Variable-diameter variable-torque tower crane suspension point acceleration follow-up optimization control method

Abstract

The invention relates to the technical field of tower type pumping unit control, in particular to a variable-diameter variable-torque tower crane suspension point acceleration follow-up optimization control method. The method comprises the steps that the stroke frequency and stroke length of a suspension center in a specified historical stroke are obtained; acquiring an upper boundary value of the acceleration of the motor according to the relationship between the radius of the roller and the number of rotation turns of the roller and the transmission relationship between the number of rotation turns of the roller and the number of rotation turns of the motor; acquiring a lower boundary value of the acceleration of the motor according to the acceleration duration, the deceleration duration, the constant speed duration, the parking duration, the stroke frequency of the suspension point and the stroke length of the motor; according to the suspension point acceleration at each moment in the specified historical stroke, a fitness function is obtained; and optimizing a motor speed curve of the current stroke based on the upper boundary value, the lower boundary value and the fitness function. According to the method, the motor speed curve of the current stroke is optimized, faults caused by motor impact are effectively avoided, and the stability and safety of operation of the tower crane are improved.

Description

Technical Field

[0001] This invention relates to the field of tower pumping unit control technology, specifically to a method for optimizing the servo acceleration of the suspension point of a variable diameter and variable torque tower pumping unit. Background Technology

[0002] Oil pumping units are used in oilfield operations to extract crude oil from downhole wells into surface pipelines using an electric motor. Traditional beam pumping units suffer from drawbacks such as high installed power, high energy consumption, and low system efficiency due to the characteristics of their conventional transmission mechanisms. Therefore, long-stroke, low-stroke tower-type pumping units have become a research hotspot, as they are suitable for various complex crude oil conditions and offer excellent energy savings. Tower-type pumping units primarily utilize a synchronous motor to drive a load belt in reciprocating linear motion; the pumping action is achieved through the forward and reverse rotation of the motor.

[0003] Optimizing the motor acceleration during the operation of a tower pumping unit can reduce vibration and impact during lifting and lowering, which is beneficial to improving the stability of the tower pumping unit. The literature "Wang Taihua, Chen Zhifu. Research on speed regulation system of tower pumping unit based on PSO self-tuning PID[J]. Journal of Electronic Measurement and Instrumentation, 2014, 28(09):998-1004.DOI:10.13382 / j.jemi.2014.09.011." introduces the PSO particle swarm optimization algorithm to adjust the parameters of the PID control algorithm by considering the nonlinearity and strong coupling in the operation of the tower pumping unit, so as to realize the speed regulation control of the motor and improve the anti-interference ability and robustness of the motor. It is known that the impact sources of tower pumping units are mainly the acceleration and rate of change of acceleration of the motor during instantaneous start-up, and secondly the impact caused by the change in the linear velocity of the suspension point due to the change in the diameter of the rollers. However, the existing methods do not consider the influence of the belt winding on the roller radius change, and the impact quantification of the suspension point during the continuous acceleration, deceleration and reversal of the motor is inaccurate, which makes it impossible to accurately control the speed of the motor, thus affecting the safe and stable operation of the tower pumping unit. Summary of the Invention

[0004] To address the technical problem of inaccurate motor speed control, the present invention aims to provide a method for optimizing and controlling the suspension point acceleration of a variable-diameter, variable-torque tower crane. The specific technical solution adopted is as follows: This invention provides a method for optimizing the servo acceleration of the suspension point of a variable-diameter, variable-torque tower crane, which includes the following steps: Obtain the number of strokes and stroke length at the suspension point in the specified historical stroke, as well as the acceleration duration, deceleration duration, constant speed duration and dwell time of the motor; Based on the relationship between the roller radius and the number of roller rotations, and the transmission relationship between the number of roller rotations and the number of motor rotations, the relationship between the suspension point acceleration and the motor acceleration is obtained, and then the upper boundary value of the motor acceleration is obtained. The lower boundary value of the motor acceleration is obtained based on the acceleration duration, deceleration duration, constant speed duration, dwell time, number of strokes at the suspension point, and stroke length. The fitness function is obtained based on the suspension point acceleration at each moment in the specified historical stroke; the motor speed curve for the current stroke is optimized based on the upper and lower boundary values ​​of the motor acceleration and the fitness function.

[0005] Furthermore, the relationship between the roller radius and the number of roller rotations is as follows: In the formula, Where is the radius of the roller; The initial radius of the roller; is the initial number of turns of the belt on the roller; h is the thickness of the belt on the roller; This refers to the number of rotations of the roller; This is consistent with rounding down.

[0006] Furthermore, the transmission relationship between the number of rotations of the roller and the number of rotations of the motor is as follows: In the formula, This represents the number of revolutions of the motor. This represents the number of rotations of the roller.

[0007] Furthermore, the method for obtaining the relationship between the suspension point acceleration and the motor acceleration is as follows: In the formula, Let be the acceleration at the suspension point at time t; To differentiate the linear velocity of the suspension point at time t; Where is the radius of the roller; This refers to the number of rotations of the roller; This represents the number of revolutions of the motor. Let be the motor acceleration at time t.

