A tension force intelligent adjusting method based on real-time volume of belt conveyor

Abstract

This invention discloses an intelligent tension adjustment method for belt conveyors based on real-time conveying capacity, belonging to the field of automatic control technology for belt conveyors. It is used to adjust the tension of the conveyor belt according to the conveying capacity. The method includes acquiring the wire rope tension, actual belt speed, material flow rate, and main drive motor speed through a tension sensor, speed sensor, weighing sensor, and encoder, respectively; calculating the real-time conveying capacity based on the material flow rate and matching the conveying capacity conditions to retrieve the theoretical target value of the tension; comparing the actual belt speed with the theoretical belt speed obtained by converting the main drive motor speed, and compensating for the theoretical target value of the tension when belt slippage occurs; and adjusting the tension by tightening or loosening the wire rope within the control range corresponding to the target tension value. This invention achieves dynamic adaptation of the target tension value to changes in conveying capacity, effectively reducing energy consumption and preventing slippage.

Description

Technical Field

[0001] This invention relates to the field of intelligent control technology for conveyors, and more particularly to the field of intelligent control technology for frequency conversion tensioning devices, specifically a method for intelligent adjustment of tension force based on the real-time transport capacity of a belt conveyor. Background Technology

[0002] Belt conveyors are core equipment for the continuous transportation of bulk materials in coal mines, ports, metallurgy, and chemical industries, and are gradually developing towards larger sizes, longer distances, higher belt speeds, and larger carrying capacities. The tensioning device, as a key component of the belt conveyor, provides appropriate tension to ensure sufficient friction between the drive drum and the conveyor belt to transmit driving force, while also limiting belt sag. The control effect of the tensioning device directly affects the operational safety and energy efficiency of the belt conveyor.

[0003] Currently, belt conveyor tensioning devices are mainly divided into three types: counterweight type, hydraulic type, and frequency conversion type. Compared with counterweight and hydraulic tensioning devices, frequency conversion tensioning devices use a programmable controller as the control core. The frequency converter adjusts the motor to wind and unwind the wire rope to achieve automatic tensioning, which has the advantages of adjustable tension force, high control precision, and fast dynamic response speed.

[0004] However, existing variable frequency tensioning devices typically set the target tension value based on the maximum load condition and operate in a constant tension control mode. This results in the tension setting far exceeding the belt tension required for normal operation when the conveyor is under no-load or light-load conditions, leading to energy waste and excessive equipment wear. Under heavy loads, insufficient tension can easily cause conveyor belt slippage. Existing variable frequency tensioning devices mostly rely on tension sensors for feedback adjustment, lacking a comparison mechanism between speed sensors and the main drive motor encoder to detect slippage, and thus cannot intelligently adjust the tension according to the operating conditions.

[0005] In summary, existing belt conveyor tensioning devices still have significant shortcomings in terms of dynamic tension adaptation, multi-source sensor fusion perception, and system collaborative control. Therefore, there is an urgent need for an intelligent tension adjustment method that can dynamically adjust the target tension value based on real-time conveying volume, integrate multi-sensor data to achieve working condition perception and slippage judgment, and coordinate with the main drive system. Summary of the Invention

[0006] The main objective of this invention is to provide an intelligent tension adjustment method based on the real-time conveying capacity of a belt conveyor, in order to solve the technical problems of existing frequency conversion tensioning devices, such as high energy consumption under light load, easy slippage under heavy load, single sensor configuration that cannot determine slippage and adjust according to different working conditions, and lack of coordination between the tensioning system and the main drive system, caused by constant tension setting.

[0007] To achieve the above objectives, the present invention provides a method for intelligent tension adjustment based on the real-time conveying capacity of a belt conveyor, comprising: S1. After the belt conveyor starts, obtain the instantaneous material flow rate of the belt conveyor, and calculate the real-time conveying capacity of the conveyor based on the instantaneous material flow rate; S2. Determine the conveyor's operating condition based on the real-time conveyor capacity, retrieve the theoretical target value of the tension corresponding to the operating condition, and control the tensioning device to adjust the tension of the conveyor belt to the theoretical target value. S3. After adjusting the tension of the conveyor belt, obtain the main drive motor speed and the actual running speed of the conveyor belt, calculate the theoretical running speed of the conveyor belt based on the main drive motor speed, compensate the theoretical target value of the tension based on the speed difference between the actual running speed and the theoretical running speed of the conveyor belt, and output the tension control target value. S4. Based on the tension control target value, set the tension control target range of the conveyor belt. According to the tension control target range of the conveyor belt, control the tensioning device to adjust the tension of the conveyor belt until the actual tension of the conveyor belt is within the tension control target range of the conveyor belt.

[0008] Furthermore, in S1, the instantaneous material flow rate of the belt conveyor is integrated over time to obtain the real-time conveying capacity of the conveyor. In S2, the conveyor's real-time transport capacity is compared to its rated transport capacity to determine the transport capacity condition. The transport capacity condition includes no-load and load conditions. , , , , , , , , , , This indicates the rated conveying capacity of the belt conveyor.

[0009] Furthermore, based on the operating conditions, the minimum tension of the drive roller driving the conveyor belt is calculated. The minimum tension required for the conveyor belt's load-bearing branches to meet sag requirements. The minimum tension required for the return branch of the conveyor belt to meet the sag requirement. ; Will , , The maximum value is taken as the theoretical target value of the tension force for the corresponding transport capacity condition. .

