Method and system for optimizing pushing speed of dumping mechanism of bulk material system
Through the combination of discrete element modeling and multi-body dynamics, the cylinder stroke control during the flip of the ear box is optimized, the problem of sharp changes in the cylinder force is solved, and a safer and more efficient flip operation is achieved.
Patent Information
- Application Number
- CN202411962387.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-30
- Publication Date
- 2025-04-18
AI Technical Summary
In the prior art, the push speed of the oil cylinder is too fast during the flip of the ear box, causing the ear to change sharply and fall, causing the cylinder force to change sharply. The push speed is too slow, which will increase the length of the flip process and affect efficiency.
Through a combination of discrete element modeling and multi-body dynamics, the cylinder stroke control is optimized and the optimal angular time-travel curve is determined to reduce the instantaneous impact force of the cylinder without increasing the total flip time.
It is achieved to reduce the instantaneous peak of the cylinder force without increasing the total flip time, and improve the safety and efficiency of flip operations.
Smart Images
Figure CN119849059A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of optimization design, and in particular to a method and system for optimizing the pushing speed of a bulk material system dumping mechanism. Background Art
[0002] The dumping mechanism including the ear box is a temporary harvesting silo for agricultural plant (such as corn) harvesters. Its function is to temporarily store the harvested ears. When the ear box is full, the cylinder is extended and retracted to drive the box to flip, so that the harvested ears can be quickly transferred to the truck hopper and transported to the designated granary. Different from the transportation of traditional materials, the ears are bulk materials. When the silo flips, the ears will slide or even fall in the box. The overall change of the center of gravity and the instantaneous impact caused by the falling ears will cause a sharp change in the cylinder force, even exceeding the design load. Increasing the cylinder specifications will significantly increase costs.
[0003] The push time curve of the oil cylinder determines the flip angle time curve of the ear box, thus affecting the overall shape of the ear pile in the box. The existing technology generally adopts the uniform push of the oil cylinder, without considering the influence of the oil cylinder push speed on the oil cylinder push force. If the oil cylinder push speed is fast, the ear pile in the box will change sharply during the rapid flipping process, which will cause the ear to fall quickly during the pushing process, causing some ears to fall instantly and cause too much impact. The sudden increase of the cylinder force will cause the cylinder load to be too large, affecting the safety of the operation. Ideally, the slower the oil cylinder push speed, the better, which will reduce the sharp changes of the ear pile in the silo, thereby reducing the impact caused by the fall, and thus avoiding the sudden increase of the cylinder force, but the slow push speed will inevitably lead to an increase in the push time, affecting the efficiency of the flipping operation. Therefore, how to set the optimal oil cylinder push stroke curve so that the cylinder force is as stable as possible during the pushing process to avoid the sudden rise peak has become a difficult problem in the industry. Summary of the invention
[0004] The purpose of the embodiments of the present application is to provide a method and system for optimizing the pushing speed of a bulk material system dumping mechanism, which is a new cylinder stroke control technology that reduces the instantaneous impact force of the cylinder during the flipping process without increasing the total flipping time.
[0005] In order to achieve the above-mentioned objectives, the first aspect of the present application provides a method for optimizing the pushing speed of a bulk material system dumping mechanism, the pushing speed optimization method comprising: determining an angle-force curve between the flipping angle of the cylinder during the flipping process of the dumping mechanism and the applied force of the cylinder by discrete element modeling according to the initial hinge point information of the cylinder on the dumping mechanism; defining a driving function of the dumping mechanism, wherein the driving function is an angle-time curve of the cylinder during the flipping process of the dumping mechanism, and the driving function includes a predetermined number of optimization coefficients; optimizing the angle-force curve according to the driving function and constraints with minimizing the maximum applied force of the cylinder as the optimization goal, so as to obtain a target optimization coefficient of the driving function when the maximum applied force of the cylinder is at the minimum value; and determining a target angle-time curve of the cylinder according to the target optimization coefficient.
[0006] In an embodiment of the present application, the angle-force curve between the flipping angle of the cylinder during the flipping process of the tipping mechanism and the applied force of the cylinder is determined by discrete element modeling based on the initial hinge point information of the cylinder on the tipping mechanism, including: determining the angle-force-arm curve between the flipping angle and the applied force arm of the cylinder based on the initial hinge point information of the cylinder on the tipping mechanism; determining the angle-torque curve between the flipping angle and the applied torque of the cylinder by discrete element modeling; and determining the angle-force curve based on the angle-force-arm curve and the angle-torque curve.
[0007] In the embodiment of the present application, the initial hinge point information includes a first fixed hinge point, a second fixed hinge point and a movable hinge point, and the angle arm curve between the flip angle and the applied force arm of the cylinder is determined according to the initial hinge point information of the oil cylinder on the dumping mechanism, including: the following formula determines the flip angle The angle between the applied force arm of the cylinder and the force arm curve :
[0008] in, is the length of the line segment AB formed by the first fixed hinge point A and the second fixed hinge point B, is the length of the line segment AC formed by the first fixed hinge point A and the movable hinge point C; the flip angle is the angle formed by taking the first fixed hinge point A as the vertex and the line segment AC and the line segment AB as the sides, is the flip angle The initial angle of .
