An automatic control system and method for rice polishing brightness value

Abstract

This invention discloses an automatic control system for the brightness value of polished rice, including a rice polishing machine, a control cabinet, a quality analyzer, and a sampling mechanism. The rice polishing machine has a raw material inlet at the top and a discharge outlet at the bottom. The discharge outlet is connected to the inlet of an elevator via a chute. The discharge outlet of the elevator is connected to the sampling mechanism. The sampling mechanism is normally open and connected to the chute of the next process step. When sampling, the sampling mechanism is connected to the inlet of the quality analyzer. This invention, under a constant background light source, visually inspects evenly arranged rice to accurately measure the broken rice rate and brightness value of the sampled rice. It eliminates unstable human and environmental factors, facilitating accurate feedback data for calculation and control.

Description

Technical Field

[0001] This invention relates to the field of food processing, specifically to an automatic control system and method for the brightness value of polished rice. Background Technology

[0002] Traditional rice polishing involves an elevator feeding rice through a feed pipe into a rotating polishing drum. The pressure is adjusted and controlled by a pressure gate at the polishing chamber outlet. Higher polishing pressure results in more vigorous impact and more breakage after polishing; lower pressure results in gentler impact and less breakage, allowing the rice to undergo sufficient friction within the drum to remove surface bran. Simultaneously, water is sprayed evenly in a specific ratio, causing the starch on the rice grain surface to gelatinize, improving the rice's brightness and texture.

[0003] Brightness, or lightness, is the degree of lightness or darkness. It is calculated using the CIE (International Commission on Illumination) standard spectral brightness function and is a key concept in color science. It describes the human eye's response to different wavelengths of light, particularly brightness (or luminance). The CIE 1931 colorimetric system defines the spectral brightness function for a standard observer, which is the basis for calculating color brightness and represents the standard observer's relative brightness response to different wavelengths of light (380nm to 780nm).

[0004] In process control, the PID controller (also known as a PID regulator), which controls based on the proportional (P), integral (I), and derivative (D) of the deviation, is the most widely used type of automatic controller. It has advantages such as simple principle, ease of implementation, wide applicability, independent control parameters, and relatively simple parameter selection.

[0005] Traditionally, after rice is polished, workers need to take rice and observe its brightness with the naked eye. They then adjust the discharge pressure and water intake of the rice polishing machine according to their visual perception. However, the brightness of polished rice is affected by various factors such as ambient light and visual errors of different people, resulting in inconsistent brightness of rice polished by different people in different scenarios, which affects its appearance and taste.

[0006] Traditional rice polishing primarily tests whiteness. However, the essence of polishing is to change the lightness value (L) by gelatinizing the surface starch, making the rice surface appear crystal clear. At the same time, the color of rice is fixed during the growth process and cannot be changed by polishing. Some polishing machines combine visual inspection with other processes, but the high-power motor inside the polishing machine generates a large magnetic field and vibration, which affects the camera's image detection. In addition, it is difficult to perform fine-grained inspection on stacked rice to calculate accurate data.

[0007] The PID algorithm is only suitable for single-variable environments. For nonlinear and time-varying systems, the performance of the PID control algorithm may be poor, with obvious overshoot, significant oscillations, and stability issues. Summary of the Invention

[0008] The present invention addresses the shortcomings of the prior art by proposing an automatic control system and method for the polishing brightness value of rice, thus resolving the problems mentioned in the background art, such as the inability to calculate accurate data.

[0009] To achieve the above objectives, the present invention provides the following technical solution:

[0010] An automatic control system for rice polishing brightness value includes a rice polishing machine, a control cabinet, a quality analyzer, and a sampling mechanism. The rice polishing machine has a raw material inlet at the top and a discharge outlet at the bottom. The discharge outlet is connected to the inlet of an elevator via a chute. The discharge outlet of the elevator is connected to the sampling mechanism. In its normally open state, the sampling mechanism is connected to the chute of the next process. In its sampling action state, the sampling mechanism is connected to the inlet of the quality analyzer. The discharge outlet of the quality analyzer returns the material to the elevator and discharges it to the next process. A touch screen all-in-one machine is embedded in the front of the control cabinet.

