Grain friction coefficient measuring device and measuring method thereof

Abstract

According to the grain friction coefficient measuring device and the measuring method thereof, the sensor is used for judging grain falling, the inclination angle during static friction measurement is controlled through a sensor signal, the precision is high, measurement is carried out according to multiple grains falling for multiple times, the measuring efficiency is high, and the measuring precision is high. And the static and dynamic friction coefficients of the same sampling batch can be continuously measured. According to the measuring method, the average angle is calculated through weight of different falling angles and the number of multiple grains sampled at a time, and the method is closer to a static friction test of a comprehensive whole. Comprising a static friction measuring table used for measuring the static friction coefficient, and a disc collecting bin mechanism used for receiving materials falling from the static friction measuring table at different inclination angles; the single-grain discharging mechanism is used for receiving the materials output by the discharging holes and discharging the materials in a single-grain mode. And the dynamic friction coefficient measuring mechanism is used for receiving the material falling from the single grain discharging mechanism and measuring the dynamic friction coefficient of the grains.

Description

Technical Field

[0001] The invention relates to the technical field of grain friction coefficient measurement, in particular to a grain friction coefficient measurement device and a measurement method thereof. Background Art

[0002] During the cleaning, sowing, harvesting, processing and transportation of grain kernels, the coefficient of friction between the kernels and the contact surface is an important characteristic parameter that needs to be considered.

[0003] In 2019, Li Zhaodong, Zhang Xu, et al. developed an automatic measurement system for the friction coefficient based on a parallel four-bar mechanism [Li Zhaodong, Zhang Xu, Zhang Miaomiao, et al. Automatic measurement system for the friction coefficient based on a parallel four-bar mechanism [J]. Hubei Agricultural Sciences, 2019, 58(2): 6. DOI: 10.14088 / j.cnki.issn0439-8114.2019.02.027.]. Based on the measurement principle of the inclined plane method, the four-bar mechanism is driven by a stepper motor to control the lifting of the inclined plane, and the rotation is controlled by the mobile phone Bluetooth serial port software control panel. Through human eye observation, when most of the agricultural materials on the inclined plane slide down, the mobile phone is used to control the motor to pause and the panel remains in this position. The agricultural materials will slide into the collection box. The angle of the inclined plane is calculated by the number of pulses emitted by the motor, and the static friction coefficient value is further obtained. However, this measurement method requires waiting until most of the agricultural materials have fallen to measure the slope angle, so that the angles of the agricultural materials that have fallen successively before the measurement angle is determined are not taken into account, and therefore this measurement is not accurate.

[0004] The Chinese invention patent application discloses an automatic detection test device and method for the static friction coefficient of crop grains, with publication number CN 114659976 A and publication date 2022.06.24. The device places the crop grains to be tested on the material to be tested, and adjusts the installation position of the through-beam laser sensor according to the outer dimensions of the crop grains to ensure that the initial position of the crop grains to be tested is placed in a straight line with the through-beam laser sensor; when the placement position of the crop grains to be tested is correct, that is, the through-beam laser sensor signal is blocked by the crop grains to be tested, the green indicator light of the control box lights up, indicating that the test preparation work is completed and the test can be carried out. The operator clicks the start test button on the touch screen, and the DC brushless motor starts to drive the test platform to maintain a low-speed and stable rotation. When the test platform rotates to a certain angle, the crop grains to be tested begin to slide, and the through-beam laser sensor is disconnected and turned off. When the test platform stops rotating, the angle measured by the single-turn absolute encoder is the rotation angle of the test platform, that is, the static friction angle α of the tested crop grains. This measurement method can only measure one crop grain at a time. When it is necessary to measure a batch or a type of crop grains, measuring only one grain cannot represent the friction angle of most crops. If hundreds of grains are sampled and the average value is calculated, although the static friction angle of the batch can be reflected to a certain extent, the efficiency of the device for measuring grain by grain is very low.

[0005] In 2009, Cheng Hongsheng, Li Changyou and others conducted an experimental study on the friction coefficient of litchi shells [Cheng Hongsheng, Li Changyou, Bao Yanhua, et al. Experimental study on the measurement of friction coefficient of litchi shells [J]. Journal of Agricultural Sciences of Yanbian University, 2009, 31(3):5. DOI:10.3969 / j.issn.1004-7999.2009.03.012]. Based on Newton's second law, they designed an automatic measurement device for the friction coefficient of agricultural materials. The static friction coefficient measurement process is to slowly lift the inclined plate by hand until the litchi shell slides down, and read and record the inclination angle of the inclined plane from the angle disk on the side frame; the dynamic friction coefficient is measured by the sensors arranged in sequence on the inclined plane to detect the time required for the litchi shell to slide along the inclined plane, calculate the acceleration of the litchi shell sliding down, and then calculate the dynamic friction coefficient value of the litchi shell, and conduct experiments through the device. However, the static friction test is to change the angle manually and judge the sliding by naked eye, so the accuracy is low.

[0006] From the above background technology, it can be known that the existing dynamic friction and static friction devices are mostly independently studied or independently set up devices, and the test accuracy is low or one by one is measured to improve the test accuracy, which leads to low efficiency. Summary of the invention

[0007] The purpose of the present invention is to provide a grain friction coefficient measuring device and a measuring method thereof, which uses a sensor to judge the grain drop and controls the tilt angle during static friction measurement through the sensor signal, has high accuracy, and measures multiple grains that have fallen multiple times, has high measurement efficiency, and can continuously measure the static and dynamic friction coefficients of the same sampling batch. This measurement method weights the different falling angles and quantities of multiple grains sampled at one time to calculate the average angle, which is closer to a comprehensive overall static friction test.

[0008] The technical solution of the present invention is:

[0009] A grain friction coefficient measuring device comprises a frame, and further comprises:

[0010] The static friction measuring platform is composed of a load-bearing inclined plane, a static friction measuring inclined plane fixedly attached to the load-bearing inclined plane, and first photoelectric opposing switches on both sides of the static friction measuring inclined plane where the material is placed. The bottom of the middle part of the load-bearing inclined plane is connected to an inclined plane rotating shaft via a connecting piece, the inclined plane rotating shaft is rotatably connected to the frame, and the inclined plane rotating shaft is connected to a first stepper motor fixed to the frame via a first coupling;

[0011] A disc collecting bin mechanism, which is composed of a funnel placed at the lower end of the carrying inclined discharge surface for receiving the material dropped therefrom, a turntable collecting bin placed at the lower end of the funnel for receiving the material in the funnel, a collecting bin base at the bottom of the turntable collecting bin, a collecting bin rotating shaft rotatably connected to the frame, and a second stepper motor. A plurality of collecting bins that are transparent from top to bottom are evenly arranged in a circle on the turntable collecting bin. The collecting bin base is used to block the collecting bin and has a material discharge hole. The second stepper motor drives the turntable collecting bin to rotate relative to the collecting bin base via the collecting bin rotating shaft.