[0009] In the embodiment of the present application, the determining the angle force curve according to the angle arm curve and the angle torque curve includes: determining the angle force curve according to the angle arm curve and angle torque curve , the angle force curve is determined by the following formula :
[0010] In an embodiment of the present application, the driving function is any one of the following: a cubic polynomial function, a quartic polynomial function, a high-order polynomial function greater than fourth order, a power function, and a trigonometric function; wherein the cubic polynomial function includes three optimization coefficients, and the quartic polynomial function, the trigonometric function, and the power function include four optimization coefficients.
[0011] In the embodiment of the present application, when the driving function is the cubic polynomial function, the following formula represents the driving function: : When the driving function is the fourth-order polynomial function, the following formula represents the driving function: ： When the driving function is the power function, the driving function is expressed by the following equation: ： Or when the driving function is the trigonometric function, the driving function is expressed by the following equation: ： in, is the optimization coefficient.
[0012] In the embodiment of the present application, the constraint condition includes one or more of the following: a minimum specified angle constraint, a maximum specified angle constraint, and a flip angular velocity constraint.
[0013] In the embodiment of the present application, in the driving function When it is a cubic polynomial function, the following equations represent the minimum specified angle constraint, the maximum specified angle constraint, and the flip angular velocity constraint:
[0014]
[0015]
[0016] in, is the optimization coefficient, is the maximum flip angle, is the total flipping time.
[0017] In an embodiment of the present application, the angle time history curve is optimized by at least one of the following algorithms: genetic algorithm, downhill method, annealing method.
[0018] A second aspect of the present application provides a method for optimizing the pushing speed of a bulk material system dumping mechanism, the method comprising: determining a cylinder stroke force curve between the stroke of the cylinder during the tipping process of the dumping mechanism and the applied force of the cylinder by multi-body dynamics + discrete element modeling according to the initial hinge point information of the cylinder on the dumping mechanism; defining a driving function of the dumping mechanism, wherein the driving function is a cylinder stroke time-history curve of the cylinder during the tipping process of the dumping mechanism, and the driving function includes a predetermined number of optimization coefficients; optimizing the stroke force curve according to the driving function and constraints with minimizing the maximum applied force of the cylinder as the optimization goal to obtain a target optimization coefficient of the driving function when the maximum applied force of the cylinder is at the minimum value; and determining a target cylinder stroke time-history curve of the cylinder according to the target optimization coefficient.
[0019] The third aspect of the present application provides a pushing speed optimization system for a bulk material system dumping mechanism, the pushing speed optimization system comprising: a discrete element modeling device, for determining an angle-force curve between the flipping angle of the cylinder during the flipping process of the dumping mechanism and the applied force of the cylinder in a discrete element modeling manner according to the initial hinge point information of the cylinder on the dumping mechanism; a driving function determination device, for defining a driving function of the dumping mechanism, wherein the driving function is an angle-time curve of the cylinder during the flipping process of the dumping mechanism, and the driving function includes a predetermined number of optimization coefficients; an optimization device, for optimizing the angle-force curve according to the driving function and constraints with minimizing the maximum applied force of the cylinder as the optimization goal, so as to obtain a target optimization coefficient of the driving function when the maximum applied force of the cylinder is at a minimum; and a target curve determination device, for determining a target angle-time curve of the cylinder according to the target optimization coefficient.
[0020] The existing technology generally adopts the uniform speed of the cylinder push, without considering the impact of the cylinder push speed on the cylinder push force. If the cylinder push speed is too fast, the ears in the silo will change drastically during the rapid flipping process, resulting in a huge impact of the instantaneous fall, causing a sharp increase in the instantaneous load of the cylinder; if the push speed is too slow, it will greatly increase the duration of the entire flipping process, affecting the efficiency of the flipping operation.
[0021] Through the above-mentioned technical scheme of the present invention, an "optimal cylinder stroke time curve control technology for minimizing the instantaneous cylinder force peak" is proposed. By optimizing the "box flip angle time curve", an equivalent optimization method of obtaining the "optimal cylinder stroke time curve" is obtained. This can effectively reduce the instantaneous peak of the cylinder force compared to the previous constant speed cylinder push while keeping the total pushing time unchanged.
[0022] That is to say, the present invention reasonably distributes the angular velocity of the box rotation without increasing the total duration of the flipping action. In the range where the center of gravity is not likely to move significantly, the angular velocity of the box rotation is appropriately accelerated; in the travel range where falling is likely to occur, the angular velocity of the box rotation is appropriately slowed down. In this way, the most reasonable cylinder pushing scheme with the smallest cylinder force peak can be obtained.
[0023] In addition, the present invention proposes a method for calculating the cylinder force during the tipping process of a discrete system using only a discrete element model, which can obtain accurate cylinder force response results more quickly and provide feasibility for the subsequent optimization of the flip angle time curve.
