A method for cooperative material taking control of multiple spiral heads at the end of a screw conveyor

Abstract

This invention relates to the field of screw conveyor technology, specifically to a method for controlling the coordinated material handling of multiple screw heads at the end of a screw conveyor. This invention analyzes the screw head power, angular velocity, rotational speed, and motor input power of each screw head at each moment during both no-load and material handling operations. This yields the blockage risk factor of each screw head in each sampling period and the mechanical input efficiency at each moment. Based on the blockage risk factors of all screw heads in different sampling periods and the load power distribution at different moments, the system coordination degree and final priority adjustment coefficient of each screw head at each moment are obtained. Furthermore, the comprehensive control weight of each screw head at each moment is obtained. Based on the comprehensive control weight of different screw heads at real-time and the preset adjustment speed, a speed control function is constructed to obtain the real-time adjustment speed of each screw head during material handling. This invention improves the efficiency of coordinated material handling by obtaining appropriate speeds when screw heads work together.

Description

Technical Field

[0001] This invention relates to the field of screw conveyor technology, and more specifically to a method for controlling the coordinated material handling of multiple screw heads at the end of a screw conveyor. Background Technology

[0002] In the unloading operations of bulk carriers, screw conveyors are widely used in the conveying of bulk materials such as grain, coal, ore, and fertilizer due to their advantages such as compact structure, good sealing, and stable conveying. The screw conveyor, located at the dock or on the mobile equipment, extends its screw head into the cargo hold through the hatch of the hold. Through the rotation of the screw blades, it grabs the bulk materials in the hold and conveys them backward. Finally, the materials are transferred to the dock yard through the subsequent conveying system.

[0003] In the existing technology, the end of the screw conveyor used for loading and unloading bulk carriers is usually designed to pick up materials with a single screw head; however, considering that a single screw head can only cover a limited width and lacks the ability to perceive and dynamically analyze the physical state of the material in real time, the system cannot accurately identify the differences in the working state of each screw head, which often leads to problems such as uneven load and local blockage during the material picking process, resulting in poor material picking efficiency. Summary of the Invention

[0004] To address the technical problems of a single screw head only being able to cover a limited width and lacking real-time sensing and dynamic analysis capabilities of the material's physical state, resulting in the system's inability to accurately identify the differences in the working states of each screw head and poor material handling efficiency, the present invention aims to provide a multi-screw head collaborative material handling control method at the end of a screw conveyor. The specific technical solution adopted is as follows: This invention proposes a control method for coordinated material handling by multiple spiral heads at the end of a screw conveyor, applicable to a multi-spiral head coordinated material handling device. The control method includes: The angular velocity, rotational speed, screw head power, and input power of the material handling drive device are acquired in real time at every moment within a preset sampling period when the material handling device is unloaded and handling material. Based on the power and angular velocity of each screw head at each moment during no-load and material picking, the load power of each screw head at each moment during material picking is obtained; for the material picking device, based on the load power, rotation speed, and motor input power of the screw head at different moments, the blockage risk factor of the screw head in each sampling period and the mechanical input efficiency at each moment are obtained; based on the distribution of the blockage risk factors of all screw heads in the sampling period at each moment, the system coordination degree at each moment is obtained. Based on the blockage risk factors of different spiral heads in different sampling periods and the load power distribution at different times, the final priority adjustment coefficient of each spiral head at each time is obtained; based on the mechanical input efficiency, system coordination and final priority adjustment coefficient of each spiral head at each time, and the blockage risk factor of the sampling period, the comprehensive control weight of each spiral head at each time is obtained. Based on the comprehensive control weights of different spiral heads at real time and the preset adjustment speed, a speed control function is constructed to obtain the real-time adjustment speed of each spiral head when picking up material.

[0005] Furthermore, the method for obtaining the load power includes: For any screw head, the ratio of the difference in angular velocity between the next moment and the previous moment to the difference at the corresponding moment is obtained, which is used as the rate of change of angular velocity at each moment; for no-load conditions, the screw head power and the rate of change of angular velocity of each screw head at each moment are obtained to form the data point at each moment. Obtain the fitted line by fitting the data points at all times, and obtain the slope of the fitted line as the moment of inertia. When taking materials, the product between the moment of inertia and the rate of change of angular velocity at each moment is obtained. The difference between the power of the screw head at each moment and the product result is calculated as the load power of the screw head at each moment.

[0006] Furthermore, the method for obtaining the congestion risk factor and mechanical input efficiency includes: The average ratio between load power and speed at all times within each sampling period is obtained and normalized to serve as the congestion risk factor for each sampling period. When the material handling device is handling material, the product of the angular velocity and load power of each screw head at each moment is obtained. The ratio of the product result to the motor input power is calculated and normalized to serve as the mechanical input efficiency of each screw head at each moment.