[0010] Furthermore, the minimum tension of the drive roller driving the conveyor belt winding. for: ; ; ; ; ; In the formula, Indicates the conveyor start-up coefficient. Represents the Euler coefficient. This represents the coefficient of friction between the drive roller and the conveyor belt. Indicates the wrap angle of the conveyor belt on the drive roller. Indicates circumferential driving force. Indicates the main resistance. Indicates additional resistance. Indicates the main resistance of special types, Indicates special additional resistance. Indicates the resistance to tilting. This represents the simulated friction coefficient. Represents gravitational acceleration. Indicates the length of the conveyor belt section. Represents the equivalent total mass linear density. This indicates the mass of the rotating portion per meter of the supporting branch idler roller. This indicates the mass of the rotating portion per meter of the return branch idler roller. This indicates the mass of the conveyor belt per meter. This indicates the mass of material conveyed per meter. Indicates the conveyor tilt angle. This indicates the theoretical transport capacity corresponding to the transport capacity condition. This indicates the actual operating speed of the conveyor belt.

[0011] Furthermore, the minimum tension required for the conveyor belt's load-bearing branches to meet sag requirements. for: ; In the formula, Indicates the spacing between the supporting branch idlers. Indicates the allowable sag rate of the load-bearing branch; Minimum tension required for the return branch of the conveyor belt to meet sag requirements for: ; In the formula, Indicates the spacing between the return branch idlers. This indicates the allowable sag rate of the return branch.

[0012] Furthermore, in S3, the speed difference between the actual running speed of the conveyor belt and the theoretical running speed of the conveyor belt is compared with a preset slippage threshold. When the speed difference does not exceed the preset slippage threshold, it is determined that the conveyor belt has not slipped. When the speed difference exceeds the preset slippage threshold, it is determined that the conveyor belt has slipped. The target value for tension control is: ; ; In the formula, This indicates the target value for tension control. Indicates the amount of compensation. Minimum value function Indicates the compensation coefficient. This represents the speed difference between the actual operating speed and the theoretical operating speed of the conveyor belt. This indicates the upper limit of the compensation amount. When it is determined that the conveyor belt has not slipped, the compensation amount is zero, and the theoretical target value of the tension is used as the target value for tension control.

[0013] Furthermore, the theoretical operating speed of the conveyor belt for: ; In the formula, Indicates the diameter of the main drive roller. The encoder collects the main drive motor speed. This indicates the speed ratio of the reducer in the main drive unit.

[0014] Furthermore, in S4, the target range for tension control of the conveyor belt is set around the target value for tension control. Based on the conversion relationship between the conveyor belt tension and the wire rope tension, the target control range for the wire rope tension is determined. ; ; ; ; In the formula, This indicates the lower limit of the target range for tension control. This indicates the lower limit of the target tension of the wire rope corresponding to the target range of tension control. This indicates the upper limit of the target range for tension control. This indicates the lower limit of the target tension of the wire rope corresponding to the target range of tension control. This represents the half-width factor used to calculate the target range. express The corresponding wire rope tension, This indicates the conversion factor for the tension of the wire rope.

[0015] Furthermore, the tensioning device is a variable frequency tensioning device, including a variable frequency motor, a tensioning reducer, a brake, a drum, a wire rope, a tension sensor, a speed sensor, a weighing sensor, an encoder, a programmable control box, and a frequency converter, wherein the programmable control box is equipped with a programmable controller.

[0016] Furthermore, when the tension in the wire rope is greater than At this time, the programmable controller sends a reverse operating frequency command to the frequency converter, which controls the frequency converter motor to reverse and drive the drum to loosen the rope. By reducing the tension of the wire rope, the tension of the conveyor belt is reduced until the actual tension of the conveyor belt falls back to the tension control target range of the conveyor belt. When the tension of the wire rope is less than At this time, the programmable controller sends a forward rotation frequency command to the frequency converter, which controls the frequency converter motor to rotate forward and drive the drum to tighten the rope. By increasing the tension of the wire rope, the tension of the conveyor belt is increased until the actual tension of the conveyor belt returns to the tension control target range of the conveyor belt. When the wire rope tension is within the target range, the actual tension of the conveyor belt is within the target range for tension control. The programmable controller does not send frequency adjustment commands to the frequency converter, the variable frequency motor remains unchanged, and the frequency converter does not output the drive frequency.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention establishes a quantitative calculation model for real-time conveying capacity and the theoretical target value of conveyor belt tension. Based on the real-time conveying capacity, it can retrieve the corresponding theoretical target value of conveyor belt tension. Using a variable frequency tensioning device, it dynamically adjusts the conveyor belt tension during material transport according to the real-time conveying capacity, achieving automatic adaptation of tension to changes in conveying capacity. Compared to the existing technology that sets the tension constant under maximum load conditions, this invention can significantly reduce the tension setting value under no-load and light-load conditions, thereby reducing equipment energy consumption and mechanical wear. This invention utilizes a multi-source sensor fusion architecture. Building upon the traditional closed-loop adjustment of tension sensors, it adds a speed sensor and an encoder to form a conveyor belt slippage detection channel. This allows it to independently determine the conveyor belt's operating status and automatically increase the conveyor belt tension compensation when slippage occurs. It also calculates the conveyor belt control target value in real time based on the transport volume and the conveyor belt's operating status. While ensuring that the conveyor belt tension is dynamically adjusted according to the real-time transport volume, it quickly suppresses conveyor belt slippage, solving the technical problem that existing frequency conversion tensioning devices rely on a single tension sensor and cannot actively detect slippage. This invention connects the programmable controller to the main drive system, enabling the tensioning device and the main drive system to operate in coordination. This allows the tension force to be adaptively and coordinatedly adjusted according to the operating conditions of the main drive system, thus solving the technical problem of the lack of coordination between the existing tensioning system and the main drive system. Attached Figure Description

[0018] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In the drawings: Figure 1 This is a schematic diagram of the structure of the frequency conversion tensioning device provided by the present invention; Figure 2 for Figure 1 Top view Figure 3 This is a schematic diagram of the inverter structure provided by the present invention; Figure 4 This is a schematic diagram of the structure of the programmable control box provided by the present invention.

