Non-destructive fruit quality tap testing device based on pneumatic-electromagnetic combination

Abstract

A non-destructive fruit quality tap testing device based on pneumatic-electromagnetic combination. Two ends of a bellows support member (5) are respectively connected to a connecting plate (1) and a bellows (6); a pneumatic connector (2) is connected to the bellows support member (5); the bottom end of a support spring (27) is connected to the bottom end of the bellows support member (5); the top end of the support spring (27) is fixedly connected to the bottom end of an impactor casing cover (28); two ends of an impactor casing (17) are respectively connected to the impactor casing cover (28) and the bottom of the bellows (6); an insulating sleeve (22) is mounted inside the impactor casing (17); a hollow space for placing an electromagnetic coil (24) is present between the insulating sleeve (22) and the inner side wall of the impactor casing (17); a core (14) is provided inside the insulating sleeve (22); a sliding column (11) is movably connected to the interior of the core (14); two annular magnets (12, 15) are connected to two ends of the sliding column (11) by means of magnetic ring bases (10, 21); a sensor (16) is nested within a sensor base (20); and a flexible tapping head (19) is fixedly connected to the bottom of the sensor base (20). The device can be used for fruit quality testing, so as to implement fruit quality grading and standardization, thus improving the efficiency of supply chains, and increasing the added value of fruits.

Description

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

[0001] The invention belongs to the field of agricultural machinery, and in particular relates to a percussion-type fruit texture non-destructive 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 reached 300 million tons, with per capita consumption reaching 175.27 kilograms. In recent years, with the continuous improvement of people's living standards, consumers' increased focus on their health and pursuit of a quality life have created a greater market for high-quality fruit. In 2021, the proportion of imported fruit consumed in my country rose to 2.51%, and the proportion of imported fruit consumption continues to increase. The fruit industry encompasses multiple stages, including production, harvesting, sorting, packaging, transportation, storage, and processing. Post-harvest sorting, which assesses weight, size, external appearance, and internal quality, plays a key role in ensuring fruit quality, extending its shelf life, and improving its market competitiveness. Fruit texture is an important indicator of its internal quality and taste, and is also an indirect measure of ripeness and freshness. Post-harvest fruit texture testing can be used to guide fruit harvesting, sorting, transportation, storage, and marketing. 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, ensuring the excellent quality of fruits provided to consumers.

[0003] There are relatively few devices currently available for post-harvest fruit texture detection, both domestically and internationally. These detection systems primarily consist of an excitation device, a detection sensor, and a signal processing module. By employing different excitation methods and devices, the fruit can exhibit free or forced vibration. Common devices for free vibration include a spherical pendulum, an instrument hammer, a wooden stick, and compressed air. Different excitation devices often result in varying detection accuracy and affect the integrity of the fruit. Furthermore, the fruit's response signal is also affected by the detection method and sensor. Commonly used sensors include microphone sensors, accelerometers, piezoelectric sensors, and laser displacement sensors. In general, existing fruit texture detection devices and methods suffer from low detection autonomy, limited detection accuracy, unstable repeatability, limited applicability, and the tendency to cause fruit damage.

