the upper annular magnet and the lower annular magnet are respectively installed on the upper magnetic ring base and the lower magnetic ring base; the top end of the sensor base is connected to the bottom end of the lower magnetic ring base, the sensor is installed in the sensor base, and the flexible knocking head is fixedly connected to the bottom of the sensor base, so that the flexible knocking head can move up and down along its own axis.

[0012] The electromagnetic coil is connected to the control circuit through a control line. The iron core is made of magnetic material. The electromagnetic coil and the iron core constitute an electromagnet structure. The control circuit is used to control the magnetic pole direction of the electromagnet structure, thereby controlling the adsorption state between the annular magnet and the electromagnet structure, and then controlling the up and down movement state of the sliding column.

[0013] A plurality of rectangular sliding grooves are arranged on the inner side wall of the bellows support, each of which is arranged along the axial direction of the bellows support, and the impactor housing cover is connected in the rectangular sliding groove of the bellows support so as to be movable up and down.

[0014] The sensor is connected to the sensor signal acquisition card through a signal line. The sensor is used to collect knocking signals after knocking the fruit, and then judge the texture of the fruit.

[0015] The lower surface of the bellows contacts with the fruit to be tested, and the two sides of the lower surface of the bellows are arranged obliquely, so that the detection device is suitable for fruits of different shapes.

[0016] The upper magnetic ring base, the sliding column, the insulating sleeve, the lower magnetic ring base, the sensor base, the impactor housing cover and the impactor housing body are all made of tough resin material.

[0017] The flexible knocking head is used for knocking the fruit to be detected, and the flexible knocking head is made of silicone or rubber with a preset ratio.

[0018] The bellows acts as an extension joint for the internal impactor motion unit, providing flexible component alignment, noise and vibration absorption, and protecting system components from dust, moisture, oil, chemicals, UV rays and other environmental factors.

[0019] The clamp is an annular structure, and the annular clamp steel belt is provided with equally spaced through holes. The two ends of the clamp steel belt form a closed ring through a fastening lock. The fastening lock is provided with a fastening screw, and the fastening screw cooperates with the through hole to achieve the contraction of the clamp steel belt. The clamp steel belt is tightly wrapped on the stepped annular boss of the bellows. The contraction and reinforcement of the clamp steel belt makes the clamp firmly fixed on the bellows, and combined with the barbed interface on the inner side of the stepped annular boss, it effectively reduces the risk of gas leakage inside the bellows and enhances the sealing of the system. The overall structure of the clamp is made of stainless steel with excellent corrosion resistance to ensure its service life in various environments.

[0020] The I-shaped wheel structure of the insulating sleeve provides reliable support and positioning, so that the coil can be tightly wound on the I-shaped wheel, ensuring the stability and uniformity of the coil.

[0021] The insulating sleeve, electromagnetic coil and iron core form an electromagnet structure. According to Ampere's loop law, a current passing through a closed loop will generate a magnetic field surrounding the loop, and the magnetic field strength is proportional to the magnitude of the current. According to Faraday's law of electromagnetic induction, when the magnetic flux of the magnetic field changes, an induced electromotive force will be generated in the surrounding conductors. By changing the flow direction of direct current, the magnetic flux can change over time, thereby generating an induced electromotive force inside the coil, thereby generating a reverse current to control the direction of the magnetic field.

[0022] In the structure of the electromagnet, the enameled wire is on the outside of the insulating sleeve, forming multiple coils to form the electromagnetic coil, which is in the shape of a solenoid. The electromagnetic coil uses polyimide coated enameled round copper wire. When current is passed through, each coil will generate a magnetic field. Since the current directions between the coils are the same, their magnetic fields will be superimposed together, enhancing the magnetic field strength of the entire electromagnet; the iron core in the insulating sleeve is made of magnetic material, which has the characteristics of high magnetic permeability and easy magnetization. When current passes through the coil, the magnetic field generated by the coil will cause the iron core to magnetize, thereby attracting and concentrating the magnetic field lines, enhancing the strength of the magnetic field, and improving the response speed of the electromagnet.

[0023] In the initial state, the magnetic poles of the lower annular magnet are in opposite directions to those of the upper annular magnet, and a positive direct current is passed into the electromagnetic coil, so that the magnetic poles of the electromagnet are in the same direction as those of the lower annular magnet, thereby causing the lower annular magnet and the electromagnet to be attracted together. In the knocking state, the direction of the direct current is changed by the control circuit, and the magnetic poles of the electromagnet are changed so that the magnetic poles of the electromagnet and the lower annular magnet are in opposite directions, thereby generating a repulsive effect, and the magnetic poles of the electromagnet and the upper annular magnet are in the same direction, thereby generating an attractive effect, thereby driving the sliding column to move downward to achieve the knocking action. In the knocking end state, the magnetic poles of the upper annular magnet and the electromagnet are in the same direction, and the initial state can be restored by changing the direction of the direct current by the control circuit.