[0019] The reference numerals in the above figures are as follows: 1. Variable frequency motor; 2. Brake; 3. Tensioning reducer; 4. Drum; 5. Variable frequency drive; 6. Programmable control box; 7. Tension sensor; 8. Wire rope; 9. Tensioning trolley. Detailed Implementation

[0020] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. 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.

[0021] A method for intelligent tension adjustment based on real-time conveying capacity of a belt conveyor includes: S1. After the belt conveyor starts, obtain the instantaneous material flow rate of the belt conveyor, and calculate the real-time conveying capacity of the conveyor based on the instantaneous material flow rate; S2. Determine the conveyor's operating condition based on the real-time conveyor capacity, retrieve the theoretical target value of the tension corresponding to the operating condition, and control the tensioning device to adjust the tension of the conveyor belt to the theoretical target value. S3. After adjusting the tension of the conveyor belt, obtain the main drive motor speed and the actual running speed of the conveyor belt, calculate the theoretical running speed of the conveyor belt based on the main drive motor speed, compensate the theoretical target value of the tension based on the speed difference between the actual running speed and the theoretical running speed of the conveyor belt, and output the tension control target value. S4. Based on the tension control target value, set the tension control target range of the conveyor belt. According to the tension control target range of the conveyor belt, control the tensioning device to adjust the tension of the conveyor belt until the actual tension of the conveyor belt is within the tension control target range of the conveyor belt.

[0022] In S1, the instantaneous material flow rate of the belt conveyor is integrated over time to obtain the real-time conveying capacity of the conveyor. In S2, the conveyor's real-time transport capacity is compared to its rated transport capacity to determine the transport capacity condition. The transport capacity condition includes no-load and load conditions. , , , , , , , , , , This indicates the rated conveying capacity of the belt conveyor.

[0023] Calculate the minimum tension of the drive roller driven conveyor belt based on the operating conditions. The minimum tension required for the conveyor belt's load-bearing branches to meet sag requirements. The minimum tension required for the return branch of the conveyor belt to meet the sag requirement. ; Will , , The maximum value is taken as the theoretical target value of the tension force for the corresponding transport capacity condition. .

[0024] Minimum tension of the drive roller driving the conveyor belt for: ; ; ; ; ; In the formula, Indicates the conveyor start-up coefficient. Represents the Euler coefficient. This represents the coefficient of friction between the drive roller and the conveyor belt. Indicates the wrap angle of the conveyor belt on the drive roller. Indicates circumferential driving force. Indicates the main resistance. Indicates additional resistance. Indicates the main resistance of special types, Indicates special additional resistance. Indicates the resistance to tilting. This represents the simulated friction coefficient. Represents gravitational acceleration. Indicates the length of the conveyor belt section. Represents the equivalent total mass linear density. This indicates the mass of the rotating portion per meter of the supporting branch idler roller. This indicates the mass of the rotating portion per meter of the return branch idler roller. This indicates the mass of the conveyor belt per meter. This indicates the mass of material conveyed per meter. Indicates the conveyor tilt angle. This indicates the theoretical transport capacity corresponding to the transport capacity condition. This indicates the actual operating speed of the conveyor belt.

[0025] Minimum tension required for the conveyor belt's load-bearing branches to meet sag requirements for: ; In the formula, Indicates the spacing between the supporting branch idlers. Indicates the allowable sag rate of the load-bearing branch; Minimum tension required for the return branch of the conveyor belt to meet sag requirements for: ; In the formula, Indicates the spacing between the return branch idlers. This indicates the allowable sag rate of the return branch.

[0026] In S3, the speed difference between the actual running speed of the conveyor belt and the theoretical running speed of the conveyor belt is compared with a preset slippage threshold. When the speed difference does not exceed the preset slippage threshold, it is determined that the conveyor belt has not slipped. When the speed difference exceeds the preset slippage threshold, it is determined that the conveyor belt has slipped. The target value for tension control is: ; ; In the formula, This indicates the target value for tension control. Indicates the amount of compensation. Minimum value function Indicates the compensation coefficient. This represents the speed difference between the actual operating speed and the theoretical operating speed of the conveyor belt. This indicates the upper limit of the compensation amount. When the conveyor belt is determined not to slip, the compensation amount is zero, and the theoretical target value of the tension is used as the target value for tension control. The upper limit of the compensation amount is the maximum allowable tension of the conveyor belt when simultaneously satisfying safety constraints such as the maximum allowable tension of the conveyor belt, the allowable tensile force of the wire rope, the non-slipping limit of the drive drum, the rated output of the tensioning device and drum, the overload capacity of the variable frequency motor and tensioning reducer, the travel of the tensioning trolley, the load-bearing capacity of the drums and idlers, and the sag and running stability of the conveyor belt. It is determined through theoretical calculation, simulation analysis, and field test calibration, and can be corrected online according to the load, belt speed, friction coefficient, and degree of slippage.

