A method for optimizing the layout of hinge points of a pitch mechanism

Abstract

The present invention discloses a pitch mechanism articulated fulcrum layout optimization design method, and the present invention relates to the field of electromechanical technology. The method comprises the following steps: establishing a pitch mechanism finite element model, setting different articulated fulcrum positions based on the pitch mechanism finite element model, and recording the articulated fulcrum position coordinates; performing force analysis of the pitch mechanism based on the pitch mechanism finite element model, and performing feature selection on the pitch mechanism performance parameters through correlation analysis to obtain optimization target parameters, including pitch load torque, electric cylinder axial thrust, and pitch motor output torque requirements; setting a constraint function, establishing an optimization target function based on the optimization target parameters and the constraint function, using the optimization target function as a fitness function, solving the optimal articulated fulcrum position through a genetic algorithm, analyzing the pitch mechanism motion error and environmental error, and correcting the optimal articulated fulcrum position based on the obtained error value to obtain the optimal articulated fulcrum position accurate value.

Description

Technical Field

[0001] The present invention relates to the field of electromechanical technology, and in particular to a method for optimizing the layout of hinged fulcrums of a pitch mechanism. Background Art

[0002] In modern mechanical design, pitch mechanisms are widely used in aerospace, robotics, heavy machinery and other fields. Their main function is to achieve the tilt and adjustment of equipment to meet the needs of different working conditions. However, with the development of technology, the performance requirements for pitch mechanisms are getting higher and higher, especially in terms of accuracy, stability and load capacity. These requirements make the design and optimization of pitch mechanisms more complicated. The traditional articulated fulcrum layout is often designed based on experience and trial and error, lacking systematic theoretical support and computational analysis, resulting in many problems in practical applications, such as motion errors, uneven load, and low efficiency. These problems not only affect the operating efficiency of the equipment, but may also lead to serious safety hazards. Therefore, how to scientifically and reasonably arrange the articulated fulcrums and improve the overall performance of the pitch mechanism has become a technical challenge that needs to be solved urgently.

[0003] Finite element method-based simulation analysis techniques have been gradually introduced into the design and optimization of pitch mechanisms, becoming an important tool for addressing the aforementioned issues. Finite element models can accurately simulate the forces acting on the mechanism under different operating conditions, thus providing a theoretical basis for optimizing the position of the articulated pivot points. However, existing approaches to optimizing the layout of articulated pivot points based on finite element analysis are often one-sided, lacking a comprehensive analysis and integrated evaluation of the target optimization parameters. Furthermore, the impact of environmental factors such as temperature fluctuations and vibration on the pitch mechanism is often overlooked. These factors can significantly degrade performance in actual use, impacting the mechanism's stability and reliability. Furthermore, with the advancement of electric actuator (EMA) manufacturing processes, electric actuators have achieved positioning accuracy, response speed, transmission stiffness, and operating efficiency far exceeding those of electric hydraulic actuators (EHAs). Therefore, using electric actuators to drive linear vertical pitch mechanisms can improve transmission and control accuracy. The development of EMA manufacturing processes provides technical support for high-precision control of pitch mechanisms. Therefore, incorporating multiple influencing factors into the optimization design process to enhance the adaptability of pitch mechanisms is a key research direction.

[0004] Prior art, Chinese patent application CN117521297A discloses a method for optimizing the layout of hinged fulcrums for an electromechanical pitch mechanism. This method calculates performance parameters such as the electric cylinder extension ratio, pitch load torque, pitch transmission ratio, electric cylinder axial thrust, and pitch motor output torque and speed requirements based on the location of the hinged fulcrum. Design variables, objective functions, and constraint functions are then selected to establish a mathematical model for the optimization problem. A sensitivity analysis is then performed to obtain derivatives of the objective and constraint functions with respect to the design variables. Finally, a gradient optimization algorithm is used to solve the optimization problem, efficiently optimizing based on the sensitivity information to obtain the optimized design. This approach improves the performance of the electromechanical pitch mechanism while achieving an optimized design that satisfies the constraints. However, this approach only considers the analysis of the electromechanical pitch mechanism using an ideal model. This leads to various errors in actual operation, resulting in the optimization results obtained using the ideal model failing to achieve the desired results, thereby reducing the accuracy and effectiveness of the pitch mechanism optimization design.

