A control system and method for a belt conveyor based on fixed-point visual cross-section monitoring

Abstract

This invention discloses a control system and method for a belt conveyor based on fixed-point visual cross-section monitoring, relating to the field of material conveying technology. The system includes a belt conveyor body, a gantry support, a fixed-point visual probe, and a main control cabinet. The belt conveyor body comprises a frame and a conveyor belt mechanism. The conveyor belt mechanism is located at the upper end of the frame and is used to carry and convey bulk materials in a left-right direction. The upper ends of the frame located on the front and rear sides of the conveyor belt mechanism are respectively connected to the bottom ends of an inverted U-shaped gantry support. The fixed-point visual probe is fixedly installed at the center of the top crossbeam of the gantry support. The optical axis of the fixed-point visual probe's lens is vertically downward and aligned with the upper surface of the conveyor belt for data acquisition. The main control cabinet is installed on the frame below the conveyor belt mechanism and is used to receive the data from the fixed-point visual probe and control the output speed of the conveyor belt mechanism. This invention solves the problem of conveyor speed regulation.

Description

Technical Field

[0001] This invention relates to the field of material conveying technology, and specifically to a belt conveyor control system and method based on fixed-point visual cross-section monitoring. Background Technology

[0002] Belt conveyors are indispensable continuous transport equipment for bulk materials in heavy industries such as coal mines, ports, power generation, and metallurgy, and are known as the "main artery" of industrial production. In their long-term actual operation, due to the randomness and discontinuity of upstream mining, loading, or feeding links, the amount of material on the conveyor belt is often in a highly unstable dynamic fluctuation state, sometimes fully loaded, sometimes lightly loaded, and sometimes even empty for a long time due to coal shortage.

[0003] However, traditional belt conveyors typically operate at a constant speed, meaning the main drive motor runs at its rated maximum speed regardless of whether there is material on the belt. This "overpowered" approach not only wastes a lot of electrical energy but also causes significant ineffective friction and fatigue wear on mechanical transmission components such as the conveyor belt, idlers, and speed reducers, greatly shortening the equipment's lifespan and increasing the company's overall operating costs.

[0004] Currently, the most common method used in industrial settings is contact weighing via electronic belt scales, which then provide feedback to the frequency converter for speed control. However, the environments in mines and other similar locations are extremely harsh, with severe interference factors such as intense vibration, dust accumulation, and frequent changes in belt tension. Electronic belt scales are prone to zero-point drift, resulting in significant measurement errors. Furthermore, the mechanical structure of the belt scales is easily damaged by large pieces of coal gangue, requiring frequent shutdowns for manual recalibration. This leads to a substantial workload for subsequent maintenance and makes it impossible to meet the requirements for long-term, high-reliability automated operation.

[0005] Therefore, there is an urgent need for a belt conveyor control system and method based on fixed-point visual cross-section monitoring to solve the conveyor speed regulation problem. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a belt conveyor control system and method based on fixed-point visual cross-section monitoring to solve the conveyor speed regulation problem.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A belt conveyor control system based on fixed-point visual cross-section monitoring is characterized by comprising a belt conveyor body, a gantry support, a fixed-point visual probe, and a main control cabinet. The belt conveyor body includes a frame and a conveyor belt mechanism. The conveyor belt mechanism is located at the upper end of the frame and is used to carry and convey bulk materials in the left-right direction. The upper ends of the frame located on the front and rear sides of the conveyor belt mechanism are respectively connected to the bottom ends of the inverted U-shaped gantry support. The fixed-point visual probe is fixedly installed in the center of the top crossbeam of the gantry support. The optical axis of the fixed-point visual probe lens is vertically downward and aligned with the upper end face of the conveyor belt for data acquisition. The main control cabinet is installed on the frame below the conveyor belt mechanism and is used to receive the data from the fixed-point visual probe and control the output speed of the conveyor belt mechanism.