[0024] Other features and advantages of the embodiments of the present application will be described in detail in the subsequent specific implementation section. BRIEF DESCRIPTION OF THE DRAWINGS
[0025] The accompanying drawings are used to provide a further understanding of the embodiments of the present application and constitute a part of the specification. Together with the following specific implementations, they are used to explain the embodiments of the present application, but do not constitute a limitation on the embodiments of the present application. In the accompanying drawings: Figure 1 A schematic diagram of a process flow of a method for optimizing the pushing speed of a dumping mechanism of a bulk material system according to an embodiment of the present application is schematically shown; Figure 2 A schematic diagram schematically shows a calculation process of an objective function according to an embodiment of the present application; Figure 3 A schematic diagram showing the change of the hinge point position during the flipping process of the box according to an embodiment of the present application is shown; Figure 4 A schematic diagram showing the change of the bending moment value during the box flipping process according to an embodiment of the present application is shown; Figure 5 A schematic diagram schematically shows an optimization model analysis process according to an embodiment of the present application; Figure 6 The schematic diagram shows the structure of a pushing speed optimization system of a bulk material system dumping mechanism according to an embodiment of the present application. DETAILED DESCRIPTION
[0026] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. It should be understood that the specific implementation methods described herein are only used to illustrate and explain the embodiments of the present application, and are not used to limit the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.
[0027] It should be noted that the acquisition, transmission, storage, use, and processing of data in the technical solution of this application are in compliance with the relevant provisions of national laws and regulations. In the embodiments of this application, some existing solutions in the industry such as certain software, components, and models may be mentioned, which should be considered as exemplary. Their purpose is only to illustrate the feasibility of implementing the technical solution of this application, but it does not mean that the applicant has or will necessarily use the solution.
[0028] It should be noted that if the embodiments of the present application involve directional indications (such as up, down, left, right, front, back...), such directional indications are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.
[0029] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present application, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by this application.
[0030] In view of the problem that the cylinder force curve is not stable and has a large peak value in the existing cylinder stroke linear control, the present invention provides an optimal cylinder stroke time curve control technology to achieve the minimum cylinder force peak. Figure 1 The schematic diagram of the process of optimizing the push speed of a bulk material system dumping mechanism according to an embodiment of the present application is shown schematically, which can be used to optimize the push speed of dumping mechanisms including ear boxes. It should be noted that the optimization method provided by this patent only uses corn ear boxes as an example. In addition, the optimization of the push speed of the loading and unloading process involving discrete materials in other bulk materials such as minerals, crops, and food can also be performed with reference to the optimization method proposed in this patent.
[0031] In addition, the overall technical route of the present invention is: first see Figure 2 Based on multiple input parameters and discrete element software, the objective function of the optimization model, namely the angle force curve , the corresponding curve of the required cylinder force changing with time and the maximum peak can be obtained through the angle time curve of the box during the flipping process; then based on the objective function, the angle time curve of the box during the flipping process is optimized to obtain the optimal cylinder stroke time curve that minimizes the maximum force. The specific implementation process is: the box flip angle time curve is parameterized, for example, by a "cubic polynomial", with the total flip angle and total flip time of the box unchanged as constraints, and the maximum cylinder force minimization during the flipping process as the optimization goal, and the optimization algorithm is used to solve the optimal box flip angle time curve, and finally combined with the hinge position relationship, the optimal cylinder push time curve is obtained. Therefore, based on the cylinder stroke control of this curve, the peak of the cylinder force curve during the flipping process of the box can be minimized.
[0032] Specifically, the push speed optimization method 100 of the present invention may include the following steps S110-S140.
[0033] Step S110: according to the initial hinge point information of the oil cylinder on the dumping mechanism, determine the angle force curve between the turning angle of the oil cylinder during the turning process of the dumping mechanism and the applied force of the oil cylinder by discrete element modeling.
[0034] The initial hinge point information may include initial position information of at least two fixed hinge points and at least one mobile hinge point, for example, the initial hinge point information may include a first fixed hinge point, a second fixed hinge point and a mobile hinge point. In the embodiment of the present application, step S110 may also include the following steps S111-S113.
[0035] Step S111: Determine an angle-lever curve between a turning angle and an applied lever arm of the oil cylinder according to the initial hinge point information of the oil cylinder on the dumping mechanism.
[0036] Among them, during the pushing process, the cylinder stroke and the box flip angle are in a one-to-one correspondence, which can be represented by a mathematical expression. Specifically, Figure 3 The hinge information of the dumping mechanism in an embodiment is given in the figure, which adopts the arrangement of a single-side oil cylinder. Among them, A, B, and C are the initial hinges of the dumping mechanism. Hinge points A and B are fixed hinges fixed to the frame, and their positions do not change with the rotation of the dumping mechanism. Hinge point C is a follower hinge on the box body, that is, a mobile hinge. C' is the new hinge position after C moves during the pushing process. Among them, is the distance between AB, is the distance between AC, both of which are constants; the distance between BC That is, the length of the cylinder. Since the length of the cylinder changes with the position of the moving hinge point C, it can be defined The length of the cylinder over time The function of the change, is the length of the cylinder in the initial state.
