A flexible koji block conveying device for a liquor koji production line and a method thereof

Abstract

The present application relates to the field of liquor brewing machinery and automatic material conveying, in particular to a flexible koji block conveying device for a liquor koji production line and a method thereof; the device comprises a main frame and a driving roller assembly, an annular base belt with a compensation air chamber and a particle variable stiffness bag, and a negative pressure and mechanical proportional valve air path control module; the system flexibly carries the koji block through the free flow state of the polyhedral ceramic particles under normal pressure to conform to the koji block contour; the core is to use the particle jamming blocking effect to improve the shear resistance when the negative pressure is drawn, and the extracted gas is introduced into the compensation air chamber to generate expansion support to offset the volume shrinkage force of the bag; the present application solves the problems of easy sliding and local stress concentration of irregular koji blocks climbing, avoids surface cracking and ensures smooth operation of the base belt, effectively realizes lossless protection and conveying stability of the koji block.

Description

Technical Field

[0001] This invention relates to the field of baijiu brewing machinery and equipment and automated material conveying technology, specifically to a flexible conveying device and method for koji blocks used in baijiu koji making production lines. Background Technology

[0002] In the current operating conditions of baijiu (Chinese liquor) koji (fermentation starter) production, materials such as koji blocks need to be continuously transferred between different processing stations. Koji blocks typically exhibit irregular surfaces and are fragile, and the conveying routes often include incline sections with a certain gradient. To continuously convey these koji blocks, existing solutions generally employ a conventional belt conveyor architecture. This involves a drive unit driving the first and last rollers, causing the circular conveyor belt to circulate periodically. The material is received and conveyed by the surface friction of the smooth, flexible belt, or by adding rigid push plates and baffles to the belt surface. While this solution has a certain continuous processing capacity in straight conveying scenarios, due to… Its bearing belt has a single physical property and cannot be dynamically adjusted. When facing irregular materials, the purely flexible bearing surface is prone to micro-slippage and overall rollover of materials on the uphill section due to insufficient friction and self-locking ability. On the other hand, if a rigid bearing surface is used or physical baffles are added, mechanical stress concentration is likely to occur at the local protrusions of the curved blocks, which will cause the material edges to crack or the whole to break. In addition, existing conventional belt conveyor equipment lacks real-time perception of the material contact state and stiffness adjustment mechanism, resulting in a high breakage rate and unstable operation during the conveying process. It is difficult to support the dual requirements of close protection and high shear resistance under complex working conditions.

[0003] Therefore, how to improve the deformation compliance and climbing stability of irregular and fragile blocks in the belt conveyor process, while taking into account the non-destructive protection of the material surface and dynamic shear resistance and anti-slip, has become an urgent technical problem to be solved. Summary of the Invention

[0004] To solve the above-mentioned technical problems, the present invention provides a flexible conveying device and method for koji blocks in a baijiu koji-making production line. Specifically, the technical solution of the present invention is as follows: A flexible conveying device for koji blocks in a baijiu (Chinese liquor) koji-making production line includes: A main frame, wherein a drive roller and a redirecting roller are respectively provided at both ends of the main frame; A servo motor is connected to the shaft end of the drive roller; An annular base belt is wound around the outer cylindrical surface of the drive roller and the redirecting roller. The outer surface of the annular base belt is provided with compensation air chambers arranged in an array along the running direction. The top of the compensation air chamber is provided with a particle variable stiffness bag, and the inside of the particle variable stiffness bag is filled with polyhedral ceramic particles. A negative pressure pump is mounted on the main frame and is connected to the follow-up main air circuit; The mechanical proportional valve connects the follow-up main air path to the inner cavity exhaust end of the particle variable stiffness bag, while the positive pressure exhaust end of the negative pressure pump is connected to the inner cavity inlet end of the compensation air chamber through the bypass air path. A gas flow meter and a vacuum sensor are connected in series on the main gas path, and a servo driver for collecting the reactive current of the motor is configured on the main frame or the servo motor end. The controller is connected to the gas flow meter, the vacuum sensor and the servo driver to control the servo motor, the negative pressure pump and the mechanical proportional valve.

[0005] Optionally, the compensation chamber is a directional expansion airbag with a corrugated tube structure on the sidewall, wherein the outer layer of the particle variable stiffness bag is a highly elastic latex film, and the particle variable stiffness bag is sealed and bonded to the top of the compensation chamber with silicone.

[0006] Optionally, the particle size of the polyhedral ceramic particles is 2 mm to 3 mm, wherein the polyhedral ceramic particles are made of alumina and have a micro-textured surface sintered to provide a coefficient of friction between particles.

[0007] Optionally, the servo motor is connected to the drive roller via a plum blossom-shaped flexible coupling, wherein the drive roller and the redirecting roller are mounted in parallel at both ends of the main frame via seated bearings, and the annular base belt is made of polyurethane.

[0008] Optionally, the suction port of the negative pressure pump is connected to the follow-up main air passage through a pneumatic rotary joint, wherein the bypass air passage is inverted.

[0009] A method for flexible conveying control of koji blocks in a baijiu (Chinese liquor) koji-making production line includes: S1. Control the negative pressure pump to be in a normal pressure state, so that the polyhedral ceramic particles inside the particle stiffness bag are in a loose free-flowing state to conform to the bottom contour of the curved block. S2. Control the negative pressure pump to start and output suction power according to the preset basic duty cycle to evacuate the air inside the particle variable stiffness bag. S3. Integrate the transient flow rate during the period from the start of the negative pressure pump to the achievement of the preset vacuum threshold to calculate the total pumping volume, and subtract the total pumping volume from the preset initial cavity volume of the particle variable stiffness bag to calculate the discharge volume. S4. Continuously sample the reactive current of the servo motor at high frequency and perform fast Fourier transform to extract the current spectrum features. S5. Find the low-frequency harmonic amplitude in the 5Hz to 10Hz frequency band in the current spectrum characteristics, and adjust the pulse width modulation duty cycle of the negative pressure pump according to the discharge volume and the low-frequency harmonic amplitude to dynamically adjust the overall stiffness of the particle variable stiffness bag.