[0012] Single-grain feeding mechanism, which is used to receive the material output from the feeding hole and feed the material as a single grain;

[0013] The dynamic friction coefficient measuring mechanism is composed of an inclined support plate, a dynamic friction measuring inclined surface fixedly attached to the support plate, and a plurality of groups of second photoelectric opposing switches arranged at intervals along the length direction of the dynamic friction measuring inclined surface. Each group of second photoelectric opposing switches is arranged on the support plate on both sides of the width direction of the dynamic friction measuring inclined surface. The upper end of the dynamic friction measuring inclined surface is used to receive the material dropped from the single-grain feeding mechanism.

[0014] Preferably, an indicator line is provided on the static friction measurement inclined surface below the opposing laser line of the first photoelectric opposing switch.

[0015] Preferably, a baffle for blocking materials is fixed on the funnel.

[0016] Preferably, the single-grain feeding mechanism consists of a single-grain feeding bin, a single-grain feeding fixed sleeve and a single-grain feeding rotor. The single-grain feeding bin is used to receive materials output from the feeding hole. The single-grain feeding rotor is rotatably connected in the single-grain feeding fixed sleeve. A plurality of single-grain feeding grooves are evenly distributed on the circumferential surface of the single-grain feeding rotor. A channel connected to the single-grain feeding rotor is provided at the upper end of the single-grain feeding fixed sleeve. The channel is used to receive materials from the single-grain feeding bin and transport them to the single-grain feeding rotor. A scraper with one end abutting against the outer circumferential surface of the single-grain feeding rotor is fixed in the channel. A feeding hole is provided at the bottom of the single-grain feeding fixed sleeve.

[0017] Preferably, the lower end of the support plate of the dynamic friction coefficient measuring mechanism is rotatably connected to the frame, the back of the upper end of the support plate is connected to a support rod, arc-shaped adjustment holes are respectively opened on the frame on both sides of the width direction of the support plate, and external threads are respectively provided at both ends of the support rod and pass through the arc-shaped adjustment holes, and locking nuts are respectively screwed on the external threads at both ends of the arc-shaped adjustment holes.

[0018] Preferably, the lower end of the collecting bin rotating shaft passes through the collecting bin base and is rotatably connected to the collecting bin bearing seat via a bearing, the collecting bin bearing seat is fixed on the frame, and the upper end of the collecting bin rotating shaft is connected to the second stepper motor fixed on the frame via a second coupling.

[0019] Preferably, the single-grain feeding rotor is connected to the third stepping motor via the feeder shaft and the third coupling.

[0020] A method for measuring the friction coefficient of grain particles by the grain friction coefficient measuring device is characterized by comprising the following steps:

[0021] First, place the static friction measuring slope in a horizontal state, take a plurality of grains and place them in a row on one side of the first laser beam sensor of the static friction measuring slope;

[0022] Second, turn on the first stepper motor. Under the control of the single-chip microcomputer, the first stepper motor rotates with the static friction measuring inclined plane. When the first photoelectric shooting switch detects that there is material passing through, the first stepper motor stops rotating. At this time, the fallen material passes through the funnel along the static friction measuring inclined plane and falls into the collecting bin. After the first collecting bin receives the material, the second stepper motor rotates, driving the turntable collecting bin to rotate one station, turning away the collecting bin with material and turning the next empty collecting bin to the receiving station; then the first stepper motor continues to rotate, and when the first photoelectric shooting switch detects that there is material passing through, the first stepper motor stops rotating, and the fallen material enters the collecting bin. Then the second stepper motor rotates, driving the turntable collecting bin to rotate one station, turning away the collecting bin with material and turning the next empty collecting bin to the receiving station; then continue the above steps until all the granular materials on the static friction measuring inclined plane have fallen.

[0023] Third, the number of material particles in the multiple collection bins of the turntable collection bin is calculated and recorded;

[0024] Fourth, turn on the second stepper motor, first rotate the first collecting bin that receives the material to the discharge hole position, and then the material in the collecting bin falls from the discharge hole into the single-grain discharge mechanism, and the single-grain discharge mechanism discharges the material particles one by one onto the dynamic friction measurement slope of the dynamic friction coefficient measurement mechanism;

[0025] Fifth, the distances between multiple groups of second photoelectric counter-beam switches and the inclination angles of the dynamic friction measuring slope are measured in advance. Material particles fall on the dynamic friction measuring slope and are detected by multiple groups of second photoelectric counter-beam switches during the process. The time of passing through each group of second photoelectric counter-beam switches is recorded until the material particles received by the single unloading mechanism are unloaded;

[0026] Sixth, turn the second stepper motor again to discharge the second material receiving collection bin toward the lower hole, and then the single-grain discharge mechanism drops the material particles one by one onto the dynamic friction measurement slope until the material received by the single-grain discharge mechanism is discharged; repeat the above actions of the second stepper motor and the single-grain discharge mechanism until all the materials in the collection bin are emptied.

[0027] Preferably, for the calculation of the static friction coefficient, the pulses given by the single-chip microcomputer to the first stepper motor when the first stepper motor stops are read, and the tan value is calculated by calculating the angle of rotation of the static friction measurement inclined plane through the number of pulses. Then, the pulses when the first stepper motor stops each time are continuously read, and the tan value when the first stepper motor stops each time due to the first photoelectric beam switch detecting an object is calculated, that is, the static friction coefficient of the grain particles that fall each time. After the number of grain particles that fall each time and the static friction coefficient are determined, the number of grain particles that fall each time is multiplied by the corresponding friction coefficient to obtain the product, the products of multiple drops are added and divided by the total number of grain particles to obtain the average value of the static friction coefficient of the grain particles this time.

[0028] Preferably, for the calculation of the dynamic friction coefficient, at least two distances are calculated through multiple groups of sensors, the time to pass through the two distances is calculated according to the second photoelectric beam switch, the acceleration is calculated through the distance and the passing time, and then the corresponding dynamic friction coefficient is calculated through the acceleration and the slope angle.

[0029] Preferably, the amount of grains taken in the first step is 100-300 grains.

[0030] The discharge hole is located at the previous station of the collecting silo collecting station. The inclination angle of the support plate satisfies that the material can move freely on the dynamic friction measuring inclined plane. There are at least three groups of second photoelectric opposing switches, and preferably, four groups are provided. A collecting bucket for receiving fallen materials is provided on the frame at the lower end of the support plate of the dynamic friction measuring mechanism. The end of the turntable collecting silo facing away from the static friction measuring table is exposed to the outside, so that people can check the number of particles in each collecting silo. Edge guards are provided on both sides of the width direction of the static friction measuring inclined plane to prevent grains such as wheat from falling out.