[0005] The above information disclosed in this Background section is only for enhancement of understanding of the background of the present disclosure and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art. Summary of the Invention

[0006] The purpose of the present invention is to provide a method for optimizing the layout of hinge fulcrums of a pitch mechanism to solve the problems raised in the above-mentioned background technology.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A pitch mechanism hinge point layout optimization design method, specifically comprising the following steps:

[0009] Establish a finite element model of the pitch mechanism, set different articulated fulcrum positions based on the finite element model of the pitch mechanism, and record the coordinates of the articulated fulcrum positions. The articulated fulcrums include the articulated fulcrum between the lower lug of the electric cylinder and the front lug of the working platform, the articulated fulcrum between the upper lug of the electric cylinder and the front lug of the landing gear, and the articulated fulcrum between the rear lug of the landing gear and the rear lug of the working platform.

[0010] Based on the finite element model of the pitch mechanism at different hinge fulcrum positions, a force analysis is performed on the finite element model of the pitch mechanism, and the corresponding pitch mechanism performance parameters are calculated as optimization target parameters. The pitch mechanism performance parameters include the pitch load moment, the axial thrust of the electric cylinder, and the output torque requirement of the pitch motor;

[0011] Setting a constraint function, establishing an optimization objective function based on the optimization objective parameter and the constraint function, using the optimization objective function as a fitness function, and solving the optimal hinge fulcrum position by a genetic algorithm, wherein the optimal hinge fulcrum position is the hinge fulcrum position corresponding to the individual with the maximum fitness after satisfying the iteration conditions;

[0012] The pitch mechanism motion error and environmental error are analyzed, and based on the obtained error values, the optimal hinge fulcrum position is corrected to obtain the precise value of the optimal hinge fulcrum position. The motion error includes geometric error and vibration error, and the environmental error is temperature error.

[0013] Furthermore, a plane coordinate system is established with the vertical working platform upward as the positive direction of the y-axis and the horizontal working platform to the right as the positive direction of the x-axis, and the hinge support point between the lower support ear of the electric cylinder and the front support ear of the working platform is calibrated as The hinge point between the upper support ear of the electric cylinder and the front support ear of the landing gear is The hinge point between the rear lug of the landing gear and the rear lug of the working platform is ,but The initial position coordinates are , The initial position coordinates are , The initial position coordinates are ;

[0014] The specific logic for calculating the performance parameters of the pitch mechanism is:

[0015] The formulas for calculating the pitch load moment, electric cylinder axial thrust, and pitch motor output torque requirements are:

[0016] ;

[0017] ;

[0018] ;

[0019] Where, is the pitching load moment at time t, is the total mass of the landing gear and the load, is the acceleration due to gravity, represents the hinge point at time t Distance to the center of gravity of the load on the landing gear, is the landing gear pitch angle at time t, The landing gear and its payload at the hinge point at time t The moment of inertia, is the angular acceleration of the landing gear at time t, is the friction force at time t, is the axial thrust of the electric cylinder at time t, Hinge fulcrum and The distance between It represents the angle between the electric cylinder and the horizontal plane at time t, is the pitch motor output torque requirement at time t, is the pitch motor transmission ratio.

[0020] Furthermore, the hinge point and The distance between The calculation is based on the formula:

[0021] ;

[0022] Friction It consists of Coulomb friction, viscous friction and friction index terms. The specific calculation formulas include:

[0023] ;

[0024] Where, is the maximum static friction, is the friction index term at time t, is the viscous friction at time t, where the friction exponent term The calculation is based on the formula:

[0025] ;

[0026] Where, is the kinetic friction, is the angular velocity constant;

[0027] Viscous friction The calculation is based on the formula:

[0028] ;

[0029] Where, is the viscous friction coefficient.