[0024] The impactor motion unit is installed inside the impactor outer shell in a threaded nesting manner, wherein the electromagnet structure is nested at the upper end of the impactor outer shell. The sliding column is installed inside the electromagnet structure and can move under the action of the electromagnet structure.

[0025] The bellows motion unit, the impactor motion unit and the impactor outer cover unit are installed together to form an integrated detection device; a sealed chamber is formed between the bellows motion unit and the impactor outer cover unit, which is connected to an external air pump through a pneumatic joint. Applying a vacuum in the bellows support can make the bellows contract, and providing pressurized air can make it expand and stretch downward.

[0026] The present invention uses an impactor motion unit to strike the surface of the fruit to stimulate the vibration response of the fruit, uses a sensor to collect the vibration signal of the fruit surface, and extracts characteristic parameters through signal processing and analysis. Then, a mathematical model is established between the characteristic parameters and the texture or maturity of the fruit. Finally, the extracted characteristic parameters are input into the model for inference and evaluation using the established model to obtain an estimated result of the texture or maturity of the fruit.

[0027] The present invention adopts a two-stage motion knocking detection method combining pneumatic and electromagnetic. First, the bellows is pneumatically controlled to expand and move, driving the internal impactor motion unit close to the surface of the fruit. Then, the impactor is electromagnetically driven to perform knocking detection. The two-stage motion knocking detection method has controllability over the knocking force and knocking distance of the excitation device, thereby solving the problem that the existing fruit texture detection device is affected by the fruit shape and size and is easy to damage the fruit, and improving the accuracy and repeatability of fruit texture detection.

[0028] The device of the present invention is mainly used for quality detection of fruits such as watermelon, mango, kiwi, peach, etc. It is suitable for indoor intelligent fruit sorting workshop scenes, can individually check the fruits on the conveyor line, and perform non-destructive classification of fruit maturity or quality according to sensor signals. The device has high detection autonomy, high detection accuracy, stable repeatability, wide application range, and is not easy to cause fruit damage. It has broad application prospects in high-throughput and high-precision online detection of fruit texture.

[0029] The beneficial effects of the present invention are:

[0030] 1. The device of the present invention can realize non-destructive quality detection of fruits after harvest, and is suitable for indoor intelligent fruit sorting workshop scenes. It can individually inspect the fruits on the conveyor line and perform non-destructive grading of fruit maturity or quality based on sensor signals.

[0031] 2. The present invention has the advantages of high detection autonomy, high detection accuracy, stable repeatability, wide application range and not easy to cause fruit damage. It is of great significance for realizing fruit quality grading and standardization, increasing fruit added value, improving fruit supply chain efficiency, creating a high-end fruit market and promoting the development of the fruit industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is an axonometric view of the device of the present invention;

[0033] Figure 2 It is the appearance and full cross-sectional view of the device of the present invention.

[0034] Figure 3 is an exploded view of the device of the present invention;

[0035] Figure 4 is a full cross-sectional view of the external bellows motion unit of the device of the present invention;

[0036] Figure 5 It is a full cutaway axonometric view of the external bellows motion unit of the device of the present invention;

[0037] Figure 6 It is an axonometric view of the impactor motion unit inside the device of the present invention;

[0038] Figure 7 is a full cross-sectional view of the impactor motion unit inside the device of the present invention;

[0039] Figure 8 It is a schematic diagram of different working states of the electromagnet structure in the impactor motion unit inside the device of the present invention when detecting the texture of fruit;

[0040] Fig. 9 is a schematic diagram of different working states of the device of the present invention when detecting the texture of fruit;

[0041] Fig.10 is an axonometric view of an embodiment;