[0007] Furthermore, the method for obtaining the system's degree of cooperation includes: Obtain the range of the blockage risk factor for all spiral heads in the sampling period at each moment; obtain the mean of the blockage risk factor for all spiral heads in the sampling period at each moment, as the overall blockage risk factor; The ratio of the range value to the overall congestion risk factor is obtained and normalized to represent the system synergy at each time step.

[0008] Furthermore, the method for obtaining the final priority adjustment coefficient includes: Based on the blockage risk factors of different spiral heads in different sampling periods, the bottleneck priority adjustment coefficient of each spiral head at each moment is obtained; Based on the load power distribution of each screw head at different times, the load power change response efficiency of each screw head at each time is obtained. The bottleneck priority adjustment factor and the load power change response efficiency of each spiral head are obtained as the final priority adjustment factor of each spiral head at each moment.

[0009] Furthermore, the method for obtaining the bottleneck priority adjustment coefficient includes: If among all the spiral heads, there is one spiral head whose blockage risk factor value is the largest in all sampling periods within the local sampling period range at every moment, the corresponding spiral head is regarded as the bottleneck spiral head. The difference between the blockage risk factor and the overall blockage risk factor of the bottleneck spiral head at each sampling period is obtained as the risk difference; If the spiral head corresponds to the bottleneck spiral head, the bottleneck priority adjustment coefficient of the spiral head at each moment is set as the risk difference; if the spiral head does not correspond to the bottleneck spiral head, the ratio of the risk difference to the number of other spiral heads is calculated and used as the bottleneck priority adjustment coefficient of the corresponding spiral head at each moment.

[0010] Furthermore, the method for obtaining the load power change response efficiency includes: For any spiral head, obtain the difference in load power between each moment and the previous moment, as the load power change at each moment; obtain the sum of the load power changes at all moments, as the overall load power change. Obtain the average load power over all time periods as the overall load power; obtain the maximum difference between the load power at different time periods and the overall load power within the neighborhood of each time period as the overall load deviation at each time period. The load power change response efficiency at each moment is obtained based on the overall load deviation and the overall load power change. The overall load deviation and the load power change response efficiency are negatively correlated, while the overall load power change and the load power change response efficiency are positively correlated.

[0011] Furthermore, the mechanical input efficiency and system coordination are both negatively correlated with the comprehensive control weight, while the final priority adjustment coefficient and congestion risk factor are both positively correlated with the comprehensive control weight.

[0012] Furthermore, the method for obtaining the real-time adjusted rotational speed includes: Obtain the degree of fluctuation of the preset adjustment speed of all spiral heads at real time, as the degree of speed fluctuation; The sum of the cumulative value of the comprehensive control weight of all screw heads at real time and the sum of the speed fluctuation degree are obtained as the speed control function; The preset adjustment speed in the speed control function is solved based on the adaptive gradient optimization algorithm to obtain the real-time adjustment speed when each screw head picks up material.

[0013] The present invention has the following beneficial effects: This invention analyzes the power, angular velocity, rotational speed, and motor input power of each screw head at every moment during both no-load and material-harvesting operations. It obtains the blockage risk factor of each screw head in each sampling period and the mechanical input efficiency at each moment, reflecting the likelihood of blockage and measuring how much of the drive unit's input power is effectively used for material transport. Based on the blockage risk factors of all screw heads in different sampling periods and the load power distribution at different moments, it obtains the system coordination degree and final priority adjustment coefficient of each screw head at each moment, assessing the impact of the coordination of all screw heads and their own blockage risk on the system state, and quantifying the final priority adjustment coefficient. Based on the mechanical input efficiency, system coordination degree, and final priority adjustment coefficient of each screw head at each moment, as well as the blockage risk factor of the sampling period, it obtains the comprehensive control weight of each screw head at each moment, which helps to focus on handling screw heads with higher risks. Based on the comprehensive control weight of different screw heads at real-time and the preset adjustment speed, a speed control function is constructed to obtain the real-time adjustment speed of each screw head during material harvesting. This invention improves the efficiency of multi-screw head collaborative material harvesting by obtaining the appropriate speed when screw heads work collaboratively. Attached Figure Description

[0014] To more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a first-view structural schematic diagram of a multi-screw head collaborative material handling device at the end of a screw conveyor according to an embodiment of the present invention. Figure 2 This is a second-view structural schematic diagram of a multi-screw head collaborative material handling device at the end of a screw conveyor according to an embodiment of the present invention. Figure 3 This is a third-view structural diagram of a multi-screw head collaborative material handling device at the end of a screw conveyor according to an embodiment of the present invention; Figure 4 This is a fourth-view structural diagram of a multi-screw head collaborative material handling device at the end of a screw conveyor provided in an embodiment of the present invention; Figure 5A flowchart illustrating a control method provided in one embodiment of the present invention; Figure 6 This is a flowchart illustrating a method for obtaining the final priority adjustment coefficient according to an embodiment of the present invention.