[0011] As a further technical solution of the present invention: the rice polishing machine includes an atomizing nozzle, an electric proportional valve, a servo driver, a servo motor and a pressure gate; the control cabinet includes a touch screen all-in-one machine and a PLC; the quality analyzer includes an analyzer host, a relay board, a backlight, a vibrating feeder, a conveyor and a vision camera; and the sampling mechanism includes a solenoid valve, a cylinder and a flip plate.

[0012] As a further technical solution of the present invention: the control cabinet is equipped with a PLC, which is configured with a PLC analog output module. One output of the PLC analog output module controls the output pressure of the electro-proportional valve through analog signal control. The inlet end of the electro-proportional valve is connected to the water inlet end of the water pipe, and the outlet end of the electro-proportional valve is connected to the atomizing nozzle. The PLC controls the water pressure of the electro-proportional valve by adjusting the magnitude of the analog output current, thereby controlling the water volume sprayed by the atomizing nozzle. The other output of the PLC analog output module controls the discharge pressure gate through a servo system. The servo driver of the servo system is set to the torque mode controlled by analog current through parameter settings. The servo motor is connected and fixed to the pressure gate at the discharge port through a vertical axis reducer and a coupling. The PLC controls the pressure of the pressure gate by adjusting the magnitude of the analog output current.

[0013] As a further technical solution of the present invention: the PLC network port in the control cabinet is connected to the network port of the analyzer host through a switch. The analyzer host controls the relay board, vibrating feeder, conveyor and vision camera respectively through the 485 bus. The relay board controls the backlight and the solenoid valve of the sampling mechanism through relays. The solenoid valve of the sampling mechanism controls the cylinder. The air rod controls the flip-plate action through the linkage mechanism. The PLC network port in the control cabinet is connected to the touch screen all-in-one machine through a switch. The touch screen all-in-one machine collects PLC data through communication, organizes and summarizes it through the database, and at the same time serves as a human-machine interface for equipment control and parameter viewing.

[0014] As a further technical solution of the present invention: the touch screen all-in-one machine is equipped with customized control software as the host computer of the PLC. The PLC collects the quality data detected by the quality analyzer in a cycle and the control data under the same time, and transmits them to the touch screen all-in-one machine in real time through the communication protocol.

[0015] As a further technical solution of the present invention: the touch screen all-in-one machine summarizes historical data into a database and displays it on the touch screen all-in-one machine interface. The touch screen all-in-one machine interface is provided with a manual / automatic switching button and a switching interface, which is used to select manual adjustment or automatic algorithm adjustment.

[0016] As a further technical solution of the present invention: the PLC controls the quality analyzer and the rice polishing machine through communication control and switching, and maps the control signals to the host computer software of the touch screen all-in-one machine through communication.

[0017] An automatic control method for the brightness value of polished rice, employing the aforementioned system, is as follows: Raw rice enters the rice polishing machine through the feed inlet. After polishing, the rice is conveyed to the next process by an elevator. The quality analyzer controls the sampling mechanism, causing the sampling mechanism's flap to rotate, allowing some rice to fall into the quality analyzer's vibrating feeder. Subsequently, the sampling mechanism's flap resets, and the vibrating feeder evenly shakes the sampled rice onto one end of the conveyor belt. As the flat rice is conveyed along the conveyor belt, a vision camera takes pictures under a standard background light source. The other end of the conveyor belt returns the rice to the feed pipe and back to the elevator, then discharges it to the next process. The rice detected by the vision camera in the quality analyzer is converted into image signals and transmitted to the image processing system of the analyzer's host. Based on pixel distribution, brightness, and color information, it is converted into digital signals. The image processing system performs calculations on these signals to extract the target's size and color features. The size feature represents the broken rice condition, and the color feature is obtained as an RGB image. Each pixel is composed of three components: red, green, and blue. The brightness value L is calculated using RGB color grading. The quality analyzer uses a sampling mechanism to cyclically sample and detect the data. The analyzer's main unit transmits the detected broken rice rate and brightness value L data to the PLC via a communication protocol. Operators use a touchscreen interface to set the desired brightness value and broken rice rate to the PLC, and also set upper and lower limits for automatic adjustment. The PLC controls the brightness value and broken rice rate, setting target values ​​for brightness and broken rice rate based on the type and quality of the rice. The difference between the brightness value detected by the quality analyzer and the value of the lightness value is used as the e(t) parameter of the self-tuning PID algorithm. The proportional coefficient Kp, integral coefficient Ki, and derivative coefficient Kd are used to adjust the output value u(t) through the self-tuning system. At the same time, the difference in the broken rice rate is used as the feedforward control to adjust the weight of the pressure gate, and finally the actual values ​​of brightness and broken rice rate are obtained. Meanwhile, the brightness detection feedback value continues to be used as the closed-loop feedback control of the water inflow, and the broken rice rate detection feedback value is used as the feedforward control of the pressure gate weight, which indirectly affects the brightness value and broken rice rate.