[0008] Furthermore, the method for obtaining the upper boundary value is as follows: The maximum value of the preset suspension point acceleration is the first reference value. The minimum preset roller radius is the second reference value. ; Based on the first reference value Second reference value It can be inferred that: ; Through derivation, we can conclude that: ; in, This is the upper boundary value.

[0009] Furthermore, the method for obtaining the lower boundary value is as follows: In the formula, S is the stroke length; This refers to the acceleration during the motor's acceleration phase. This refers to the acceleration during the motor's deceleration phase. This refers to the acceleration time of the motor; This represents the duration of the motor's constant speed. This refers to the deceleration time of the motor; T is the dwell time of the motor; T is the total duration of the specified historical stroke; N is the number of strokes at the suspension point; Through derivation, it can be concluded that: (1); (2); (3); Substitute formulas (1), (2), and (3) into... In the middle, we get: (4); Simplifying formula (4) yields: (5); Divide formula (5) by ,get: (6); Will Substituting into formula (6), we get: ; The discriminant for finding the real roots of a quadratic equation in one variable is used. We can obtain: ; It can be deduced that: ; get: ; in, This is the lower boundary value.

[0010] Furthermore, the method for obtaining the fitness function is as follows: Obtain the rate of change of the suspension point acceleration at each moment in the specified historical stroke, and take the largest rate of change as the first feature value; The summation of the squares of the suspension point accelerations at all times in the specified historical stroke is used as the second characteristic value. The fitness function is constructed by taking the negative of the sum of the first and second eigenvalues.

[0011] Furthermore, the rate of change of the suspension point acceleration is the derivative of the suspension point acceleration.

[0012] Furthermore, the method for determining the motor speed curve for the current stroke is as follows: Based on the upper and lower boundary values ​​of motor acceleration, and according to the relationship between suspension point acceleration and motor acceleration, the fitness function is processed by a genetic algorithm to obtain an optimized motor acceleration curve. An optimized motor speed curve is obtained based on the optimized motor acceleration curve, and used as the motor speed curve for the current stroke.

[0013] Furthermore, the specified historical stroke is the previous complete stroke of the current stroke.

[0014] The present invention has the following beneficial effects: This invention obtains the upper and lower boundary values ​​of motor acceleration based on the roller diameter change phenomenon and motor speed curve, accurately determining the range of motor acceleration and effectively avoiding excessive impact due to inaccurate motor speed, which is beneficial to the stable operation of the tower crane. To more rationally control the motor's operating speed and improve the service life of the tower crane, a fitness function is obtained based on the suspension point acceleration at each moment in a specified historical stroke, providing a basis for subsequent optimization of the motor's operating speed. Furthermore, based on the upper and lower boundary values ​​of motor acceleration and the fitness function, the motor speed curve for the current stroke is accurately optimized. This solves the problems of neglecting the influence of belt winding on the roller radius in traditional impact analysis, as well as the uncertainty of the load at the sucker rod and the difficulty in quantifying the suspension point impact during continuous motor acceleration, deceleration, and commutation. This makes the motor speed control of the tower crane more accurate, effectively avoiding tower crane stoppages caused by motor impact, and improving the stability and safety of tower crane operation. Attached Figure Description

[0015] 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.

[0016] Figure 1 A schematic flowchart illustrating a method for optimizing the servo acceleration of a variable-diameter, variable-torque tower crane suspension point according to an embodiment of the present invention; Figure 2 A flowchart illustrating a method for obtaining the upper boundary value of motor acceleration according to an embodiment of the present invention; Figure 3 This is a schematic diagram illustrating the variation of roller radius with the number of roller revolutions according to an embodiment of the present invention; Figure 4 A flowchart illustrating a method for obtaining a fitness function according to an embodiment of the present invention; Figure 5This is a structural diagram of a suspension point acceleration follow-up optimization control system for a variable diameter and variable torque tower crane, provided in one embodiment of the present invention. Figure 6 This is a schematic diagram of a computer device provided according to an embodiment of the present invention. 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 variable-diameter, variable-torque tower crane suspension point acceleration follow-up optimization control method proposed 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 description, in conjunction with the accompanying drawings, details the specific scheme of the variable diameter and variable torque tower crane suspension point acceleration follow-up optimization control method provided by the present invention. Example 1:

[0020] The specific scenario in this embodiment is as follows: Impact is one of the most important considerations during the operation of a tower pumping unit. Excessive impact can affect the safety of the entire tower pumping unit's operation and reduce its lifespan. Tower pumping units differ from beam pumping units in their operation mode; the motor undergoes continuous acceleration, deceleration, and reversal, making it difficult to quantify the impact throughout the entire operation of a tower pumping unit. Furthermore, due to the uncertainty of the load at the suspension point of the sucker rod, precise control of the suspension point impact of the tower pumping unit remains a challenge that needs to be overcome. It is known that the impact sources of a tower pumping unit are mainly determined by the instantaneous acceleration of the motor during startup and the rate of change of acceleration, and secondly by the impact caused by the change in the linear velocity of the suspension point due to the change in roller diameter. When using a genetic algorithm to optimize the motor's operating speed curve, the construction of the fitness function becomes crucial. To make the control algorithm of the tower pumping unit more precise, reduce the impact throughout the entire operation of the tower pumping unit, and improve the service life of the equipment, this invention provides a control algorithm with a minimum impact mode. First, the motor speed curve is obtained by setting a function to establish a mathematical relationship between the tower crane's suspension point impact and the motor speed, providing a theoretical basis for designing an operating mode that reduces impact. Second, to explore the motor operating mode with the least impact, a genetic algorithm is used to optimize the motor speed curve parameters. An impact-acceleration relationship is established as the fitness function, and the optimized parameters for the motor operating mode with the least impact, i.e., the motor speed, are obtained. Finally, the control objective of the least impact mode is achieved. It should be noted that motor speed is the same as motor rotational speed.

[0021] This invention proposes a method for dynamic optimization control of suspension point acceleration of a variable diameter and variable torque tower crane. Please refer to [link / reference]. Figure 1 The diagram illustrates a schematic flowchart of a method for optimizing the suspension point acceleration of a variable-diameter, variable-torque tower crane according to an embodiment of the present invention. The method includes the following steps: Step S1: Obtain the number of strokes and stroke length at the suspension point in the specified historical stroke, as well as the acceleration duration, deceleration duration, constant speed duration, and parking duration of the motor.

[0022] Specifically, this embodiment aims to analyze the motor speed during the previous complete stroke, combine the effect of the variable diameter effect on the suspension point speed, and then use a genetic algorithm to optimize and control the motor speed for the next stroke, thereby avoiding excessive impact, reducing motor losses and the risk of pumping unit shutdown, and improving the operating efficiency of the pumping unit. Therefore, in order to obtain the motor speed during the current stroke, this embodiment sets a specified historical stroke as the previous complete stroke.

[0023] In order to accurately analyze a specified historical stroke and thus optimize the motor speed to make the motor speed more reasonable in the current stroke and improve the safety and stability of the tower crane operation in the current stroke, this embodiment obtains the number of strokes and stroke length of the suspension point in the specified historical stroke, as well as the acceleration time, deceleration time, constant speed time and parking time of the motor. At the same time, it obtains the initial radius of the rollers in the tower crane and the thickness of the belt on the rollers.

[0024] Step S2: Based on the relationship between the roller radius and the number of roller rotations, and the transmission relationship between the number of roller rotations and the number of motor rotations, obtain the relationship between the suspension point acceleration and the motor acceleration, and then obtain the upper boundary value of the motor acceleration.

[0025] It is known that in existing technical analyses, the impact of belt winding on the roller radius is not considered. In this case, based on the transmission ratio between the motor and the roller, the roller speed can be directly obtained from the motor speed. In a tower-type pumping unit, the roller is directly connected to the suspension point via a wire rope, and the suspension point is connected to the sucker rod. Therefore, the roller speed is directly equivalent to the movement rate of the suspension point during its up and down strokes. However, in reality, the belt on the roller undergoes a diameter change as the roller rotates; that is, the belt gradually winds around the roller, and the speed of the suspension point also changes accordingly. This is because the linear velocity of the suspension point changes with the change in roller radius. To ensure more accurate impact at the suspension point and avoid instability in the tower-type pumping unit, the corresponding motor speed should be changed. To ensure the motor operates within a reasonable speed range, this embodiment first obtains the relationship between the suspension point acceleration and the motor acceleration based on the relationship between the roller radius and the number of roller rotations, and the transmission relationship between the number of roller rotations and the number of motor rotations. Then, the upper boundary value of the motor acceleration is obtained, and the motor speed is reasonably controlled to avoid excessive impact.

[0026] Preferably, in one feasible embodiment, a method for obtaining the upper boundary value of motor acceleration is described in [reference needed]. Figure 2 The document presents a flowchart of a method for obtaining the upper boundary value of motor acceleration provided in this embodiment. The method includes the following steps: Step S201: Obtain the relationship between the roller radius and the number of roller rotations.

[0027] It is known that the radius of the rollers changes during the operation of a tower-type pumping unit, such as... Figure 3 The diagram shows the variation of the roller radius with the number of roller revolutions. Figure 3 When there is only one loop of belt wrapped around the roller, the radius of the roller is . When the belt is wound around the roller twice, the radius of the roller is [value missing]. In the formula, Indicates the radius of the roller; This indicates the radius of the roller when the belt is wound one full turn; The initial radius of the roller is represented by ; h represents the thickness of the belt on the roller. This represents the radius of the roller when the belt has wrapped around the wheel twice. From this, we can deduce the general formula for obtaining the roller radius: In the formula, This represents the number of rotations of the roller.

[0028] Considering the need for sufficient friction and safety in practice, an initial number of belt turns is typically present on the roller, generally greater than 1 and less than 2. This initial number of turns affects the roller radius. Let's define the initial number of belt turns as... Based on the initial number of belt turns, when the roller rotates... After each rotation, the roller radius increases by one h value. Thereafter, for every rotation of the roller, the roller radius increases by one h value. Therefore, the relationship between the roller radius and the number of rotations can be deduced as follows: In the formula, Where is the radius of the roller; The initial radius of the roller; is the initial number of turns of the belt on the roller; h is the thickness of the belt on the roller; This refers to the number of rotations of the roller; This is consistent with rounding down.