[0031] The beneficial effects of the present invention are:

[0032] 1. The friction coefficient measuring device designed this time combines the advantages of previous measuring mechanisms, and has made structural innovations on its basis. Through the upper and lower layout, it realizes the measurement of dynamic and static friction coefficients on the same device. The turntable receives the falling materials, and the feeder feeds accurately, realizing the automatic transition from measuring the static friction coefficient of multiple particles to measuring the dynamic friction coefficient of a single particle. This simplifies the measurement process, improves the continuity of the measurement system, and increases the measurement speed. The device connects the stepper motor and the inclined plane shaft through a coupling. There is no need to calculate the transmission ratio. The inclined plane angle value is calculated by reading the number of pulses sent to the stepper motor by the single-chip microcomputer, and then the required static friction coefficient is calculated. The detection of material falling is replaced by a through-beam photoelectric switch, which improves the measurement accuracy.

[0033] 2. The present invention realizes the automatic conversion from the simultaneous measurement of the static friction coefficient of multiple grains to the measurement of the dynamic friction coefficient of a single grain by arranging a disc collecting bin structure and a single grain unloading mechanism between the static friction measurement and the dynamic friction measurement, thereby improving the continuity and efficiency of the measurement. The material particles falling at multiple angles are collected separately by the disc collecting bin, and the overall average value of the friction coefficient can be obtained by the number of particles falling each time and the value of the static friction coefficient. Multiple particles fall each time instead of just one, which greatly improves the measurement efficiency of the static friction coefficient, and the average value makes the overall friction condition of the grain particles more referenceable. The dynamic friction coefficient and the static friction coefficient of multiple materials in a single collection bin of the disc collecting bin can be obtained, providing useful data for the study of the dynamic and static friction coefficients. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying any creative work.

[0035] Figure 1 This is a main structural diagram of the present invention; Figure 2This is a perspective view of the present invention; Figure 3 This is a perspective view of the present invention from the second perspective; Figure 4 This is a three-dimensional view of the present invention; Figure 5 A three-dimensional diagram with the rack removed; Figure 6 The three-dimensional static friction measuring platform of the present invention Figure 1 ; Figure 7 The three-dimensional static friction measuring platform of the present invention Figure 2 ; Figure 8 The three-dimensional disk collection bin mechanism of the present invention Figure 1 ; Fig. 9 The three-dimensional disk collection bin mechanism of the present invention Figure 2 ; Fig.10 The rotary collecting bin and the collecting bin base of the present invention are connected in a three-dimensional manner. Figure 1 ; Fig.11 The rotary collecting bin and the collecting bin base of the present invention are connected in a three-dimensional manner. Figure 2 ; Fig.12 The three-dimensional single-grain feeding mechanism of the present invention Figure 1 ; Fig.13 The three-dimensional single-grain feeding mechanism of the present invention Figure 2 ; Fig.14 It is a cross-sectional view of the single-grain feeding mechanism of the present invention; Fig.15 It is a stereoscopic diagram of the fixed sleeve and the rotor for single-grain feeding of the present invention; Fig.16 A three-dimensional diagram of a dynamic friction coefficient measuring mechanism of the present invention; Fig.17 This is the force analysis diagram of the material being tested above the inclined plane; Fig.18 The schematic diagram of the arrangement of sensors along the inclined surface; Fig.19 This is a display diagram of the serial port input interface; Fig. 20 This is the flow chart of static friction coefficient measurement; Fig.21 This is the flow chart of the dynamic friction coefficient measurement; Fig. 22 Name the image for the dashboard button.

[0036] In the figure, wherein: rack 1;

[0037] Static friction measuring platform 2, carrying inclined plane 201, static friction measuring inclined plane 202, first photoelectric opposing switch 203, inclined plane rotating shaft 204, first coupling 205, first stepping motor 206, indicating line 207, connecting piece 208;

[0038] Disc collecting bin mechanism 3, funnel 301, rotating disc collecting bin 302, collecting bin base 303, collecting bin rotating shaft 304, second stepping motor 305, collecting bin 306, feeding hole 307, collecting bin bearing seat 308, second coupling 309, baffle 310;

[0039] Single-grain feeding mechanism 4, single-grain feeding bin 401, single-grain feeding fixed sleeve 402, single-grain feeding rotor 403, single-grain feeding trough 404, channel 405, scraper 406, feeding hole 407, feeding device rotating shaft 408, third coupling 409, third stepping motor 410;

[0040] Dynamic friction coefficient measuring mechanism 5, support plate 501, dynamic friction measuring inclined surface 502, second photoelectric opposing switch 503, support rod 504, arc-shaped adjustment hole 505, locking nut 506. Specific embodiments

[0041] The following will be combined with the attached embodiment of the present invention Figure 1-22 , the technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] Derivation of the static friction coefficient measurement formula:

[0043] The material being tested that is stationary on the inclined plane will be affected by the gravity G, the support force N perpendicular to the normal direction of the inclined plane, and the friction force F upward along the inclined plane, such as Fig.17 When the angle α is relatively small, the component of gravity parallel to the inclined plane is smaller than the friction force, and the material being measured remains stationary. As the angle α of the inclined plane increases, the gravity component is greater than the friction force, and the material being measured slides down the inclined plane. At the moment when the material being measured slides, its force condition can be derived from the following formula:

[0044] F=mgsinα (1.1)

[0045] N=mgcosα (1.2)

[0046] F is numerically the same as the component f of gravity along the slope, but in the opposite direction, so F = μN.

[0047] Derive the static friction coefficient:

[0048] μ s =F / N=mgsinα / mgcosα=tanα(1.3)

[0049] Derivation of the dynamic friction coefficient measurement formula:

[0050] According to Newton's second law of motion, when the material being tested slides freely along the inclined plane, it satisfies:

[0051] ma=mgsinα-μ k mgcosα(1.4)

[0052] Can be simplified to:

[0053] Analysis shows that: when the angle of the inclined plane is known, the dynamic friction coefficient of the material being measured can be obtained by simply obtaining the acceleration. To obtain the acceleration, Fig.18 As shown in the figure, when the material to be measured slides down any position above point A on the inclined plane, we assume that the speed passing through the first sensor arrangement point A is v0, the speed passing through the second point B is v1, the time it takes to slide through the distance AB is t1, the speed passing through point C is v2, and the time it takes to slide through point CD is t2. We derive the formula for calculating acceleration based on the kinematic equation:

[0054]

[0055] Combining the three equations in (1.5) we get:

[0056]

[0057] This experimental device is equipped with four sets of second photoelectric switches. The distances between the four sets of second photoelectric switches along the inclined plane are set to 0.15m, 0.22m, and 0.15m. Substituting the values ​​into formula 1.6, we get:

[0058]

[0059] Analysis shows that the only unknown quantity for calculating the acceleration is the time it takes for the object to pass through two of the four pairs of sensors. Substituting the acceleration a back into formula 1.4 yields:

[0060]

[0061] The formula derived in this way is conducive to direct single-chip microcomputer programming to achieve automatic detection of the device.