[0018] As a further technical solution of the present invention: the formula for calculating the brightness value L is:

[0019] L = (2.2 times)√[(R / 255)^2.2 + (1.5G / 255)^2.2 + (0.6B / 255)^2.2] / (1 + 1.5^2.2 + 0.6^2.2)].

[0020] As a further technical solution of the present invention: the PLC adopts a feedforward control algorithm based on a self-tuning PID algorithm to control the brightness value and broken rice rate. The formula of the PID algorithm is:

[0021] u(t)=Kp*e(t)+Ki*∫e(t)dt+Kd*de(t) / dt

[0022] Where e(t) is the difference between the feedback signal and the desired signal, that is, the difference between the set brightness target value and the brightness value detected by the quality analyzer, ∫e(t)dt is the integral of e(t), de(t) / dt is the derivative of e(t), which is automatically adjusted by the system self-tuning algorithm, and u(t) is the output value, that is, the amount of water entering the system.

[0023] Compared with the prior art, the beneficial effects of the present invention are:

[0024] This application uses visual inspection under a constant background light source to accurately measure the broken rice rate and brightness value of evenly placed rice samples, eliminating unstable human and environmental factors and facilitating the use of accurate feedback data for calculation and control.

[0025] This application can accurately represent the polishing effect of rice by detecting its brightness, and thus ensure the stability of rice quality through algorithmic control.

[0026] The feedforward PID control algorithm in this application calculates a control quantity by comparing the difference between the target value and the actual value, and then outputs it to the controlled object for control. Feedforward control can reduce system overshoot, shorten response time, and make the system more stable.

[0027] The separate placement of the quality analyzer and the rice polisher in this application can effectively reduce the electromagnetic interference and vibration impact of the high-power motor on the quality analyzer.

[0028] The touch screen all-in-one machine of this application can be placed in the control room via an extension cable. As a human-machine interface, the touch screen all-in-one machine can facilitate staff to operate the rice polishing machine and quality analyzer, and view real-time and historical data. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the structure of the present invention;

[0030] Figure 2 This is a system schematic diagram of the present invention;

[0031] Figure 3 This is a diagram of the control algorithm architecture of the present invention.

[0032] In the diagram: 1-Raw material inlet, 2-Elevator, 3-Sampling mechanism, 4-Rice polishing machine, 5-Discharge outlet, 6-Control cabinet, 7-Quality analyzer. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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 are within the scope of protection of the present invention.

[0034] like Figure 1-3 As shown, this invention discloses an automatic control system for the brightness value of polished rice. The system consists of a control cabinet 6, a quality analyzer 7, a rice polishing machine 4, an elevator 2, and a sampling mechanism 3. The rice polishing machine 4 has a raw material inlet at the top and a discharge outlet at the bottom. The discharge outlet is connected to the inlet of the elevator 2 via a chute. The discharge outlet of the elevator 2 is connected to the sampling mechanism 3. The sampling mechanism 3 is normally open and connected to the chute of the next process. When the sampling mechanism 3 is in sampling action, it is connected to the inlet of the quality analyzer 7. The discharge outlet of the quality analyzer 7 returns the material to the elevator 2 and discharges it to the next process.