[0037] Furthermore, the flip angle between AC and AB is defined as ,but is the initial angle of the flip angle. , so the flip angle can be determined by the following formula :
[0038] In the formula, is the length of the oil cylinder; is the initial distance of the line segment AB formed by the first fixed hinge point A and the second fixed hinge point B, is the initial distance of the line segment AC formed by the first fixed hinge point A and the movable hinge point C; the flip angle is the angle formed by the first fixed hinge point A as the vertex and the line segments AC and AB as the sides, Flip Angle The initial angle of .
[0039] Therefore, the force arm corresponding to the cylinder force That is the distance from A to BC', which can be expressed as:
[0040]
[0041] Therefore, the flip angle can be determined as follows Angle arm curve between the applied force arm of the cylinder :
[0042] in, is the length of the line segment AB formed by the first fixed hinge point A and the second fixed hinge point B, is the length of the line segment AC formed by the first fixed hinge point A and the movable hinge point C; the flip angle is the angle formed by the first fixed hinge point A as the vertex and the line segments AC and AB as the sides, Flip Angle The initial angle of .
[0043] In addition, since the flip angle also changes over time, we can define is the flip angle over time The function of the change. Then in the flipping process, , so the flip angle can also be determined by the following formula With the push time Angle time curve :
[0044] Similarly, the force arm corresponding to the cylinder force That is the distance from A to BC', which can be expressed as:
[0045]
[0046] Due to the flip angle In fact, it is an intermediate conversion term. To obtain the time history curve of the force arm, the time history curve of the flip angle is required. Therefore, the final force arm can also be expressed as Function :
[0047] in, is the length of the line segment AB formed by the first fixed hinge point A and the second fixed hinge point B, is the length of the line segment AC formed by the first fixed hinge point A and the movable hinge point C; the flip angle is the angle formed by the first fixed hinge point A as the vertex and the line segments AC and AB as the sides, Flip Angle The initial angle of .
[0048] Step S112: Determine the angle-torque curve between the flip angle and the applied torque of the cylinder by discrete element modeling.
[0049] Among them, discrete material parameters are, for example, ear parameters. In the actual modeling process of the ear, the load of the ear involves the contact calculation between particles and between particles and the wall. In this regard, the applicant takes into account that the source of the load, except for the deadweight of the box itself, the application of the remaining loads only comes from the discrete system of the ear. That is, this article proposes the need to establish a discrete model of corn ears (including particle size, shape, size distribution, etc.) based on the ear parameters in the ear box, regard the ear pile at the tilt angle as a whole, and calculate the compressive stress on the ear box by the total mass of the remaining ears. In this way, only the input parameters such as the shape and total mass of the ear pile are required, combined with the boundary conditions such as the contact parameters between the corn ears and the wall of the box (static and dynamic friction coefficients, rebound coefficient, etc.) to complete the modeling.
[0050] The physical significance of this method is that the total bending moment applied by discrete particles to the wall is only related to the shape of the particles in the box, and the shape of the ear pile of particles in the box is only related to the flip angle of the box. Since the flipping process of the ear box is actually a rotational motion around the hinge point A, the driving function of the box can be directly defined in the discrete element model: Through simulation calculation, the moment load applied by the discrete system to the wall of the box can be obtained. ,See Figure 4 .
[0051] Step S113: Determine the angle force curve according to the angle arm curve and the angle moment curve.
[0052] Since the fruit ears in the box are bulk materials, the shape of the pile in the box changes during the overturning process, and its center of mass also changes accordingly. If the center of mass position is regarded as unchanged relative to the bin, the calculation of the cylinder force will be inaccurate. Therefore, the present invention adopts discrete element simulation technology, uses the rotation of the box as a drive, and uses the total bending moment value applied to the box by the discrete system at any time. , and according to the rotation angle of the box The corresponding cylinder position and cylinder force arm can be obtained , through the total bending moment value And cylinder force arm The corresponding dynamic curve of the cylinder force during the flipping process can be obtained That is, since there are two symmetrically distributed oil cylinders in the ear box, the bending moment value borne by each oil cylinder is , then according to the angle arm curve and angle torque curve , the angle force curve is determined by the following formula :
[0053] Similarly, the cylinder force arm can also be obtained by step S111 , the total bending moment applied by the discrete system is obtained by step S112 , from which the cylinder force time history curve of a single cylinder can be obtained :
[0054] Step S120: define the driving function of the dumping mechanism.