[0062] All moving parts in the present invention must achieve a certain position accuracy during the operation of the device, so a stepper motor is used for control. The stepper motor has low cost, relies on pulses to control the rotation angle, has no cumulative error, and has high rotation accuracy. The rotating shaft and the driving motor are both directly connected by a coupling. This connection method has high transmission accuracy, but it cannot increase the torque of the transmission system. The torque of the system is equal to the torque of the motor. The inclined surface of the static friction coefficient measurement part is relatively long. If the inclined surface rotating shaft 204 is fixed from the end of the inclined surface, the motor needs to have a very large torque, and the supporting inclined surface 201 needs to have a strong rigidity to ensure the reliable connection with the shaft, which will undoubtedly increase a lot of costs. Therefore, a central layout of the transmission shaft is adopted to balance most of the torque required during the rotation process, and only a small force is needed to drive the inclined surface to complete the rotation.

[0063] The design of the static friction inclined plane lifting mechanism in the present invention:

[0064] According to previous research results, there is too much human intervention in the process of measuring the static friction coefficient. For example, during the process of lifting the inclined plane, the gear transmission or the soft rope pulling, the gear gap will cause vibration during the transmission process. In the past, most experiments on angle measurement were read by a ruler. The scale of the ruler is mostly 1mm. The degree error of the human eye at different angles is about 1°. The grasp of the moment when the measured object slides is also observed by the human eye. The human reaction time is about 200 to 250 milliseconds. All the key steps of this measurement process have errors. The superposition of various errors will make the measurement results inaccurate. Reducing the factors of human intervention in the measurement process is the key to relatively accurate measurement results of the static friction coefficient. The accuracy of measurable reduction of human intervention can be improved through mechanical substitution. Observation of falling can be achieved by sensor detection. The response time of the photoelectric switch is as short as 0.5ms, which is 400 to 500 times higher than that of the human eye. The conventional method of reading the angle uses an angle sensor, but this usually requires a host computer to implement, which will undoubtedly increase the complexity of the control system and reduce the convenience of the equipment. Considering that if a stepper motor is used to control the rotation of the inclined plane, conventional transmission methods, whether belt drive or gear drive, will produce gaps or errors, and the problems encountered by traditional measurement methods have not been solved. Only by directly connecting the inclined plane shaft 204 through a coupling can the problem be solved, and such a drive and transmission method will also solve the angle measurement. By reading the number of pulses emitted during the control of the stepper motor through the single-chip microcomputer, the angle of the motor can be directly converted. There is no problem of transmission ratio here, so the angle measurement is easier to solve.

[0065] But such a design is not perfect. It will cause new problems. The inclined plane is composed of a bearing surface and a measuring surface. The design of the measuring surface material is expected to directly measure materials similar to the white cast iron on agricultural machinery equipment. Its weight is relatively large, and it can measure multiple materials to be measured. The number of materials to be measured is determined by the size of the measuring platform in the width direction (all materials can only be lined up in a row to ensure that they will not be blocked by other materials with a larger friction coefficient when sliding down the inclined plane). Therefore, the size of such a sliding platform cannot be controlled to be very small. As a result, the motor needs to have a large enough torque, the shaft needs to withstand a large torque, and the connecting piece 208 between the shaft and the inclined plane also needs to have sufficient strength, which increases the cost of the system hardware and the difficulty of hardware selection. Therefore, this problem is solved by changing the position of the rotating shaft and arranging the rotating shaft position to the geometric center of the inclined plane. This will balance the huge torque required during the rotation process. This is similar to the design of the counterweight block in the elevator, and the strength requirement of the shaft is also reduced.

[0066] An indication line 207 can be drawn on the static friction measurement slope 202 below the reflected laser line of the first photoelectric reflected switch 203. The indication line 207 is used to indicate the position of the laser line. When placing a row of wheat grains, they can be placed close to the indication line 207.

[0067] The static friction measuring platform 2 of the present invention is composed of a bearing inclined plane 201, a static friction measuring inclined plane 202 fixedly attached to the bearing inclined plane 201, and a first photoelectric corresponding switch 203 on both sides of the static friction measuring inclined plane 202 where the material is placed. The bottom of the middle part of the bearing inclined plane 201 is connected to an inclined plane rotating shaft 204 via a connecting piece 208, and the inclined plane rotating shaft 204 is rotatably connected to the frame 1. The inclined plane rotating shaft 204 is connected to a first stepper motor 206 fixed to the frame 1 via a first coupling 205.

[0068] The design of the turntable collecting bin 302 mechanism in the present invention is as follows:

[0069] In previous studies, there are few devices that can measure multiple grains of measured materials at the same time. Only in the automatic measurement system of friction coefficient based on parallel four-bar mechanism, its measurement accuracy is difficult to guarantee. It is mentioned that the pause button is pressed when most of the wheat is observed to fall. This most is difficult to define. If so, the wheat in the collection bin must be within a relatively wide angle range to ensure that most of it falls. Such measurement results have no reference value. However, this study has inspired my design. Using the idea of ​​limit, it is assumed that there are as many collection bins under the inclined plane as the measured objects on the inclined plane, and each bin only collects one measured object. Then each collection bin actually corresponds to an angle value, which can ensure the accuracy of the measurement results. However, according to preliminary experiments, in the process of measuring the static friction coefficient once, most of the wheat will slide down at almost the same angle, that is, most of the wheat friction coefficients will be similar. If the change value of the angle each time is controlled within the effective range of the experimental results, it can be achieved that one collection bin 306 can collect multiple measured objects with similar friction coefficients at the same time. Therefore, a turntable collection bin is designed, which is convenient for switching the collection bins by connecting to a stepper motor.

[0070] In order to facilitate the subsequent measurement of the dynamic friction coefficient, the rotating disc collection bin 302 adopts a hollow design, that is, the collection bin 306 is made transparent from top to bottom, and the collection bin base 303 is rotated to enable materials with the same static friction coefficient to fall into the single grain feeding mechanism 4 (the single grain feeding mechanism 4 will be described in detail below) at a fixed position, so as to improve the continuity of the device measurement process. The collection bin base 303 and the rotating disc collection bin 302 are rotated together, and the rotational cooperation can be that there is a certain gap between the two, but the gap cannot cross the grain to be measured. Of course, the collection bin base 303 and the rotating disc collection bin 302 can also contact each other, and the contact surface is made into a smooth plane to facilitate rotation between each other.