[0016] In the structural diagram, 1 is the discharge belt; 2 is the material handling drive device; 3 is the bucket; 4 is the material handling baffle; 5 is the auger head; 6 is the flow sensor; 7 is the speed sensor; 8 is the discharge port; and 9 is the conical guide plate. Detailed Implementation

[0017] To further illustrate the technical means and effects adopted by the present invention to achieve its intended purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation, structure, features, and effects of a multi-screw head collaborative material handling control method for the end of a screw conveyor according to the present invention. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0019] The following describes in detail, with reference to the accompanying drawings, a specific scheme for a multi-screw head collaborative material handling control method at the end of a screw conveyor provided by the present invention.

[0020] One embodiment of the present invention provides a multi-screw head cooperative material handling device for the end of a screw conveyor, including a multi-screw head material handling device body, the multi-screw head material handling device comprising a structural combination Figure 1 , Figure 2 , Figure 3 as well as Figure 4 A detailed analysis is provided: the device comprises a discharge belt 1, a material handling drive 2, a bucket 3, a material handling deflector 4, a spiral head 5, a flow sensor 6, a speed sensor 7, a discharge port 8, and a conical guide plate 9. The material handling device includes three spiral heads 5. The bucket 3 digs and holds the material, and the material handling deflector 4 evenly directs the material scooped by the bucket 3 towards the spiral heads 5. The flow sensor 6 obtains the total output flow rate of the system, the speed sensor 7 obtains the angular velocity and rotational speed of the spiral heads, and the power detection module in the material handling device obtains the power of the spiral heads and the input power of the material handling drive 2. The output control signal is then output through the material handling drive 2 to regulate the rotational speed of each spiral head 5. The material is pushed through the conical guide plate 9 to the circular discharge port 8, and then transported from the material handling device to other equipment via the discharge belt 1. The device also includes a controller, and a speed sensor and a power detection module connected to the controller.

[0021] One embodiment of the present invention provides a control method for coordinated material handling by multiple spiral heads at the end of a screw conveyor. This control method is applied in a multi-spiral head material handling device and is executed by a controller. For details on the control method, please refer to [link to relevant documentation]. Figure 5 The diagram illustrates a flowchart of a control method provided in one embodiment of the present invention, the specific method including: Step S1: Real-time acquisition of the angular velocity, rotational speed, screw head power, and input power of the material handling drive device for each screw head at every moment within the preset sampling period when the material handling device is unloaded and handling material.

[0022] In the embodiments of the present invention, the difference in response characteristics of each actuator is not considered when adjusting the rotation speed of the multi-spiral shaft. Too fast an adjustment will cause system oscillation, while too slow an adjustment will not be able to suppress the risk in time. It is necessary to analyze the load status and energy efficiency level of each spiral head. First, the angular velocity, rotation speed, spiral head power and input power of the material picking drive device of each spiral head at each moment within the preset sampling period are obtained in real time when the material picking device is unloaded and picking up material.

[0023] It should be noted that angular velocity and rotational speed can be converted to each other, and the linear relationship is calculated by summing angular velocity and rotational speed. The ratio between two values ​​is taken as the rotational speed, where the angular velocity is measured in radians per second and the rotational speed is measured in revolutions per second.

[0024] It should be noted that, in one embodiment of the present invention, the angular velocity of the screw head, the power of the screw head, and the input power of the material handling drive device at each moment are obtained at a sampling frequency of 100Hz, that is, the preset sampling period is 0.01 seconds, and each 0.01 seconds contains 100 sampling moments; in other embodiments of the present invention, the sampling frequency is a technical means well known to those skilled in the art, and is not limited or described here.

[0025] It should be noted that, in order to facilitate subsequent data processing, a low-pass filter was selected to process the acquired data and effectively filter out high-frequency vibration noise. The specific methods are well known to those skilled in the art and will not be described in detail here.

[0026] Step S2: Based on the power and angular velocity of each screw head at each moment during no-load and material picking, obtain the load power of each screw head at each moment during material picking; for the material picking device, based on the load power, rotation speed, and motor input power of the screw head at different moments, obtain the blockage risk factor of the screw head in each sampling period and the mechanical input efficiency at each moment; based on the distribution of blockage risk factors of all screw heads in the sampling period at each moment, obtain the system coordination degree at each moment.