[0009] To optimize the above technical solution, the specific measures also include: Furthermore, the conveyor belt mechanism includes a variable frequency drive motor, a main drive roller, a driven roller, and a conveyor belt. The left and right sides of the upper end of the frame are respectively provided with a main drive roller and a driven roller sleeve that are parallel to each other and rotatable. The conveyor belt is sleeved on the main drive roller and the driven roller sleeve. The variable frequency drive motor is mounted on the frame and is used to connect to and drive the main drive roller to rotate, and the main drive roller drives the conveyor belt to move in the left and right direction.

[0010] Furthermore, the main control cabinet integrates a PLC controller and a frequency converter. The data output terminal of the fixed-point vision probe is connected to the communication port of the PLC controller, the power output terminal of the frequency converter is electrically connected to the variable frequency drive motor, and the control signal output terminal of the PLC controller is connected to the frequency converter for dynamically adjusting the motor speed of the variable frequency drive motor.

[0011] Furthermore, the main control cabinet also integrates an industrial Ethernet switch. The fixed-point vision probe transmits data to the PLC controller in real time via the industrial Ethernet protocol. The PLC controller sends the frequency command signal to the frequency converter via the fieldbus or analog interface.

[0012] Furthermore, a method applied to the above-mentioned belt conveyor control system based on fixed-point visual cross-section monitoring is characterized by comprising the following steps: When the conveyor belt mechanism is started under no-load for the first time, the fixed-point vision probe scans the empty conveyor belt in the absence of material and stores the obtained surface height matrix into the system as the bottom surface reference profile. Subsequently, during normal conveying operations, the fixed-point vision probe continuously scans downwards to acquire real-time surface height contour data of the material and sends the data to the main control cabinet. The main control cabinet performs a subtraction operation between the real-time acquired surface height profile data and the bottom reference profile to extract the actual net height of the material. It then performs discrete point integration or accumulation in conjunction with the system's preset effective width parameters of the conveyor belt to calculate the instantaneous true cross-sectional area of ​​the material at the current section. The main control cabinet has preset heavy load thresholds and no-load thresholds, and the heavy load threshold is greater than the no-load threshold. The calculated instantaneous material cross-sectional area is compared and judged in real time. Based on the judgment result, the corresponding control of the conveyor belt mechanism is to enter the 100% full load speed operation state, the energy-saving operation state of speed reduction, or the extremely low speed creeping standby operation state for automatic speed adjustment.

[0013] Furthermore, the step of controlling the conveyor belt mechanism according to the judgment result includes the following steps: When the instantaneous actual cross-sectional area of ​​the material is greater than or equal to the heavy load threshold, it is determined to be a heavy load state, and the main control cabinet controls the conveyor belt mechanism to run at 100% full load speed. When the instantaneous actual cross-sectional area of ​​the material is less than the heavy load threshold and greater than or equal to the no-load threshold, it is determined to be a light load state, and the main control cabinet controls the conveyor belt mechanism to operate in an energy-saving state with reduced speed. When the instantaneous actual cross-sectional area of ​​the material is less than the no-load threshold, it is determined to be in a no-load state, and the main control cabinet controls the conveyor belt mechanism to operate in a very low-speed creeping standby state.

[0014] Furthermore, it also includes the following steps: When the main control cabinet controls the conveyor belt mechanism to switch operating states, it calls the internal preset flexible acceleration and deceleration mechanism, and completes the linear and smooth switching of the output frequency within the preset smooth transition time according to the set acceleration and deceleration time constant.

[0015] Furthermore, it also includes the following steps: The main control cabinet system has built-in safety redundancy logic: if no valid contour data from the fixed-point vision probe is received within a preset period, the rated high frequency is output to drive the conveyor belt mechanism to enter a 100% full-load speed operation state to prevent material accumulation.

[0016] The beneficial effects of this invention are: This invention uses a non-contact fixed-point vision probe to directly acquire the cross-sectional area of ​​the material, and combines it with a simplified threshold grading logic to directly control the frequency converter, achieving the energy-saving effect of "high speed when there is a lot of material, low speed when there is little material, and extremely low speed standby when there is no material". The system has a simple structure, strong applicability to industrial sites, and high stability.