[0010] Optionally, step S5 is followed by: S601. Compare the displaced volume with a preset volume safety threshold, and compare the low-frequency harmonic amplitude with a preset stability threshold. S602. If the discharge volume is greater than a preset volume safety threshold and the low-frequency harmonic amplitude is less than a preset stability threshold, reduce the pulse width modulation duty cycle of the negative pressure pump to reduce the amount of air pumped, so that the particle variable stiffness bag remains micro-flexible. S603. If the amplitude of the low-frequency harmonic is greater than or equal to the preset stability threshold, increase the pulse width modulation duty cycle of the negative pressure pump to increase the pumping speed, so that the polyhedral ceramic particles will have a jamming and blocking effect. S604. If the discharge volume is less than or equal to a preset volume safety threshold and the low-frequency harmonic amplitude is less than a preset stability threshold, maintain the current pulse width modulation duty cycle of the negative pressure pump.

[0011] Optionally, step S5 is followed by: S701. When increasing the pulse width modulation duty cycle of the negative pressure pump, the extracted airflow is forced into the compensation air chamber through the bypass air passage. S702. The expansion support force generated by the side wall of the compensation chamber is used to counteract the volume contraction force generated by the particle variable stiffness bag. S703. The offset of the running axis of the annular baseband is kept within a preset range according to the balance between the volume contraction force and the expansion support force, so as to ensure the high signal-to-noise ratio of the servo motor current spectrum acquisition.

[0012] The present invention has the following beneficial effects: 1. This invention solves the problems of slippage and local stress concentration of irregular curved blocks when climbing slopes by setting a compensating air chamber and a particle variable stiffness bag on an annular base belt and filling it with polyhedral ceramic particles; under normal pressure, the particles are in a free-flowing state and conform to the bottom contour of the curved block, avoiding surface cracking; when the air is pumped under negative pressure, the particles experience a jamming and blocking effect, and the overall stiffness of the particle variable stiffness bag is dynamically adjusted to provide strong shear resistance; in addition, the expansion support force generated by the extracted gas being introduced into the compensating air chamber through the bypass air path effectively offsets the volume contraction force of the bag, keeps the offset of the running axis of the annular base belt within a preset range, ensures stable operation, and effectively achieves non-destructive protection of the curved block and stable conveying. 2. This invention overcomes the shortcomings of traditional equipment in lacking real-time contact status perception and adjustment, and proposes a control method. The controller calculates the discharge volume by integrating the transient flow of the negative pressure pump and extracts the low-frequency harmonic amplitude by performing a fast Fourier transform on the reactive current of the servo motor. The system compares the discharge volume with a preset volume safety threshold and the low-frequency harmonic amplitude with a preset stability threshold, dynamically scheduling the pulse width modulation duty cycle of the negative pressure pump. When the discharge volume is greater than the preset volume safety threshold and the low-frequency harmonic amplitude is less than the preset stability threshold, it maintains microscopic flexibility. When the low-frequency harmonic amplitude is greater than or equal to the preset stability threshold, it rapidly increases the pumping speed, achieving a dynamic balance between material protection and slope climbing anti-slip under complex working conditions. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In the drawings: Figure 1 This is a schematic diagram of the overall structure of the device; Figure 2 This is a schematic diagram of the annular baseband structure of the device; Figure 3 This is a schematic diagram of the compensation chamber structure of the device; Figure 4 This is a schematic diagram of the main and bypass air passages of the device; Figure 5 This is a flowchart of the method of the present invention.

[0014] In the diagram: 100, main frame; 200, drive roller; 300, redirecting roller; 400, servo motor; 500, annular base belt; 600, compensation air chamber; 700, particle variable stiffness bag; 800, polyhedral ceramic particles; 900, negative pressure pump; 1000, follow-up main air passage; 1100, mechanical proportional valve; 1200, bypass air passage; 1300, high elastic latex film; 1400, silicone; 1500, plum blossom-shaped flexible coupling; 1600, seated bearing; 1700, pneumatic rotary joint. Detailed Implementation

[0015] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0016] Example 1: Combination Figure 1 and Figure 2 As shown, a flexible conveying device for koji blocks used in a baijiu (Chinese liquor) koji-making production line includes: The main frame 100 has a drive roller 200 and a redirecting roller 300 respectively installed at its two ends; Servo motor 400 is connected to the shaft end of drive roller 200; An annular base belt 500 is wound around the outer cylindrical surface of the drive roller 200 and the redirecting roller 300. The outer surface of the annular base belt 500 is provided with compensation air chambers 600 arranged in an array along the running direction. The top of the compensation air chamber 600 is provided with a particle stiffness bag 700, and the particle stiffness bag 700 is filled with polyhedral ceramic particles 800. The negative pressure pump 900 is mounted on the main frame 100 and is connected to the follow-up main air circuit 1000. The mechanical proportional valve 1100 and the follow-up main air passage 1000 are connected to the inner cavity exhaust end of the particle variable stiffness bag 700 through the mechanical proportional valve 1100, while the positive pressure exhaust end of the negative pressure pump 900 is connected to the inner cavity inlet end of the compensation air chamber 600 through the bypass air passage 1200. A gas flow meter and a vacuum sensor are connected in series on the main gas path 1000, and a servo driver for collecting the reactive current of the motor is configured on the main frame 100 or the servo motor 400. The controller is connected to the gas flow meter, vacuum sensor and servo driver to control the servo motor 400, negative pressure pump 900 and mechanical proportional valve 1100. In this embodiment, when the existing baijiu koji making conveying equipment conveys irregular and fragile koji blocks, a common problem is that the flexible bearing surface is prone to slippage on the uphill section, while the rigid bearing surface is prone to stress concentration in local areas of the koji block. The main frame 100 adopts a rectangular welded frame structure, with a length that can be set from 3m to 12m and a width that can be set from 0.6m to 1.2m. The drive roller 200 and the redirecting roller 300 are respectively arranged at both ends of the main frame 100 and limit the running trajectory of the annular base belt 500. The servo motor 400 outputs torque to the drive roller 200, driving the annular base belt 500 to run continuously. Multiple compensation chambers 600 are evenly spaced along the length of the outer surface of the annular base belt 500. Each compensation chamber 600 has a particle stiffness-changing bag 700 fixed at the top. The stiffness change in the particle stiffness-changing bag 700 specifically refers to the mechanical state transformation of the polyhedral ceramic particles 800 between a loose and free-flowing state and a tightly interlocked blocked state by changing the internal pressure through air extraction or inflation. The granular variable stiffness bag 700 is used to directly contact the bottom of the curved block. Under normal pressure, the polyhedral ceramic particles 800 can be redistributed within the bag so that the surface of the bag conforms to the contour of the bottom surface of the curved block. Under negative pressure, the geometric self-locking reinforcement between the polyhedral ceramic particles 800 makes the granular variable stiffness bag 700 exhibit greater overall stiffness than under normal pressure, so as to provide support against the curved block sliding down the slope. The negative pressure pump 900 is connected to the particle variable stiffness bag 700 through the follow-up main air passage 1000. The mechanical proportional valve 1100 is used to adjust the pumping speed and pumping volume of the particle variable stiffness bag 700. The bypass air passage 1200 introduces the positive pressure airflow generated at the exhaust end of the negative pressure pump 900 into the compensation air chamber 600, causing the compensation air chamber 600 to expand and provide reverse support to the annular base belt 500. The controller adopts an industrial controller or a programmable logic controller, which receives the current signal of the servo motor 400 and the flow and vacuum signals of the negative pressure pump 900, and outputs servo speed commands, pulse width modulation commands of the negative pressure pump 900 and opening commands of the mechanical proportional valve 1100. In order to achieve stable acquisition of the above gas path signals, a gas flow meter and a vacuum sensor are also connected in series on the follow-up main gas path 1000. The signal output terminals of the two are electrically connected to the controller, thus providing a hardware basis for subsequent calculation of the displacement volume. This structure enables the bearing surface to maintain deformation compliance matching the contour of the curved block during the material receiving stage, has adjustable stiffness during the climbing stage, and utilizes the bypass air passage 1200 to form support compensation corresponding to the shrinkage of the bag, thereby taking into account both curved block protection and conveying stability.