[0071] The rotating disc collecting bin 302 mechanism has two supporting side plates fixed on the frame 1, and the funnel 301 is fixedly connected between the two supporting side plates. The rotating disc collecting bin 302 is arranged below the funnel 301, and a plurality of collecting bins 306 that are transparent from top to bottom are evenly arranged on the circumference of the rotating disc collecting bin 302. The bottom of the rotating disc collecting bin 302 is blocked with a collecting bin base 303, and the collecting bin base 303 is fixed on the frame 1. A feeding hole 307 that is transparent from top to bottom is opened on the collecting bin base 303, and the feeding hole 307 is located at the previous station of the collecting bin 306 receiving station. The funnel 301 is used to receive the grain particles falling from the static friction measuring inclined surface 202, and the collecting bin 306 on the rotating disc collecting bin 302 is used to receive the grain particles output by the funnel 301. The rotating direction of the rotating disc collecting bin 302 is the direction in which the first collecting bin 306 that receives the material is away from the feeding hole 307. When the first collecting bin 306 rotates to the position of the discharge hole 307, the material is discharged from the discharge hole 307. A collecting bin rotating shaft is fixed to the central part of the rotating disk collecting bin 302, the lower end of which passes through the collecting bin base 303 and is rotatably connected to the collecting bin bearing seat 308 through the bearing, the collecting bin bearing seat 308 is fixed on the frame 1, and the upper end of the collecting bin rotating shaft 304 is connected to the second stepping motor 305 fixed on the frame 1 through the second coupling 309.

[0072] A baffle 310 for blocking materials is fixed on the funnel 301 . The baffle 310 may be U-shaped, with its opening facing the static friction measuring slope 202 , so as to block the falling materials and make them all fall into the funnel 301 .

[0073] The design of the single-grain feeding mechanism 4 in the present invention is as follows:

[0074] According to the dynamic friction coefficient measurement formula, the acceleration of the material needs to be measured. The acceleration measurement process cannot be interfered by other materials, so it is impossible to achieve simultaneous measurement of multiple particles. If it is necessary to measure the dynamic and static friction coefficients on the same device, only a single-particle feeding mechanism 4 can be developed to realize the transition from static friction coefficient measurement to dynamic friction coefficient measurement to complete the automatic measurement of dynamic friction coefficient.

[0075] The single-grain feeding mechanism 4 here has roughly the same function and structure as the seeding device in the seeding machine. Therefore, a feeding mechanism for wheat was trial-produced with reference to the structural design of the seeding device of the seeding machine. Since the properties of the grains to be tested are very different, the single-grain feeding mechanism 4 can only be developed for a specific object to be tested. It is difficult to solve the problem of poor versatility only through structural innovation. For the feeders for other grains, it is only necessary to replace the single-grain feeding rotor 403 with a different groove (single-grain feeding groove 404) structure. The installation is also very convenient. The single-grain feeding fixed sleeve 402 has a hole on one side. The rotating body can be removed by removing the axial fixation, and the same is true for installation. A special design is made in the shell part, and a scraper 406 is used to prevent two grains of wheat from entering one seed groove.

[0076] This mechanism is still controlled by the third stepper motor 410. The easy programming feature of the stepper motor reduces the control difficulty of the system and facilitates the automation of the entire system. The designed single-grain wheat feeding mechanism 4 has a total of 8 grooves (single-grain feeding grooves 404) in the circumferential direction, that is, every time the motor rotates 45 degrees, a grain of wheat will fall by gravity onto the dynamic friction coefficient measuring device at the discharge hole below.

[0077] The single-grain feeding mechanism 4 is composed of a single-grain feeding bin 401, a single-grain feeding fixed sleeve 402 and a single-grain feeding rotor 403. The single-grain feeding bin 401 is used to receive materials output from the feeding hole 307. The single-grain feeding rotor 403 is rotatably connected in the single-grain feeding fixed sleeve 402. A plurality of single-grain feeding grooves 404 are evenly distributed on the circumferential surface of the single-grain feeding rotor 403. A channel 405 connected to the single-grain feeding rotor 403 is formed at the upper end of the single-grain feeding fixed sleeve 402. The channel 405 is used to receive materials from the single-grain feeding bin 401 and transport them to the single-grain feeding rotor 403. A scraper 406 with one end abutting against the outer circumferential surface of the single-grain feeding rotor 403 is fixed in the channel 405. A feeding hole 407 is formed at the bottom of the single-grain feeding fixed sleeve 402. The single-grain feeding fixed sleeve 402 has a circular cavity, and the single-grain feeding rotor 403 rotates and fits in the cavity, and the two are slidably matched. The single-grain feeding rotor 403 rotates in the direction of the scraper 406, so that when there are more than two materials on a single-grain feeding trough 404, the material pressed on the upper part of the single-grain feeding trough 404 can be hung up by the scraper 406. The single-grain feeding trough 404 is designed not to fully accommodate two material particles at the same time. If there are two material particles placed in the trough, one of the material particles must protrude outward, which highlights the importance of the scraper 406. The material particles protruding outward can be scraped off, and only the material particles completely placed in the single-grain feeding trough 404 are retained. The opening of the channel 405 opened on the single-grain feeding fixed sleeve 402 is upward. The single-grain feeding rotor 403 is connected to the third stepping motor 410 through the feeder shaft 408 and the third coupling 409.

[0078] The design of the dynamic friction coefficient measuring mechanism 5 in the present invention is as follows:

[0079] The dynamic friction coefficient measuring device cooperates with the single-grain feeding mechanism 4. The material to be tested drops through the single-grain feeding mechanism 4 and automatically slides down the measuring slope due to gravity. Four pairs of sensors are arranged along the slope, such as Fig.18 As shown, S0 is set to 15cm, S1 is set to 22cm, and S2 is set to 15cm. When it is detected that there is material passing through, the time of passing through the two distances S0 and S2 is automatically calculated, and then the acceleration is obtained. The angle of the inclined plane is connected by a hinge and can move within a certain range, which is convenient for exploring experimental angles suitable for different measurement objects in future experiments.

[0080] The materials involved in agricultural machinery are diverse. One of the innovative points of the device is the ability to replace different test plates (static friction measurement bevel 202 and dynamic friction measurement bevel 502). The test plate can be fixed to the bottom plate below it (bearing bevel 201 or support plate 501) by screws. It can be the material directly used to make agricultural machinery in the grain field. In this way, the measurement can simulate different surface conditions in actual applications, so that the experimental results are closer to the actual situation. In the past, most of the tests conducted could not replace the test plate. The material of the measurement platform was the material of the test plate, which would increase the impact of accidental errors and systematic errors on the experimental results. The device is very convenient for replacing the test plate, so the advantage of the wide range of application of the device can be verified.