[0035] A touch screen all-in-one machine is embedded in the hollowed-out front of the control cabinet 6. Inside the control cabinet 6 is a PLC equipped with an analog output module. One output of the PLC analog output module controls the output pressure of an electro-proportional valve via analog signals. The inlet of the electro-proportional valve is connected to the water inlet of the water pipe, and the outlet of the electro-proportional valve is connected to the atomizing nozzle. The PLC controls the water pressure of the electro-proportional valve by adjusting the magnitude of the analog output current, thereby controlling the water volume sprayed by the atomizing nozzle. The other output of the PLC analog output module controls the discharge pressure gate via a servo system. The servo driver of the servo system is set to torque mode controlled by analog current through parameter settings. The servo motor is connected and fixed to the pressure gate at the discharge port via a vertical axis reducer and coupling. The PLC controls the pressure of the pressure gate by adjusting the magnitude of the analog output current.

[0036] The PLC network port in control cabinet 6 is connected to the network port of the analyzer host via a switch. The analyzer host controls the relay board, vibrating feeder, conveyor, and vision camera via a 485 bus. The relay board controls the backlight and the solenoid valve of the sampling mechanism via relays. The solenoid valve of the sampling mechanism controls the cylinder, and the cylinder rod controls the flapping action via a linkage mechanism.

[0037] The PLC network port in control cabinet 6 is connected to the touch screen all-in-one machine via a switch. The touch screen all-in-one machine collects PLC data through communication, organizes and summarizes it through a database, and also serves as a human-machine interface to facilitate staff to control the equipment and view parameters.

[0038] The working principle is as follows:

[0039] During production, rice raw materials enter the rice polishing machine through the feed inlet. After polishing, the rice is conveyed to the next process by an elevator. The quality analyzer controls the sampling mechanism, causing the flip plate of the sampling mechanism to rotate, allowing some rice to fall into the vibrating feeder of the quality analyzer. Then, the flip plate of the sampling mechanism resets. The vibrating feeder evenly shakes the sampled rice onto one end of the conveyor belt. As the flat rice is conveyed along the conveyor belt, a vision camera takes pictures under the standard light source of the background light. The other end of the conveyor belt sends the rice back to the feed pipe and back to the elevator, and then it is discharged to the next process.

[0040] In the quality analyzer, the visual camera converts the rice being inspected into image signals, which are then transmitted to the analyzer's main unit's image processing system. Based on pixel distribution, brightness, color, and other information, these signals are converted into digital signals. The image processing system then processes these signals to extract the target's size and color features. The size feature represents the broken rice grains, and the color feature is captured as an RGB image. Each pixel consists of three components: red, green, and blue. The brightness (L) is then calculated using the RGB colors.

[0041] RGB brightness (L) calculation formula:

[0042] L = (2.2 times)√[(R / 255)^2.2 + (1.5G / 255)^2.2 + (0.6B / 255)^2.2] / (1 + 1.5^2.2 + 0.6^2.2)]

[0043] The quality analyzer uses a sampling mechanism to cyclically sample and test the rice. The analyzer host transmits the detected broken rice rate and brightness value L to the PLC via a communication protocol. The operator sets the desired brightness value and broken rice rate to the PLC via a touch screen all-in-one machine, and sets the upper and lower limits for automatic adjustment. The PLC uses a feedforward control algorithm based on a self-tuning PID algorithm to control the brightness value and broken rice rate.

[0044] The formula for the PID algorithm is: u(t)=Kp*e(t)+Ki*∫e(t)dt+Kd*de(t) / dt

[0045] Where e(t) represents the difference between the feedback signal and the desired signal, that is, the difference between the set brightness target value and the brightness value detected by the quality analyzer.

[0046] ∫e(t)dt is the integral of e(t).

[0047] de(t) / dt is the differential of e(t).

[0048] Kp, Ki, and Kd are the proportional, integral, and derivative coefficients, which are automatically adjusted by the system's self-tuning algorithm.