[0017] like Figure 3 As shown, the compensation chamber 600 is a directional expansion airbag with a corrugated tube structure on the side wall. The outer layer of the particle variable stiffness bag 700 is a high elastic latex film 1300. The particle variable stiffness bag 700 is sealed and bonded to the top of the compensation chamber 600 by silicone 1400. In this embodiment, in order to enable the compensation air chamber 600 to obtain a controllable expansion amount within a limited thickness, the compensation air chamber 600 adopts a hot-pressed elastic airbag structure, and its sidewall is provided with continuous corrugated tube pleats. The crests and troughs are arranged laterally along the annular base belt 500. Anisotropic expansion means that when the airbag is inflated under pressure, the lateral and longitudinal expansion amount is greater than the vertical bulging amount, so as to reduce the direct lifting amplitude on the curved block bearing surface and improve the compensation ability for the plane shape of the base belt. The material of the compensation chamber 600 can be thermoplastic polyurethane film or rubber composite film, with a thickness of 0.5mm to 2mm, a length of 60mm to 150mm for a single chamber, and a width of 80mm to 180mm. The outer layer of the granular variable stiffness bag 700 is made of a high-elasticity latex film 1300, the thickness of which can be set from 0.3mm to 1mm, and the elongation of the material can be greater than 400%, so as to ensure that elastic deformation adapts to the local protrusion of the curved block when the curved block is pressed in without producing cracks. The particle variable stiffness bag 700 is sealed and bonded to the top of the compensation air chamber 600 with silicone 1400. The silicone 1400 layer not only achieves airtight sealing, but also forms a flexible transition interface between the bag and the air chamber, avoiding the seam peeling caused by repeated bending during operation. When the combination of corrugated pipe sidewall and latex film is adopted, the airflow mainly exhibits planar expansion when entering the compensation chamber 600, while the particle variable stiffness bag 700 mainly exhibits local contraction when pumping air. The two produce deformations in different directions, which helps to reduce the amount of wrinkles on the surface of the annular baseband 500 and reduce the adverse effects on the contact stress distribution of the curved block.

[0018] The polyhedral ceramic particles 800 have a particle size of 2 mm to 3 mm. The polyhedral ceramic particles 800 are made of alumina and have a micro-textured surface sintered to provide the coefficient of friction between particles. In this embodiment, the polyhedral ceramic particles 800 filled inside the particle variable stiffness bag 700 are used to form a load-bearing core that transforms from a fluid dynamic state to a blocked state. The particle size is set to 2mm to 3mm, which is a size range determined by the concave and convex dimensions of the bottom surface of the baijiu koji block, the thickness of the latex film, and the thickness of the capsule. When the particle size is less than 2mm, the number of particles increases, the internal air flow resistance increases, the air extraction response time is prolonged, and the probability of local compaction between particles increases, which is not conducive to forming obvious stiffness switching. When the particle size is greater than 3mm, the equivalent discrete support points on the surface of the bag are reduced, and deep indentations are easily generated at the local protrusions of the curved block; the particles are made of alumina material, which has stable bulk density and high wear resistance, and is suitable for long-term use under high-frequency circulating air pumping conditions. The particles are shaped like irregular polyhedra rather than spheres to improve their geometric self-locking ability under negative pressure. After the particle surface is sintered to form a micro-textured surface, the friction coefficient between particles and between particles and latex film increases, which can enable the particles to obtain higher shear resistance under the same negative pressure level. One feasible filling method is to control the filling rate of a single particle variable stiffness bag 700 to 70% to 90% of the bag's free volume. This filling rate not only retains the flowable space under normal pressure, but also ensures the formation of a continuous stress-bearing skeleton after evacuation. With this particle parameter, the particle variable stiffness bag 700 can fit the bottom surface of the curved block without gaps in the receiving area, and can continuously suppress micro-slippage in the climbing area.

[0019] The servo motor 400 is connected to the drive roller 200 via a plum blossom-shaped flexible coupling 1500. The drive roller 200 and the redirecting roller 300 are mounted in parallel at both ends of the main frame 100 via seated bearings 1600. The annular base belt 500 is made of polyurethane. In this embodiment, the servo motor 400 and the drive drum 200 are connected by a plum blossom-shaped flexible coupling 1500. The coupling consists of two metal claw discs and an intermediate elastic body, which allows for a radial deviation of 0.1mm to 0.5mm and an angular deviation of 1 degree to 2 degrees between the motor shaft and the drum shaft, thereby reducing the transmission of installation errors to the drum bearing and the motor bearing. Both the drive roller 200 and the redirecting roller 300 are mounted on both ends of the main frame 100 via seated bearings 1600. The axes of the two rollers are kept parallel. The outer circumference of the rollers can be coated with rubber to improve the friction transmission capability between them and the annular base belt 500. The annular base belt 500 is made of polyurethane material. Its longitudinal tensile strength meets the operating tension requirements, and its damp heat resistance meets the environmental requirements of the koji-making workshop, making it suitable for the high humidity environment of the koji-making workshop. One feasible parameter combination is as follows: the thickness of the annular base belt 500 is set to 2mm to 6mm, the tension layer can adopt a fiber-reinforced structure, the diameter of the drive roller 200 is set to 120mm to 260mm, the diameter of the redirecting roller 300 is set to 100mm to 220mm, and the conveying speed is set to 0.05m / s to 0.5m / s. With the above structure, the torque output of the drive system and the baseband operation maintain a stable transmission relationship. The load fluctuation information in the current of the servo motor 400 can accurately reflect the change in the contact state between the particle variable stiffness bag 700 and the curved block, providing a usable signal basis for subsequent spectrum analysis.