[0030] Furthermore, the constraint function includes: the landing gear pitch angle range, the landing gear movement height range, the total mass of the landing gear and the load, and the working platform length range; the formula for establishing the optimization objective function based on the optimization target parameters and the constraint function is:

[0031] ;

[0032] Where, Indicates the hinge point 、 and The corresponding optimization objective function is Indicates the landing gear movement height, and Represent the minimum and maximum values ​​of the total mass of the landing gear and the load, is the total mass of the landing gear and the load, is the landing gear pitch angle, Indicates the maximum pitch angle of the landing gear, is the length of the working platform, and They represent the minimum and maximum lengths of the working platform, respectively. n is the time of one movement cycle of the landing gear, that is, the working cycle time of the landing gear moving from the minimum elevation angle to the maximum elevation angle. The established optimization objective function is used as the fitness function, and the optimal hinge fulcrum position is obtained through the genetic algorithm. 、 、 and are the weight coefficients of the total pitch load torque, the electric cylinder axial thrust, the pitch motor output torque requirement, and the total mass of the landing gear and load; and 、 、 and Both are greater than 0.

[0033] Furthermore, a total of m groups of hinge point combinations are set as the initial population, and the hinge point combinations include hinge point 、 and The initial position of the hinge point is obtained by optimizing the objective function as the fitness function and solving the optimal hinge point position through genetic algorithm. The optimal hinge point position includes Initial position , Initial position and Initial position .

[0034] Furthermore, the motion error and environmental error of the pitch mechanism are analyzed. The logic is as follows: obtain the geometric error, which includes the processing error and the assembly error, and calibrate the processing horizontal error as , the machining vertical error is , the assembly level error is , the assembly vertical error is ;

[0035] Based on the vibration acceleration of the electric cylinder, the displacement data of the landing gear is calculated. The specific formula is:

[0036] ;

[0037] Where, represents the ideal displacement of the electric cylinder in the time period from 0 to n, is the vibration acceleration at time t;

[0038] The horizontal and vertical offsets caused by the vibration error are calculated based on the ideal displacement of the landing gear. The horizontal and vertical offsets caused by the vibration error are calculated based on the following formula:

[0039] ;

[0040] ;

[0041] Where, is the horizontal offset caused by vibration error, is the vertical offset caused by vibration error, is the difference between the simulated displacement and the ideal displacement of the landing gear at time n, represents the pitch angle of the landing gear at time n; The calculation is based on the formula:

[0042] ;

[0043] Where, represents the simulated displacement of the landing gear, obtained by analyzing the finite element model of the pitch mechanism;

[0044] The environmental error includes a temperature error, and the temperature deformation of the pitch mechanism hinge support at the working environment temperature is calculated. The deformation of the hinge support caused by the temperature change is calculated based on the formula:

[0045] ;

[0046] Where, is the deformation of the hinge support, is the linear thermal expansion coefficient of the electric cylinder material, is the initial length of the hinge support; The maximum temperature difference of the environment.

[0047] Furthermore, based on the obtained error value, the optimal hinge fulcrum position is corrected to obtain the optimal hinge fulcrum position accurate value, wherein for the hinge fulcrum and Considering geometric errors and temperature errors, for the hinge support Considering geometric error, vibration error and temperature error, the corrected hinge support The exact value of the optimal hinge support position is expressed as:

[0048] ;

[0049] Corrected hinge point The exact value of the optimal hinge support position is expressed as:

[0050] ;

[0051] Corrected hinge point The exact value of the optimal hinge support position is expressed as:

[0052] ;

[0053] Where, and Indicates the hinge point The optimal hinge point position coordinates obtained by genetic algorithm, and Hinge fulcrum The optimal hinge point position coordinates, and Hinge fulcrum The optimal hinge fulcrum position coordinates.

[0054] Compared with the prior art, the present invention has the following beneficial effects:

[0055] This solution can effectively identify the optimal hinge fulcrum layout by establishing a finite element model of the pitch mechanism and conducting a systematic force analysis of different hinge fulcrum positions based on this model. By calculating and analyzing key performance parameters such as the pitch load torque, electric cylinder axial thrust, and motor output torque requirements, combined with the optimization solution of the genetic algorithm, it is possible to find the optimal solution in the complex design space, thereby significantly improving the performance of the mechanism. This optimization design method not only improves the scientific nature of the hinge fulcrum layout, but also makes the design process more efficient and accurate. In addition, the analysis and correction of motion errors and environmental errors in the solution ensure the accuracy of the final hinge fulcrum position and reduce performance fluctuations caused by changes in the external environment. This enables the pitch mechanism to maintain good stability and reliability under various working conditions, improving the working efficiency and service life of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 Schematic diagram of the overall method flow of the present invention;

[0057] Figure 2 Schematic diagram of the position of the hinge fulcrum of the pitch mechanism. DETAILED DESCRIPTION

[0058] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to specific embodiments.