[0017] This invention uses a fixed three-dimensional vision probe for non-contact cross-sectional scanning, which is unaffected by conveyor belt tension fluctuations and mechanical vibrations, effectively reducing the daily maintenance workload on site, improving the reliability of material detection and reducing maintenance costs; and it does not change the original mechanical load-bearing body and main drive frame of the conveyor, making it suitable for rapid intelligent upgrades of existing traditional belt conveyors, with low engineering implementation costs and good on-site modification compatibility.

[0018] This invention adopts a control strategy of "area calculation + multi-level fixed threshold comparison", which has low algorithm load and can complete fast response with conventional PLC, thus ensuring the stability required by industrial field equipment.

[0019] This system acquires the cross-sectional area of ​​materials in real time through a vision probe and automatically controls the frequency converter to switch between rated high frequency, energy-saving medium frequency and sleep low frequency, avoiding the phenomenon of the conveyor being "oversized" and realizing on-demand output, effectively reducing the equipment's ineffective energy consumption.

[0020] When switching between different frequency gears, this invention uses the ramp function of the frequency converter to perform a smooth transition buffer, which reduces the transient physical strain on the conveyor belt, idlers, and reducer during acceleration and deceleration. This helps to extend the equipment overhaul cycle and avoids the problem of the conveyor frequently and drastically changing speeds to follow small fluctuations in the amount of material, which can easily lead to overheating of the main drive motor and uneven stress on the conveyor belt. It also reduces mechanical impact and extends the service life of the electromechanical equipment. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall structure of a belt conveyor control system based on fixed-point visual cross-section monitoring proposed in this invention; Figure 2 This is a schematic diagram illustrating the control principle of one of the methods proposed in this invention; Figure 3 This is a schematic diagram of the control flow of a method proposed in this invention.

[0022] Reference numerals in the attached diagram: 1. Belt conveyor body; 2. Gantry support; 3. Fixed-point vision probe; 4. Variable frequency drive motor; 5. Main control cabinet. Detailed Implementation

[0023] The technical solutions in 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.

[0024] As attached Figure 1As shown, an embodiment of the present invention discloses a belt conveyor control system based on fixed-point visual cross-section monitoring, comprising a belt conveyor body 1, a gantry support 2, a fixed-point visual probe 3, and a main control cabinet 5. The belt conveyor body 1 includes a frame and a conveyor belt mechanism. The conveyor belt mechanism is located at the upper end of the frame and is used to carry and convey bulk materials in the left-right direction. The upper ends of the frame located on the front and rear sides of the conveyor belt mechanism are respectively connected to the bottom ends of the inverted U-shaped gantry support 2. The fixed-point visual probe 3 is fixedly installed in the center of the top crossbeam of the gantry support 2. The optical axis of the lens of the fixed-point visual probe 3 is vertically downward and aligned with the upper end face of the conveyor belt for data acquisition. The main control cabinet 5 is installed on the frame below the conveyor belt mechanism and is used to receive the data from the fixed-point visual probe 3 and control the output speed of the conveyor belt mechanism.

[0025] In the above scheme, the installation height of the crossbeam of the gantry support 2 can be preset according to the field of view of the fixed-point vision probe 3, so that the downward scanning monitoring area of ​​the fixed-point vision probe 3 completely covers the effective load-bearing width of the conveyor belt, and ensures that the monitoring blind zone is located outside the two side edges of the conveyor belt. The fixed-point vision probe 3 can be used to acquire the three-dimensional surface contour data of the conveyor belt cross-section in real time. The gantry support 2 is fixedly installed above the conveyor belt mechanism in a straddle manner, and is preferably installed at a preset distance downstream of the receiving point to allow for speed adjustment response time.

[0026] In a specific embodiment based on the above, the conveyor belt mechanism includes a variable frequency drive motor 4, a main drive roller, a driven roller, and a conveyor belt. The left and right sides of the upper end of the frame are respectively provided with a main drive roller and a driven roller sleeve that are parallel to each other and rotatable. The conveyor belt is sleeved on the main drive roller and the driven roller sleeve. The variable frequency drive motor 4 is mounted on the frame and is used to connect to and drive the main drive roller to rotate, and the main drive roller drives the conveyor belt to move in the left and right directions.