[0027] The theoretical operating speed of the conveyor belt at the current moment is calculated by real-time acquisition of the main drive motor speed by the encoder. The actual operating speed of the conveyor belt at the current moment is taken from the real-time acquisition of the speed sensor. The speed difference between the actual and theoretical operating speeds is calculated and compared with a preset slippage threshold. If the speed difference does not exceed the preset slippage threshold, the conveyor belt is determined not to be slipping; if the speed difference exceeds the preset slippage threshold, the conveyor belt is determined to be slipping. The tension control target value for determining that the conveyor belt is not slipping is: .

[0028] The theoretical operating speed of the conveyor belt for: ; In the formula, Indicates the diameter of the main drive roller. The encoder collects the main drive motor speed. This indicates the speed ratio of the reducer in the main drive unit.

[0029] In S4, the target range for tension control of the conveyor belt is set with the tension control target value as the center. Based on the conversion relationship between the conveyor belt tension and the wire rope tension, the target control range for the wire rope tension is determined. ; ; ; ; In the formula, This indicates the lower limit of the target range for tension control. This indicates the lower limit of the target tension of the wire rope corresponding to the target range of tension control. This indicates the upper limit of the target range for tension control. This indicates the lower limit of the target tension of the wire rope corresponding to the target range of tension control. This represents the half-width factor used to calculate the target range. express The corresponding wire rope tension, This indicates the conversion factor for the tension of the wire rope.

[0030] The tensioning device is a variable frequency tensioning device, including a variable frequency motor, a tensioning reducer, a brake, a drum, a wire rope, a tension sensor, a speed sensor, a weighing sensor, an encoder, a programmable control box, and a frequency converter. The programmable control box is equipped with a programmable controller.

[0031] When the tension of the wire rope is greater than At this time, the programmable controller sends a reverse operating frequency command to the frequency converter, which controls the frequency converter motor to reverse and drive the drum to loosen the rope. By reducing the tension of the wire rope, the tension of the conveyor belt is reduced until the actual tension of the conveyor belt falls back to the tension control target range of the conveyor belt. When the tension of the wire rope is less than At this time, the programmable controller sends a forward rotation frequency command to the frequency converter, which controls the frequency converter motor to rotate forward and drive the drum to tighten the rope. By increasing the tension of the wire rope, the tension of the conveyor belt is increased until the actual tension of the conveyor belt returns to the tension control target range of the conveyor belt. When the wire rope tension is within the target range, the actual tension of the conveyor belt is within the target range for tension control. The programmable controller does not send frequency adjustment commands to the frequency converter, the variable frequency motor remains unchanged, and the frequency converter does not output the drive frequency.

[0032] Specifically, belt conveyor layouts include upward-moving belt conveyors, horizontal-moving belt conveyors, downward-moving belt conveyors, and long-distance variable-slope belt conveyors. Tensioning devices are typically located at the tail and head of the conveyor. The normal operation of a belt conveyor depends primarily on the tensioning device providing the required tension force. Changes in the material on the belt conveyor directly affect the tension distribution, and consequently, the magnitude of the tension force required by the tensioning device.

[0033] Specifically, the belt conveyor includes a conveyor belt, a drive roller, a redirecting roller, a carrying idler, a return idler, an intermediate frame, a head discharge hopper, a tail receiving hopper, and a main drive system. The main drive system consists of a main drive motor and a main drive reducer; the output shaft of the main drive motor is connected to the drive roller via the main drive reducer. The conveyor belt winds between the drive roller and the redirecting roller, forming a closed loop. The carrying branch of the conveyor belt is supported by carrying idlers and is used to carry and transport materials; the return branch of the conveyor belt is supported by return idlers and is used to complete the return journey of the conveyor belt. Preferably, the conveyor belt is a rubber belt.

[0034] Specifically, the variable frequency tensioning device includes a drive unit, a tensioning unit, a detection component, and a control unit. The drive unit includes a variable frequency motor, a tensioning reducer, and a brake, which provides power to the tensioning unit for winding and unwinding the wire rope. The tensioning unit includes a drum and a wire rope. The output shaft of the variable frequency motor is connected to the input shaft of the tensioning reducer via the brake. The output shaft of the tensioning reducer is connected to the drum drive, which drives the drum to rotate forward or backward to achieve the winding and unwinding of the wire rope. One end of the wire rope is fixed and wound around the outer circumference of the drum, and the other end of the wire rope is led out from the drum and connected to the belt conveyor, or it passes around the tensioning adjustment control of the belt conveyor and is fixed to the frame or fixed base of the variable frequency tensioning device.

[0035] Preferably, the tension adjustment control of the belt conveyor is a tensioning trolley. After the wire rope is led out from the drum, it passes through the reversing pulley between the frequency conversion tensioning device and the conveyor belt tensioning trolley in sequence, and is then connected to the tensioning trolley through the wire rope seat.