[0020] like Figure 4 As shown, the suction port of the negative pressure pump 900 is connected to the follow-up main air passage 1000 through the pneumatic rotary joint 1700, wherein the bypass air passage 1200 is set up in reverse. In this embodiment, since the annular base belt 500 is in a continuous cyclic motion state, the fixed negative pressure pump 900 and the follow-up main air passage 1000 that moves synchronously with the annular base belt 500 need to establish a stable air passage connection through a rotatable seal. Therefore, a pneumatic rotary joint 1700 is provided between the air intake of the negative pressure pump 900 and the follow-up main air passage 1000. The pneumatic rotary joint 1700 can adopt a single-channel mechanical seal structure, with its stator end connected to a fixed air extraction main pipe and its rotor end connected to the internal air passage of the drum shaft or the air distribution cavity embedded in the base belt, so as to keep the air passage open when the drum rotates continuously. The inverted configuration of the bypass air passage 1200 means that the inlet of the bypass air passage 1200 is located at a lower position on the exhaust side of the mechanical proportional valve 1100, and the outlet is located at a higher position on the inlet end of the compensation air chamber 600. Both the higher and lower positions are relative to the horizontal plane when the annular base belt 500 runs to the upper load-bearing working section of the main frame 100. That is, an upward folding guide path is formed along the installation direction relative to the main frame 100. This layout helps to limit the entry of dust, condensate and particulate debris into the compensation air chamber 600, while increasing the flow stability of the airflow before entering the compensation air chamber 600. In one possible implementation, the inner diameter of the bypass air passage 1200 is set to 4mm to 10mm, the length is set to 80mm to 250mm, and a filter or drain valve is installed at the inlet to reduce the impact of impurity accumulation on the airflow compensation effect. Through the cooperation of the pneumatic rotary joint 1700 and the inverted bypass air passage 1200, the gas extracted by the negative pressure pump 900 can be stably transmitted between the moving base belt and the fixed pump body, and continuously provide compensating airflow to the compensating air chamber 600 during the conveyor belt circulation operation.