[0042] In the figure: 1. connecting plate; 2. pneumatic connector; 3. signal line; 4. control line; 5. bellows support; 6. bellows; 7. clamp; 8. screw; 9. upper magnetic ring cover; 10. upper magnetic ring base; 11. sliding column; 12. upper annular magnet; 13. matching iron cylinder; 14. iron core; 15. lower annular magnet; 16. sensor; 17. impactor outer shell; 18. sealing rubber ring; 19. knocking head; 20. sensor base; 21. lower magnetic ring base; 22. insulating sleeve; 23. rubber gasket; 24. electromagnetic wire ring; 25, spring baffle; 26, baffle screw; 27, support spring; 28, impactor housing cover; 29, fruit; 101, waist-shaped hole; 102, bolt mounting hole a; 103, wire hole a; 104, through hole a; 105, bolt mounting hole b; 501, straight pipe threaded hole; 502, wire hole b; 503, rectangular sliding groove; 504, annular limiting flange B; 505, annular limiting groove a; 601, stepped annular boss; 602, barbed interface; 603, annular limiting groove b; 604, V-shaped Wrinkles; 605, annular limiting groove c; 606, annular bevel; 607, cylindrical through hole; 701, fastening lock; 702, clamp steel belt; 901, internal thread b; 902, through hole c; 1001, threaded hole; 1002, external thread B; 1101, annular flange D; 1102, external thread C; 1103, annular limiting groove e; 1104, external thread D; 1105, annular boss; 1106, annular step a; 1701, annular step b; 1702, annular step c; 1703, external Thread F; 1704, internal thread e; 1705, annular flange C; 1901, blind hole; 2001, hexagonal limiting groove; 2002, connecting through hole; 2003, internal thread a; 2101, external thread A; 2102, annular limiting groove d; 2103, internal thread c; 2104, through hole b; 2201, wire drum support frame; 2202, annular limiting groove f; 2203, external thread E; 2204, wire hole c; 2801, wire hole d; 2802, rectangular boss; 2803, internal thread f. DETAILED DESCRIPTION

[0043] The following takes the texture detection of mango as an example, and further describes the specific implementation of the present invention in detail in combination with the accompanying drawings and specific embodiments. The following examples are used to illustrate the present invention, but are not used to limit the scope of the present invention.

[0044] The device includes a retractable bellows motion unit, an impactor motion unit and an impactor outer cover unit; the impactor outer cover unit is installed inside the bellows motion unit, a flexible striking head 19 in the impactor motion unit is installed inside the impactor outer cover unit movably up and down, the bellows motion unit is connected to an external air pump, and the air pump is used to change the length of the bellows motion unit along the up and down directions; the impactor motion unit is used to strike the fruit 29 to be detected, and a sensor 16 is provided in the impactor motion unit, and the sensor 16 is used to detect the texture of the fruit 29.

[0045] like Figure 1 As shown, the bellows motion unit includes an L-shaped connecting plate 1, a pneumatic joint 2, a bellows support 5 and a retractable bellows 6; the top of the bellows support 5 is fixedly connected to the bottom end of the connecting plate 1 by a screw 8, the pneumatic joint 2 is connected to the top of the bellows support 5, and the top of the bellows 6 is sleeved on the outer side wall of the bottom of the bellows support 5; the pneumatic joint 2 is externally connected to an air pump, and the air pump is used to apply vacuum or pressurized air to the bellows support 5, thereby changing the telescopic length of the bellows 6.

[0046] The top of the bellows 6 is buckled on the annular flange of the bellows support 5 , and the top of the bellows 6 is fixedly connected to the bottom of the bellows support 5 through a fastening member 7 .

[0047] like Figure 2 and Figure 3 As shown, the impactor outer cover unit includes an impactor outer shell 17, an annular support spring 27 and an annular impactor outer shell cover 28; the support spring 27 and the impactor outer shell cover 28 are both located inside the bellows support 5, the bottom end of the support spring 27 is connected to the inner side wall of the bottom end of the bellows support 5 through a spring baffle 25, and the top end of the support spring 27 is coaxially fixedly connected to the bottom end of the impactor outer shell cover 28; the top end of the impactor outer shell 17 is fixedly connected to the inner side wall of the bottom end of the impactor outer shell cover 28, and the bottom end of the impactor outer shell 17 is sealed and connected to the bottom of the bellows 6 through a sealing rubber ring 18;

[0048] By changing the internal air pressure of the bellows 6 , the position of the bottom end of the bellows 6 is changed, so that the bottom end of the bellows 6 drives the impactor outer shell 17 and the impactor outer shell cover 28 to move up and down synchronously.

[0049] An annular groove is formed at the lower end of the bellows 6, and an annular boss is provided at the upper end; the lower end of the impactor outer shell 17 is arranged in the annular groove of the bellows 6, and the bottom of the impactor outer shell cover 28 is supported on the annular boss at the upper end of the bellows 6 by a support spring 27 and a spring baffle 25, and the support spring 27 is sleeved on the outer side wall of the impactor outer shell 17.