[0027] In a further specific embodiment based on the above, the main control cabinet 5 integrates a PLC controller and a frequency converter. The data output terminal of the fixed-point vision probe 3 is connected to the communication port of the PLC controller. The power output terminal of the frequency converter is electrically connected to the variable frequency drive motor 4. The control signal output terminal of the PLC controller is connected to the frequency converter for dynamically adjusting the motor speed of the variable frequency drive motor 4.

[0028] In a further specific embodiment based on the above, the main control cabinet 5 also integrates an industrial Ethernet switch. The fixed-point vision probe 3 transmits the three-dimensional surface contour data to the PLC controller in real time via the industrial Ethernet protocol. The PLC controller sends the frequency command signal to the frequency converter through the fieldbus or analog interface.

[0029] As attached Figure 2 As shown, a method applied to the above-mentioned belt conveyor control system based on fixed-point visual cross-section monitoring includes the following steps: Step S1: No-load reference calibration and dynamic acquisition of cross-sectional profile: When the conveyor belt mechanism is started for the first time under no-load conditions, the fixed-point vision probe 3 scans the empty conveyor belt in the absence of material and stores the obtained surface height matrix into the system as the bottom reference profile. Subsequently, during normal conveying operations, the fixed-point vision probe 3 continuously scans downwards to acquire the surface height contour data of the material in real time, and sends the data to the PLC controller in the main control cabinet 5. Step S2: Subtraction and Instantaneous Area Calculation: The PLC controller in the main control cabinet 5 performs subtraction calculation between the real-time acquired surface height profile data and the bottom reference profile to extract the actual net height of the material. It then combines the system's preset effective width parameter of the conveyor belt with discrete point integration or accumulation to calculate the instantaneous true cross-sectional area of ​​the material at the current section. Step S3 Threshold Comparison and Speed ​​Adjustment: The PLC controller in the main control cabinet 5 has preset heavy load threshold and no-load threshold, and the heavy load threshold is greater than the no-load threshold. The calculated instantaneous material cross-sectional area is compared and judged in real time. Based on the judgment result, the corresponding control of the conveyor belt mechanism is to enter the 100% full load speed operation state, the energy-saving operation state of speed reduction, or the extremely low speed creeping standby operation state for automatic speed adjustment.

[0030] As attached Figure 3 As shown, the above-mentioned control of the conveyor belt mechanism based on the judgment result includes the following steps: When the instantaneous actual cross-sectional area of ​​the material is greater than or equal to the overload threshold, it is determined to be in an overload state. The PLC controller in the main control cabinet 5 then instructs the frequency converter to output the rated high frequency, controlling the frequency drive motor 4 of the conveyor belt mechanism to run at 100% full load speed. When the instantaneous actual cross-sectional area of ​​the material is less than the heavy load threshold and greater than or equal to the no-load threshold, it is determined to be a light load state. The PLC controller in the main control cabinet 5 then instructs the frequency converter to output energy-saving intermediate frequency, and controls the frequency conversion drive motor 4 of the conveyor belt mechanism to operate in an energy-saving state with reduced speed. When the instantaneous actual cross-sectional area of ​​the material is less than the no-load threshold, it is determined to be in no-load state. The PLC controller in the main control cabinet 5 then instructs the frequency converter to output a low-frequency sleep mode, controlling the frequency drive motor 4 of the conveyor belt mechanism to run in a very low-speed creeping standby state.

[0031] This also includes the following steps: Step S4 Smooth Transition and Disconnection Protection Control: When the main control cabinet 5 controls the switching of the conveyor belt mechanism, that is, after the frequency converter receives the frequency switching command issued by the PLC, it calls the internal preset flexible acceleration and deceleration mechanism. According to the set acceleration and deceleration time constant, it completes the linear smooth switching of the output frequency within the preset smooth transition time to reduce mechanical shock.