[0055] As mentioned above, the total bending moment imposed by the fruit ear discrete system on the wall is only related to its shape in the box, and the shape of the fruit ear pile in the box is only related to the flip angle of the box. Therefore, by controlling the flip angle time history curve of the box, the variation range of the total bending moment can be controlled, thereby controlling the fluctuation range of the cylinder force. Based on this, this technology proposes an optimization control technology for "achieving the optimal box flip angle curve with the smallest peak of the cylinder force steep rise". The technical route is as follows: Figure 5 shown. The driving function is defined as the angle time curve of the oil cylinder during the flipping process of the dumping mechanism. For example, the driving function can be any of the following: a cubic polynomial function, a quartic polynomial function, a higher-order polynomial function greater than the fourth order, a power function, a trigonometric function, etc. At the same time, the driving function should also include a predetermined number of optimization coefficients (parameters to be optimized), which are the flip angle curve control parameters. The cubic polynomial function includes three optimization coefficients; the quartic polynomial function, the trigonometric function, and the power function include four optimization coefficients; and the higher-order polynomial function greater than the fourth order includes more than four optimization coefficients. It can be understood that the number of optimization coefficients corresponds to its degree.
[0056] Among them, when the driving function is a polynomial function, the purpose of this model is to obtain the variable flip angular velocity of the box, then the flip angular velocity The curve is at least The quadratic curve, therefore, flips the angle curve At least for time In this way, the initial zero-time flip angle can be defined as 0°. The following formula represents the driving function in the case of a cubic polynomial function: :
[0057] Therefore, it can be seen that the control parameters of the box flip angle curve include Third, the purpose of optimization is to finally get The optimal parameter value of .
[0058] In addition, the parameterization of the cabinet rotation angle time history curve in this patent is through conversion into a cubic polynomial. In addition, polynomials greater than cubic, trigonometric functions, power functions, etc., as long as they can reflect the function of the cabinet rotation angular velocity process, can also be used as an alternative solution for the parameterization of the cabinet rotation angle time history curve. The details are as follows: 1) When the driving function is a quartic polynomial function, the driving function can be expressed as follows: :
[0059] 2) When the driving function is a power function, the driving function can be expressed as follows: :
[0060] 3) When the driving function is a trigonometric function, the driving function can be expressed as follows: :
[0061] Among them, They are all optimization coefficients, that is, the control parameters of the cabinet flip angle curve. The purpose of optimization is to ultimately obtain the optimal parameter values of these optimization coefficients.
[0062] Step S130, according to the driving function and the constraint conditions, the angle force curve is optimized with minimization of the maximum applied force of the cylinder as the optimization goal, so as to obtain the target optimization coefficient of the driving function when the maximum applied force of the cylinder is at the minimum value.
[0063] Specifically, the optimization model can be optimized by using relevant optimization algorithms such as genetic algorithm, downhill method, annealing method, etc., and the optimization goal is to minimize the maximum value in the cylinder force curve obtained by S110. After multiple rounds of iterative optimization calculations, the residual of the minimum value of the objective function reaches stability (reaches a convergence state), and it can be considered that the minimum value of the objective function has been found, that is, the optimal flip angle control parameter with the minimum cylinder force corresponding to the constraint conditions is found.
[0064] In the entire optimization model, the constraint conditions may include one or more of the following: a minimum specified angle constraint, a maximum specified angle constraint, a flip angular velocity constraint, and the like.
[0065] The minimum specified angle constraint indicates the flip duration When it is 0, the flip angle is also 0, and the optimization process needs to satisfy:
[0066] When the flip time (total flip time), the flip angle should reach the maximum specified angle. That is, if the maximum flip angle of the box is , the total flipping time is , then the maximum specified angle constraint of the optimization process must satisfy:
[0067] In addition, in order to prevent the box from falling back during the flipping process, the box is required to always flip in one direction during the flipping and dumping process, so the flipping angular velocity is required to be always greater than 0, that is, the optimization process must satisfy:
[0068] That is, in the driver function When it is a cubic polynomial function, the flip angular velocity constraint can be expressed as follows:
[0069] in, is the optimization coefficient, is the maximum flip angle, is the total flipping time.
[0070] Then, if we define The optimal solution is 、 、 , then the optimal box flip angle time history curve is:
[0071] Step S140: Determine the target angle time curve of the cylinder according to the target optimization coefficient.
[0072] As mentioned above, the optimization model can be optimized by using genetic algorithms, downhill method, annealing method and other related optimization algorithms, and the optimization goal is to minimize the maximum value of the cylinder force curve obtained by S110. Correspondingly, after multiple rounds of iterative optimization calculations, the residual of the minimum value of the objective function reaches stability (reaches a convergence state), and it can be considered that the minimum value of the objective function has been found, that is, the optimal flip angle control parameter with the minimum cylinder force corresponding to the constraint conditions is found.
[0073] For example, if we define The optimal solution is 、 、 , then the optimal box flip angle time curve is:
[0074] Then, the optimal cylinder push time curve needs to be equivalently transformed. Since the final box is driven by the cylinder, the optimal angle flip time curve needs to be Transformed into the optimal push control stroke of the cylinder , thereby achieving precise control of the expected flip angle.
[0075] Among them, the total length of the cylinder can be obtained from the position relationship of the hinge point The function is:
[0076] Cylinder extension function That is, the total length of the cylinder during the flipping process Subtract the initial length ,Right now:
[0077] Therefore, according to By controlling the extension of the oil cylinder, the box turning speed control with the minimum oil cylinder force can be achieved.