[0029] Step S202: Obtain the transmission relationship between the number of rotations of the roller and the number of rotations of the motor.

[0030] Given that the transmission relationship between the motor and the roller is known in this embodiment, the transmission relationship between the number of rotations of the roller and the number of rotations of the motor is as follows: In the formula, This represents the number of revolutions of the motor. This represents the number of rotations of the roller. It should be noted that the coefficient 28 is determined by the transmission ratio between the motor and the roller.

[0031] It should be noted that the transmission relationship between the number of rotations of the roller and the number of rotations of the motor is assumed to be the relationship per unit time, which indirectly means that the number of rotations can be assumed to be the rotational speed.

[0032] Step S203: Obtain the relationship between the suspension point acceleration and the motor acceleration.

[0033] In practice, due to the effect of roller diameter variation, there is a difference between the linear velocity of the suspension point and the motor speed. The acceleration at the suspension point is mainly related to the motor speed. Based on the relationship in steps S201 and S202, the relationship between the acceleration of the suspension point and the acceleration of the motor can be deduced as follows: In the formula, Let be the acceleration at the suspension point at time t; To differentiate the linear velocity of the suspension point at time t; Where is the radius of the roller; This refers to the number of rotations of the roller; This represents the number of revolutions of the motor. Let be the motor acceleration at time t.

[0034] It should be noted that, as can be seen from step S202, and The default value is the rotational speed per unit time, therefore, it can be determined through... Represents the linear velocity of the suspension point. The purpose of comparing to 60 is to convert minutes to seconds; because The default value is the rotational speed per unit time, which will then... Let be the motor acceleration at time t.

[0035] Step S204: Obtain the upper boundary value of the motor acceleration.

[0036] Since the relationship between the suspension point acceleration and the motor acceleration is known from step S203, this embodiment presets the maximum value of the suspension point acceleration as the first reference value. The minimum preset roller radius is the second reference value. Based on the first reference value Second reference value It can be inferred that: Through derivation, it can be concluded that: ;in, This is the upper boundary value of the motor acceleration.

[0037] In technical manuals, the maximum value of the suspension point acceleration is usually specified as follows: Therefore, in this embodiment, the first reference value is... The value is set to 0.8; in traditional analysis, the effect of the belt winding around the roller is not considered, thus allowing the motor acceleration to be obtained based on the maximum value of the suspension point acceleration. However, in reality, due to the effect of roller diameter variation, The value is uncertain. In this embodiment, in order to calculate the upper boundary value of the motor acceleration, the radius of the roller when a single turn of belt is wound on the roller is set as the second reference value. Given that the radius of a roller when a single loop of belt is wound around it is typically 0.287m, this embodiment uses the second reference value. The value is set to 0.287. Implementers can set the first reference value according to their actual needs. Second reference value The size is not limited here. and Bring into From this, we can conclude that That is, the upper boundary value of the motor acceleration is .

[0038] Based on the above analysis, it can be concluded that the boundary value of the motor acceleration must not exceed [a certain value]. .

[0039] Step S3: Obtain the lower boundary value of the motor acceleration based on the acceleration duration, deceleration duration, constant speed duration, dwell time, number of strokes at the suspension point, and stroke length.

[0040] Specifically, to ensure the safe and stable operation of the tower-type pumping unit, it is necessary to further analyze the motor's operating speed, obtain the lower boundary value of the motor's acceleration, and then determine the acceleration range for safe motor operation. It is known that the shape of the motor speed curve during a complete stroke is typically trapezoidal, triangular, or S-shaped. The trapezoidal curve corresponds to a motor speed pattern of initial acceleration, followed by constant speed and then deceleration, and is widely used in acceleration and deceleration control of various motors. The S-shaped curve uses variable acceleration to make the motor's acceleration and deceleration smoother, but the motor's start-up and stop times are longer, and the computational complexity is greater. In this embodiment, a trapezoidal speed curve is used to represent the motor speed curve for better subsequent optimization of the motor speed.

[0041] Under ideal conditions, when the motor operates according to a trapezoidal speed curve, the acceleration and deceleration times need to be controlled to ensure that the suspension point operates within a specified stroke count. Therefore, it is necessary to establish the relationship between the motor's acceleration / deceleration time and its acceleration based on a fixed stroke and number of strokes. In reality, tower-type pumping units have a certain dwell time during operation, meaning the motor has a certain dwell duration to facilitate motor startup and circumferential rotation. Furthermore, the acceleration and deceleration times of the motor may vary during actual operation. Therefore, in this embodiment, the motor's acceleration time is set as follows: Deceleration time is The duration of uniform speed is and the duration of the stopover is Among them, acceleration time and deceleration time The relationship between them is ;in, This indicates the ratio of motor acceleration to deceleration time during a specified historical stroke.