[0081] The dynamic friction coefficient measuring mechanism 5 is composed of an inclined support plate 501, a dynamic friction measuring inclined surface 502 fixedly attached to the support plate 501, and a plurality of groups of second photoelectric opposing switches 503 arranged at intervals along the length direction of the dynamic friction measuring inclined surface 502. Each group of second photoelectric opposing switches 503 is arranged on the support plate 501 on both sides of the width direction of the dynamic friction measuring inclined surface 502, and the upper end of the dynamic friction measuring inclined surface 502 is used to receive the material dropped by the single-grain feeding mechanism 4. The second photoelectric opposing switches 503, since each group of photoelectric opposing switches has two photoelectric components, and four groups are arranged in the length direction of the support plate 501, the four photoelectric components on the same side of the four groups can be fixed on a photoelectric switch fixing plate, and the photoelectric switch fixing plate is fixed on the support plate 501, so as to facilitate installation and overall change of the distance between the two photoelectric switch components that cooperate with each other.

[0082] The lower end of the support plate 501 of the dynamic friction measuring mechanism is rotatably connected to the frame 1, and the back of the upper end of the support plate 501 is connected to a support rod 504. Arc-shaped adjustment holes 505 are respectively opened on the frame 1 on both sides of the width direction of the support plate 501, and external threads are respectively provided at both ends of the support rod 504 and pass through the arc-shaped adjustment hole 505. Locking nuts 506 are respectively screwed on the external threads at both ends of the arc-shaped adjustment hole 505.

[0083] The lower end of the support plate 501 of the dynamic friction coefficient mechanism is tilted toward the static friction measurement mechanism, so that a V-shape is formed between the static friction plate and the dynamic friction plate.

[0084] The present invention is generally described as follows:

[0085] The device as a whole adopts a staggered upper and lower distribution layout, which minimizes the transportation of the measured material during the conversion from static friction coefficient measurement to dynamic friction coefficient measurement. During the rotation of the turntable collection bin 302, it will automatically enter the single-grain discharge bin 401 and wait for the measurement of the dynamic friction coefficient.

[0086] The overall control steps of the present invention are as follows:

[0087] (1) Power-on initialization, the inclined plane for measuring the static friction coefficient rotates until it hits the limit switch (a limit switch is set on the frame 1 so that the inclined plane stops when it rotates to the horizontal plane and touches the limit switch). At this time, the inclined plane is in a horizontal position (the motor number is here, and the abbreviations mentioned below are all abbreviations. The first stepper motor 206 (motor 1 in the figure) drives the static friction coefficient measuring inclined plane to rotate, the second stepper motor 305 (motor 2 in the figure) drives the turntable collection bin 302 to rotate, and the third stepper motor 410 (motor 3 in the figure) drives the single-grain feeding mechanism 4 to rotate). The second stepper motor 305 drives the lower turntable, and the sensor detects that the marked position is the initial position. The third stepper motor 410 drives the feeder to rotate to the marked position as the initial position (the two marked positions are protrusions on the top of the hardware, and the protrusions cooperate with the sensors at the corresponding positions to detect the positions of the corresponding components), and the sensor monitoring is turned on.

[0088] (2) Press the first start button, the system starts, and the first stepper motor 206 starts to run slowly and steadily. When the photoelectric switch on the inclined plane detects that there is material falling, the first stepper motor 206 stops rotating. The angle of the inclined plane (from the horizontal position to the moment when the photoelectric signal is detected) is calculated by the number of pulses sent to the first stepper motor 206, and the required data tan value is calculated, and the measurement results are printed out on the screen.

[0089] (3) Press the second button, the second stepper motor 305 rotates 18 degrees (the result here is calculated by the number of turntable collection bins 302: 360° / 20=18°), then the first stepper motor 206 rotates 1 degree (a delay is required here), and the OLED display screen displays the tan value measured after each rotation in real time.

[0090] (4) Press the second button again to repeat the previous process. This logic will continue until all materials have fallen off before the system is initialized again. Fig. 20 shown.

[0091] (5) Press the third control button of the third stepper motor 410, and the third stepper motor 410 rotates 45 degrees (the calculation result here is obtained from the eight feeding holes 307 on the single-grain feeding mechanism 4). The control logic of the third stepper motor 4103 is simple and there is no parallel motion with the other two motors.

[0092] (6) Until material falls below the single-grain unloading mechanism 4, the sensors arranged in sequence along the slope detect the material, and the controller automatically calculates the time it takes for the material to pass through two of the distances between the four sensors, and calculates the acceleration through the distance, and then calculates the required friction coefficient value through the acceleration and the slope angle (the slope angle here is input through the serial port after the system is initialized). The final calculated dynamic friction coefficient value will be displayed on the OLED screen. The dynamic friction coefficient measurement process is as follows: Fig.21 shown.

[0093] The following is a description of a specific experimental process for the present invention:

[0094] In order to verify the accuracy of the measurement data of the experimental device, this device uses wheat with different moisture contents as the experimental object, and conducts multiple groups of comparative experimental analysis on white cast iron plates and stainless steel plates. Through experiments, the relationship between the static and dynamic friction coefficients of grains and the single factor between the grain moisture content and the contact material is studied, and compared with the data measured in similar studies, the accuracy and stability of the device's measurement data are verified.

[0095] 1.1 Experimental Preparation

[0096] 1.1.1 Preparation of measurement samples

[0097] In order to obtain wheat with different moisture contents, we need to temper the wheat according to the agricultural industry standards. The initial moisture content of the experimental wheat used is 8.66%. To prepare wheat samples with six different moisture contents of 10%, 11%, 14%, 16%, 18%, and 20%, they are divided into two cases according to the standards:

[0098] (1) The target moisture content after tempering is increased by ≤4%. The required moisture content can be achieved by adding water once. The tempering time is 16 to 24 hours to balance the moisture content of each part of the sample, thereby obtaining consistent experimental results. The wheat with a moisture content of 10% or 11% to be prepared can be achieved by tempering once.

[0099] (2) The target moisture content after tempering is increased by >4%, which needs to be achieved through two temperings. According to the initial moisture content of the wheat, an appropriate amount of water is calculated and added to make the moisture content of the wheat reach 13.5% after the first tempering. The tempering time needs to be more than 48 hours. The second water addition makes the moisture content reach the target value. The experiment can be carried out after the second tempering time reaches 18 hours. The four moisture contents of 14%, 16%, 18% and 20% to be prepared need to be achieved through the second tempering.

[0100] The amount of water added for tempering wheat can be calculated according to the moisture adjustment table in the standard or calculated according to the formula. The amount of water added in the moisture adjustment table is the amount of water added from the initial moisture to the target moisture of 1000g wheat. The corresponding moisture content can be calculated by multiplying the actual weight of tempered wheat by the corresponding percentage. For details, please refer to the industry standard regulations; the formula for calculating the amount of water added is as follows, where x0 is the original moisture, x1 is the target moisture, and the unit is percentage; m is the mass of the sample, and the unit is gram:

[0101]

[0102] Using a moisture meter to measure the actual moisture content of wheat after tempering can better compare with the data measured in similar studies. After tempering, the actual moisture content of wheat was 9.97%, 10.95%, 13.92%, 16.04%, 18.07%, and 20.06%, respectively. The difference between the obtained values ​​and the ideal value was less than ±0.1%. Experiments based on this parameter will produce more accurate results.