[0027] To more accurately reflect load changes during material handling, the data of the screw head under no-load and material handling conditions are analyzed. Under no-load conditions, the output power of the drive device is ensured to be almost entirely used to overcome the system's own inertia, minimizing the impact of measurement noise and more accurately assessing the load impact during material handling. Based on the screw head power and angular velocity of each screw head at each moment under no-load and material handling conditions, the load power of each screw head at each moment during material handling is obtained.

[0028] Preferably, in one embodiment of the present invention, the method for obtaining load power includes: For any screw head, the ratio of the difference in angular velocity between the next moment and the previous moment to the difference at the corresponding moment is obtained, which is used as the rate of change of angular velocity at each moment; for no-load conditions, the screw head power and the rate of change of angular velocity of each screw head at each moment are obtained to form the data point at each moment. Obtain the fitted line by fitting the data points at all times, and obtain the slope of the fitted line as the moment of inertia. When taking materials, the product between the moment of inertia and the rate of change of angular velocity at each moment is obtained. The difference between the power of the screw head at each moment and the product result is calculated as the load power of the screw head at each moment.

[0029] It should be noted that, in the embodiments of the present invention, the power of the spiral head is used as the data in the vertical direction and the rate of change of angular velocity is used as the data in the horizontal direction to form the data points at each moment. The least squares method or polynomial fitting algorithm is used to perform linear fitting. The specific means are well known to those skilled in the art and will not be described in detail here.

[0030] The efficiency and stability of a screw conveyor system directly depend on the physical state of the material. Different materials have different particle size distributions, moisture content, bulk density, viscosity, and other characteristics, which can lead to significant differences in their conveying capacity. Furthermore, changes in the state of the same material during the conveying process can also affect the conveying efficiency of each screw head. For screw conveyors, the root cause of blockage is the decreased flowability of the material, which means that the screw blades need to expend more power to move a small amount of material, i.e., more power is needed to maintain the angular velocity, making blockage more likely. When the load power increases and the angular velocity increases, more effective power is obtained, and the mechanical input power increases. Therefore, when the material receiving device is receiving material, the blockage risk factor of the screw head in each sampling period and the mechanical input efficiency at each moment can be obtained based on the load power, rotation speed, and motor input power of the screw head at different times.

[0031] Preferably, in one embodiment of the present invention, the method for obtaining the congestion risk factor includes: The average ratio between load power and speed at all times within each sampling period is obtained and normalized to serve as the congestion risk factor for each sampling period.

[0032] It should be noted that in the embodiments of the present invention, linear normalization or a normalization function is used for normalization, such as maximum and minimum value normalization, that is, all sampling periods are analyzed, and the maximum and minimum values ​​in the ratio mean result are selected for maximum and minimum value normalization to the range of 0-1; the specific means are well known to those skilled in the art and will not be described in detail here.

[0033] Preferably, in one embodiment of the present invention, the method for obtaining mechanical input efficiency includes: When the material handling device is handling material, the product of the angular velocity and load power of each screw head at each moment is obtained. The ratio of the product result to the motor input power is calculated and normalized to serve as the mechanical input efficiency of each screw head at each moment.

[0034] It should be noted that, in the embodiments of the present invention, linear normalization or a normalization function is used for normalization, such as maximum and minimum value normalization, that is, all screw heads are analyzed at each moment, and the maximum and minimum values ​​in the ratio results are selected for maximum and minimum value normalization to the range of 0-1; the specific means are technical means well known to those skilled in the art, and will not be described in detail here.

[0035] In screw conveying, multiple screw heads work together, and their working states are interconnected. The overall performance of the system is not determined by the optimal performance of a single screw head, but is limited by the worst-performing key unit. The blockage risk factor reflects the degree of blockage of the screw head. The higher the blockage risk factor, the greater the material resistance the screw head experiences at the same rotation speed, and the more likely it is to stall, affecting the system's synergistic effect. The system synergy at each moment is obtained by analyzing the blockage risk factor distribution of all screw heads in the sampling period at each moment.

[0036] Preferably, in one embodiment of the present invention, the method for obtaining system coordination degree includes: Obtain the range of the blockage risk factor for all spiral heads in the sampling period at each moment; obtain the mean of the blockage risk factor for all spiral heads in the sampling period at each moment, as the overall blockage risk factor; The ratio of the range value to the overall congestion risk factor is obtained and normalized to represent the system synergy at each time step.

[0037] It should be noted that the range represents the difference between the maximum and minimum values ​​of the congestion risk factor.