[0004] Patent Publication No. US5372030 proposes a laser air blowing instrument and method for testing fruit texture. The instrument delivers a stream of pressurized air to stationary fruit and uses a laser displacement sensor to record the resulting surface deformation. A texture prediction model is then established based on the relationship between the maximum surface deformation and the fruit's puncture hardness. However, this device is limited to testing soft-textured fruit, and its accuracy is significantly affected by environmental vibrations. The repeatability of the test results is unstable, making it unsuitable for online sorting production lines. Patent Publication No. US6539781B1 proposes a device and method for measuring fruit hardness. This device uses an electromagnetically driven slug to strike the fruit. Two signal sensors detect the fruit's vibrations, and the fruit's ripeness is predicted through model analysis. This device uses a combination of signal sensors for detection, increasing the reliability of fruit hardness detection. However, this device is susceptible to changes in fruit shape and size, and the adjustment of striking force and stroke is not flexible, which can easily lead to fruit damage. Patent publication number EP0981744 B1 proposes a device for evaluating fruit and vegetable quality. This device pneumatically controls the expansion of a bellows until the nose contacts the fruit. An internal impactor, acting under inertia, strikes the fruit, and a piezoelectric sensor detects the vibration signal and generates an output pulse. While this device uses pneumatic drive to address the issue of fruit damage, the impactor's detection relies on the movement of the bellows, which introduces randomness. Furthermore, the device uses a passive sensor, resulting in low sensitivity and a 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 solutions adopted in the present invention are 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, and the flexible striking head in the impactor motion unit is installed inside the impactor outer cover unit so as to be movable 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 tested, and a sensor is provided 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 housing unit includes an impactor housing, a support spring, and an impactor housing cover; the support spring and the impactor housing 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 housing cover; the top end of the impactor housing is fixedly connected to the inner side wall of the bottom end of the impactor housing cover, and the bottom end of the impactor housing is sealed with 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 includes 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 arranged inside the iron core so as to be movable up and down; 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 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] The inner side wall of the bellows support is provided with a plurality of rectangular sliding grooves, each of which is arranged along the axial direction of the bellows support. The impactor housing cover is connected to 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 the knocking signal after knocking the fruit, and then judge the texture of the fruit.

[0015] The lower surface of the corrugated tube contacts the fruit to be tested, and both sides of the lower surface of the corrugated tube are arranged at an angle, 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 are all made of tough resin material.

[0017] The flexible knocking head is used for knocking the fruit to be tested, 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 clamping piece is an annular structure with equally spaced through-holes on the steel band. The ends of the band are secured to form a closed loop with locking screws. The locking screws are fitted with set screws that engage the through-holes to contract the band. The band wraps tightly around the stepped annular boss of the bellows. This contraction and reinforcement of the band securely fastens the clamp to the bellows. This, combined with the barbed connections on the inside of the stepped annular boss, effectively reduces the risk of gas leakage within the bellows and enhances the system's sealing. The clamp is constructed from corrosion-resistant stainless steel to ensure a long life in various environments.

[0020] The I-shaped wheel structure of the insulating sleeve provides reliable support and positioning, allowing the coil to be tightly wound around the I-shaped wheel, ensuring the stability and uniformity of the coil.

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

[0022] In the electromagnet structure, enameled wire is placed outside an insulating sheath, forming multiple coils that form the electromagnetic coil, forming a solenoid. The electromagnetic coils are made of polyimide-coated enameled round copper wire. When current flows through them, each coil generates a magnetic field. Because the current flows in the same direction between the coils, their magnetic fields are superimposed, enhancing the magnetic field strength of the entire electromagnet. The iron core within the insulating sheath is made of a magnetic material with high magnetic permeability and easy magnetization. When current flows through the coils, the magnetic field generated by the coils magnetizes the iron core, attracting and concentrating the magnetic field lines, increasing the strength of the field and improving the response speed of the electromagnet.

[0023] In the initial state, the magnetic pole directions of the lower annular magnet are opposite to those of the upper annular magnet, and a positive direct current is passed into the electromagnetic coil, so that the magnetic pole direction of the electromagnet is the same as that 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 pole direction of the electromagnet is changed, so that the magnetic pole direction of the electromagnet is opposite to that of the lower annular magnet, generating a repulsive effect, and the magnetic pole direction is the same as that of the upper annular magnet, generating an attractive effect, thereby driving the sliding column to move downward to realize the knocking action. At the end of the knocking, the magnetic pole direction of the upper annular magnet is the same as that of the electromagnet, 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 housing by threaded fit, wherein the electromagnet structure is nested at the upper end of the impactor housing. 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 cover unit are installed together to form an integrated detection device; a sealed chamber is formed between the bellows motion unit and the impactor 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 extend downward.