[0042] A complete stroke is defined as the displacement distance of the sucker rod during its reciprocating motion, from the highest point to the lowest point or vice versa, typically measured in meters (m). The motor speed is zero at both the start and end of a complete stroke. Within a specified historical stroke range, the stroke length is equivalent to the motor's rotational distance; therefore, the stroke length can be estimated based on the motor's trapezoidal speed curve. Simultaneously specify the total duration of the historical stroke. ;in, This refers to the acceleration during the motor's acceleration phase. This refers to the acceleration of the motor's deceleration section. The stroke rate refers to the number of up-and-down reciprocating movements of the sucker rod per minute, measured in strokes / minute. The stroke rate affects the pumping unit's efficiency and energy consumption. A higher stroke rate allows the pumping unit to complete more pumping operations per unit time, but may also increase energy consumption. The duration of one round trip of the sucker rod is... Where N is the impulse of the suspension point, and... Equivalent to the duration of two complete strokes, i.e. Therefore, it can be deduced that Meanwhile, since the ending speed of the motor's acceleration phase and the initial speed of its deceleration phase are the same, this leads to... .

[0043] In order to derive the lower limit of the actual acceleration of the motor during operation, this embodiment will... , and Perform a simultaneous equation, that is, obtain In the formula, S is the stroke length; This refers to the acceleration during the motor's acceleration phase. This refers to the acceleration during the motor's deceleration phase. This refers to the acceleration time of the motor; This represents the duration of the motor's constant speed. This refers to the deceleration time of the motor; T is the dwell time of the motor; T is the total duration of the specified historical stroke; N is the number of strokes at the suspension point; Through derivation, it can be concluded that: (1); (2); (3); Substitute formulas (1), (2), and (3) into... In the middle, we get: (4); Simplifying formula (4) yields: (5); Divide formula (5) by ,get: (6); Will Substituting into formula (6), we get: ; The discriminant for finding the real roots of a quadratic equation in one variable is used. We can obtain: ; It can be deduced that: ; get: ; therefore, This is the lower boundary value.

[0044] Based on the above analysis, it can be concluded that the boundary value of the motor acceleration must not be lower than .

[0045] Step S4: Obtain the fitness function based on the suspension point acceleration at each moment in the specified historical stroke; optimize the motor speed curve for the current stroke based on the upper and lower boundary values ​​of the motor acceleration and the fitness function.

[0046] It is known that during the operation of a tower-type pumping unit, the impact sources are mainly determined by the instantaneous acceleration of the motor upon startup and the rate of change of acceleration. Secondly, there is the impact caused by the change in the linear velocity of the suspension point due to the roller diameter change. To accurately establish the relationship between impact and motor acceleration, this embodiment obtains a fitness function based on the suspension point acceleration at each moment in a specified historical stroke, indirectly analyzing the relationship between impact and motor acceleration. To improve the stability and safety of the tower-type pumping unit, this embodiment optimizes the motor acceleration curve for the current stroke based on the upper and lower boundary values ​​of the motor acceleration and the fitness function, thereby obtaining the optimized motor speed curve for the current stroke, effectively avoiding situations where excessive impact causes the tower-type pumping unit to malfunction.

[0047] Preferably, in one possible implementation of this embodiment, the method for obtaining the fitness function is described in [reference needed]. Figure 4 The document presents a flowchart of a method for obtaining a fitness function provided in this embodiment. The method includes the following steps: Step S401: Obtain the rate of change of the suspension point acceleration at each moment in the specified historical stroke, and take the largest rate of change as the first feature value.

[0048] The greater the rate of change of the suspension point acceleration, the greater the impact. As shown in step S2, there is a certain relationship between the suspension point acceleration and the motor acceleration. Therefore, this embodiment first obtains the rate of change of the suspension point acceleration at each moment in a specified historical stroke, and then uses the largest rate of change as the first characteristic value. The larger the first characteristic value, the greater the potential impact during the specified historical stroke. It should be noted that the rate of change of the suspension point acceleration is the derivative of the suspension point acceleration, i.e. In the formula, Let be the rate of change of the suspension point acceleration at time t; Let be the acceleration at the suspension point at time t; To differentiate the suspension point acceleration at time t; To perform a second derivative of the linear velocity of the suspension point at time t.

[0049] Step S402: The summation of the squares of the suspension point accelerations at all times in the specified historical stroke is used as the second characteristic value.

[0050] When the motor is in a state of frequent acceleration and deceleration for a long time during a specified historical stroke, it indirectly indicates that the possibility of an impact exists during the specified historical stroke. Therefore, in this embodiment, the summation of the squares of the suspension point acceleration at all times during the specified historical stroke is used as the second characteristic value. The larger the second characteristic value, the greater the possibility of an impact exists during the specified historical stroke.

[0051] Step S403: The opposite of the sum of the first feature value and the second feature value is used to construct the fitness function.

[0052] It is known that the larger the first and second eigenvalues ​​are, the greater the degree of impact in a given historical stroke. To accurately analyze the impact situation, the negative of the sum of the first and second eigenvalues ​​is used to construct the fitness function. The formula for the fitness function is: ;in, The first characteristic value is T; T is the total duration of the specified historical stroke. Let be the acceleration at the suspension point at time t; This is the second eigenvalue. It should be noted that... The larger the value, the smaller the impact.