[0038] It should be noted that in the embodiments of the present invention, linear normalization or a normalization function is used for normalization, such as maximum and minimum value normalization, that is, all time points are analyzed, and the maximum and minimum values ​​in the ratio results are selected for maximum and minimum value normalization to the range of 0-1; the specific means are well known to those skilled in the art and will not be described in detail here.

[0039] Step S3: Based on the blockage risk factors of different spiral heads in different sampling periods and the load power distribution at different times, obtain the final priority adjustment coefficient of each spiral head at each time; based on the mechanical input efficiency, system coordination, and final priority adjustment coefficient of each spiral head at each time, as well as the blockage risk factor of the sampling period, obtain the comprehensive control weight of each spiral head at each time.

[0040] The clogging risk factor reflects the likelihood of material blockage in the screw head. The higher the clogging risk factor, the greater the likelihood of blockage. In multi-screw head collaborative operation, the overall performance, stability, and energy consumption of the system do not depend on the average value of all screw heads, but are determined by the screw head with the worst operating conditions and closest to failure. If the clogging risk factor of a screw head is higher than that of other screw heads, and the same rotation speed is maintained, blockage is more likely to occur, requiring timely adjustment. The greater the deviation of the load power from the overall level at any given time, the slower the screw head's response to control commands, and the worse its response efficiency, requiring more adjustment. Therefore, based on the clogging risk factors of different screw heads in different sampling periods and the load power distribution at different times, the final priority adjustment coefficient of each screw head at each time moment is obtained.

[0041] Preferably, in one embodiment of the present invention, the method for obtaining the final priority adjustment coefficient is described in [reference needed]. Figure 6 It outputs a flowchart of a method for obtaining the final priority adjustment coefficient, including: Step S601: Based on the blockage risk factors of different spiral heads in different sampling periods, obtain the bottleneck priority adjustment coefficient of each spiral head at each moment.

[0042] Preferably, the higher the blockage risk factor, the greater the material resistance experienced by the screw head at the same rotational speed. This high resistance state is more likely to cause blockage, becoming a system bottleneck and requiring adjustment. In one embodiment of the present invention, the method for obtaining the bottleneck priority adjustment coefficient includes: If among all the spiral heads, there is one spiral head whose blockage risk factor value is the largest in all sampling periods within the local sampling period range at every moment, the corresponding spiral head is regarded as the bottleneck spiral head. The difference between the blockage risk factor and the overall blockage risk factor of the bottleneck spiral head at each sampling period is obtained as the risk difference; If the spiral head corresponds to the bottleneck spiral head, the bottleneck priority adjustment coefficient of the spiral head at each moment is set as the risk difference; if the spiral head does not correspond to the bottleneck spiral head, the ratio of the risk difference to the number of other spiral heads is calculated and used as the bottleneck priority adjustment coefficient of the corresponding spiral head at each moment.

[0043] It should be noted that the difference represents the absolute value of the calculated difference. The greater the risk difference, the greater the degree of adjustment required for the bottleneck spiral head.

[0044] It should be noted that, in one embodiment of the present invention, the method for obtaining the local sampling period range is to take the sampling period at each moment as a reference and obtain the range consisting of a number of adjacent historical sampling periods as the local sampling period range at each moment, wherein the number of historical periods is 9 and there are a total of 10 sampling periods within the range; in other embodiments of the present invention, the size of the local sampling period range can be set according to specific circumstances, and is not limited or described here.

[0045] Step S602: Based on the load power distribution of each spiral head at different times, obtain the load power change response efficiency of each spiral head at each time.

[0046] Preferably, considering the response time between issuing a speed command and the actual change in power, if the system response time is too long, the further it deviates from the overall load power at any given moment, the less effective it is at preventing the power from continuously increasing, ultimately leading to stalling. Conversely, if the system response time is too short, drastic changes in speed will cause drastic power fluctuations, which will be transmitted to other screw heads through the material, causing oscillations in the speed and load of the entire system, making it unable to operate stably and resulting in large load variations. In one embodiment of the present invention, the method for obtaining the load power change response efficiency includes: For any spiral head, obtain the difference in load power between each moment and the previous moment, as the load power change at each moment; obtain the sum of the load power changes at all moments, as the overall load power change. Obtain the average load power over all time periods as the overall load power; obtain the maximum difference between the load power at different time periods and the overall load power within the neighborhood of each time period as the overall load deviation at each time period. The load power change response efficiency at each moment is obtained based on the overall load deviation and the overall load power change. The overall load deviation and the load power change response efficiency are negatively correlated, while the overall load power change and the load power change response efficiency are positively correlated.