[0021] Example 2: Combination Figure 5 As shown, a flexible conveying control method for koji blocks in a baijiu (Chinese liquor) koji-making production line includes: S1. Control the negative pressure pump 900 to be in a normal pressure state, so that the polyhedral ceramic particles 800 inside the particle stiffness bag 700 are in a loose free-flowing state to conform to the bottom contour of the curved block. S2. Control the negative pressure pump 900 to start and output suction power according to the preset basic duty cycle to evacuate the inside of the particle variable stiffness bag 700. S3. Integrate the transient flow rate during the period from the start of the negative pressure pump 900 to the achievement of the preset vacuum threshold to calculate the total pumping volume, and subtract the total pumping volume from the preset initial cavity volume of the particle variable stiffness bag 700 to calculate the discharge volume. S4. Continuously sample the reactive current of the servo motor 400 at high frequency and perform fast Fourier transform to extract the current spectrum features. S5. Find the low-frequency harmonic amplitude in the 5Hz to 10Hz frequency band in the current spectrum characteristics, and adjust the pulse width modulation duty cycle of the negative pressure pump 900 according to the discharge volume and the low-frequency harmonic amplitude to dynamically adjust the overall stiffness of the particle variable stiffness bag 700. In this embodiment, the control method is used to adjust the stiffness of the particle variable stiffness bag 700 based on the air path data and motor electrical signal without relying on visual sensors and array pressure sensors. In S1, the controller keeps the negative pressure pump 900 in a stopped or depressurized state, the internal pressure of the particle variable stiffness bag 700 is close to the ambient pressure, the polyhedral ceramic particles 800 are in a flowable distribution state, after the curved block falls onto the surface of the particle variable stiffness bag 700, the latex film undergoes elastic deformation, the particles move along the bottom contour of the curved block and rearrange themselves to form a large area of ​​contact. In S2, the controller outputs the basic duty cycle to the negative pressure pump 900 before the curved block enters the climbing zone. The basic duty cycle can be set to 20% to 50%, so that the particle stiffness bag 700 starts to pump air and gradually increases the overall stiffness. In S3, the controller collects transient flow data of the negative pressure pump 900 from the start time to the time when the preset vacuum threshold is reached. The sampling period can be set from 1ms to 10ms. The flow value at each sampling time is multiplied by the corresponding time interval and accumulated to obtain the total pumping volume. The initial cavity volume of the particle variable stiffness bag 700 when it is not compressed is a pre-calibrated value. The displacement volume is obtained by subtracting the total pumping volume from the initial cavity volume. The larger the displacement volume, the larger the volume that the bottom of the curved block presses into the bag. The degree of concavity and convexity of the bottom of the curved block and the degree of mechanical fitting are usually higher. In S4, the controller performs high-frequency sampling of the servo motor's 400 reactive current. The sampling frequency can be set from 500Hz to 5000Hz. The sampled values ​​within the continuous time window are input into the fast Fourier transform program to obtain the current spectrum characteristics. In S5, the controller extracts the low-frequency harmonic amplitude in the 5Hz to 10Hz frequency band, uses this amplitude as a characterization value of micro-slip intensity, and uses it together with the discharge volume as the basis for adjusting the 900 pulse width modulation duty cycle of the negative pressure pump; when the discharge volume is lower than the preset volume threshold and the harmonic amplitude increases, the duty cycle is increased to enhance the shear resistance; when the discharge volume is higher than the preset volume threshold and the harmonic amplitude is low, the duty cycle is decreased to maintain flexible contact. This method converts the geometric information of the curved block's bottom surface into the displaced volume and the contact shear state into current spectrum information. Both participate in stiffness adjustment, keeping the curved block protection and climbing stability within a controllable range during the conveying process. To clarify the specific technical characterization of the parameters in S3 to S5, this embodiment defines the physical meaning, source, and flow direction of each parameter as follows: The preset vacuum threshold is a benchmark for terminating the volume integration of the current pumping cycle. Its physical meaning is the target negative pressure limit for the particle variable stiffness bag 700 to enter a state where a stable particle skeleton can be established from a clearly flowable state. This threshold can be obtained by calibration with an empty sample bag. During calibration, the amount of bag bending rebound or surface indentation recovery is recorded at different vacuum levels. The vacuum level that can make the bag stiffness start to rise significantly without causing excessive shrinkage of the latex film is selected as the preset vacuum threshold. An implementable range is a negative pressure of 10 kPa to 35 kPa relative to the ambient pressure. The initial cavity volume refers to the volume of free gas that can be extracted from the inside of the particle variable stiffness bag 700 when no curved block is placed, under normal pressure, and the particles are naturally spread out. This value can be obtained by static pumping calibration of a single bag after the equipment is installed and stored in the controller as a lookup parameter. Displacement volume is not an abstract evaluation quantity, but rather a characterization of how much free space that could originally be occupied by air is occupied after the bottom surface of the curved block is pressed into the bag. Its output is sent to S5 as stiffness adjustment input on the one hand, and can be used to distinguish between flat-bottomed curved blocks and curved blocks whose bottom surface is uneven beyond the preset undulation threshold. An implementable integral logic is as follows: After the negative pressure pump 900 starts, the controller reads the transient flow rate value according to the sampling period, multiplies it point by point by the corresponding time interval, and accumulates the results to obtain the total pumping volume. Then, according to: Calculate the displaced volume, where, To displace the volume, The initial cavity volume, The total pumping volume before reaching the preset vacuum threshold; when the calculation result is less than zero, the displaced volume is recorded as zero to eliminate invalid negative values ​​caused by flow rate zero drift or calibration error; The reactive current in S4 refers to the excitation component current obtained by decomposing the motor voltage phase and current phase inside the servo driver, or the component in the q-axis and d-axis components directly output by the driver that has no direct correspondence with the mechanical work. The reason for its selection is that this component can effectively identify load fluctuations caused by contact resistance, periodic abnormal jumping and micro-slip, without being affected by changes in the average delivery torque. In terms of data flow and interaction, the servo drive periodically sends the current component in its internal register to the controller in digital signal format through industrial fieldbuses such as Ethernet control automation technology or Controller Area Network Open Protocol. The controller stores the received data stream into a pre-allocated memory ring buffer. After the controller acquires the current signal, it first extracts continuous samples according to a fixed time window, which can be set to 0.2s to 1s; and performs DC bias removal processing to avoid signal masking of the low-frequency spectrum caused by the rise of the current base value. Then, a fast Fourier transform is performed. The input of this transform program is a discrete time series truncated within a circular buffer, and the output is an amplitude array in the frequency domain. The peak amplitude or energy-weighted average value in the 5Hz to 10Hz frequency band is extracted from the spectrum results as the low-frequency harmonic amplitude. The physical meaning of the low-frequency harmonic amplitude is: when there is intermittent shear release, local slippage or unstable adhesion between the curved block and the bag, the drive system will have repetitive load fluctuations in the low-frequency range. After the servo motor 400 current is mapped, the fluctuations form identifiable peaks in the 5Hz to 10Hz frequency band. Therefore, this amplitude is used as a characterization value of micro-slip intensity. The final output of the process includes two parallel quantities: the displacement volume, which characterizes the degree of geometric compression, and the low-frequency harmonic amplitude, which characterizes the degree of contact stability; both are transmitted to the negative pressure pump 900 duty cycle scheduling module to determine whether to enhance, maintain, or reduce the pumping action in the next control cycle. S3 to S5 can be regarded as a stiffness scheduling logic module inside the controller. This module is configured to indirectly determine whether to prioritize protecting the curved block or to prioritize suppressing the downward movement when the contact pressure distribution on the bottom surface of the curved block cannot be directly measured. The logic module consists of two parts: a geometric representation branch and a contact stability representation branch. The geometric characterization branch receives the initial cavity volume, transient flow rate, and preset vacuum threshold, and outputs the discharge volume; the contact stability characterization branch receives the 400 reactive current sampling value of the servo motor, and outputs the low-frequency harmonic amplitude value after time window truncation, DC bias removal, and fast Fourier transform. The scheduling unit simultaneously receives the above two outputs and generates a duty cycle adjustment command for the negative pressure pump 900. The physical relationship it represents is: the more the bottom surface of the curved block is pressed into the bag, the less free gas space there is, and the less gas can be extracted before reaching the same vacuum threshold, so the displaced volume is larger. If micro-slippage occurs between the curved block and the bag, the driving load will experience periodic disturbances. These disturbances, after being mapped by the motor current, will form identifiable changes in the 5Hz to 10Hz frequency band. Therefore, the higher the amplitude of the low-frequency harmonics, the stronger the anti-slip requirement. This module acquires data on the compression geometry and shear slip state respectively, and uses both to jointly regulate the bag stiffness, so that the control action output by the controller can accurately respond to the current actual contact state.