[0053] Through fitness function This can reflect the minimum impact force of the tower-type pumping unit during operation, providing a theoretical basis for subsequent genetic algorithm optimization of acceleration. The genetic algorithm is a well-known technique and will not be elaborated further.

[0054] Genetic algorithms begin with a population of potential solutions. This population consists of a number of individuals encoded by genes. Each individual is essentially a chromosome, a collection of genes that carries genetic material. The chromosome's internal expression (genotype) determines its external appearance; for example, black hair is determined by a specific gene combination on the chromosome. After the initial population is generated, it evolves generation by generation according to the principles of survival of the fittest, producing increasingly better approximate solutions. In each generation, individuals are selected based on their fitness in the problem domain, and genetic operators from natural genetics are used for crossover and mutation to generate a new population representing the solution set. This process leads to a population where subsequent generations are more adapted to the environment than previous generations, much like natural evolution. The best individual in the final generation, after decoding, can be considered an approximate optimal solution to the problem.

[0055] The specific process of optimizing motor acceleration using a genetic algorithm is as follows: First: Initialize the population.

[0056] According to the genetic algorithm, a real-number encoding method is used, that is, the individuals in the population are represented as: In the formula, P represents the population set in the genetic algorithm. This represents the i-th individual in the population. This represents the number of individuals in the population, which is set to 100 in this embodiment. The implementer can set the number of individuals in the population according to the actual situation, and there is no limitation here.

[0057] It should be noted that the expression for a single individual within the population differs depending on the type of the velocity curve. When the velocity curve is trapezoidal, the expression for a single individual is: Corresponding to the parameters of the trapezoidal curve. When the velocity curve is a polynomial curve, the expression for a single individual is: ,in Indicates weight, This represents the order of the polynomial.

[0058] Second: Construct the fitness function.

[0059] The fitness function in step S4 As the fitness function for genetic optimization, it should be noted that the fitness function in step S4 is related to the suspension point acceleration. In the actual calculation process, the relationship between the suspension point acceleration and the motor acceleration in step S2 is substituted into the fitness function, thereby obtaining the relationship between the impact and the motor acceleration.

[0060] Third: Individual choice.

[0061] This method selects superior individuals from a population and eliminates inferior ones. The selection is based on the individual's fitness value. It aims to ensure that superior individuals are more likely to be selected than inferior ones, while also maintaining gene integrity to achieve good global convergence. Several optimal selection methods exist, including proportional selection, sorting selection, and elite selection.

[0062] In this embodiment, a proportional selection method is used, with the proportion set at 70%. The implementer can adjust the proportion according to the actual situation; no limitation is imposed here. Simultaneously, the probability of a single individual being selected is calculated as follows: In the formula, Let represent the probability that the i-th individual is selected. Let represent the fitness value of the i-th individual, obtained by substituting the individual parameters into the fitness function. This indicates the total number of individuals.

[0063] Fourth: Intersection.

[0064] Crossover is analogous to mating in biological evolution, where selected individuals are paired up and their chromosomes partially exchanged to generate new individuals. Crossover drives continuous evolution and plays a major role in the evolution of genetic algorithms, constantly generating new individuals and opening up new search spaces. Different encoding methods employ different crossover methods; binary encoding typically uses point crossover or multi-point crossover, while real number encoding usually uses arithmetic crossover.

[0065] In this embodiment, real number encoding is used during the encoding process. The encoding method determines the crossover method of the algorithm. This embodiment uses real number encoding and an arithmetic crossover operator to perform the crossover operation, setting the crossover probability to 0.8. Implementers can set the crossover probability according to the actual situation, and there is no limitation here.

[0066] Fifth: Mutation.

[0067] During the evolution of organisms, gene mutations may occur. To simulate this process, mutation operations are introduced into genetic algorithms. Mutation operations increase the diversity of the population to a certain extent and prevent the search from getting trapped in local optima.

[0068] In this embodiment, the mutation probability is set to 0.05. Implementers can set the mutation probability according to the actual situation, and there is no limitation here.

[0069] Sixth: Maximum number of iterations.

[0070] The convergence condition of a genetic algorithm is the main control parameter of the algorithm. Generally, the algorithm can be considered to have converged when it reaches the maximum number of iterations or the fitness function value can no longer be improved; otherwise, the algorithm continues.

[0071] In this embodiment, the maximum number of iterations is set to 300. Implementers can set the maximum number of iterations according to the actual situation, and there is no limitation here.

[0072] Seventh: Constraints.

[0073] Based on steps S2 and S3, the upper and lower boundary values ​​of the motor acceleration are obtained, thus determining the boundary range of the motor acceleration. When an individual in the population exceeds the boundary range, a penalty needs to be imposed. The penalty function method is used to solve the constraints. If an individual does not satisfy the equality constraint, a penalty term is added to its objective function to reduce the probability of it being selected for inheritance, thereby transforming the constrained problem into an unconstrained problem.