[0047] Based on this, the greater the overall load deviation, the greater the deviation from the overall load power in the neighborhood at the corresponding moment, the longer the response time and the lower the load power change response efficiency; the greater the overall load power change, the faster the system adjustment speed, the greater the oscillation of the entire system speed and load, and the greater the load power change response efficiency; therefore, the overall load deviation and the load power change response efficiency are negatively correlated, while the overall load power change and the load power change response efficiency are positively correlated.

[0048] In one embodiment of the present invention, the sum of the overall load deviation and the preset adjustment coefficient is calculated as the overall load deviation correction value, and the ratio between the overall load power change and the overall load deviation correction value at each moment is obtained as the load power change response efficiency at each moment.

[0049] It should be noted that, in one embodiment of the present invention, the method for obtaining the neighborhood range includes: taking each moment as a reference, forming a range of a preset duration with historical moments, wherein the preset duration is 2 seconds; in other embodiments of the present invention, the size of the neighborhood range can be specifically set according to the specific situation, and will not be limited or described in detail here.

[0050] It should be noted that, in order to avoid the formula being meaningless when the denominator is 0, a preset adjustment coefficient is set. In order to reduce the influence of the preset adjustment coefficient on the calculation results, the preset adjustment coefficient can be set to a very small positive number with the same dimensions as the denominator. Its value is specifically set according to the range of values ​​of the denominator. The specific means are well known to those skilled in the art and will not be described in detail here.

[0051] Step S603: Obtain the product of the bottleneck priority adjustment coefficient and the load power change response efficiency for each spiral head, as the final priority adjustment coefficient for each spiral head at each moment.

[0052] Based on this, the final optimized adjustment coefficient of each spiral head at each moment is obtained. The larger the final priority adjustment coefficient, the more load redistribution is needed.

[0053] Mechanical input power reflects the efficiency of converting electrical energy into mechanical energy. The higher the mechanical input power, the more efficiently it is converted into mechanical energy, the more efficiently the screw head operates, the better the material state matches the equipment parameters, and the less adjustment is needed. System coordination reflects the level of coordinated operation of multiple screw heads. The higher the system coordination, the better the coordination of multiple screw heads, and the less adjustment is needed. The final priority adjustment coefficient reflects the degree to which the system needs adjustment. The higher the final priority adjustment coefficient, the greater the risk of blockage, and the greater the adjustment weight. Therefore, based on the mechanical input efficiency, system coordination, and final priority adjustment coefficient of each screw head at each moment, as well as the blockage risk factor of the sampling period, the comprehensive adjustment weight of each screw head at each moment is obtained.

[0054] Preferably, in one embodiment of the present invention, mechanical input efficiency and system coordination are both negatively correlated with the comprehensive control weight, while the final priority adjustment coefficient and congestion risk factor are both positively correlated with the comprehensive control weight.

[0055] In one embodiment of the present invention, the product of the mechanical input efficiency and system coordination of each screw head at each moment is obtained as the screw head energy efficiency; the product of the final priority adjustment coefficient of each screw head at each moment and the blockage risk factor of the sampling period is obtained as the screw head bottleneck degree. The first sum between the energy efficiency of the spiral head and the preset adjustment coefficient is obtained. The ratio of the bottleneck degree of the spiral head to the first sum is calculated and used as the comprehensive control weight of each spiral head at each moment. It should be noted that, in order to avoid the denominator of the formula being 0 and the formula being meaningless, a preset adjustment coefficient is set. In order to reduce the influence of the preset adjustment coefficient on the calculation results, the preset adjustment coefficient can be set to a very small positive number with the same dimension as the denominator. Its value is specifically set according to the range of the denominator. The specific means are well known to those skilled in the art and will not be described in detail here.

[0056] Step S4: Based on the comprehensive control weight of different spiral heads at real time and the preset adjustment speed, construct the speed control function to obtain the real-time adjustment speed of each spiral head when picking up material.

[0057] The speed control is to maintain the stability of the co-operation of the screw heads in material handling. Considering the randomness caused by actual environmental factors, it is necessary to combine the comprehensive control weight and the preset adjustment speed to construct the preset adjustment speed, so as to accurately adjust the control precision of the adjustment speed, so that the speed of different screw heads is naturally balanced and the speed difference is as small as possible.

[0058] Preferably, in one embodiment of the present invention, the method for obtaining the real-time rotational speed adjustment includes: Obtain the degree of fluctuation of the preset adjustment speed of all spiral heads at real time, as the degree of speed fluctuation; The sum of the cumulative value of the comprehensive control weight of all screw heads at real time and the sum of the speed fluctuation degree are obtained as the speed control function; The preset adjustment speed in the speed control function is solved based on the adaptive gradient optimization algorithm to obtain the real-time adjustment speed when each screw head picks up material.