[0078] It can be seen that the scheme of the present invention can reasonably distribute the angular velocity of the box rotation without increasing the total duration of the flipping action. In the interval where the center of gravity of the fruit ears is not likely to move significantly, the angular velocity of the box rotation can be appropriately accelerated; in the stroke interval where the fruit ears are prone to fall, the angular velocity of the box rotation can be appropriately slowed down. In this way, the most reasonable cylinder pushing scheme with the smallest cylinder force peak can be obtained.
[0079] In addition, the calculation of the cylinder force in this patent uses discrete element simulation technology, takes the rotation angle of the box as the drive, and finally obtains the time history curve of the cylinder force through the total bending moment calculated by the discrete system and the lever arm corresponding to the rotation angle. It can be seen that this patent proposes a method for calculating the cylinder force during the dumping process of a discrete system using only a discrete element model. Compared with the coupled calculation of the "multi-body dynamics + discrete element" model, it can obtain more accurate cylinder force response results more quickly, which provides feasibility for the optimization of the subsequent flip angle time history curve.
[0080] It should be noted that this patent provides an "optimal cylinder push time curve optimization technology" to achieve the minimum instantaneous cylinder force peak during the dumping process of the box bulk material system. This article only uses corn cob boxes as an example. In addition, the optimization process of the cylinder push time curve in the loading and unloading process of discrete materials in other bulk materials such as minerals, crops, and food can also be performed with reference to the method proposed in this patent.
[0081] In summary, the existing technology generally adopts the uniform speed of the cylinder push, without considering the impact of the cylinder push speed on the cylinder push force. If the cylinder push speed is too fast, the ears in the silo will change drastically during the rapid flipping process, resulting in excessive impact of the instantaneous fall, causing a sharp increase in the instantaneous load of the cylinder; if the push speed is too slow, it will greatly increase the duration of the entire flipping process, affecting the flipping efficiency.
[0082] In this regard, this patent proposes an "optimal cylinder stroke time curve control technology for minimizing the instantaneous cylinder force peak value". By optimizing the "box flip angle time curve", an equivalent optimization method of obtaining the "optimal cylinder stroke time curve" is obtained. This can effectively reduce the instantaneous peak of the cylinder force while keeping the total pushing time unchanged, compared with the previous constant speed cylinder push.
[0083] The implementation process of the present invention is to parameterize the "rotation angle time curve" when the box is flipped, for example, into a cubic polynomial, and take minimizing the peak value of the cylinder force in the cylinder force time curve during the cylinder pushing process as the optimization goal, and take the unchanged box flipping angle within the total time as a constraint condition, optimize and determine the "optimal rotation angle time curve", realize the selection of the "optimal box flipping time curve", and finally transform it to obtain the "optimal cylinder pushing stroke time curve".
[0084] In addition, in another embodiment, the present application further provides a method for optimizing the pushing speed of a bulk material system dumping mechanism, which may specifically include the following steps S210-S240: Step S210, according to the initial hinge point information of the oil cylinder on the dumping mechanism, determine the oil cylinder stroke force curve between the stroke of the oil cylinder during the tipping process of the dumping mechanism and the applied force of the oil cylinder by multi-body dynamics + discrete element modeling; Step S220, defining a driving function of the dumping mechanism, wherein the driving function is a time history curve of a cylinder stroke during a turning process of the dumping mechanism, and the driving function includes a predetermined number of optimization coefficients; Step S230, optimizing the stroke force curve according to the driving function and the constraint conditions with the minimization of the maximum applied force of the cylinder as the optimization goal, so as to obtain the target optimization coefficient of the driving function when the maximum applied force of the cylinder is at the minimum value; and Step S240: Determine the target cylinder stroke time curve of the cylinder according to the target optimization coefficient.
[0085] In other words, the time history curve of the cylinder force can also be obtained by directly using the cylinder stroke as the drive and the discrete system as the load source through the "multi-body dynamics and discrete element" coupling simulation. Correspondingly, in the subsequent optimization process, for example, the driving function that characterizes the cylinder stroke time history curve can be defined as a cubic polynomial function: Then, the control parameters a, b, c As the optimization object, the stroke force curve is optimized with the minimization of the maximum applied force of the cylinder as the optimization goal to obtain the target optimization coefficient of the drive function when the maximum applied force of the cylinder is the minimum, thereby determining the target cylinder stroke time curve of the cylinder.
[0086] on the other hand, Figure 6 A schematic diagram of a push speed optimization system of a bulk material system dumping mechanism according to an embodiment of the present application is schematically shown. In the embodiment of the present application, the optimization system 200 may include: A discrete element modeling device 210 is used to determine an angle force curve between a turning angle of the cylinder and an applied force of the cylinder during a turning process of the cylinder by discrete element modeling according to information of an initial hinge point of the cylinder on the dumping mechanism; A driving function determining device 220, used to define a driving function of the dumping mechanism, wherein the driving function is an angle time curve of the oil cylinder during the turning process of the dumping mechanism, and the driving function includes a predetermined number of optimization coefficients; The optimization device 230 is used to optimize the angle force curve according to the driving function and the constraint conditions with the minimization of the maximum applied force of the cylinder as the optimization target, so as to obtain the target optimization coefficient of the driving function when the maximum applied force of the cylinder is at the minimum value; and The target curve determining device 240 is used to determine the target angle time curve of the cylinder according to the target optimization coefficient.