[0032] This also includes the following steps: The main control cabinet 5 system has built-in safety redundancy logic: if the PLC controller of the main control cabinet 5 does not receive valid contour data from the fixed-point vision probe 3 within a preset period, it will force the automatic speed regulation logic to be exceeded, and instruct the frequency converter to output the rated high frequency to drive the conveyor belt mechanism into a 100% full-load speed operation state to prevent material accumulation.

[0033] In the above scheme, after a single speed adjustment or protection action is completed, the system returns to the initial monitoring state and continues to perform cyclic monitoring.

[0034] One specific embodiment of the present invention is as follows: In specific industrial site setups, the gantry support 2 is fixed across the material receiving section of the belt conveyor body 1. A fixed-point vision probe 3 is fixedly installed in the center of the crossbeam of the gantry support 2, with the lens pointing vertically downwards to ensure its field of view completely covers the width of the entire conveyor belt. The variable frequency drive motor 4 is mechanically connected to the main drive roller, providing power. The main control cabinet 5, containing a PLC controller and a frequency converter, is placed in a safe position on the frame. The fixed-point vision probe 3 transmits data to the PLC controller in the main control cabinet 5 via a communication cable. The frequency converter in the main control cabinet 5 is connected to the variable frequency drive motor 4 via a power cable, forming a hardware closed loop.

[0035] The specific usage steps are as follows: The first step is system initialization: After the system is powered on, the conveyor belt mechanism is first run unloaded for one cycle. The fixed-point vision probe 3 scans and acquires the baseline contour data of the bottom surface of the empty belt and stores it. Then, the overload threshold is set in the PLC controller of the main control cabinet 5 in advance, for example, the cross-sectional area is set to 0.5 square meters, and the unload threshold is set, for example, the cross-sectional area is set to 0.1 square meters.

[0036] The second step is real-time monitoring and data acquisition: the fixed-point vision probe 3 continuously scans the three-dimensional surface contour of the coal flow passing below and sends the height and contour data to the PLC controller in real time; the PLC controller calculates the instantaneous cross-sectional area of ​​the coal on the belt based on the known belt width parameters.

[0037] The third step involves logical judgment and speed adjustment in different gears. The automatic speed adjustment logic is as follows: 1) If a large amount of coal is flowing in from upstream, the PLC controller determines the instantaneous cross-sectional area. If the area is 0.5 square meters, which is considered a heavy load, a full load command is sent to the frequency converter. The frequency converter outputs a high-frequency current of 50Hz, and the frequency converter drives the motor 4 to run at 100% of its rated speed to ensure that the coal does not accumulate. 2) If the coal flow rate is moderate, the PLC controller determines that the instantaneous cross-sectional area is between 0.1 and 0.5 square meters, which is a light load. Then, it sends an energy-saving command to the frequency converter, and the frequency converter outputs a 35Hz medium-frequency current. The frequency converter drives the motor 4 to run at a reduced speed to achieve the purpose of energy saving. 3) If the upstream coal supply stops, the PLC determines the instantaneous cross-sectional area. If the area is 0.1 square meters and is unloaded, a standby command is sent to the frequency converter. The frequency converter outputs a low-frequency current of 15Hz, and the frequency converter drives the motor 4 to creep at an extremely low speed, i.e., in a sleep standby state, to avoid high-speed dry friction of the belt and to save power to the maximum extent.

[0038] When switching between the aforementioned 50Hz, 35Hz, and 15Hz frequency ranges, a direct step-down output would result in a significant mechanical torque shock. Therefore, in this embodiment, the inverter internally activates a ramp function generator, setting the acceleration time constant to 5 seconds and the deceleration time constant to 8 seconds. For example, when the system decelerates from 50Hz to 15Hz, the output frequency will decrease linearly and slowly over 8 seconds, allowing the variable frequency drive motor 4 and its connected reducer to decelerate smoothly, effectively preventing the conveyor belt from tearing due to drastic changes in longitudinal tension.