[0049] u(t) is the output value, i.e. the amount of water entering the system.

[0050] Based on the type and quality of rice, target values ​​for brightness and broken rice rate are set. The difference between the target brightness value and the brightness value detected by the quality analyzer is used as the e(t) parameter of the self-tuning PID algorithm. Kp, Ki, and Kd adjust the output value u(t) through the self-tuning system. At the same time, the difference in broken rice rate is used as feedforward control to adjust the weight of the pressure gate, and finally the actual values ​​of brightness and broken rice rate are obtained. Meanwhile, the brightness detection feedback value continues to be used as closed-loop feedback to control the water intake, and the broken rice rate detection feedback value is used as feedforward to control the weight of the pressure gate, which indirectly affects the brightness value and broken rice rate.

[0051] The touch screen all-in-one machine, acting as the host computer of the PLC, is equipped with customized control software. The PLC collects quality data from the quality analyzer's cyclic detection and control data from the same time period, and transmits it to the touch screen all-in-one machine in real time via a communication protocol. The touch screen all-in-one machine summarizes the data into historical reports through a database and displays them on the touch screen all-in-one machine interface. The touch screen all-in-one machine interface has a manual / automatic switching button and a switching interface, which can be used to select manual adjustment or automatic algorithm adjustment.

[0052] The PLC controls the quality analyzer and rice polishing machine via communication control and switching, and maps the control signals to the host computer software of the touch screen all-in-one machine. The staff can operate the quality analyzer and rice polishing machine through the touch screen all-in-one machine.

[0053] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0054] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment includes only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. An automatic control system for the brightness value of polished rice, comprising a rice polishing machine, a control cabinet, a quality analyzer, and a sampling mechanism, characterized in that, The rice polishing machine has a raw material inlet at the top and a discharge outlet at the bottom. The discharge outlet is connected to the inlet of the elevator via a chute. The discharge outlet of the elevator is connected to a sampling mechanism. The sampling mechanism is normally open and connected to the chute of the next process. When the sampling mechanism is in sampling action mode, it is connected to the inlet of the quality analyzer. The discharge outlet of the quality analyzer returns the material to the elevator and discharges it to the next process. A touch screen all-in-one machine is embedded in the front of the control cabinet. The rice polishing machine includes an atomizing nozzle, an electric proportional valve, a servo driver, a servo motor, and a pressure gate; the control cabinet includes a touch screen all-in-one machine and a PLC; the quality analyzer includes an analyzer host, a relay board, a backlight, a vibrating feeder, a conveyor, and a vision camera; and the sampling mechanism includes a solenoid valve, a cylinder, and a flip plate. The integrated control cabinet contains a PLC, which is equipped with a PLC analog output module. One output of the PLC analog output module controls the output pressure of an electro-proportional valve via analog signals. The inlet of the electro-proportional valve is connected to the water inlet of the water pipe, and the outlet of the electro-proportional valve is connected to the atomizing nozzle. The PLC controls the water pressure of the electro-proportional valve by adjusting the magnitude of the analog output current, thereby controlling the water volume sprayed by the atomizing nozzle. The other output of the PLC analog output module controls the pressure gate through a servo system. The servo driver of the servo system is set to torque mode controlled by analog current through parameter settings. The servo motor is connected and fixed to the pressure gate at the discharge port through a vertical axis reducer and a coupling. The PLC controls the pressure of the pressure gate by adjusting the magnitude of the analog output current. The PLC network port in the integrated control cabinet is connected to the network port of the analyzer host via a switch. The analyzer host controls the relay board, vibrating feeder, conveyor, and vision camera via a 485 bus. The relay board controls the backlight and the solenoid valve of the sampling mechanism via relays. The solenoid valve of the sampling mechanism controls the cylinder. The air rod controls the flip-plate action via a linkage mechanism. The PLC network port in the integrated control cabinet is connected to the touch screen all-in-one machine via a switch. The touch screen all-in-one machine collects PLC data through communication, organizes and summarizes it through a database, and also serves as a human-machine interface for equipment control and parameter viewing.