[0050] The impactor motion unit includes an upper magnetic ring base 10, a sliding column 11, an upper annular magnet 12, an internal hollow iron core 14, a lower annular magnet 15, a sensor 16, a flexible striking head 19, a sensor base 20, a lower magnetic ring base 21, an insulating sleeve 22 and an electromagnetic coil 24; the insulating sleeve 22 is installed at the upper end of the impactor outer shell 17, and a hollow area for placing the electromagnetic coil 24 is formed between the outer wall of the insulating sleeve 22 and the inner wall of the impactor outer shell 17. The electromagnetic coil 24 is wound around the outer periphery of the insulating sleeve 22, and the iron core 14 is fixedly connected to the inner wall of the insulating sleeve 22. The sliding column 11 is movably arranged up and down inside the iron core 14, and the length of the sliding column 11 is greater than the iron core 14; the upper magnetic ring base 10 and the lower magnetic ring base 21 are respectively connected to the outer side walls of the upper and lower ends of the sliding column 11, and the upper annular magnet 12 and the lower annular magnet 15 are respectively nested in the upper magnetic ring base 10 and the lower magnetic ring base 21; the top end of the sensor base 20 is connected to the bottom end of the lower magnetic ring base 21, the sensor 16 is installed in the sensor base 20, and the flexible knocking head 19 is fixedly connected to the bottom of the sensor base 20, so that the flexible knocking head 19 can move up and down along its own axis.

[0051] The upper magnetic ring cover 9 is installed on the upper magnetic ring base 10, and the upper annular magnet 12 is located between the upper magnetic ring cover 9 and the upper magnetic ring base 10; rubber washers 23 are provided at the connection points of the upper and lower ends between the iron core 14 and the insulating sleeve 22.

[0052] The electromagnetic coil 24 is connected to the control circuit through the control line 4. The iron core 14 is made of magnetic material. The electromagnetic coil 24 and the iron core 14 constitute an electromagnet structure. The control circuit is used to control the magnetic pole direction of the electromagnet structure, thereby controlling the adsorption state between the annular magnets 12, 15 and the electromagnet structure, and then controlling the up and down movement state of the sliding column 11.

[0053] Two rectangular sliding grooves 503 are provided on the inner side wall of the bellows support 5. Each rectangular sliding groove 503 is arranged along the axial direction of the bellows support 5. The side wall of the impactor housing cover 28 is connected to the rectangular sliding groove 503 of the bellows support 5 so as to be movable up and down.

[0054] The sensor 16 is connected to an external sensor signal acquisition card via a signal line 3. The sensor 16 is used to collect knocking signals after knocking the fruit, and then judge the texture of the fruit based on the collected knocking signals.

[0055] The lower surface of the bellows 6 contacts the fruit 29 to be tested, and both sides of the lower surface of the bellows 6 are arranged at an inclination, so that the detection device is suitable for fruits of different shapes.

[0056] The upper magnetic ring base 10, the upper magnetic ring cover 9, the spring baffle 25, the sliding column 11, the insulating sleeve 22, the lower magnetic ring base 21, the sensor base 20, the impactor housing cover 28 and the impactor housing 17 are all made of tough resin material, have high toughness and bending strength, and can withstand certain impact or vibration loads.

[0057] The flexible knocking head 19 is used for knocking the fruit 29 to be detected, and the flexible knocking head 19 is made of silicone or rubber with a preset ratio.

[0058] like Figure 4 and Figure 5 As shown, the connecting plate 1 is an L-shaped metal part, which consists of a vertical arm and a horizontal arm. The vertical arm is connected to the horizontal arm at a right angle and is made of high-strength stainless steel to ensure the structural stability and durability of the part. Two waist-shaped holes 101 and a bolt mounting hole a102 are provided on the vertical arm to connect the connecting plate 1 to the fruit sorting line; a through hole a104 is provided at the center of the plane of the horizontal arm, and three bolt mounting holes b105 are evenly provided in the circumferential direction with the through hole a104 as the center, and a wire hole a103 is provided in front of the through hole a104 on the central axis; the three bolt mounting holes b105 cooperate with the fixing screws 8 to install the corrugated pipe support 5 on the connecting plate 1.

[0059] The main body of the bellows support 5 is a hollow cylindrical structure, with a boss structure of a certain thickness at the upper end, on which a straight pipe threaded hole 501, a wire hole b502 and three threaded holes are provided. The straight pipe threaded hole 501 is coaxial with the through hole a104 of the connecting plate 1, and is used to install the pneumatic joint 2; the wire hole b502 is coaxial with the wire hole a103 of the connecting plate 1, and is used to lead the signal line 3 and the control line 4 from the inside of the detection device and connect them to the corresponding PLC programmable logic controller and the sensor signal acquisition card; rectangular sliding grooves 503 are provided in the vertical direction on the left and right sides of the inner wall of the bellows support 5, and an annular limiting flange B504 for nesting with the bellows 6 is provided at the lower end, and an annular limiting groove a505 for installing the spring baffle 25 is provided on the inner wall of the lower end. The bellows support is made of aluminum alloy material to ensure the lightness and high strength of the parts.