[0022] The steps following S5 include: S601. Compare the displaced volume with the preset volume safety threshold, and compare the low-frequency harmonic amplitude with the preset stability threshold. S602. If the discharge volume is greater than the preset volume safety threshold and the low frequency harmonic amplitude is less than the preset stability threshold, reduce the pulse width modulation duty cycle of the negative pressure pump 900 to reduce the pumping volume and keep the particle variable stiffness bag 700 micro-flexible. S603. If the low-frequency harmonic amplitude is greater than or equal to the preset stability threshold, increase the pulse width modulation duty cycle of the negative pressure pump 900 to increase the pumping speed, causing the polyhedral ceramic particles 800 to experience a jamming and blocking effect. S604. If the discharge volume is less than or equal to the preset volume safety threshold and the low-frequency harmonic amplitude is less than the preset stability threshold, maintain the current pulse width modulation duty cycle of the negative pressure pump 900. In this embodiment, in order to ensure that the adjustment logic has clear criteria, the controller performs a threshold branch judgment after S5; In S601, the volume safety threshold is obtained by no-load calibration and typical curved block sample calibration, and can be taken as 15% to 45% of the initial cavity volume of a single particle variable stiffness bag 700. The stability threshold is determined by the spectrum calibration value under three working conditions: no curved block operation, normal fitting operation, and slight slip operation, and can be taken as 0.02 to 0.15 of the normalized harmonic amplitude in the 5Hz to 10Hz frequency band. The working condition corresponding to S602 indicates that the amount of pressure pressed into the bottom surface of the curved block is greater than the deformation safety threshold and there is no obvious micro-slip trend. The controller will reduce the duty cycle of the negative pressure pump 900 by 5% to 20% based on the current value, or gradually reduce the pumping power according to the preset gradient, so that the particle variable stiffness bag 700 retains a certain degree of flexibility, in order to reduce the risk of surface pressure damage caused by excessive bag stiffness. The working condition corresponding to S603 indicates that micro-slippage has occurred or is about to occur between the curved block and the bearing surface. The controller increases the duty cycle of the negative pressure pump 900 by 10% to 40%, causing the pressure inside the bag to drop rapidly. The friction and geometric self-locking between the polyhedral ceramic particles 800 are enhanced, the particle system changes from a rearrangeable state to a blocked state, the overall stiffness of the bag increases, and the downward trend of the curved block decreases. To achieve the precise programmable calculation of the duty cycle, the controller has a preset proportional adjustment function: in S602, the amount of duty cycle reduction is proportional to the difference between the discharge volume and the volume safety threshold; in S603, the amount of duty cycle increase is proportional to the difference between the low-frequency harmonic amplitude and the stability threshold. Specifically, let the current duty cycle be... The amplitude of low-frequency harmonics is The stability threshold is The volume safety threshold is The target duty cycle for the next cycle is... ,when Greater than or equal to At that time, execute S603, the target duty cycle for the next cycle: in, This is the preset anti-slip ratio gain; It has units that convert amplitude dimensions to duty cycle dimensions to ensure dimensional consistency on both sides of the formula; when Greater than and Less than At that time, execute S602, the target duty cycle for the next cycle: in, The preset flexible protection ratio gain, It has units that convert volume dimensions to duty cycle dimensions to ensure dimensional consistency on both sides of the formula, and sets... The lower limit value is based on the duty cycle to prevent air extraction interruption; the above formula clarifies the specific generation process of the duty cycle instruction, enabling the control logic to be directly converted into executable software code. The operating condition corresponding to S604 indicates that the bottom surface of the curved block is pressed in a limited amount, but the sliding signal is still within the permissible range. The controller maintains the current duty cycle unchanged to avoid frequent adjustments that may cause air path fluctuations. In this branch logic, each judgment result directly affects the control quantity of the negative pressure pump 900 to avoid situations where the collected parameters are not involved in the execution. This method allows for discrete or quasi-continuous adjustment of the stiffness of the particle variable stiffness bag 700 under different curved block bottom surface shapes and different conveying slopes; the logical function of the volume safety threshold is to distinguish between working conditions where deep geometric fit has been achieved and the curved block surface can be protected first, and working conditions where geometric fit is insufficient and anti-slip needs to be prioritized. The determination steps can be as follows: First, obtain the initial cavity volume of each particle variable stiffness bag 700 under no-load conditions, then select multiple representative curved block samples for low-speed indentation test, record the distribution range of the displaced volume under the premise of no visible indentation, surface debris falling off or corner cracking, and take the lower limit value or the statistical median value of the distribution range as the volume safety threshold. The logical function of the stability threshold is to distinguish between contact stability and spectral states with micro-slipping tendencies. The determination steps can be as follows: collect amplitude samples of the 5Hz to 10Hz frequency band under three working conditions: no-bend operation without curved blocks, normal fit without slipping operation, and artificially created slight slipping instability operation. Set the stability threshold according to the dividing point between the upper limit of the normal fit sample and the lower limit of the slight slipping sample, or take the median value between the mean values ​​of the two types of samples as the stability threshold. The execution order of S601 to S604 can be limited as follows: the controller first reads the latest displacement volume and low-frequency harmonic amplitude value of the current control cycle, then performs a double threshold comparison, and then outputs only a mutual exclusion control result. To avoid frequent threshold crossings that cause high-frequency oscillations in the duty cycle, a combination of hold time and step amplitude can be used. That is, after a certain judgment result is true, it should be maintained for at least 1 to 5 control cycles, or the duty cycle should only be allowed to increase or decrease according to a preset step within each cycle. An feasible decision-making sequence is as follows: first, determine whether the amplitude of low-frequency harmonics is greater than or equal to the stability threshold. If it is true, proceed directly to S603, because the slip risk is higher than the priority of flexible protection. If it is not true, then determine whether the displacement volume is greater than the volume safety threshold. If it is true, proceed to S602. If neither of them is satisfied, proceed to S604. After adopting this sequence, the controller can suppress the instability of the conveyor and then return to the block protection logic under the premise of stability, so that there is a clear causal correspondence between the threshold criterion and the execution action; The decision module consisting of S601 to S604 is used to convert the two continuously changing characterization quantities into executable discrete control results and output a definite control command to the negative pressure pump. The input of this judgment module is the discharge volume and low-frequency harmonic amplitude, the comparison terminal is the volume safety threshold and stability threshold, and the output terminal is three types of instructions for reducing, increasing or maintaining the duty cycle of the negative pressure pump 900. The physical relationship it reflects is as follows: when the displaced volume exceeds the preset fluctuation threshold, it indicates that the bottom surface of the curved block and the bag have formed a sufficient geometric fit. At this time, further increasing the stiffness will have limited contribution to anti-slip and may instead increase local compressive stress. Therefore, it should be adjusted towards flexible protection first. When the amplitude of low-frequency harmonics increases, it indicates that the periodic disturbances related to micro-slip in the driving load are enhanced. If the pumping intensity is not increased at this time, the curved block is more likely to experience shear instability in the climbing section. Therefore, it should be adjusted in the anti-slip direction first. This module maps whether the geometric fit is sufficient and whether the risk of slippage increases to different control branches, thereby independently executing the corresponding negative pressure adjustment action according to different triggering conditions.