2. The automatic control system for rice polishing brightness value according to claim 1, characterized in that, The touch screen all-in-one machine, acting as the host computer of the PLC, is equipped with customized control software. The PLC collects quality data from the quality analyzer's cyclic detection and control data from the same time period, and transmits them to the touch screen all-in-one machine in real time via a communication protocol.

3. The automatic control system for rice polishing brightness value according to claim 1, characterized in that, The touch screen all-in-one machine aggregates historical data into reports through a database and displays them on the touch screen all-in-one machine interface. The touch screen all-in-one machine interface has a manual / automatic switching button and a switching interface, which can be used to select manual adjustment or automatic algorithm adjustment.

4. The automatic control system for rice polishing brightness value according to claim 1, characterized in that, The PLC controls the quality analyzer and rice polishing machine via communication control and switching, and maps the control signals to the host computer software of the touch screen all-in-one machine via communication.

5. A method for automatically controlling the brightness value of polished rice, characterized in that, The system according to any one of claims 1-4 is implemented as follows: Rice raw material enters the rice polishing machine through the feed inlet. After polishing, the rice is conveyed to the next process by an elevator. The quality analyzer controls the sampling mechanism, causing the flip plate of the sampling mechanism to rotate, allowing some rice to fall into the vibrating feeder of the quality analyzer. Subsequently, the flip plate of the sampling mechanism resets, and the vibrating feeder evenly shakes the sampled rice onto one end of the conveyor belt of the conveyor. During the conveying process of the flat rice, a vision camera takes pictures under the standard light source of the background light. The other end of the conveyor belt sends the rice back to the feed pipe and back to the elevator, and then discharges it to the next process. The rice detected by the vision camera in the quality analyzer is converted into image signals and transmitted to the image processing system of the analyzer host. Based on the pixel distribution, brightness, and color information, it is converted into digital signals. The image processing system performs calculations on these signals to extract the size and color features of the target. The size feature is the broken rice condition, and the color feature is an RGB image. Each pixel... The rice is composed of three components: red, green, and blue. The brightness value L is calculated using RGB color. The quality analyzer cyclically samples and detects the rice through a sampling mechanism. The analyzer host transmits the detected broken rice rate and brightness value L to the PLC via a communication protocol. The operator sets the desired brightness value and broken rice rate to the PLC through a touch screen all-in-one machine, and sets the upper and lower limits for automatic control. The PLC controls the brightness value and broken rice rate, setting target values ​​for brightness and broken rice rate based on the type and quality of the rice. The difference between the target brightness value and the brightness value detected by the quality analyzer is used as the e(t) parameter of the self-tuning PID algorithm. The proportional coefficient Kp, integral coefficient Ki, and derivative coefficient Kd adjust the output value u(t) through the self-tuning system. At the same time, the difference in broken rice rate is used as feedforward control to adjust the weight of the pressure gate, ultimately obtaining the actual values ​​of brightness and broken rice rate. Meanwhile, the brightness detection feedback value continues to be used as closed-loop feedback to control the amount of water entering the water, and the broken rice rate detection feedback value is used as feedforward control to control the weight of the pressure gate, indirectly affecting the brightness value and broken rice rate. The formula for calculating the brightness value L is: L = (2.2 times)√[(R / 255)^2.2 + (1.5G / 255)^2.2 + (0.6B / 255)^2.2] / (1 + 1.5^2.2 + 0.6^2.2)].

6. The automatic control method for the polishing brightness value of rice according to claim 5, characterized in that, The PLC uses a feedforward control algorithm based on a self-tuning PID algorithm to control the brightness value and broken rice rate. The formula for the PID algorithm is: u(t) = Kp * e(t) + Ki * ∫e(t)dt + Kd * de(t) / dt Where e(t) is the difference between the feedback signal and the desired signal, that is, the difference between the set brightness target value and the brightness value detected by the quality analyzer, ∫e(t)dt is the integral of e(t), de(t) / dt is the derivative of e(t), which is automatically adjusted by the system self-tuning algorithm, and u(t) is the output value, that is, the amount of water entering the system.

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