[0060] The upper end of the bellows 6 is open, and the outer wall of the upper end is provided with a stepped annular boss 601, and the inner side is provided with a ring-shaped barbed interface 602. The upper end of the bellows 6 is locked on the bellows support 5 by the fastening locks 701 at both ends of the clamp steel belt 702 on the clamp 7. The bottom of the inner wall of the stepped annular boss 601 is also provided with an annular limiting groove b603 that can be nested with the bellows 6 to achieve mutual sealing, so as to achieve sealing; the main body of the bellows 6 is composed of a plurality of groups of V-shaped folds 604 to form a corrugated layer, and the wave height, wall thickness and wave distance between two folds of each V-shaped fold 604 can be designed according to the actual application; the bottom of the bellows 6 It is an inverted trapezoidal end with an annular limiting groove c605 on the inner side for nesting the impactor outer shell 17 and the sealing rubber ring 18 to form a seal; the annular inclined surface 606 outside the trapezoidal end can change the plane area of ​​the bottom of the bellows 6 by designing the tilt angle, so that the detection device is suitable for fruits of different shapes; a cylindrical through hole 607 is provided in the center of the trapezoidal end to facilitate the flexible knocking head 19 of the impactor motion unit to move in and out to act on the fruit 29 to be detected; the bellows 6 can be used as an extension joint of the impactor motion unit under the action of air pressure, and plays the role of alignment, noise reduction, vibration absorption and protection. The overall structure of the bellows 6 can be made of specific rubber materials or soft rubber with different ratios for injection molding, and has certain elasticity and pressure resistance when subjected to changes in internal air pressure.

[0061] like Figure 6 and Figure 7 As shown, the main body of the flexible knocking head 19 is in the shape of a hemisphere, and can be formed by injection molding and curing of silicone or rubber with different properties. A blind hole 1901 is provided at the top center of the flexible knocking head 19, and the blind hole 1901 is convenient for embedding a plastic mating nut to provide a positioning connection between the flexible knocking head 19 and the sensor 16 and install the signal input shaft of the sensor 16. The upper end of the sensor base 20 is open, and the lower end is closed. A hexagonal limiting groove 2001 is provided inside the lower end, and a connecting through hole 2002 is provided at the center of the bottom for installing the sensor 16. An internal thread a2003 is provided on the inner side of the upper end of the sensor base 20 for connecting with the lower magnetic ring base 21.

[0062] The upper end of the upper magnetic ring base 10 is open, which is used to install the upper annular magnet 12. The outer wall of the upper end is provided with an external thread B1002 for installing the upper magnetic ring cover 9. A threaded hole 1001 is provided at the center of the bottom for installing the sliding column 11; the lower magnetic ring base 21 is in the shape of a cylindrical tube, and an annular limiting groove d2102 is provided inside the upper end for installing the lower annular magnet 15. The inner wall of the annular limiting groove d2102 is provided with an internal thread c2103 for installing the sliding column 11. The bottom of the lower magnetic ring base 21 is an annular boss, and the outer side of the boss is provided with an external thread A2101 for matching with the internal thread a2003 of the sensor base 20 to form an installation, and the center through hole b2104 is used to pass the signal line 3, etc.; the inner side of the lower end of the upper magnetic ring cover 9 is provided with an internal thread b901 for connecting the upper magnetic ring base 10, and a through hole c902 is provided at the center of the top for passing the signal line 3, etc.;

[0063] The main body of the sliding column 11 is a hollow cylinder, with an annular flange D1101 at the lower end, an external thread C1102 on the outer side for connecting to the lower magnetic ring base 21, and an annular limiting groove e1103 on the inner side for limiting the lower annular magnet 15; an annular boss 1105 is provided at the upper end of the sliding column 11, with an external thread D1104 on the outer side for connecting to the upper magnetic ring base 21, and an annular step a1106 on the inner side for assembling the matching iron cylinder 13, which can change part of the magnetic field of the upper annular magnet 12 and enhance the attraction or repulsion of the upper annular magnet 12 to other magnetic objects;

[0064] The iron core 14 is a hollow cylinder with an internal through hole slightly larger than the two ends; the iron core 14 is made of a magnetic conductive material such as iron or steel to provide good magnetic conductivity, the sliding column 11 is installed in the internal through hole of the iron core 14, and the iron core 14 is installed in the internal through hole of the insulating sleeve 22. The change in the inner diameter of the iron core 14 helps to optimize the magnetic field distribution or other specific electromagnetic properties. The design of this iron core structure provides more flexible electromagnetic adjustment capabilities and can meet the requirements of specific applications.