[0023] The steps following S5 include: S701. When the pulse width modulation duty cycle of the negative pressure pump 900 is increased, the extracted airflow is forced into the compensation air chamber 600 through the bypass air passage 1200. S702. The expansion support force generated by the side wall of the compensation chamber 600 is used to counteract the volume contraction force generated by the particle variable stiffness bag 700. S703. Based on the balance between volume contraction force and expansion support force, the offset of the running axis of the annular baseband 500 is kept within a preset range to ensure a high signal-to-noise ratio for the current spectrum acquisition of the servo motor 400. In this embodiment, when the controller increases the duty cycle of the negative pressure pump 900 due to the increase in the amplitude of low-frequency harmonics, the pressure drop rate inside the particle variable stiffness bag 700 increases, and the bag will show a shrinkage trend. If this shrinkage trend is not compensated, the annular base belt 500 will locally produce longitudinal shortening and transverse wrinkling, changing the contact state between the drive roller 200 and the base belt, causing additional spectral components related to the lateral offset and abnormal jumping of the belt to be superimposed in the current of the servo motor 400. Based on this, S701 specifies that the airflow drawn out by the negative pressure pump 900 is introduced into the bypass air passage 1200 through the exhaust side of the mechanical proportional valve 1100 and forced into the compensation air chamber 600 at the corresponding position. In S702, after the compensation chamber 600 is compressed, its bellows sidewall expands, forming an expansion support force along the plane of the annular base belt 500. This support force is opposite in direction to the volume contraction force of the particle variable stiffness bag 700, and the two change synchronously within the same bearing unit. One feasible calibration method is to record the surface shrinkage of the particle variable stiffness bag 700 and the planar expansion of the compensation air chamber 600 under different duty cycles of the negative pressure pump 900 after the equipment is assembled. By adjusting the cross-sectional area of ​​the bypass air passage 1200, the opening degree of the mechanical proportional valve 1100 and the corrugation density of the compensation air chamber 600, the two can be kept in a similar displacement compensation relationship within the commonly used negative pressure range. In S703, the controller does not need to build a complex geometric model. It can control the offset of the running axis of the ring baseband 500 to be within a predetermined range simply by maintaining the compensation relationship. For example, the lateral offset is no more than 2mm and the wrinkling height per unit length is no more than 1mm. After the geometry of the annular baseband 500 is stabilized, the main source of change in the current spectrum of the servo motor 400 is still the micro-contact change between the curved block and the particle variable stiffness bag 700, thereby improving the accuracy of the characterization of micro-slip by the low-frequency harmonic amplitude in the 5Hz to 10Hz frequency band; this implementation method enables the air path adjustment and belt surface deformation compensation to occur simultaneously, reducing the need for external tensioning mechanisms. In this embodiment, volume shrinkage force refers to the equivalent shrinkage effect formed after the particle variable stiffness bag 700 is evacuated, due to the reduction of internal free gas, the bag envelope surface contracting inward and pulling the surface of the annular base belt 500. It does not require direct measurement by a force sensor, but can be indirectly characterized by the amount of shrinkage on the bag surface, the amount of change in bag thickness, or the amount of change in local length of the base belt. Expansion support force refers to the equivalent support effect formed by the expansion of the corrugations on the sidewall of the air chamber and the extension along the plane of the base zone after the bypass airflow enters the compensation air chamber 600. The effect of this action can be indirectly characterized by the plane expansion of the compensation air chamber 600, the reduction of the local wrinkling height, or the correction of the offset of the base zone axis. Therefore, the balance lock in S703 is not an abstract expression, but refers to the controller or assembly calibration process maintaining an approximately compensatory relationship between the two types of equivalent effects under normal operating conditions, thereby keeping the baseband geometry within the allowable error range. The processing flow of S701 to S703 can be implemented in the following order: During the same control cycle when the duty cycle of the negative pressure pump 900 is increased, the controller synchronously increases the mechanical proportional valve 1100 to the opening range that matches the duty cycle, so that the extracted airflow preferentially enters the corresponding compensation air chamber 600 through the bypass air passage 1200. The matching opening range is achieved through a two-dimensional interpolation lookup table preset in the controller memory. The input parameters of the lookup table are the current duty cycle increment of the negative pressure pump 900 and the real-time vacuum degree of the system, and the output parameters are the control voltage or current command of the mechanical proportional valve 1100. To construct this two-dimensional interpolation lookup table, a gridded calibration was performed during the equipment commissioning phase: multiple vacuum reference points and multiple duty cycle increment steps were selected to form a test grid; at each grid node, the control command of the mechanical proportional valve 1100 was gradually adjusted, while the amount of surface contraction of the bag and the amount of planar expansion of the air chamber were monitored using a displacement sensor; when the local length change of the baseband caused by the two was balanced, the current control command was recorded and stored in the lookup table. After reading the duty cycle increment during controller operation, the controller queries the table and uses the bilinear interpolation algorithm to automatically output the corresponding analog signal to the mechanical proportional valve 1100 drive end, completing the data flow from logical calculation to physical execution; In subsequent sampling periods, the baseband geometric stability characterization quantity is collected. This characterization quantity can be selected from the lateral offset, the wrinkling height per unit length, the difference in the position of the strip edge at both ends of the roller, or the additional peak change related to abnormal jumping in the current spectrum. Compare the characterization quantity with the predetermined allowable range. If there is an increasing trend in baseband wrinkling or lateral offset, increase the bypass compensation intensity. If excessive compensation leads to local abnormal bulging, decrease the bypass compensation intensity. In one possible implementation, ensuring a high signal-to-noise ratio for the current spectrum acquisition of the servo motor 400 means limiting non-contact disturbance components introduced by baseband lateral offset, abnormal jumping, and wrinkles to a pre-calibrated background noise band, so that the main changes in the 5Hz to 10Hz frequency band still correspond to the changes in the contact state between the curved block and the particle variable stiffness bag 700. To verify the effectiveness of this compensation method, a comparative test was conducted during the system debugging phase: Without bypass compensation, when the duty cycle of the negative pressure pump 900 abruptly changed from 30% to 70%, the wrinkling height on the surface of the annular baseband 500 reached 4.5mm, and the background noise amplitude in the 5Hz to 10Hz frequency band increased by approximately 3 times; however, after enabling bypass compensation and applying the aforementioned lookup table, the wrinkling height under the same pumping abrupt change was suppressed to within 0.8mm, and the background noise amplitude fluctuation was less than 15%. The test data shows that the present invention can effectively improve the anti-interference capability of current spectrum acquisition by using the expansion of the compensation chamber 600 to counteract the contraction of the bag. With the above additional limitations, the inputs to S701 to S703 are the duty cycle boosting command of the negative pressure pump 900 and the bypass airflow. The processing is synchronous air guidance, comparison of geometric stability characterization quantities and correction of compensation intensity. The output results are that the baseband geometric state remains stable and the spectrum signal can be used for subsequent slip judgment. S701 to S703 can be regarded as a geometric compensation logic with a surface, the purpose of which is to eliminate the baseband deformation interference caused by the air-squeezing and shrinking of the bag, so that the slip judgment based on the current spectrum mainly reflects the contact state of the curved block, rather than the additional disturbance of the conveyor belt body. The logic includes a guide branch, a compensation branch and a verification branch: the guide branch receives the airflow extracted by the negative pressure pump 900 and the opening command of the mechanical proportional valve 1100, and sends the airflow into the bypass airway 1200. The compensation branch uses the planar expansion of the compensation chamber 600 to provide reverse support for the local shortening of the baseband caused by the contraction of the bag; the verification branch receives the baseband geometric stability characterization quantity and adjusts the bypass compensation intensity accordingly. The physical relationship it represents is as follows: because the variable stiffness bag 700 will form a contraction effect on the surface of the baseband after the air is pumped out, the baseband is more prone to wrinkles, lateral displacement or abnormal jumping. Furthermore, since the bypass airflow will cause the sidewall of the air chamber to expand along the base zone plane after entering the compensation air chamber 600, it can form a reverse compensation for the above-mentioned contraction effect. When the two are in near balance, the additional mechanical disturbance in the drive system is reduced, so the low-frequency changes in the current spectrum can better correspond to the real contact changes between the curved block and the bag. Therefore, the locking trunk axis geometric accuracy in S703 should be understood as controlling the baseband axis offset and surface wrinkling within the allowable range, rather than requiring it to remain absolutely unchanged.