[0103] 1.1.2 Other matters to be done before the experiment

[0104] Before the experiment begins, you need to prepare a notebook to record data, a laptop (with a serial port assistant pre-installed on the laptop), a USB to TTL module, a pair of tweezers, and several transparent plastic ziplock bags. Sample the wheat in advance before the experiment to determine the sample capacity. Sample wheat with different moisture contents separately and put them in ziplock bags immediately after sampling. The experiment is now ready.

[0105] 1.2 Carry out measurement experiments

[0106] 1.2.1 Experimental details

[0107] (1) Install the test board: In the same set of experiments, the test boards on the static friction coefficient measurement and dynamic friction coefficient measurement mechanisms should be made of the same material. The test board should be tightly fitted with the load-bearing plate after installation, and the test board (dynamic and static friction test inclined surface) should not be bent. The lower end surface of the test board should be fitted with the two limit screws at the end of the load-bearing plate to prevent the test board from sliding during the experiment and affecting the test results. The side end surface of the test board should be kept parallel to the side end surface of the load-bearing plate. After replacing the test board, the replaced test board should be placed horizontally on the lower floor of the device to prevent the measurement board from bending due to its own gravity when it is suspended in the air for a long time.

[0108] (2) Adjustment of the height of the photoelectric switch: Because different test boards are made of different materials, the appropriate thickness is also different. The photoelectric switch can only detect the passage of an object when the object blocks the infrared light. In the static friction coefficient measurement part, no matter what material it is, its thickness is within 2 mm due to weight restrictions, and it can be detected without adjusting the height of the photoelectric switch. The photoelectric switch fixing seat designed in the dynamic friction coefficient measurement part is height-adjustable (the freedom of the photoelectric switch in other directions is fixed). After each replacement of a test board of different thicknesses, the height of the photoelectric switch should be adjusted (the height can be adjusted by replacing the photoelectric switch fixing plate at the bottom of the photoelectric switch) so that it can sensitively detect the passing material. The sensitivity of the photoelectric switch can be tested in advance using the material to be tested, and the height of the photoelectric switch can be fixed after the test result is correct.

[0109] (3) Serial port input: Connect the laptop and the microcontroller through the USB to TTL module. After the system is powered on, press the reset button. The system will automatically drive the three motors to rotate to the initial position. Then the screen will prompt you to enter the angle information of the current dynamic friction coefficient measurement mechanism. We use the serial port assistant to send the current angle value to the microcontroller. Open the serial port assistant and first select the serial port number, then select the baud rate (the baud rate is 115200), click to open the serial port, select the sending mode as text mode, and enter the angle value in the sending area (the angle value must be entered in English mode, and 1 decimal place must be retained after the decimal point). Finally, click the send button to enter the angle value to the microcontroller. Fig.19 shown.

[0110] (4) Experimental operation: Place the wheat in front of the line drawn on the experimental board (this line is the beam path of the photoelectric switch, and the material to be tested will be detected by the photoelectric switch when it passes through this line). Use tweezers to place all the wheat in a straight line with the ventral groove facing downward, and press the start button K1 on the control panel (the distribution and naming of the control panel buttons are as follows). Fig. 22As shown in the figure, the inclined plane will automatically and steadily rise until the moment wheat passes through the sensor, and then stop when the wheat on the inclined plane slides down to the disc collection bin. Press button K5, and the disc collection bin will turn one grid first, and then the inclined plane will rise by 1 degree (the angle of the inclined plane rise here is adjustable between 0.5° and 1.5°), which can ensure that the wheat sliding down at different angles falls into different collection bins, and record the static friction coefficient of the wheat when it slides down and the number of wheat sliding down at the same angle. After all the wheat slides down, press the inclined plane reset button K2 to restore the inclined plane to a horizontal position, and then continue to place wheat on the inclined plane. Press the start button to repeat the above process to achieve continuous measurement.

[0111] After the disc collecting bin rotates one circle, wheat will fall into the storage bin for measuring the dynamic friction coefficient. Press button K6 and the single-grain feeding mechanism will rotate one grid. The feeding port of the mechanism is directly above and the discharging port is directly below. Therefore, no material falls during the first four presses. When the button is pressed for the fifth time, the material passes through the sensor arranged along the inclined surface. The microcontroller can automatically calculate the dynamic friction coefficient value of the material and print it on the screen. Press the button again to repeat the above process. The information on the screen will be updated in real time. Use a notebook to record the data measured each time.

Claims

1. A grain friction coefficient measuring device, comprising a frame (1), characterized in that: Also includes, A static friction measuring platform (2), the static friction measuring platform (2) comprising a load-bearing inclined plane (201), a static friction measuring inclined plane (202) fixedly attached to the load-bearing inclined plane (201), and first photoelectric opposing switches (203) on both sides of the material-placed end of the static friction measuring inclined plane (202); the bottom of the middle part of the load-bearing inclined plane (201) is connected to an inclined plane rotating shaft (204) via a connecting piece (208); the inclined plane rotating shaft (204) is rotatably connected to a frame (1); the inclined plane rotating shaft (204) is connected to a first stepper motor (206) fixed to the frame (1) via a first coupling (205); A disc collecting bin mechanism (3), the disc collecting bin mechanism (3) comprising a funnel (301) disposed at the lower end of the discharge of the supporting inclined surface (201) for receiving the material dropped therefrom, a rotating disc collecting bin (302) disposed at the lower end of the funnel (301) for receiving the material in the funnel (301), a collecting bin base (303) at the bottom of the rotating disc collecting bin (302), a collecting bin rotating shaft (304) rotatably connected to the frame (1), and a second stepping motor (305); a plurality of collecting bins (306) which are transparent from top to bottom are evenly arranged in a circle on the rotating disc collecting bin (302); the collecting bin base (303) is used to block the collecting bin (306) and has a material discharge hole (307); the second stepping motor (305) drives the rotating disc collecting bin (302) to rotate relative to the collecting bin base (303) via the collecting bin rotating shaft (304); A single-grain feeding mechanism (4), the single-grain feeding mechanism (4) is used to receive the material output from the feeding hole (307) and feed the material as a single grain; A dynamic friction coefficient measuring mechanism (5) is composed of an inclined support plate (501), a dynamic friction measuring inclined surface (502) fixedly attached to the support plate (501), and a plurality of groups of second photoelectric opposing switches (503) arranged at intervals along the length direction of the dynamic friction measuring inclined surface (502), each group of second photoelectric opposing switches (503) being arranged on the support plate (501) on both sides of the dynamic friction measuring inclined surface (502) in the width direction, and the upper end of the dynamic friction measuring inclined surface (502) is used to receive materials dropped by a single-grain feeding mechanism (4).