[0059] It should be noted that, unless otherwise defined, the technical or scientific terms used in the present invention should have the usual meanings understood by people with ordinary skills in the field to which the present invention belongs. The "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative position relationships. When the absolute position of the object being described changes, the relative position relationship may also change accordingly.

[0060] Example:

[0061] See also Figure 1-Figure 2 , the present invention provides a technical solution:

[0062] A pitch mechanism hinge point layout optimization design method, specifically comprising the following steps:

[0063] Step 1: Establish a finite element model of the pitch mechanism, set different articulated fulcrum positions based on the finite element model of the pitch mechanism, and record the coordinates of the articulated fulcrum positions. The articulated fulcrums include the articulated fulcrum between the lower lug of the electric cylinder and the front lug of the working platform, the articulated fulcrum between the upper lug of the electric cylinder and the front lug of the landing gear, and the articulated fulcrum between the rear lug of the landing gear and the rear lug of the working platform.

[0064] Establish a plane coordinate system with the vertical working platform upward as the positive direction of the y-axis and the horizontal working platform to the right as the positive direction of the x-axis, and calibrate the hinge point between the lower support ear of the electric cylinder and the front support ear of the working platform as The hinge point between the upper support ear of the electric cylinder and the front support ear of the landing gear is The hinge point between the rear lug of the landing gear and the rear lug of the working platform is ,but The initial position coordinates are , The initial position coordinates are , The initial position coordinates are The origin can be selected based on the actual pitch mechanism structure. For example, the top left corner of the cross section of the work platform can be used as the origin. Figure 2 .

[0065] Step 2: Based on the finite element model of the pitch mechanism at different hinge fulcrum positions, perform a force analysis on the finite element model of the pitch mechanism and calculate the corresponding pitch mechanism performance parameters as the optimization target parameters. The pitch mechanism performance parameters include the pitch load moment, the electric cylinder axial thrust, and the pitch motor output torque requirement;

[0066] Among them, the LASSO regression algorithm is used to select the features of the pitch mechanism performance parameters. The specific steps include: organizing all relevant input features (such as the position of the hinge support point, environmental parameters, etc.) into a feature matrix, and taking the performance parameters (such as the electric cylinder extension ratio coefficient, pitch load torque, electric cylinder axial thrust, electric cylinder extension speed and pitch motor output torque requirement, etc.) as the target variables, and standardizing the feature matrix to ensure that each feature has the same scale; selecting the regularization parameter of LASSO regression, which can be determined by cross-validation; using the optimal regularization parameter value to train the LASSO model; extracting the coefficient of each feature in the LASSO model, and the features with zero coefficients will be automatically excluded, and finally obtaining the pitch mechanism performance parameters, including pitch load torque, electric cylinder axial thrust and pitch motor output torque requirement.

[0067] The specific logic for calculating the performance parameters of the pitch mechanism is:

[0068] The formulas for calculating the pitch load moment, electric cylinder axial thrust, and pitch motor output torque requirements are:

[0069] ;

[0070] ;

[0071] ;

[0072] Where, is the pitching load moment at time t, is the total mass of the landing gear and the load, is the acceleration due to gravity, represents the hinge point at time t Distance to the center of gravity of the load on the landing gear, is the landing gear pitch angle at time t, The landing gear and its payload at the hinge point at time t The moment of inertia, is the angular acceleration of the landing gear at time t, is the friction force at time t, is the axial thrust of the electric cylinder at time t, Hinge fulcrum and The distance between It represents the angle between the electric cylinder and the horizontal plane at time t, is the pitch motor output torque requirement at time t, is the pitch motor transmission ratio. The transmission ratio can be calculated by knowing the motor output angle and the landing gear movement angle.

[0073] The hinge point and The distance between The calculation is based on the formula:

[0074] ;

[0075] Friction It consists of Coulomb friction, viscous friction and friction index terms. The specific calculation formulas include:

[0076] ;

[0077] Where, is the maximum static friction, is the friction index term at time t, is the viscous friction at time t, where the friction exponent term The calculation is based on the formula:

[0078] ;

[0079] Where, is the kinetic friction, is the angular velocity constant;

[0080] Viscous friction The calculation is based on the formula:

[0081] ;

[0082] Where, is the viscous friction coefficient.