[0039] In addition, this embodiment also incorporates a built-in safety redundancy protection mechanism: if the fixed-point vision probe 3 is obstructed by foreign objects, damaged, or the communication cable is accidentally disconnected, and the PLC controller does not receive valid contour data within 2 seconds, a communication loss alarm will be triggered. At this time, the PLC will forcibly exceed the above-mentioned automatic speed regulation logic and directly instruct the frequency converter to output the rated frequency of 50Hz, keeping the conveyor running at full speed to ensure production continuity based on the principle of "safety first, no material blockage." The energy-saving speed regulation mode will automatically resume after maintenance personnel have troubleshooted the fault.

[0040] After completing a full logical judgment and control output, the system seamlessly returns to the data acquisition status, realizing 24 / 7 unattended closed-loop energy control.

[0041] Compared to existing electronic belt scales used in belt conveyors for contact measurement, which are prone to zero-point drift in dusty and vibrating industrial environments and whose mechanical structures are easily damaged by impacts from large materials, requiring frequent manual calibration, this invention employs a fixed 3D vision probe for non-contact cross-sectional scanning. This method is unaffected by conveyor belt tension fluctuations and mechanical vibrations, effectively reducing daily maintenance workload, improving the reliability of material detection, and lowering maintenance costs.

[0042] Furthermore, some existing continuous stepless speed regulation schemes or complex image recognition models require high computing power from the host computer, and are prone to data delays or system crashes in environments with strong electromagnetic interference and large temperature variations. This invention employs a control strategy of "area calculation + multi-level fixed threshold comparison," which has a low algorithm load and can achieve millisecond-level response using a conventional PLC, ensuring the stability required by industrial field equipment.

[0043] Meanwhile, in response to the problem that traditional belt conveyors operate at a constant speed for a long time and waste a lot of electricity under light load and no-load conditions, this system uses a vision probe to obtain the cross-sectional area of ​​the material in real time and automatically controls the frequency converter to switch between rated high frequency, energy-saving medium frequency and sleep low frequency. This avoids the phenomenon of the conveyor being "overpowered" and achieves on-demand output, effectively reducing the equipment's ineffective energy consumption.

[0044] When switching between different frequency gears, this invention uses the ramp function of the frequency converter to perform a smooth transition buffer, which reduces the transient physical strain on the conveyor belt, idlers, and reducer during acceleration and deceleration. This helps to extend the equipment overhaul cycle and avoids the problem of the conveyor frequently and drastically changing speeds to follow small fluctuations in the amount of material, which can easily lead to overheating of the main drive motor and uneven stress on the conveyor belt. It also reduces mechanical impact and extends the service life of the electromechanical equipment.

[0045] The visual perception unit of this invention is independently installed above the conveyor belt using a gantry bracket 2. It does not change the original mechanical load-bearing body and main drive frame of the conveyor, making it suitable for rapid intelligent upgrades of existing traditional belt conveyors. The engineering implementation cost is low, and it has good compatibility with on-site modifications.

[0046] It should be noted that the terms such as "upper", "lower", "left", "right", "front", and "back" used in the invention are only for clarity of description and are not intended to limit the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention.

[0047] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0048] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that those skilled in the art will understand that various changes, modifications, substitutions, refinements, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and these variations should be considered within the scope of protection of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A belt conveyor control system based on fixed-point visual cross-sectional monitoring, characterized in that: The system includes a belt conveyor body (1), a gantry support (2), a fixed-point vision probe (3), and a main control cabinet (5). The belt conveyor body (1) includes a frame and a conveyor belt mechanism. The conveyor belt mechanism is located at the top of the frame and is used to carry and convey bulk materials in the left and right directions. The top of the frame located on the front and rear sides of the conveyor belt mechanism is connected to the bottom ends of the inverted U-shaped gantry support (2). The fixed-point vision probe (3) is fixedly installed in the center of the top beam of the gantry support (2). The optical axis of the lens of the fixed-point vision probe (3) is vertically downward aligned with the upper surface of the conveyor belt for data collection. The main control cabinet (5) is installed on the frame below the conveyor belt mechanism and is used to receive the data from the fixed-point vision probe (3) and control the output speed of the conveyor belt mechanism.