[0024] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A flexible conveying device for koji blocks used in a baijiu (Chinese liquor) koji-making production line, characterized in that, include: A main frame (100) is provided with a drive roller (200) and a redirecting roller (300) at its two ends. A servo motor (400) is connected to the shaft end of the drive roller (200); An annular base belt (500) is wound around the outer cylindrical surface of the drive roller (200) and the redirecting roller (300). The outer surface of the annular base belt (500) is provided with compensation air chambers (600) arranged in an array along the running direction. The top of the compensation air chamber (600) is provided with a particle variable stiffness bag (700). The particle variable stiffness bag (700) is filled with polyhedral ceramic particles (800). A negative pressure pump (900) is installed on the main frame (100), and the negative pressure pump (900) is connected to the follow-up main air passage (1000). The mechanical proportional valve (1100) connects the follow-up main air passage (1000) to the inner cavity exhaust end of the particle variable stiffness bag (700) through the mechanical proportional valve (1100), while the positive pressure exhaust end of the negative pressure pump (900) is connected to the inner cavity inlet end of the compensation air chamber (600) through the bypass air passage (1200). A gas flow meter and a vacuum sensor are connected in series on the follow-up main gas path (1000), and a servo driver for collecting the reactive current of the motor is configured on the main frame (100) or the servo motor (400). The controller is connected to the gas flow meter, the vacuum sensor and the servo driver to control the servo motor (400), the negative pressure pump (900) and the mechanical proportional valve (1100).

2. The flexible conveying device for koji blocks in a baijiu koji-making production line according to claim 1, characterized in that, The compensation chamber (600) is a directional expansion airbag with a corrugated tube structure on the side wall. The outer layer of the particle variable stiffness bag (700) is a high elastic latex film (1300). The particle variable stiffness bag (700) is sealed and bonded to the top of the compensation chamber (600) with silicone (1400).

3. The flexible conveying device for koji blocks in a baijiu koji-making production line according to claim 1, characterized in that, The polyhedral ceramic particles (800) have a particle size of 2 mm to 3 mm, wherein the polyhedral ceramic particles (800) are made of alumina and have a micro-textured surface sintered to improve the friction coefficient between particles.

4. The flexible conveying device for koji blocks in a baijiu koji-making production line according to claim 1, characterized in that, The servo motor (400) is connected to the drive roller (200) via a plum blossom-shaped flexible coupling (1500). The drive roller (200) and the redirecting roller (300) are mounted in parallel at both ends of the main frame (100) via seated bearings (1600). The annular base belt (500) is made of polyurethane.

5. The flexible conveying device for koji blocks in a baijiu koji-making production line according to claim 1, characterized in that, The air intake of the negative pressure pump (900) is connected to the follow-up main air passage (1000) through a pneumatic rotary joint (1700), wherein the bypass air passage (1200) is inverted.

6. A control method, applied to the flexible conveying device for koji blocks in a baijiu koji-making production line as described in claim 1, characterized in that, include: S1. Control the negative pressure pump (900) to be in a normal pressure state, so that the polyhedral ceramic particles (800) inside the particle stiffness bag (700) are in a loose free-flowing state to conform to the bottom contour of the curved block. S2. Control the negative pressure pump (900) to start and output suction power according to the preset basic duty cycle to evacuate the inside of the particle variable stiffness bag (700); S3. The transient flow rate during the period from the start of the negative pressure pump (900) to the achievement of the preset vacuum threshold is integrated over time to calculate the total pumping volume, and the discharge volume is obtained by subtracting the total pumping volume from the preset initial cavity volume of the particle variable stiffness bag (700). S4. Continuously sample the reactive current of the servo motor (400) at high frequency and perform fast Fourier transform to extract the current spectrum features. S5. Find the low-frequency harmonic amplitude in the 5Hz to 10Hz frequency band in the current spectrum characteristics, and adjust the pulse width modulation duty cycle of the negative pressure pump (900) according to the discharge volume and the low-frequency harmonic amplitude to dynamically adjust the overall stiffness of the particle variable stiffness bag (700).

7. The control method according to claim 6, characterized in that, Step S5 is followed by: S601. Compare the displaced volume with a preset volume safety threshold, and compare the low-frequency harmonic amplitude with a preset stability threshold. S602. If the discharge volume is greater than a preset volume safety threshold and the low frequency harmonic amplitude is less than a preset stability threshold, reduce the pulse width modulation duty cycle of the negative pressure pump (900) to reduce the amount of air pumped, so that the particle variable stiffness bag (700) remains micro-flexible. S603. If the amplitude of the low-frequency harmonic is greater than or equal to the preset stability threshold, increase the pulse width modulation duty cycle of the negative pressure pump (900) to increase the pumping speed, so that the polyhedral ceramic particles (800) will have a jamming and blocking effect. S604. If the discharge volume is less than or equal to a preset volume safety threshold and the low-frequency harmonic amplitude is less than a preset stability threshold, maintain the current pulse width modulation duty cycle of the negative pressure pump (900).

8. The control method according to claim 6, characterized in that, Step S5 is followed by: S701. When the pulse width modulation duty cycle of the negative pressure pump (900) is increased, the extracted airflow is forced into the compensation air chamber (600) through the bypass air passage (1200). S702. The expansion support force generated by the side wall of the compensation chamber (600) is used to counteract the volume contraction force generated by the particle variable stiffness bag (700). S703. The offset of the running axis of the annular baseband (500) is kept within a preset range according to the balance between the volume contraction force and the expansion support force, so as to ensure the high signal-to-noise ratio of the current spectrum acquisition of the servo motor (400).

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