[0026] The present invention uses an impactor motion unit to strike the surface of fruit, stimulating a vibration response. Sensors are then used to collect the surface vibration signals. After signal processing and analysis, characteristic parameters are extracted. A mathematical model is then constructed by combining the characteristic parameters with the fruit's texture or maturity. Finally, the extracted characteristic parameters are input into the established model for inference and evaluation, yielding an estimate of the fruit's texture or maturity.

[0027] This invention utilizes a two-stage, pneumatic and electromagnetically-controlled percussion detection method. First, the bellows' expansion motion is pneumatically controlled, driving the internal impactor's motion unit close to the fruit's surface. Next, the impactor is electromagnetically driven to perform percussion detection. This two-stage percussion detection method offers controllable control over the impact force and distance of the excitation device, thereby resolving issues with existing fruit texture detection devices, such as being affected by fruit size and prone to fruit damage. This method improves the accuracy and repeatability of fruit texture detection.

[0028] The device is primarily used for quality testing of fruits such as watermelon, mango, kiwi, and peach. It is suitable for use in indoor intelligent fruit sorting workshops. It can individually inspect fruit on a conveyor line and non-destructively grade its maturity or quality based on sensor signals. This device boasts high detection autonomy, high accuracy, stable repeatability, a wide range of applicability, and minimal damage to fruit. It holds broad application prospects for high-throughput, high-precision online testing 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 post-harvest fruits. It is suitable for indoor intelligent fruit sorting workshop scenarios. It can individually inspect 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 is not prone to causing damage to fruits. It is of great significance for achieving fruit quality grading and standardization, increasing fruit added value, improving the efficiency of the fruit supply chain, creating a high-end fruit market and promoting the development of the fruit industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] FIG1 is an axonometric view of the device of the present invention;

[0033] FIG2 is an appearance and a full cross-sectional view of the device of the present invention.

[0034] FIG3 is an exploded view of the device of the present invention;

[0035] FIG4 is a full cross-sectional view of the external bellows motion unit of the device of the present invention;

[0036] FIG5 is a full cross-sectional isometric view of the external bellows motion unit of the device of the present invention;

[0037] FIG6 is an axonometric view of the impactor motion unit within the device of the present invention;

[0038] FIG7 is a full cross-sectional view of the impactor motion unit within the device of the present invention;

[0039] FIG8 is a schematic diagram of the electromagnet structure in the impactor motion unit of the device of the present invention in different working states when detecting the texture of fruit;

[0040] FIG9 is a schematic diagram of the apparatus of the present invention in different working states when detecting fruit texture;

[0041] Figure 10 is an axonometric view of an embodiment;

[0042] 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 ring magnet; 13. Matching iron cylinder; 14. Iron core; 15. Lower ring magnet; 16. Sensor; 17. Impactor outer shell; 18. Sealing rubber ring; 19. Striking head; 20. Sensor base; 21. Lower magnetic ring base; 22. Insulation 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 Wrinkle; 605, annular limiting groove c; 606, annular bevel; 607, cylindrical through hole; 701, fastening lock; 702, clamp steel strip; 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 uses the texture detection of mango as an example to further describe the specific embodiments of the present invention in combination with the accompanying drawings and specific embodiments. The following examples are used to illustrate the present invention, but are not intended 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, and the flexible striking head 19 in the impactor motion unit can be installed inside the impactor outer cover unit so as to be movable 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 in the up and down directions; the impactor motion unit is used to strike the fruit 29 to be tested, 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] As shown in Figure 1, 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 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 tightening member 7 .

[0047] As shown in Figures 2 and 3, the impactor housing unit includes an impactor housing 17, an annular support spring 27 and an annular impactor housing cover 28; the support spring 27 and the impactor housing 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 the spring baffle 25, and the top end of the support spring 27 is coaxially fixedly connected to the bottom end of the impactor housing cover 28; the top end of the impactor housing 17 is fixedly connected to the inner side wall of the bottom end of the impactor housing cover 28, and the bottom end of the impactor housing 17 is sealed with the bottom of the bellows 6 through the 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 provided 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 upper and lower connections between the iron core 14 and the insulating sleeve 22.