[0074] In this embodiment, when a single individual does not meet the boundary range, the selection probability is reduced by a factor of k, where k is an integer less than 1. The more severe the penalty for an individual that does not meet the constraint, the larger the value of k will be.

[0075] The optimized motor acceleration curve is obtained, and then the optimized motor speed curve is derived based on the optimized motor acceleration curve, serving as the motor speed curve for the current stroke. Therefore, the method of using a genetic algorithm to optimize speed curve parameters is feasible, providing a theoretical basis and methodological support for designing control methods for tower pumping units with different working strokes and durations, reducing the impact on tower pumping units during operation, and improving the service life of tower pumping units.

[0076] Based on the motor speed curve with minimum output impact, the angular velocity of the collected motor operating speed is converted into linear velocity, and then the measured motor speed is dynamically adjusted by an adaptive PID controller to make it approximate the motor speed curve optimized by the genetic algorithm. This improves the stability of the tower crane operation, avoids failures caused by motor impact, and ensures the stable and safe operation of the tower crane.

[0077] In summary, this embodiment obtains the number of strokes and stroke length at the suspension point in a specified historical stroke; based on the relationship between the roller radius and the number of roller rotations, and the transmission relationship between the number of roller rotations and the number of motor rotations, it obtains the upper boundary value of the motor acceleration; based on the motor's acceleration duration, deceleration duration, constant speed duration, dwell time, number of strokes at the suspension point, and stroke length, it obtains the lower boundary value of the motor acceleration; based on the suspension point acceleration at each moment in the specified historical stroke, it obtains the fitness function; and based on the upper boundary value, lower boundary value, and fitness function, it optimizes the motor speed curve for the current stroke. This invention, by optimizing the motor speed curve for the current stroke, effectively avoids faults caused by motor impact, improving the stability and safety of the tower crane operation. Example 2:

[0078] This invention also proposes a variable diameter and variable torque tower crane suspension point acceleration follow-up optimization control system. Please refer to [link / reference]. Figure 5 The diagram shows a structural diagram of a variable diameter and variable torque tower crane suspension point acceleration follow-up optimization control system provided by an embodiment of the present invention. The system includes: a data acquisition module 10, an upper boundary value acquisition module 20, a lower boundary value acquisition module 30, and an optimization module 40.

[0079] The data acquisition module 10 is used to acquire the number of strokes and stroke length of the suspension point in a specified historical stroke, as well as the acceleration duration, deceleration duration, constant speed duration and parking duration of the motor.

[0080] The upper boundary value acquisition module 20 is used to obtain the relationship between the suspension point acceleration and the motor acceleration based on the relationship between the roller radius and the number of roller rotations, and the transmission relationship between the number of roller rotations and the number of motor rotations, and then obtain the upper boundary value of the motor acceleration.

[0081] The lower boundary value acquisition module 30 is used to acquire the lower boundary value of the motor acceleration based on the acceleration duration, deceleration duration, constant speed duration, dwell time, number of strokes at the suspension point, and stroke length.

[0082] The optimization module 40 is used to obtain the fitness function based on the suspension point acceleration at each moment in the specified historical stroke; and optimize the motor speed curve of the current stroke based on the upper and lower boundary values ​​of the motor acceleration and the fitness function.

[0083] It should be noted that the system provided in the above embodiments is only an example of the division of the above functional modules. In practical applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the computer equipment can be divided into different functional modules to complete all or part of the functions described above. In addition, the variable diameter and variable torque tower crane suspension point acceleration follow-up optimization control system and the variable diameter and variable torque tower crane suspension point acceleration follow-up optimization control method embodiment provided in the above embodiments belong to the same concept. The specific implementation process is detailed in the method embodiment and will not be repeated here. Example 3:

[0084] This invention also proposes a device for optimizing the suspension point acceleration of a variable-diameter, variable-torque tower crane. This device includes a memory and a processor. The memory stores executable program code, and the processor calls and executes this executable program code to perform the optimization control method for suspension point acceleration of a variable-diameter, variable-torque tower crane provided in the embodiments of this application. Specifically, the device may be a chip, component, or module. The chip may include a connected processor and memory; the memory stores instructions, and when the processor calls and executes the instructions, the chip can perform the optimization control method for suspension point acceleration of a variable-diameter, variable-torque tower crane provided in the above embodiments.

[0085] Furthermore, this application also protects a computer device; please refer to [link to relevant documentation]. Figure 6 The computer device includes a memory 401, a processor 402, and a computer program 403 stored in the memory 401 and running on the processor 402. When the processor 402 executes the computer program 403, the computer device can execute any of the aforementioned variable diameter and variable torque tower crane suspension point acceleration follow-up optimization control methods. Example 4:

[0086] This embodiment also provides a computer-readable storage medium storing computer program code. When the computer program code is run on a computer, the computer executes the above-mentioned related method steps to implement the variable diameter and variable torque tower crane suspension point acceleration follow-up optimization control method provided in the above embodiment. Example 5:

[0087] This embodiment also provides a computer program product. When the computer program product is run on a computer, it causes the computer to perform the above-mentioned related steps to realize the variable diameter and variable torque tower crane suspension point acceleration follow-up optimization control method provided in the above embodiment.