[0065] The impactor housing cover 28 is an inverted hollow cylindrical structure, the upper end is closed, a wire hole d2801 is provided on the outer periphery of the top surface, rectangular bosses 2802 are axially provided on both sides of the outer wall, and the lower end is open, and the inner wall of the end is provided with internal threads f2803; the rectangular bosses 2802 on both sides of the impactor housing cover 28 can be inserted into the rectangular sliding groove 503 of the corrugated tube support 5 to achieve smooth linear motion and precise positioning; the wire hole d2801 on the top of the impactor housing cover 28, the wire hole c2204 on the upper end of the insulating sleeve 22, the wire hole a103 on the connecting plate 1 and the wire hole b502 on the corrugated tube support 5 are all arranged along a common central axis, which is used to lead the signal line 3 and the control line 4 out from the inside of the detection device;

[0066] The spring baffle 25 is in the shape of a semicircular ring, with two pieces, and the inner diameter formed is slightly larger than the outer diameter of the main section of the impactor outer shell 17, and three countersunk holes are provided along the circumferential direction. The two spring baffles 25 are fixed to the annular limiting groove a505 of the bellows support 5 by baffle screws 26; the two ends of the support spring 27 are respectively connected to the impactor outer shell cover 28 and the spring baffle 25 to form an elastic connection. The support spring 27 provides a restoring force through its elastic characteristics to realize the resetting of the bellows 6, reduce the load and impact of the bellows, and reduce the damage caused by fatigue;

[0067] The main body of the impactor outer shell 17 is in the shape of a hollow cylinder, and two spaced annular steps b1701 and annular steps c1702 are distributed on its inner wall. An external thread F1703 is provided on the outer side of the upper end for cooperation with the internal thread f2803 on the inner side of the lower end of the impactor outer shell cover 28 for installation. An internal thread e1704 is provided on the inner side for cooperation with the external thread E2203 of the upper end support frame of the insulating sleeve 22 for installation. An annular flange C1705 is provided on the lower end; the annular step b1701 provides a support surface for the nested installation of the insulating sleeve 22, and the annular step c1702 provides movement space and guidance for the impactor motion unit; the sealing rubber ring 18 is nested between the lower end annular flange C1705 and the bellows 6 to fill the gap between the parts, which can effectively prevent the leakage of fluid or gas and maintain the integrity and performance of the system.

[0068] The insulating sleeve 22 is a wire drum frame, which is a hollow cylinder with an I-shaped cross section. The annular boss structures at the upper and lower ends are wire drum support frames 2201. The outer side of the upper wire drum support frame 2201 is provided with an external thread E2203 for fixing in the outer shell 17 of the impact body; the outer sides of the top and bottom center holes of the insulating sleeve 22 are provided with annular limiting grooves f2202, and the outer side of the top annular limiting groove f2202 is provided with a wire hole c2204. The rubber gasket 23 is installed in the upper and lower annular limiting grooves f2202, which can absorb vibration and impact during knocking, reduce contact and friction between mechanical parts, and thus reduce the transmission of noise and vibration; the electromagnetic coil 24 is neatly and tightly wound layer by layer on the main cylindrical wall between the two wire drum support frames 2201 of the insulating sleeve 22 according to the determined diameter, number of turns and number of layers. The two ends of the electromagnetic coil 24 are welded to the plug-in terminal for packaging, one end is connected to the positive pole or power supply, and the other end is connected to the negative pole or ground;

[0069] The sensor 16 may be a piezoelectric accelerometer, which is provided with a piezoelectric sensor and a built-in charge amplifier. The power supply and signal output of the sensor 16 share a cable (two-wire system) and can be directly connected to the measuring device without the need for an additional amplifier and signal conditioner.