[0052] The electromagnetic coil 24 is connected to the control circuit via 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 angle, 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. The flexible knocking head 19 is made of silicone or rubber with a preset ratio.

[0058] As shown in Figures 4 and 5, the connecting plate 1 is an L-shaped metal component consisting of a vertical arm and a horizontal arm connected at right angles. The vertical arm is made of high-strength stainless steel to ensure structural stability and durability. The vertical arm has two waist-shaped holes 101 and a bolt mounting hole a102, which are used to connect the connecting plate 1 to the fruit sorting line. The horizontal arm has a through-hole a104 at the center of the plane. Three bolt mounting holes b105 are evenly distributed around this through-hole a104, and a wire hole a103 is located in front of through-hole a104 on the central axis. These three bolt mounting holes b105, combined with the fixing screws 8, allow the bellows support 5 to be mounted on the connecting plate 1.

[0059] The bellows support 5 is a hollow cylindrical structure with a thick boss at its upper end. This boss features a threaded hole 501 for a straight pipe, a wire hole b502, and three threaded holes. The threaded hole 501 is coaxial with the through-hole a104 of the connecting plate 1 and is used to mount the pneumatic connector 2. The wire hole b502 is coaxial with the wire hole a103 of the connecting plate 1 and is used to route the signal line 3 and control line 4 from the detection device and connect them to the corresponding PLC programmable logic controller and sensor signal acquisition card. Rectangular sliding grooves 503 are vertically defined on the left and right sides of the inner wall of the bellows support 5. The lower end features an annular retaining flange B504 for nesting with the bellows 6. The inner wall of the lower end also features an annular retaining groove a505 for mounting the spring baffle 25. The bellows support is made of aluminum alloy to ensure its lightweight and high strength.

[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 clamping steel belt 702 on the tightening member 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 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 actual application; the bottom of the bellows 6 It is an inverted trapezoidal end with an annular limiting groove c605 on the inside 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 striking head 19 of the impactor motion unit to move in and out to act on the fruit 29 to be detected; under the action of air pressure, the bellows 6 can be used as an extension joint of the impactor motion unit to play the role of alignment, noise reduction, vibration absorption and protection. The overall structure of the bellows 6 can be made of a specific rubber material or soft rubber with different ratios through mold injection molding, and has a certain degree of elasticity and pressure resistance when subjected to changes in internal air pressure.

[0061] As shown in Figures 6 and 7, 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. 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 to 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 to the lower magnetic ring base 21.

[0062] The upper end of the upper magnetic ring base 10 is open, for installing 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, and 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, and an internal thread c2103 is provided on the inner wall of the annular limiting groove d2102 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 cooperating with the internal thread a2003 of the sensor base 20 to form an installation, and the central through hole b2104 is used for passing 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 to 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 outside for connecting to the lower magnetic ring base 21, and an annular limiting groove e1103 on the inside for limiting the lower annular magnet 15. The upper end of the sliding column 11 is equipped with an annular boss 1105, which is provided with an external thread D1104 on the outside for connecting to the upper magnetic ring base 21, and an annular step a1106 on the inside for mounting the iron cylinder 13. The iron cylinder 13 can change part of the magnetic field of the upper annular magnet 12, thereby enhancing the attraction or repulsion of the upper annular magnet 12 to other magnetic objects.

[0064] The core 14 is a hollow cylinder with an internal through-hole slightly larger in diameter than its ends. Made of a magnetically conductive material such as iron or steel, the core 14 provides excellent magnetic conductivity. The sliding post 11 is mounted within the internal through-hole of the core 14, which in turn is mounted within the internal through-hole of the insulating sleeve 22. Varying the inner diameter of the core 14 helps optimize magnetic field distribution or other specific electromagnetic properties. This core design 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 with a closed upper end, a wire hole d2801 on the outer periphery of the top surface, rectangular bosses 2802 axially provided on both sides of the outer wall, and an open lower end with internal threads f2803 on the inner wall of the end. The rectangular bosses 2802 on both sides of the impactor housing cover 28 can be inserted into the rectangular sliding grooves 503 of the corrugated tube support 5, achieving smooth linear motion and precise positioning. The wire hole d2801 at the top of the impactor housing cover 28, the wire hole c2204 at 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 interior of the detection device.