[0036] The detection components include a tension sensor, a speed sensor, a load cell, and an encoder. The tension sensor is mounted on the wire rope to collect the wire rope tension signal in real time, serving as the basis for tension adjustment feedback. The speed sensor is used to monitor the running speed of the conveyor belt in real time. The load cell is located in the loading section (weighing section) of the belt conveyor to collect the weight signal of the conveyor belt in real time and calculate the material flow rate of the conveyor belt. The encoder is located at the output shaft end of the main drive motor of the belt conveyor to collect the speed of the main drive motor in real time. Preferably, a tension sensor is installed near the rope seat of the tensioning device's wire rope to collect the wire rope tension signal in real time, serving as the basis for tension adjustment feedback. A speed sensor is used to monitor the belt running speed in real time. This parameter is processed and compared with the main drive motor speed collected by the encoder to determine whether the belt is slipping, serving as a reference for judging whether the adjusted tension meets the tension requirements. A weighing sensor is installed in the loading section of the belt conveyor (located at the material receiving point of the conveyor, equivalent to the weighing section) to collect the weight signal of the conveyor belt in real time, calculate the instantaneous material flow, and calculate the amount of material on the belt by integration and accumulation. The material flow rate is used as the basis for judging the load state and is analyzed in conjunction with other parameters to control the variable frequency tensioning device to output appropriate tension. An encoder is arranged at the tail end of the main drive motor to monitor the speed of the main drive motor, determining whether the main drive motor is in electric or generator mode. Based on the collected data, the belt conveyor is controlled according to the tension adjustment logic under different conveying conditions, achieving safe, reliable, and energy-saving operation of the belt conveyor.

[0037] The control unit includes a programmable controller box and a frequency converter. The programmable controller box contains a programmable logic controller (PLC), an analog signal acquisition module, a communication module, relays, and a power supply module. The PLC receives signals from tension sensors, speed sensors, weighing sensors, and encoders via the analog signal acquisition module, processes the signals, and calculates instantaneous material flow rate, real-time conveying capacity, actual conveyor belt tension, and target conveyor belt tension. The PLC's signal output is connected to the frequency converter's control terminal via the communication module. The programmable controller controls the frequency converter to adjust the wire rope winding and unwinding operations based on the target tension of the conveyor belt (including the theoretical target tension value and the adjustable tension target value). By adjusting the wire rope tension, the actual tension of the conveyor belt is adjusted to the target tension. Relays control the start or stop of the frequency converter according to the PLC's instructions, and the power supply module supplies power to the frequency converter tensioning device.

[0038] The programmable control box of the variable frequency tensioning device is based on a programmable logic controller (PLC). It acquires the wire rope tension signal in real time through an analog signal acquisition module and interacts with the main drive inverter to exchange operating parameters via a communication module. It performs a closed-loop comparison between the actual tension of the conveyor belt calculated based on the wire rope tension signal and the set target value of the conveyor belt tension (including the theoretical target value and the tension control target value). When the deviation exceeds the preset target value allowable range (equivalent to the tension control target range), the PLC adjusts the operating frequency and rotation direction of the tension inverter according to the direction of the deviation, driving the drum to perform rope winding or unwinding actions to increase or decrease the tension, until the tension of the conveyor belt returns to the target value range, and then stops frequency adjustment. At the same time, the system integrates the acquired and processed dynamic data of the main drive motor into the control logic, so that the tension can be adaptively and collaboratively adjusted according to the working conditions of the main machine, thereby ensuring the stability and accuracy of the tension under all working conditions.

[0039] In S1, the load cell collects the weight signal generated by the material and the conveyor belt together on the weighing section in real time. The programmable controller receives the weight signal output by the load cell through the analog acquisition module, and performs filtering, analog-to-digital conversion, tare, zero-point correction, and calibration processing on it. After deducting the weight of the conveyor belt itself, the weight of the weighing idler rollers, and zero-point drift, the weight of the material on the weighing section of the conveyor belt is calculated. Based on the weight of the material on the weighing section and the length of the weighing section, the programmable controller calculates the weight of the material per unit length of the conveyor belt. Combined with the actual running speed of the conveyor belt, the instantaneous material flow rate is obtained. The instantaneous material flow rate is integrated and accumulated over a unit time (sampling period) to obtain the total amount of material transported by the conveyor belt from the metering time to the current time (within the sampling period), thus obtaining the real-time conveyor belt capacity.

[0040] In S2, based on the rated capacity of the belt conveyor, the working conditions from no-load to full-load are divided into equally spaced capacity intervals to obtain multiple capacity intervals. Each capacity interval corresponds to a capacity working condition. The theoretical capacity corresponding to each capacity working condition is set as needed, and the theoretical target value of the tension force corresponding to each capacity working condition is calculated based on the theoretical capacity.

[0041] Specifically, based on the ratio of real-time transport volume to rated transport volume, according to empty load ( ), , , , , , , , , The capacity space is divided, and each capacity space corresponds to a capacity operating condition. The capacity operating conditions include no-load ( ), , , , , , , , , , For each transport capacity condition, the maximum transport capacity in the corresponding transport capacity space is taken as the theoretical transport capacity for that condition. The theoretical target value of the tension force for that condition is calculated and stored in the programmable controller's data table. In actual operation, the programmable controller directly looks up the corresponding tension force control target value in the table based on the real-time transport capacity's level range, thereby shortening the calculation time and improving the response speed.

[0042] Specifically, the ratio of real-time transport volume to the rated transport volume of the belt conveyor. for: ; In the formula, This indicates real-time transport volume. Indicates the rated conveying capacity of the belt conveyor; when At that time, the real-time traffic volume is located at Within the specified transport capacity range, the corresponding transport capacity condition for the conveyor belt is as follows: The theoretical transport capacity corresponding to this transport capacity condition is: .