[0070] The knocking parameters based on the device of the present invention include the material of the knocking head, the knocking force and the knocking distance. The magnitude of the knocking force will affect the deformation degree of the fruit, the knocking distance determines the contact area between the knocking head and the fruit and the impact energy transmitted, and the material of the knocking head will affect the impact transmission efficiency and the vibration response of the fruit. The knocking force can be adjusted by changing the wire diameter of the enameled wire in the electromagnet structure and the maximum outer diameter of the insulating sleeve 22. At the same time, by adjusting the limit height of the annular step b1701 of the impactor outer shell 17, the distance between the flexible knocking head 19 and the bottom of the bellows 6 can be adjusted, thereby further adjusting the knocking distance. Flexible knocking heads 19 of different hardness and softness can be made of silicone or rubber in different proportions. By adjusting the structure of the internal impactor unit or the material of the flexible knocking head 19, it is possible to flexibly adapt to the non-destructive testing needs of fruits of different textures, ensure that the knocking parameters match the characteristics of the fruit, achieve accurate and reliable texture detection, and minimize damage to the fruit.

[0071] like Figure 8-Figure 10 As shown, the fruit texture flexible percussion nondestructive testing process can be divided into five processes, including the initial state, the air intake state, the contact state, the detection state and the end state. The working operation of the present invention is:

[0072] 1) In the initial state, the device is fixed on the fruit sorting line, the sensor 16 is connected to the sensor signal acquisition card through the signal line 3, the electromagnetic coil 24 is connected to the drive board and the PLC programmable logic controller through the control line, and the entire device is connected to the pneumatic control system through the pneumatic connector 2. The bellows 6 is in a static state and maintains its original length. The impactor motion unit relies on the interaction between the lower annular magnet 15 and the iron core 14 to be adsorbed on the lower end of the insulating sleeve 22. The fruit 29 to be tested is placed in the free fruit tray on the fruit sorting line and transported to the bottom of the entire non-destructive testing device through the transmission line.

[0073] 2) In the air intake state, the pneumatic control system passes the pressurized air into the entire detection device through the pneumatic joint 2. The pressurized air flows through the cavity above the bellows support 5 and the rectangular sliding groove 503, and then diffuses downward into the bellows 6; the bellows 6 expands downward in the vertical direction and drives the entire impactor motion unit close to the surface of the fruit 29 to be detected.

[0074] 3) In the contact state, the bottom of the bellows 6 contacts the surface of the fruit 29, and the pressurized air continues to flow into the entire detection device. The downward expansion movement of the bellows 6 is blocked, and the air pressure inside the entire detection system increases accordingly. The pressure sensor in the pneumatic control system transmits an analog signal of the air pressure in the system to the PLC programmable logic controller in real time, and the PLC determines whether the system air pressure exceeds a predetermined threshold. When the PLC determines that the system air pressure reaches the predetermined threshold, it indicates that the bellows 6 has contacted the fruit;

[0075] 4) In the detection state, after the PLC programmable logic controller receives and processes the analog signal transmitted by the pressure sensor, it sends a signal to the solenoid valve in the pneumatic control system to stop the inflow of pressurized air, and sends a signal to the electromagnet circuit control module, i.e., the control circuit, to perform knock detection. The sensor 16 converts the detected fruit surface vibration signal into an electrical signal, which is transmitted to the host computer through the sensor signal acquisition card for signal processing and analysis.

[0076] 5) In the end state, the PLC programmable logic controller sends a signal to the electromagnet circuit control module to achieve the reset of the impactor, and sends a signal to the solenoid valve in the pneumatic control system to start the vacuum generator, thereby achieving the rapid reset of the bellows 6.

[0077] Among them, the pneumatic control system includes an air compressor, an air source processor, a two-position five-way solenoid valve, a two-position two-way solenoid valve, a pressure sensor, a switching power supply, a PLC controller, a control drive module and a vacuum generator.

[0078] The above specific implementation modes are used to explain the present invention rather than to limit the present invention. Any modification and change made to the present invention within the spirit of the present invention and the protection scope of the claims shall fall within the protection scope of the present invention.