2. A grain friction coefficient measuring device according to claim 1, characterized in that: An indication line (207) is provided on the static friction measurement inclined surface (202) below the corresponding laser line of the first photoelectric corresponding switch (203).

3. A grain friction coefficient measuring device according to claim 1, characterized in that: A baffle (310) for blocking materials is fixed on the funnel (301).

4. A grain friction coefficient measuring device according to claim 1, characterized in that: The single-grain feeding mechanism (4) is composed of a single-grain feeding bin (401), a single-grain feeding fixed sleeve (402) and a single-grain feeding rotor (403). The single-grain feeding bin (401) is used to receive materials output from the feeding hole (307). The single-grain feeding rotor (403) is rotatably connected in the single-grain feeding fixed sleeve (402). A plurality of single-grain feeding grooves (404) are evenly spaced on the outer circumference of the single-grain feeding rotor (403). A channel (405) connected to the single-grain feeding rotor (403) is formed at the upper end of the single-grain feeding fixed sleeve (402). The channel (405) is used to receive materials from the single-grain feeding bin (401) and transport them to the single-grain feeding rotor (403). A scraper (406) with one end abutting against the outer circumferential surface of the single-grain feeding rotor (403) is fixed in the channel (405). A material discharge hole (407) is formed at the bottom of the single-grain feeding fixed sleeve (402).

5. A grain friction coefficient measuring device according to claim 1, characterized in that: The lower end of the support plate (501) of the dynamic friction coefficient measuring mechanism (5) is rotatably connected to the frame (1), the upper end of the support plate (501) is connected to a support rod (504) at its back, arc-shaped adjustment holes (505) are respectively opened on the frame (1) on both sides of the support plate (501) in the width direction, the two ends of the support rod (504) are respectively provided with external threads and pass through the arc-shaped adjustment holes (505), and locking nuts (506) are respectively screwed on the external threads at both ends of the arc-shaped adjustment holes (505).

6. A grain friction coefficient measuring device according to claim 1, characterized in that: The lower end of the collection bin rotating shaft (304) passes through the collection bin base (303) and is rotatably connected to the collection bin bearing seat (308) via a bearing. The collection bin bearing seat (308) is fixed on the frame (1). The upper end of the collection bin rotating shaft (304) is connected to a second stepping motor (305) fixed on the frame (1) via a second coupling (309).

7. A grain friction coefficient measuring device according to claim 4, characterized in that: The single-grain feeding rotor (403) is connected to the third stepping motor (410) via the feeding device rotating shaft (408) and the third coupling (409).

8. A method for measuring the friction coefficient of grains using the grain friction coefficient measuring device according to any one of claims 1 to 7, characterized in that: The following steps are involved: First, placing the static friction measuring inclined surface (202) in a horizontal state, taking a plurality of grains and placing them in a row at intervals on one side of a first laser beam sensor of the static friction measuring inclined surface (202); Second, the first stepper motor (206) is turned on. Under the control of the single chip microcomputer, the first stepper motor (206) rotates with the static friction measuring inclined plane (202). When the first photoelectric shooting switch detects that a material has passed, the first stepper motor (206) stops rotating. At this time, the fallen material passes through the funnel (301) along the static friction measuring inclined plane (202) and falls into the collecting bin (306). After the first collecting bin (306) receives the material, the second stepper motor (305) rotates, driving the turntable collecting bin (302) to rotate one station, and the collecting bin (306) with the material is turned away and the lower collecting bin (306) is moved away. An empty collecting bin (306) is transferred to the material receiving station; then the first stepper motor (206) continues to rotate, and when the first photoelectric beam switch detects that the material has passed, the first stepper motor (206) stops rotating, and the fallen material enters the collecting bin (306), and then the second stepper motor (305) rotates, driving the turntable collecting bin (302) to rotate one station, and the collecting bin (306) with material is transferred away and the next empty collecting bin (306) is transferred to the material receiving station; then the above steps are continued until all the granular materials on the static friction measurement inclined surface (202) have fallen. Third, the number of material particles in the plurality of collecting bins (306) of the rotating disk collecting bin (302) is calculated and recorded after the calculation; Fourth, turn on the second stepper motor (305), first rotate the first collecting bin (306) that receives the material to the position of the discharge hole (307), and then the material in the collecting bin (306) falls from the discharge hole (307) into the single-grain discharge mechanism (4), and the single-grain discharge mechanism discharges the material particles one by one onto the dynamic friction measuring inclined surface (502) of the dynamic friction coefficient measuring mechanism (5); Fifth, the distances between the multiple groups of second photoelectric counter-beam switches and the inclination angles of the dynamic friction measuring inclined plane (502) are measured in advance, and the material particles fall on the dynamic friction measuring inclined plane (502), and are detected by the multiple groups of second photoelectric counter-beam switches (503) during the process, and the time of passing through each group of second photoelectric counter-beam switches (503) is recorded until the material particles received by the single-particle unloading mechanism are unloaded; Sixth, the second stepper motor (305) is rotated again to discharge the second collecting bin (306) for receiving the material toward the lower hole, and then the single-grain discharge mechanism (4) drops the material particles one by one onto the dynamic friction measuring inclined surface (502) until the material received by the single-grain discharge mechanism (4) is discharged; the above actions of the second stepper motor (305) and the single-grain discharge mechanism (4) are repeated until the materials in all the collecting bins (306) are emptied.

9. The measuring method according to claim 8, characterized in that: For the calculation of the static friction coefficient, the pulses given by the single chip microcomputer to the first stepper motor (206) when the first stepper motor (206) stops are read, and the angle of rotation of the static friction measuring inclined plane (202) is calculated by the number of pulses to calculate the tan value. Then, the pulses when the first stepper motor (206) stops each time are continuously read, and the tan value when the first stepper motor (206) stops each time after the first photoelectric opposing switch (203) detects an object is calculated, that is, the static friction coefficient of the grain particles that fall each time. After the number of grain particles that fall each time and the static friction coefficient are determined, the number of grain particles that fall each time is multiplied by the corresponding friction coefficient to obtain a product, and the products of multiple falls are added and divided by the total number of grain particles to obtain the average static friction coefficient of the grain particles this time.

10. The measuring method according to claim 8, characterized in that: For the calculation of the dynamic friction coefficient, at least two distances are calculated by using multiple sets of sensors, the time to pass through the two distances is calculated according to the second photoelectric radiation switch (503), the acceleration is calculated by the distance and the passing time, and then the corresponding dynamic friction coefficient is calculated by the acceleration and the angle of the inclined plane.

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