[0087] In an embodiment of the present application, the discrete element modeling device 210 is specifically used to perform: determining an angle-lever arm curve between the flip angle and the applied lever arm of the cylinder based on the initial hinge point information of the cylinder on the dumping mechanism; determining an angle-torque curve between the flip angle and the applied torque of the cylinder by discrete element modeling; and determining an angle-force curve based on the angle-lever arm curve and the angle-torque curve.
[0088] In the embodiment of the present application, the initial hinge point information includes the first fixed hinge point, the second fixed hinge point and the mobile hinge point. According to the initial hinge point information of the oil cylinder on the dumping mechanism, the angle arm curve between the flip angle and the applied force arm of the oil cylinder is determined, including: the following formula determines the flip angle Angle arm curve between the applied force arm of the cylinder :
[0089] in, is the length of the line segment AB formed by the first fixed hinge point A and the second fixed hinge point B, is the length of the line segment AC formed by the first fixed hinge point A and the movable hinge point C; the flip angle is the angle formed by the first fixed hinge point A as the vertex and the line segments AC and AB as the sides, Flip Angle The initial angle of .
[0090] In the embodiment of the present application, the angle force curve is determined according to the angle arm curve and the angle torque curve, including: according to the angle arm curve and angle torque curve , the angle force curve is determined by the following formula :
[0091] In an embodiment of the present application, the driving function is any one of the following: a cubic polynomial function, a quartic polynomial function, a higher-order polynomial function greater than fourth order, a power function, and a trigonometric function; wherein the cubic polynomial function includes three optimization coefficients, and the quartic polynomial function, the trigonometric function, and the power function include four optimization coefficients.
[0092] In the embodiment of the present application, when the driving function is a cubic polynomial function, the following formula represents the driving function: : When the driving function is a quartic polynomial function, the following formula represents the driving function: ： When the driving function is a power function, the following formula represents the driving function: ： Or when the driving function is a trigonometric function, the following formula represents the driving function: ： in, is the optimization coefficient.
[0093] In the embodiment of the present application, the constraint condition includes one or more of the following: a minimum specified angle constraint, a maximum specified angle constraint, and a flip angular velocity constraint.
[0094] In the embodiment of the present application, in the driving function When is a cubic polynomial function, the following equations represent the minimum specified angle constraint, the maximum specified angle constraint, and the flip angular velocity constraint:
[0095]
[0096]
[0097] in, is the optimization coefficient, is the maximum flip angle, is the total flipping time.
[0098] In the embodiment of the present application, the angle time history curve is optimized by at least one of the following algorithms: genetic algorithm, downhill method, annealing method.
[0099] The existing technology generally adopts the uniform speed of the cylinder push, without considering the impact of the cylinder push speed on the cylinder push force. If the cylinder push speed is too fast, the ears in the silo will change drastically during the rapid flipping process, resulting in a huge impact of the instantaneous fall, causing a sharp increase in the instantaneous load of the cylinder; if the push speed is too slow, it will greatly increase the duration of the entire flipping process, affecting the efficiency of the flipping operation.
[0100] Through the above-mentioned technical scheme of the present invention, an "optimal cylinder stroke time curve control technology for minimizing the instantaneous cylinder force peak" is proposed. By optimizing the "box flip angle time curve", an equivalent optimization method of obtaining the "optimal cylinder stroke time curve" is obtained. This can effectively reduce the instantaneous peak of the cylinder force compared to the previous constant speed cylinder push while keeping the total pushing time unchanged.
[0101] That is to say, the present invention reasonably distributes the angular velocity of the box rotation without increasing the total duration of the flipping action. In the range where the center of gravity is not likely to move significantly, the angular velocity of the box rotation is appropriately accelerated; in the travel range where falling is likely to occur, the angular velocity of the box rotation is appropriately slowed down. In this way, the most reasonable cylinder pushing scheme with the smallest cylinder force peak can be obtained.
[0102] In addition, the present invention proposes a method for calculating the cylinder force during the tipping process of a discrete system using only a discrete element model, which can obtain accurate cylinder force response results more quickly and provide feasibility for the subsequent optimization of the flip angle time curve.
[0103] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.
[0104] The above are only embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included within the scope of the claims of the present application.
Claims
1. A method for optimizing the pushing speed of a bulk material system dumping mechanism, characterized in that: The push speed optimization method comprises: According to the initial hinge point information of the oil cylinder on the dumping mechanism, determining the angle force curve between the flipping angle of the oil cylinder during the flipping process of the dumping mechanism and the applied force of the oil cylinder by discrete element modeling; Defining a driving function of the dumping mechanism, wherein the driving function is an angle time curve of the oil cylinder during the tipping process of the dumping mechanism, and the driving function includes a predetermined number of optimization coefficients; According to the driving function and the constraint conditions, the angle force curve is optimized with minimization of the maximum applied force of the oil cylinder as the optimization goal, so as to obtain the target optimization coefficient of the driving function when the maximum applied force of the oil cylinder is at the minimum value; and According to the target optimization coefficient, a target angle time curve of the oil cylinder is determined.