[0083] Among them, the maximum static friction The static friction coefficient between the landing gear and the load can be obtained through experiments. The maximum static friction can be calculated based on the static friction coefficient using the static friction formula. When obtaining the static friction coefficient, multiple experiments can be conducted using different material combinations, and the static friction under different normal forces can be recorded. A graph can be drawn to find the maximum static friction.

[0084] The angular velocity constant is obtained by directly measuring the angular velocity of the system using a sensor such as a rotary encoder or a gyroscope and recording the data to obtain an average value.

[0085] Viscous friction coefficient The method for obtaining is as follows: it can be measured experimentally. The specific steps include: sliding an object at a known speed and recording the force required, calculating the friction coefficient using Newton's second law, rotating the object under test at a known angular velocity and recording the driving force required at this time, and calculating the viscous friction coefficient based on the driving force and the known angular velocity.

[0086] Step 3: Set the constraint function, establish the optimization objective function based on the optimization target parameters and the constraint function, use the optimization objective function as the fitness function, and solve the optimal hinge fulcrum position through the genetic algorithm. The optimal hinge fulcrum position is the hinge fulcrum position corresponding to the individual with the maximum fitness after satisfying the iteration conditions;

[0087] The constraint function includes: the landing gear elevation angle range, the landing gear movement height range, the total mass of the landing gear and the load, and the working platform length range; the formula for establishing the optimization objective function based on the optimization target parameters and the constraint function is:

[0088] ;

[0089] Where, Indicates the hinge point 、 and The corresponding optimization objective function is Indicates the landing gear movement height, and Represent the minimum and maximum values ​​of the total mass of the landing gear and the load, is the total mass of the landing gear and the load, is the landing gear pitch angle, Indicates the maximum pitch angle of the landing gear, is the length of the working platform, and They represent the minimum and maximum lengths of the working platform, respectively. n is the time of one movement cycle of the landing gear, that is, the working cycle time of the landing gear moving from the minimum elevation angle to the maximum elevation angle. The established optimization objective function is used as the fitness function, and the optimal hinge fulcrum position is obtained through the genetic algorithm. 、 、 and are the weight coefficients of the total pitch load torque, the electric cylinder axial thrust, the pitch motor output torque requirement, and the total mass of the landing gear and load; and 、 、 and Both are greater than 0.

[0090] Among them, the landing gear's elevation angle range, landing gear movement height range, total mass of the landing gear and load, and working platform length range are constrained. The landing gear's elevation angle range meets engineering needs, and limiting the elevation angle can prevent the landing gear from losing balance at extreme angles and prevent overturning or tilting; limiting the movement height ensures that the landing gear can adapt to the needs of different tasks and environments, and supports effective coordination with the ground or other equipment; determines the maximum load-bearing capacity of the landing gear and its load to prevent structural damage or loss of control due to overload; the working platform length range, that is, controls the hinge fulcrum. 、 and The value range of the position is reduced; the number of samples is reduced, which improves the efficiency of obtaining the optimal solution.

[0091] For the optimization objective function , which is inversely proportional to the total pitch load moment, electric cylinder axial thrust, and pitch motor output torque requirements of the mechanism's motion state. That is, the optimal solution is the hinge fulcrum position that can complete the full cycle of the pitch mechanism while minimizing the total pitch load moment, electric cylinder axial thrust, and pitch motor output torque requirements.

[0092] In order to avoid falling into the local optimal solution, the total mass of the landing gear and the load is introduced as the optimization objective function , and the total mass of the landing gear and the load is proportional to the optimization objective function, that is, the greater the total mass of the landing gear and the load that the pitch mechanism can withstand, the greater the output value of the optimization objective function;

[0093] Since the axial thrust of the electric cylinder is the first optimization target, it is hoped that the thrust required for the pitch mechanism movement is minimized, and the output torque requirement of the pitch motor is also relatively small. The total mass of the landing gear and the load determines the maximum carrying capacity of the landing gear and its load to prevent structural damage or loss of control due to overload. Therefore, and 、 、 and Both are greater than 0.