2. The belt conveyor control system based on fixed-point visual cross-section monitoring according to claim 1, characterized in that: The conveyor belt mechanism includes a variable frequency drive motor (4), a main drive roller, a driven roller and a conveyor belt. The left and right sides of the upper end of the frame are respectively provided with a main drive roller and a driven roller sleeve that are parallel to each other and rotatable. The conveyor belt is sleeved on the main drive roller and the driven roller sleeve. The variable frequency drive motor (4) is installed on the frame and is used to connect and drive the main drive roller to rotate, and the main drive roller drives the conveyor belt to move in the left and right directions.

3. A belt conveyor control system based on fixed-point visual cross-section monitoring according to claim 2, characterized in that: The main control cabinet (5) integrates a PLC controller and a frequency converter. The data output terminal of the fixed-point vision probe (3) is connected to the communication port of the PLC controller. The power output terminal of the frequency converter is electrically connected to the variable frequency drive motor (4). The control signal output terminal of the PLC controller is connected to the frequency converter to dynamically adjust the motor speed of the variable frequency drive motor (4).

4. A belt conveyor control system based on fixed-point visual cross-section monitoring according to claim 2, characterized in that: The main control cabinet (5) also integrates an industrial Ethernet switch. The fixed-point vision probe (3) transmits data to the PLC controller in real time via the industrial Ethernet protocol. The PLC controller sends the frequency command signal to the frequency converter via the fieldbus or analog interface.

5. A method applied to the belt conveyor control system based on fixed-point visual cross-section monitoring as described in any one of claims 1 to 4, characterized in that, Includes the following steps: When the conveyor belt mechanism is started without load for the first time, the fixed-point vision probe (3) scans the empty conveyor belt in the absence of material and stores the obtained surface height matrix into the system as the bottom reference profile. Subsequently, during normal conveying operations, the fixed-point vision probe (3) continuously scans downwards to acquire the surface height contour data of the material in real time and sends the data to the main control cabinet (5). The main control cabinet (5) performs a subtraction operation between the real-time surface height profile data and the bottom reference profile to extract the actual net height of the material, and performs discrete point integration or accumulation in combination with the system's preset effective width parameters of the conveyor belt to calculate the instantaneous true cross-sectional area of ​​the material at the current section. The main control cabinet (5) has a pre-set heavy load threshold and no load threshold. The heavy load threshold is greater than the no load threshold. The calculated instantaneous material cross-sectional area is compared and judged in real time. Based on the judgment result, the corresponding control of the conveyor belt mechanism is to enter the 100% full load speed operation state, the energy-saving operation state of speed reduction, or the extremely low speed creep standby operation state for automatic speed adjustment.

6. A method according to claim 5, characterized in that, The step of controlling the conveyor belt mechanism according to the judgment result includes the following steps: When the instantaneous material cross-sectional area is greater than or equal to the heavy load threshold, it is determined to be in a heavy load state. The main control cabinet (5) controls the conveyor belt mechanism to run at 100% full load speed. When the instantaneous material cross-sectional area is less than the heavy load threshold and greater than or equal to the no-load threshold, it is determined to be a light load state, and the main control cabinet (5) controls the conveyor belt mechanism to operate in an energy-saving state with reduced speed. When the instantaneous actual cross-sectional area of ​​the material is less than the no-load threshold, it is determined to be in no-load state, and the main control cabinet (5) controls the conveyor belt mechanism to run in a very low-speed creeping standby state.

7. A method according to claim 5, characterized in that, It also includes the following steps: When the main control cabinet (5) controls the conveyor belt mechanism to switch operating states, it calls the internal preset flexible acceleration and deceleration mechanism and completes the linear smooth switching of the output frequency within the preset smooth transition time according to the set acceleration and deceleration time constant.

8. A method according to claim 5, characterized in that, It also includes the following steps: The main control cabinet (5) system has built-in safety redundancy logic: if no valid contour data of the fixed-point vision probe (3) is received within the preset period, the rated high frequency is output to drive the conveyor belt mechanism to enter the 100% full load speed operation state to prevent material accumulation.

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