[0043] The minimum tension of a conveyor belt is primarily based on Euler's formula (the condition for the conveyor belt not to slip), but in actual engineering, the conveyor belt sag condition must also be met. The sag condition mainly constrains the degree of deflection of the conveyor belt in the carrying section between the idlers, preventing material spillage and excessive bending of the conveyor belt, and is an important basis for determining the lower limit of tension. When the conveyor belt tension is too low, the sag increases, the running resistance increases, and material may spill from both sides of the conveyor belt.

[0044] Specifically, according to Calculate the minimum tension of the drive roller driven conveyor belt. The minimum tension required for the conveyor belt's load-bearing branches to meet sag requirements. The minimum tension required for the return branch of the conveyor belt to meet the sag requirement. ;Will , , The maximum value is taken as the theoretical target value of the tension force for the corresponding transport capacity condition. Calculate the minimum tension of the drive conveyor belt. The start-up coefficient of a conveyor is determined by the performance and operating conditions of the conveyor. The minimum tension required for the conveyor belt to unwind when driven by the drive roller refers to the minimum tension the conveyor belt must maintain when leaving the drive roller (unwinding point / separation point) to prevent slippage between the drive roller and the conveyor belt. This is the minimum tension used to ensure that, under the theoretical operating conditions of the conveyor belt, there is no slippage between the drive roller and the conveyor belt, and that the load-bearing branches of the conveyor belt meet the sag requirements. The minimum tension used to ensure that the sag of the load-bearing branch of the conveyor belt does not exceed the limit and that the sag of the return branch of the conveyor belt meets the sag requirements. These three factors are used to ensure that the sag of the return branch does not exceed the limit. They correspond to independent constraints that the safe and stable operation of the conveyor must meet simultaneously, while the tensioning device can only provide a uniform tension level. Taking the maximum value of the three factors can simultaneously meet the requirements of non-slippage and sag, and is also the minimum theoretical tension required to meet all constraints. This can avoid excessive tension leading to increased conveyor belt tension, drive energy consumption, roller and idler load, and wire rope wear, thus ensuring reliable operation of the conveyor while taking into account economy and service life.

[0045] In practical applications, the theoretical target value of the tension force corresponding to the conveyor belt's operating conditions is stored in the programmable controller. The corresponding operating conditions are determined based on the real-time conveyor belt capacity, and the allowable theoretical target range is set around this theoretical target value for closed-loop adjustment of the actual tension force.

[0046] Since theoretical target values ​​are calculated based on steady-state or rated operating conditions, they are difficult to cover dynamic fluctuations and random factors in actual operation. When actual operating conditions deteriorate, even if the conveyor belt tension has reached the theoretical target value, the friction between the drive roller and the conveyor belt may still be insufficient to transmit the required traction force, resulting in the actual belt speed being lower than the theoretical belt speed calculated from the main drive speed, drive roller diameter, and transmission ratio, i.e., conveyor belt slippage. Therefore, it is necessary to calculate the speed difference by comparing the actual belt speed with the theoretical belt speed in real time. When the speed difference exceeds a set threshold (slippage threshold), it is determined that the conveyor belt has slipped. Once slippage is determined, speed compensation is performed based on the theoretical target value, i.e., the tension target value is dynamically increased according to the size of the speed difference, so that the actual tension is increased accordingly, thereby increasing the normal pressure and friction between the conveyor belt and the drive roller, and restoring the actual belt speed to synchronization with the theoretical belt speed. When the conveyor belt does not slip, the compensation amount is zero, the tension control target value is equal to the theoretical tension target value, and the tension adjustment function of the frequency converter is not triggered.

[0047] After compensating for the theoretical target value of tension, the tension control target value calculated based on the speed difference and the theoretical target value of tension is used as the theoretical target value of tension for the corresponding conveying capacity condition and stored in the programmable controller (PLC). The data stored in the PLC is then updated. Through speed compensation, the actual tension of the conveyor belt is dynamically corrected according to the real-time slippage degree. This avoids excessive tension under normal operating conditions, preventing energy consumption, wear, and increased conveyor belt tension, while providing additional tension in a timely manner under slippage conditions to ensure reliable conveyor operation. The slippage threshold is jointly determined by the design parameters of the belt conveyor, operating conditions, detection accuracy, and control requirements. It is typically determined through a combination of theoretical analysis, simulation calculations, field tests, and operational experience, and can be corrected online according to actual operating conditions. This ensures timely identification of slippage and speed compensation of tension without frequent malfunctions due to measurement noise or instantaneous fluctuations.

[0048] The inverter's operating frequency is adjusted using a PID control algorithm. The programmable controller calculates the actual tension of the conveyor belt based on the wire rope tension, and calculates the inverter's operating frequency and provides the operating direction (rotation) based on the deviation between the actual tension and the target tension value. The drum is adjusted according to the operating frequency and direction to control the wire rope winding and unwinding. During adjustment, the wire rope tension is monitored in real time, and the corresponding conveyor belt tension is calculated until the actual tension of the conveyor belt falls within the target tension control range. By setting a target tension control range instead of a single target point, it effectively adapts to sensor measurement errors, mechanical inertia, control lag, actuator resolution, and operating condition fluctuations, avoiding frequent drum winding and unwinding and system oscillations, thus improving the stability, reliability, and service life of tension control. The wire rope tension conversion factor is used to convert the wire rope tension collected in real time by the tension sensor into the actual tension of the conveyor belt. It mainly depends on the winding method of the wire rope between the drum, reversing pulley, moving pulley and tensioning trolley, the pulley block ratio, the number of moving pulleys and fixed pulleys, the reversing angle of the wire rope and the angle between the tension direction and the direction of the conveyor belt tension, the friction of the pulley bearings and the bending resistance of the wire rope, the friction loss between the wire rope and the pulley, the friction resistance of the tensioning trolley along the tensioning track, the mechanical efficiency of the tensioning drum and guide mechanism, the wrap angle and elastic deformation of the conveyor belt on the tensioning drum, the installation coaxiality and calibration error, as well as factors such as temperature, lubrication, wear and load conditions. It can usually be determined through mechanical calculations, factory calibration or field tests, and is regarded as a constant during operation or corrected online according to the working conditions.