Claims

1. A percussion-type fruit texture nondestructive testing device based on pneumatic and electromagnetic combination, characterized in that: The invention comprises a retractable bellows motion unit, an impactor motion unit and an impactor outer cover unit; the impactor outer cover unit is installed inside the bellows motion unit, a flexible striking head (19) in the impactor motion unit is installed inside the impactor outer cover unit in a manner that it can move up and down, the bellows motion unit is connected to an external air pump, and the air pump is used to change the length of the bellows motion unit; the impactor motion unit is used to strike a fruit (29) to be detected, and a sensor (16) is provided in the impactor motion unit, and the sensor (16) is used to detect the texture of the fruit (29); The bellows motion unit comprises a connecting plate (1), a pneumatic joint (2), a bellows support (5) and a retractable bellows (6); the top end of the bellows support (5) is fixedly connected to the connecting plate (1), the pneumatic joint (2) is connected to the top end of the bellows support (5), and the top end of the bellows (6) is sleeved on the outer side wall of the bottom end of the bellows support (5); the pneumatic joint (2) is externally connected to an air pump, and the air pump is used to apply vacuum or pressurized air to the bellows support (5), thereby changing the telescopic length of the bellows (6); The impactor outer cover unit comprises an impactor outer shell (17), a support spring (27) and an impactor outer shell cover (28); the support spring (27) and the impactor outer shell cover (28) are both located inside the bellows support (5), the bottom end of the support spring (27) is connected to the inner side wall of the bottom end of the bellows support (5), and the top end of the support spring (27) is fixedly connected to the bottom end of the impactor outer shell cover (28); the top end of the impactor outer shell (17) is fixedly connected to the inner side wall of the bottom end of the impactor outer shell cover (28), and the bottom end of the impactor outer shell (17) is sealedly connected to the bottom of the bellows (6); By changing the internal air pressure of the bellows (6), the position of the bottom end of the bellows (6) is changed, so that the bottom end of the bellows (6) drives the impactor outer shell (17) and the impactor outer shell cover (28) to move up and down synchronously; The impactor motion unit comprises an upper magnetic ring base (10), a sliding column (11), an upper annular magnet (12), an iron core (14), a lower annular magnet (15), a sensor (16), a flexible striking head (19), a sensor base (20), a lower magnetic ring base (21), an insulating sleeve (22) and an electromagnetic coil (24); the insulating sleeve (22) is installed at the upper end of the impactor outer shell (17); a hollow area for placing the electromagnetic coil (24) is formed between the insulating sleeve (22) and the inner side wall of the impactor outer shell (17); the iron core (14) is fixedly connected to the inner side wall of the insulating sleeve (22); The moving column (11) is arranged inside the iron core (14) so ​​as to be movable up and down; the upper magnetic ring base (10) and the lower magnetic ring base (21) are respectively connected to the upper and lower ends of the sliding column (11); the upper annular magnet (12) and the lower annular magnet (15) are respectively installed on the upper magnetic ring base (10) and the lower magnetic ring base (21); the top end of the sensor base (20) is connected to the bottom end of the lower magnetic ring base (21); the sensor (16) is installed in the sensor base (20); and the flexible knocking head (19) is fixedly connected to the bottom of the sensor base (20), so that the flexible knocking head (19) can move up and down along its own axis.

2. The pneumatic and electromagnetic combined percussion-type fruit texture nondestructive testing device according to claim 1 is characterized in that: The electromagnetic coil (24) is connected to a control circuit via a control line (4); the iron core (14) is made of magnetic material; the electromagnetic coil (24) and the iron core (14) form an electromagnet structure; the control circuit is used to control the magnetic pole direction of the electromagnet structure, thereby controlling the adsorption state between the annular magnet (12, 15) and the electromagnet structure, and further controlling the up and down movement state of the sliding column (11).

3. The pneumatic and electromagnetic combined percussion-type fruit texture nondestructive testing device according to claim 1 is characterized in that: A plurality of rectangular sliding grooves (503) are provided on the inner side wall of the bellows support (5), each rectangular sliding groove (503) is arranged along the axial direction of the bellows support (5), and the impactor housing cover (28) is connected to the rectangular sliding groove (503) of the bellows support (5) so as to be movable up and down.

4. The pneumatic and electromagnetic combined percussion-type fruit texture nondestructive testing device according to claim 1 is characterized in that: The sensor (16) is connected to a sensor signal acquisition card via a signal line (3); the sensor (16) is used to collect knocking signals after the fruit is knocked, thereby determining the texture of the fruit.

5. The pneumatic and electromagnetic combined percussion-type fruit texture nondestructive testing device according to claim 1 is characterized in that: The lower surface of the bellows (6) contacts the fruit (29) to be tested, and the two sides of the lower surface of the bellows (6) are arranged at an inclination, so that the detection device is suitable for fruits of different shapes.

6. The pneumatic and electromagnetic combined percussion-type fruit texture nondestructive testing device according to claim 1 is characterized in that: The upper magnetic ring base (10), the sliding column (11), the insulating sleeve (22), the lower magnetic ring base (21), the sensor base (20), the impactor housing cover (28) and the impactor housing body (17) are all made of tough resin material.

7. The pneumatic and electromagnetic combined percussion-type fruit texture nondestructive testing device according to claim 1 is characterized in that: The flexible knocking head (19) is used for knocking the fruit (29) to be detected, and the flexible knocking head (19) is made of silica gel or rubber with a preset ratio.

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