[0066] The spring baffle 25 is in the form of a semicircular ring and consists of two pieces. The inner diameter formed is slightly larger than the outer diameter of the main section of the impactor housing 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 member 5 by baffle screws 26. The two ends of the support spring 27 are respectively connected to the impactor housing cover 28 and the spring baffle 25 to form an elastic connection. The support spring 27 provides a restoring force through its elastic properties to achieve the reset of the bellows 6, reduce the load and impact on the bellows, and reduce damage caused by fatigue.

[0067] The main body of the impactor outer shell 17 is hollow cylindrical, 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 cooperating 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 cooperating with the external thread E2203 of the upper end support frame of the insulating sleeve 22 for installation. An annular flange C1705 is provided at 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 rack with an I-shaped hollow cylinder in 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 it 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 terminal blocks with plugs 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 common 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 of 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 degree of deformation 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 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] As shown in Figures 8 to 10, the fruit texture flexible tapping nondestructive testing process can be divided into five stages, including the initial state, the air intake state, the contact state, the testing state, and the end state. The working operation of the present invention is as follows:

[0072] 1) In the initial state, the device is fixed to the fruit sorting line. The sensor 16 is connected to the sensor signal acquisition card via the signal line 3. The electromagnetic coil 24 is connected to the driver board and the PLC programmable logic controller via the control line. The entire device is connected to the pneumatic control system via 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 a free fruit tray on the fruit sorting line and transported to the bottom of the entire nondestructive testing device via the transmission line.

[0073] 2) In the air intake state, the pneumatic control system introduces pressurized air into the entire detection device through the pneumatic connector 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 tested.

[0074] 3) In the contact state, the bottom of bellows 6 contacts the surface of fruit 29, and pressurized air continues to flow into the entire detection device. This hinders the downward expansion of bellows 6, and the air pressure within the entire detection system increases. The pressure sensor in the pneumatic control system transmits an analog signal of the system air pressure to the programmable logic controller (PLC) in real time. 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 bellows 6 has made contact with the fruit.

[0075] 4) In the detection state, the PLC programmable logic controller receives and processes the analog signal transmitted by the pressure sensor, sends a signal to the solenoid valve in the pneumatic control system to stop the flow 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 reset the impactor, and sends a signal to the solenoid valve in the pneumatic control system to start the vacuum generator, thereby achieving 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 embodiments are used to illustrate the present invention rather than to limit the present invention. Any modifications and changes 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).

2. The pneumatic and electromagnetic combined percussion-type fruit texture nondestructive testing device according to claim 1 is characterized in that: 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).

3. The pneumatic and electromagnetic combined percussion-type fruit texture nondestructive testing device according to claim 2 is characterized in that: 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.

4. The pneumatic and electromagnetic combined percussion-type fruit texture nondestructive testing device according to claim 3 is characterized in that: 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.

5. The pneumatic and electromagnetic combined percussion-type fruit texture nondestructive testing device according to claim 4 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).

6. The pneumatic and electromagnetic combined percussion-type fruit texture nondestructive testing device according to claim 4 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.

7. The pneumatic and electromagnetic combined percussion-type fruit texture nondestructive testing device according to claim 4 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.

8. The pneumatic and electromagnetic combined percussion-type fruit texture nondestructive testing device according to claim 2 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.

9. The pneumatic and electromagnetic combined percussion-type fruit texture nondestructive testing device according to claim 4, 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.

10. The pneumatic and electromagnetic combined percussion-type fruit texture nondestructive testing device according to claim 4, 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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