[0049] Figure 1 This is a schematic diagram of the overall structure of the frequency conversion tensioning device for the conveyor of the present invention. Figure 2 for Figure 1 Top view, Figure 3 This is a schematic diagram of the inverter structure. Figure 4This is a schematic diagram of the programmable controller box. Figure 1 and Figure 2 As shown, the variable frequency motor 1, brake 2, tension reducer 3, and drum 4 are coaxially connected in sequence; the output end of the variable frequency motor 1 is connected to the brake 2, and the output end of the brake 2 is connected to the input end of the tension reducer 3. The output end of the tension reducer 3 drives the drum 4 to rotate; a steel wire rope 8 is wound on the drum 4, and a tension sensor 7 is installed in series in the rope path of the steel wire rope 8. After the steel wire rope 8 is connected to the tensioning trolley 9 of the conveyor belt, it is connected to the variable frequency tensioning device through the rope seat; the electrical control end of the variable frequency motor 1 is connected to... Figure 3 The inverter 5 shown is electrically connected to, and the inverter 5 is connected to Figure 4 The programmable control box 6 shown is connected to the signal network; the tension signal collected by the tension sensor 7 is sent to the programmable control box 6.

[0050] The specific working state of the intelligent tension adjustment method based on the real-time conveying capacity of a belt conveyor provided by this invention is as follows: A variable frequency tensioning device is installed on the belt conveyor. Before the belt conveyor is put into operation, the amount of conveyor to be transported is assessed. Based on the amount of conveyor, the theoretical target value of the conveyor belt tension under the corresponding working condition is retrieved as the initial value of the conveyor belt tension. The initial value of the tension is set in the variable frequency tensioning device. The actual tension of the conveyor belt is adjusted to the target range corresponding to the theoretical value through the variable frequency tensioning device.

[0051] After the initial tension is set, the belt conveyor is started. The weight signal of the weighing section of the conveyor belt is collected in real time by the weighing sensor to calculate the material flow rate of the conveyor belt, and then to calculate the real-time conveying capacity of the conveyor belt. According to the real-time conveying capacity, the corresponding conveying capacity condition is matched, and the theoretical target value of the tension corresponding to the conveying capacity condition is retrieved. Through the frequency conversion tensioning device, the real-time conveying capacity of the conveyor belt is theoretically adjusted according to the theoretical value of the tension. During the adjustment process, the tension of the steel wire rope is monitored in real time by the tension sensor to calculate the actual tension of the conveyor belt. When the actual tension of the conveyor belt is detected to match the target tension, the adjustment is stopped.

[0052] After adjusting the conveyor belt tension based on theoretical values, the actual operating speed of the conveyor belt is monitored in real time by a speed sensor and compared with the theoretical operating speed obtained by converting the main drive speed monitored by an encoder. When the speed difference between the actual and theoretical operating speeds exceeds the slippage threshold, speed compensation is applied to the theoretical tension target value based on the speed difference. The tension control target value is calculated, and the tension control target range is set. Based on the tension control target range, the tensioning device adjusts the conveyor belt tension until the actual tension falls within the tension control target range.

[0053] Of course, the above description is not intended to limit the present invention, and the present invention is not limited to the examples given above. Any changes, modifications, additions or substitutions made by those skilled in the art within the scope of the present invention should also fall within the protection scope of the present invention.

Claims

1. A method for intelligent tension adjustment based on real-time conveying capacity of a belt conveyor, characterized in that, include: S1. After the belt conveyor starts, obtain the instantaneous material flow rate of the belt conveyor, and calculate the real-time conveying capacity of the conveyor based on the instantaneous material flow rate; S2. Determine the conveyor's operating condition based on the real-time conveyor capacity, retrieve the theoretical target value of the tension corresponding to the operating condition, and control the tensioning device to adjust the tension of the conveyor belt to the theoretical target value. S3. After adjusting the tension of the conveyor belt, obtain the main drive motor speed and the actual running speed of the conveyor belt, calculate the theoretical running speed of the conveyor belt based on the main drive motor speed, compensate the theoretical target value of the tension based on the speed difference between the actual running speed and the theoretical running speed of the conveyor belt, and output the tension control target value. S4. Based on the tension control target value, set the tension control target range of the conveyor belt. According to the tension control target range of the conveyor belt, control the tensioning device to adjust the tension of the conveyor belt until the actual tension of the conveyor belt is within the tension control target range of the conveyor belt.

2. The intelligent tension adjustment method based on the real-time conveying capacity of a belt conveyor according to claim 1, characterized in that, In S1, the instantaneous material flow rate of the belt conveyor is integrated over time to obtain the real-time conveying capacity of the conveyor. In S2, the conveyor's real-time transport capacity is compared to its rated transport capacity to determine the transport capacity condition. The transport capacity condition includes no-load and load conditions. , , , , , , , , , , This indicates the rated conveying capacity of the belt conveyor.