[0059] It should be noted that, in one embodiment of the present invention, the standard deviation is used to characterize the degree of fluctuation. The larger the standard deviation, the greater the degree of fluctuation, and the smaller the standard deviation, the smaller the degree of fluctuation. In other embodiments of the present invention, variance can also be used to characterize the degree of fluctuation. The specific means are well known to those skilled in the art and will not be limited or described here.

[0060] It should be noted that constructing the speed control function is transformed into an optimization problem. By solving the function, the optimal preset adjustment speed can be found under certain conditions. The speed control function is solved using an adaptive gradient optimization algorithm. The parameters of the adaptive gradient optimization algorithm can be set by the implementers based on relevant experience: initial step size is 0.05, convergence threshold is 0.005, maximum number of iterations is 50, and flow fluctuation limit is 0.03. The specific iterative process is as follows: First, obtain the angular velocity and load power of each screw head at real time to obtain the initial value of the speed control function; then, enter the iterative optimization stage: First, by simulating the system state after a slight increase and decrease in the angular velocity of each screw head, determine whether to accelerate or decelerate. If acceleration reduces the speed control function, then accelerate; otherwise, decelerate. Second, obtain the total system output flow based on the flow sensor, and automatically adjust according to the deviation between the total system output flow and the target flow at real time. When the deviation is large, use a larger step size to quickly approach the target flow; when the deviation is small, use a smaller step size for fine adjustment. Third, update the angular velocity of all screw heads, and simultaneously... Fourth, verify the total output flow of the system. If it exceeds the allowable fluctuation range, that is, the difference between the total output flow of the system and the target flow is within the flow fluctuation limit, obtain the ratio of the fluctuation range boundary value closest to the total output flow of the system to the total output flow of the system, calculate the product of the ratio result and the angular velocity, and correct all angular velocities. Finally, calculate the correction value of the speed control function, obtain the difference between the initial value and the correction value. If the difference is less than the convergence threshold or reaches the maximum number of iterations, obtain the solution value of the preset speed adjustment, that is, obtain the real-time speed adjustment. The specific algorithm is a technical means well known to those skilled in the art, and will not be described in detail here.

[0061] Based on this, the real-time adjustment speed of the spiral head is obtained, which effectively avoids system oscillation caused by excessively fast adjustment or control failure caused by excessively slow adjustment, thereby improving the efficiency of collaborative material handling.

[0062] It should be noted that the equipment safety range and target traffic are obtained in advance by real-time personnel based on relevant professional knowledge.

[0063] In summary, this invention analyzes the power, angular velocity, rotational speed, and motor input power of each screw head at every moment during both no-load and material-harvesting operations. This yields the blockage risk factor and mechanical input efficiency of the screw head in each sampling cycle. Based on the blockage risk factors of all screw heads in different sampling cycles and the load power distribution at different times, the system coordination degree and final priority adjustment coefficient of each screw head at each moment are obtained. Furthermore, the comprehensive control weight of each screw head at each moment is obtained. Based on the comprehensive control weights of different screw heads at real-time and the preset adjustment speed, a speed control function is constructed to obtain the real-time adjustment speed of each screw head during material harvesting. This invention improves the efficiency of multi-screw head collaborative material harvesting by obtaining the appropriate rotational speed when screw heads are working collaboratively.

Claims

1. A spiral conveyor end multi-spiral head cooperative taking control method applied to a multi-spiral head cooperative taking device, characterized in that, The control method includes: The angular velocity, rotational speed, screw head power, and input power of the material handling drive device are acquired in real time at every moment within a preset sampling period when the material handling device is unloaded and handling material. Based on the power and angular velocity of each screw head at each moment during no-load and material picking, the load power of each screw head at each moment during material picking is obtained; for the material picking device, based on the load power, rotation speed, and motor input power of the screw head at different moments, the blockage risk factor of the screw head in each sampling period and the mechanical input efficiency at each moment are obtained; based on the distribution of the blockage risk factors of all screw heads in the sampling period at each moment, the system coordination degree at each moment is obtained. Based on the blockage risk factors of different spiral heads in different sampling periods and the load power distribution at different times, the final priority adjustment coefficient of each spiral head at each time is obtained; based on the mechanical input efficiency, system coordination and final priority adjustment coefficient of each spiral head at each time, and the blockage risk factor of the sampling period, the comprehensive control weight of each spiral head at each time is obtained. Based on the comprehensive control weights of different spiral heads at real time and the preset adjustment speed, a speed control function is constructed to obtain the real-time adjustment speed of each spiral head when picking up material.