2. The push speed optimization method according to claim 1, characterized in that: The method of determining the angle force curve between the turning angle of the oil cylinder during the turning process of the oil cylinder and the applied force of the oil cylinder in a discrete element modeling manner according to the initial hinge point information of the oil cylinder on the dumping mechanism includes: Determining an angle-arm curve between the flip angle and the applied arm of the oil cylinder according to the initial hinge point information of the oil cylinder on the dumping mechanism; Determining an angle-torque curve between the flip angle and the applied torque of the cylinder by discrete element modeling; and The angle force curve is determined according to the angle arm curve and the angle moment curve.
3. The push speed optimization method according to claim 2, characterized in that: The initial hinge point information includes a first fixed hinge point, a second fixed hinge point and a mobile hinge point, The step of determining the angle arm curve between the flip angle and the applied arm of the oil cylinder according to the initial hinge point information of the oil cylinder on the dumping mechanism comprises: The flip angle is determined by the following formula The angle between the applied force arm of the cylinder and the force arm curve : in, is the length of the line segment AB formed by the first fixed hinge point A and the second fixed hinge point B, is the length of the line segment AC formed by the first fixed hinge point A and the movable hinge point C; The flip angle is the angle formed by taking the first fixed hinge point A as the vertex and the line segment AC and the line segment AB as the sides, is the flip angle The initial angle of .
4. The push speed optimization method according to claim 2 or 3, characterized in that: Determining the angle force curve according to the angle arm curve and the angle moment curve comprises: According to the angle arm curve and angle torque curve , the angle force curve is determined by the following formula : 。 5. The push speed optimization method according to claim 1, characterized in that: The driving function is any one of the following: a cubic polynomial function, a quartic polynomial function, a higher-order polynomial function greater than the quartic, a power function, and a trigonometric function; The cubic polynomial function includes three optimization coefficients, and the quartic polynomial function, the trigonometric function, and the power function include four optimization coefficients.
6. The push speed optimization method according to claim 5, characterized in that: When the driving function is the cubic polynomial function, the following equation represents the driving function: : When the driving function is the fourth-order polynomial function, the following formula represents the driving function: : When the driving function is the power function, the driving function is expressed by the following equation: : or When the driving function is the trigonometric function, the driving function is expressed by the following equation: : in, is the optimization coefficient.
7. The push speed optimization method according to claim 1, 5 or 6, characterized in that: The constraint conditions include one or more of the following: a minimum specified angle constraint, a maximum specified angle constraint, and a flip angular velocity constraint.
8. The push speed optimization method according to claim 7, characterized in that: In the driver function When it is a cubic polynomial function, the following equations represent the minimum specified angle constraint, the maximum specified angle constraint, and the flip angular velocity constraint: in, is the optimization coefficient, is the maximum flip angle, is the total flipping time.
9. A method for optimizing the pushing speed of a bulk material system dumping mechanism, characterized in that: The push speed optimization method comprises: According to the initial hinge point information of the oil cylinder on the dumping mechanism, a cylinder stroke force curve between the stroke of the oil cylinder during the tipping process of the dumping mechanism and the applied force of the oil cylinder is determined by multi-body dynamics + discrete element modeling; Defining a driving function of the dumping mechanism, wherein the driving function is a time history curve of the cylinder stroke of the cylinder during the tipping process of the dumping mechanism, and the driving function includes a predetermined number of optimization coefficients; According to the driving function and the constraint conditions, the stroke force curve is optimized with minimization of the maximum applied force of the oil cylinder as the optimization goal, so as to obtain a target optimization coefficient of the driving function when the maximum applied force of the oil cylinder is at a minimum value; and According to the target optimization coefficient, a target cylinder stroke time curve of the cylinder is determined.
10. A pushing speed optimization system for a bulk material system dumping mechanism, characterized in that: The push speed optimization system comprises: A discrete element modeling device, used to determine an angle force curve between a turning angle of the cylinder during a turning process of the cylinder and an applied force of the cylinder in a discrete element modeling manner according to initial hinge point information of the cylinder on the dumping mechanism; A driving function determining device, used to define a driving function of the dumping mechanism, wherein the driving function is an angle time curve of the oil cylinder during the turning process of the dumping mechanism, and the driving function includes a predetermined number of optimization coefficients; an optimization device, for optimizing the angle force curve according to the drive function and the constraint conditions with the minimization of the maximum applied force of the oil cylinder as the optimization goal, so as to obtain a target optimization coefficient of the drive function when the maximum applied force of the oil cylinder is at a minimum value; and The target curve determining device is used to determine the target angle time curve of the cylinder according to the target optimization coefficient.