[0088] In this embodiment, the device, computer-readable storage medium, computer program product, or chip are all used to execute the corresponding methods provided above. Therefore, the beneficial effects they can achieve can be referred to the beneficial effects in the corresponding methods provided above, and will not be repeated here.

[0089] It should be noted that the order of the above embodiments of the present invention is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. The processes depicted in the accompanying drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0090] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

Claims

1. A method for optimizing control of a suspension point acceleration servo of a variable diameter and moment tower crane, characterized in that, The method comprises the following steps: obtaining the stroke length and the stroke frequency of the suspension point in the specified historical stroke, and the acceleration time, the deceleration time, the uniform speed time and the stationary time of the motor; obtaining the relationship between the suspension point acceleration and the motor acceleration according to the relationship between the roller radius and the number of roller rotation, and the transmission relationship between the number of roller rotation and the number of motor rotation, and then obtaining the upper boundary value of the motor acceleration; obtaining the lower boundary value of the motor acceleration according to the acceleration time, the deceleration time, the uniform speed time, the stationary time, the stroke length and the stroke frequency of the suspension point; obtaining the fitness function according to the suspension point acceleration at each time in the specified historical stroke, and optimizing the motor speed curve of the current stroke based on the upper boundary value and the lower boundary value of the motor acceleration and the fitness function.

2. A method of optimizing control of the suspension point acceleration of a variable diameter and variable pitch tower according to claim 1, characterized in that, The relationship between the roller radius and the number of roller rotation turns is: ; in the formula, is the roller radius; is the initial radius of the roller; is the initial number of turns of the belt on the roller; h is the thickness of the belt on the roller; is the number of roller rotation turns; is the downward rounding consistent.

3. A method of optimizing control of the suspension point acceleration of a variable diameter and variable pitch tower according to claim 2, characterized in that, The transmission relationship between the rolling wheel rotation number and the motor rotation number is: ; in the formula, is the motor rotation number; is the rolling wheel rotation number.

4. A method of optimizing control of the suspension point acceleration of a variable diameter and variable pitch tower according to claim 3, characterized in that, The method for obtaining the relationship between the suspension point acceleration and the motor acceleration is: ; wherein, is the suspension point acceleration at the tth moment; is the derivation of the suspension point linear velocity at the tth moment; is the roller radius; is the number of rotations of the roller; is the number of rotations of the motor; is the motor acceleration at the tth moment.

5. A method of optimizing control of the suspension point acceleration of a variable diameter and variable pitch tower according to claim 4, characterized in that, The method for obtaining the upper boundary value is: The maximum value of the preset suspension point acceleration is a first reference value The minimum value of the preset roller radius is a second reference value ​ based on a first reference value and a second reference value It can be inferred that: ; By derivation, we can obtain: ; wherein is the upper boundary value.

6. A method of optimizing control of the suspension point acceleration of a variable diameter and variable pitch tower according to claim 1, characterized in that, The method for obtaining the lower boundary value is: ; where S is the stroke length; is the acceleration of the motor acceleration segment; is the acceleration of the motor deceleration segment; is the acceleration duration of the motor; is the constant speed duration of the motor; is the deceleration duration of the motor; is the dwell duration of the motor; T is the total time of the specified historical stroke; N is the stroke frequency of the suspension point. It is derived that: (1); (2); (3); Substituting equations (1), (2), (3) into equation (4) gives (4)​ Simplifying equation (4) gives: (5); Dividing equation (5) by , we obtain (6). Will Substituting into formula (6), we get: ; According to the discriminant of the real root of the quadratic equation, , we have ; It can be derived that: ; Obtained: ; wherein is the lower boundary value.

7. A method of optimizing control of the suspension point acceleration of a variable diameter and variable pitch tower according to claim 1, characterized in that, The method for obtaining the fitness function is: obtaining the change rate of the suspension point acceleration at each time in the specified historical stroke, and taking the maximum change rate as the first characteristic value; obtaining the cumulative result of the square of the suspension point acceleration at all times in the specified historical stroke as the second characteristic value; constructing the opposite number of the sum of the first characteristic value and the second characteristic value as the fitness function.

8. A method of optimizing control of the suspension point acceleration of a variable diameter and variable pitch tower according to claim 7, characterized in that, The change rate of the suspension point acceleration is the derivative result of the suspension point acceleration.

9. A method of optimizing control of the suspension point acceleration of a variable diameter and variable pitch tower according to claim 1, characterized in that, The method for obtaining the motor speed curve of the current stroke is: processing the fitness function through the genetic algorithm based on the upper boundary value and the lower boundary value of the motor acceleration, and according to the relationship between the suspension point acceleration and the motor acceleration, to obtain the optimized motor acceleration curve; obtaining the optimized motor speed curve based on the optimized motor acceleration curve, as the motor speed curve of the current stroke.

10. A method of optimizing control of the suspension point acceleration of a variable diameter and variable pitch tower according to claim 1, characterized in that, The specified historical stroke is the previous complete stroke of the current stroke.

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