2. The method according to claim 1, wherein The method for obtaining the load power includes: For any screw head, the ratio of the difference in angular velocity between the next moment and the previous moment to the difference at the corresponding moment is obtained, which is used as the rate of change of angular velocity at each moment; for no-load conditions, the screw head power and the rate of change of angular velocity of each screw head at each moment are obtained to form the data point at each moment. Obtain the fitted line by fitting the data points at all times, and obtain the slope of the fitted line as the moment of inertia. When taking materials, the product between the moment of inertia and the rate of change of angular velocity at each moment is obtained. The difference between the power of the screw head at each moment and the product result is calculated as the load power of the screw head at each moment.

3. The method of claim 1, wherein the method further comprises: The methods for obtaining the congestion risk factor and mechanical input efficiency include: The average ratio between load power and speed at all times within each sampling period is obtained and normalized to serve as the congestion risk factor for each sampling period. When the material handling device is handling material, the product of the angular velocity and load power of each screw head at each moment is obtained. The ratio of the product result to the motor input power is calculated and normalized to serve as the mechanical input efficiency of each screw head at each moment.

4. The method for controlling the coordinated material handling of multiple spiral heads at the end of a screw conveyor according to claim 1, characterized in that, The method for obtaining the system's degree of coordination includes: Obtain the range of the blockage risk factor for all spiral heads in the sampling period at each moment; obtain the mean of the blockage risk factor for all spiral heads in the sampling period at each moment, as the overall blockage risk factor; The ratio of the range value to the overall congestion risk factor is obtained and normalized to represent the system synergy at each time step.

5. The method for controlling the coordinated material handling of multiple spiral heads at the end of a screw conveyor according to claim 4, characterized in that, The method for obtaining the final priority adjustment coefficient includes: Based on the blockage risk factors of different spiral heads in different sampling periods, the bottleneck priority adjustment coefficient of each spiral head at each moment is obtained; Based on the load power distribution of each screw head at different times, the load power change response efficiency of each screw head at each time is obtained. The bottleneck priority adjustment factor and the load power change response efficiency of each spiral head are obtained as the final priority adjustment factor of each spiral head at each moment.

6. The method for controlling the coordinated material handling of multiple spiral heads at the end of a screw conveyor according to claim 5, characterized in that, The method for obtaining the bottleneck priority adjustment coefficient includes: If among all the spiral heads, there is one spiral head whose blockage risk factor value is the largest in all sampling periods within the local sampling period range at every moment, the corresponding spiral head is regarded as the bottleneck spiral head. The difference between the blockage risk factor and the overall blockage risk factor of the bottleneck spiral head at each sampling period is obtained as the risk difference; If the spiral head corresponds to the bottleneck spiral head, set the bottleneck priority adjustment coefficient of the spiral head at each moment to the risk difference; If the spiral head does not correspond to the bottleneck spiral head, calculate the ratio of the risk difference to the number of other spiral heads, and use it as the bottleneck priority adjustment coefficient for the corresponding spiral head at each moment.

7. The method for controlling the coordinated material handling of multiple spiral heads at the end of a screw conveyor according to claim 5, characterized in that, The method for obtaining the load power change response efficiency includes: For any spiral head, obtain the difference in load power between each moment and the previous moment, as the load power change at each moment; obtain the sum of the load power changes at all moments, as the overall load power change. Obtain the average load power at all times as the overall load power; obtain the maximum difference between the load power at different times and the overall load power in the neighborhood of each time as the overall load deviation at each time. The load power change response efficiency at each moment is obtained based on the overall load deviation and the overall load power change at each moment. The overall load deviation and the load power change response efficiency are negatively correlated, while the overall load power change and the load power change response efficiency are positively correlated.

8. The method for controlling the coordinated material handling of multiple spiral heads at the end of a screw conveyor according to claim 1, characterized in that, The mechanical input efficiency and system coordination are both negatively correlated with the comprehensive control weight, while the final priority adjustment coefficient and congestion risk factor are both positively correlated with the comprehensive control weight.

9. A method for controlling the coordinated material handling of multiple spiral heads at the end of a screw conveyor according to claim 1, characterized in that, The method for obtaining the real-time adjusted rotation speed includes: Obtain the degree of fluctuation of the preset adjustment speed of all spiral heads at real time, as the degree of speed fluctuation; The sum of the cumulative value of the comprehensive control weight of all screw heads at real time and the sum of the speed fluctuation degree are obtained as the speed control function; The preset adjustment speed in the speed control function is solved based on the adaptive gradient optimization algorithm to obtain the real-time adjustment speed when each screw head picks up material.

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