3. The intelligent tension adjustment method based on the real-time conveying capacity of a belt conveyor according to claim 2, characterized in that, Calculate the minimum tension of the drive roller driven conveyor belt based on the operating conditions. The minimum tension required for the conveyor belt's load-bearing branches to meet sag requirements. The minimum tension required for the return branch of the conveyor belt to meet the sag requirement. ; Will , , The maximum value is taken as the theoretical target value of the tension force for the corresponding transport capacity condition. .

4. The intelligent tension adjustment method based on the real-time conveying capacity of a belt conveyor according to claim 3, characterized in that, Minimum tension of the drive roller driving the conveyor belt for: ； ； ； ； ； In the formula, Indicates the conveyor start-up coefficient. Represents the Euler coefficient. This represents the coefficient of friction between the drive roller and the conveyor belt. Indicates the wrap angle of the conveyor belt on the drive roller. Indicates circumferential driving force. Indicates the main resistance. Indicates additional resistance. Indicates the main resistance of special types, Indicates special additional resistance. Indicates the resistance to tilting. This represents the simulated friction coefficient. Represents gravitational acceleration. Indicates the length of the conveyor belt section. Represents the equivalent total mass linear density. This indicates the mass of the rotating portion per meter of the supporting branch idler roller. This indicates the mass of the rotating portion per meter of the return branch idler roller. This indicates the mass of the conveyor belt per meter. This indicates the mass of material conveyed per meter. Indicates the conveyor tilt angle. This indicates the theoretical transport capacity corresponding to the transport capacity condition. This indicates the actual operating speed of the conveyor belt.

5. The intelligent tension adjustment method based on the real-time conveying capacity of a belt conveyor according to claim 4, characterized in that, Minimum tension required for the conveyor belt's load-bearing branches to meet sag requirements for: ； In the formula, Indicates the spacing between the supporting branch idlers. Indicates the allowable sag rate of the load-bearing branch; Minimum tension required for the return branch of the conveyor belt to meet sag requirements for: ； In the formula, Indicates the spacing between the return branch idlers. This indicates the allowable sag rate of the return branch.

6. The intelligent tension adjustment method based on the real-time conveying capacity of a belt conveyor according to claim 5, characterized in that, In S3, the speed difference between the actual running speed of the conveyor belt and the theoretical running speed of the conveyor belt is compared with a preset slippage threshold. When the speed difference does not exceed the preset slippage threshold, it is determined that the conveyor belt has not slipped. When the speed difference exceeds the preset slippage threshold, it is determined that the conveyor belt has slipped. The target value for tension control is: ； ； In the formula, This indicates the target value for tension control. Indicates the amount of compensation. Minimum value function Indicates the compensation coefficient. This represents the speed difference between the actual operating speed and the theoretical operating speed of the conveyor belt. This indicates the upper limit of the compensation amount. When it is determined that the conveyor belt has not slipped, the compensation amount is zero, and the theoretical target value of the tension is used as the target value for tension control.

7. The intelligent tension adjustment method based on the real-time conveying capacity of a belt conveyor according to claim 6, characterized in that, The theoretical operating speed of the conveyor belt for: ； In the formula, Indicates the diameter of the main drive roller. The encoder collects the main drive motor speed. This indicates the speed ratio of the reducer in the main drive unit.

8. The intelligent tension adjustment method based on the real-time conveying capacity of a belt conveyor according to claim 6, characterized in that, In S4, the target range for tension control of the conveyor belt is set with the tension control target value as the center. Based on the conversion relationship between the conveyor belt tension and the wire rope tension, the target control range for the wire rope tension is determined. ; ； ； ； In the formula, This indicates the lower limit of the target range for tension control. This indicates the lower limit of the target tension of the wire rope corresponding to the target range of tension control. This indicates the upper limit of the target range for tension control. This indicates the lower limit of the target tension of the wire rope corresponding to the target range of tension control. This represents the half-width factor used to calculate the target range. express The corresponding wire rope tension, This indicates the conversion factor for the tension of the wire rope.

9. The intelligent tension adjustment method based on the real-time conveying capacity of a belt conveyor according to claim 8, characterized in that, The tensioning device is a variable frequency tensioning device, including a variable frequency motor, a tensioning reducer, a brake, a drum, a wire rope, a tension sensor, a speed sensor, a weighing sensor, an encoder, a programmable control box, and a frequency converter. The programmable control box is equipped with a programmable controller.

10. The intelligent tension adjustment method based on the real-time conveying capacity of a belt conveyor according to claim 9, characterized in that, When the tension of the wire rope is greater than At this time, the programmable controller sends a reverse operating frequency command to the frequency converter, which controls the frequency converter motor to reverse and drive the drum to loosen the rope. By reducing the tension of the wire rope, the tension of the conveyor belt is reduced until the actual tension of the conveyor belt falls back to the tension control target range of the conveyor belt. When the tension of the wire rope is less than At this time, the programmable controller sends a forward rotation frequency command to the frequency converter, which controls the frequency converter motor to rotate forward and drive the drum to tighten the rope. By increasing the tension of the wire rope, the tension of the conveyor belt is increased until the actual tension of the conveyor belt returns to the tension control target range of the conveyor belt. When the wire rope tension is within the target range, the actual tension of the conveyor belt is within the target range for tension control. The programmable controller does not send frequency adjustment commands to the frequency converter, the variable frequency motor remains unchanged, and the frequency converter does not output the drive frequency.

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