[0094] The genetic algorithm is used to iterate the initial population through population selection, crossover and mutation operations until the fitness function converges or reaches the set maximum number of iterations. In this embodiment, the number of iterations is set to 200. After the iteration is completed, the hinge position corresponding to the maximum fitness value in the iteration process is output. A total of m groups of hinge combinations are set as the initial population. The hinge combination includes hinge points. 、 and The initial position of the hinge point is obtained by optimizing the objective function as the fitness function and solving the optimal hinge point position through genetic algorithm. The optimal hinge point position includes Initial position , Initial position and Initial position .

[0095] Step 4: Analyze the pitch mechanism motion error and environmental error, and based on the obtained error value, correct the optimal hinge support point position to obtain the precise value of the optimal hinge support point position. The motion error includes geometric error and vibration error, and the environmental error is temperature error.

[0096] The analysis of the pitch mechanism motion error and environmental error is based on the following logic: obtain the geometric error, which includes the processing error and assembly error. During processing and assembly, due to the limitations of processing accuracy and assembly accuracy, the errors generated by the mechanism parts themselves and between parts are calibrated to obtain the horizontal processing error. , the machining vertical error is , the assembly level error is , the assembly vertical error is ;The geometric error is mainly manifested between the hinge seats. Different geometric errors will cause different degrees of errors in the electric cylinder lifting transmission ratio. Due to the limitations of processing accuracy and assembly accuracy, geometric errors always exist.

[0097] Based on the vibration acceleration of the electric cylinder, the displacement data of the landing gear is calculated. The specific formula is:

[0098] ;

[0099] Where, represents the ideal displacement of the electric cylinder in the time period from 0 to n, is the vibration acceleration at time t;

[0100] The horizontal and vertical offsets caused by the vibration error are calculated based on the ideal displacement of the landing gear. The horizontal and vertical offsets caused by the vibration error are calculated based on the following formula:

[0101] ;

[0102] ;

[0103] Where, is the horizontal offset caused by vibration error, is the vertical offset caused by vibration error, is the difference between the simulated displacement and the ideal displacement of the landing gear at time n, represents the pitch angle of the landing gear at time n; The calculation is based on the formula:

[0104] ;

[0105] Where, represents the simulated displacement of the landing gear, obtained by analyzing the finite element model of the pitch mechanism;

[0106] The environmental error includes a temperature error, and the temperature deformation of the pitch mechanism hinge support at the working environment temperature is calculated. The deformation of the hinge support caused by the temperature change is calculated based on the formula:

[0107] ;

[0108] Where, is the deformation of the hinge support, is the linear thermal expansion coefficient of the electric cylinder material, is the initial length of the hinge support; is the maximum temperature difference of the environment, where Refers to the maximum temperature difference that exists when the pitch mechanism goes from a stationary state to the end of operation.

[0109] Based on the obtained error value, the optimal hinge fulcrum position is corrected to obtain the optimal hinge fulcrum position accurate value, wherein, for the hinge fulcrum and Considering geometric errors and temperature errors, for the hinge support Considering geometric error, vibration error and temperature error, the corrected hinge support The exact value of the optimal hinge support position is expressed as:

[0110] ;

[0111] Corrected hinge point The exact value of the optimal hinge support position is expressed as:

[0112] ;

[0113] Corrected hinge point The exact value of the optimal hinge support position is expressed as:

[0114] ;

[0115] Where, and Indicates the hinge point The optimal hinge point position coordinates obtained by genetic algorithm, and Hinge fulcrum The optimal hinge point position coordinates, and Hinge fulcrum The optimal hinge fulcrum position coordinates.

[0116] The above formulas are all dimensionless and numerical calculations. The formulas are obtained by collecting a large amount of data and performing software simulation to obtain the most recent real situation. The preset parameters in the formulas are set by technicians in this field according to actual conditions.

[0117] The above embodiments can be implemented in whole or in part by software, hardware, firmware, or any other combination thereof. When implemented using software, the above embodiments can be implemented in whole or in part in the form of a computer program product. Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed by hardware or software depends on the specific application and design constraints of the technical solution.

[0118] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, and may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment as needed.

[0119] The above is only a specific implementation method of the present application, but the scope of protection of the present application is not limited thereto. Any technician familiar with this technical field can easily think of changes or replacements within the technical scope disclosed in this application, which should be covered by the scope of protection of the present application.

Claims

1. A pitch mechanism hinge point layout optimization design method, characterized in that: The specific steps include: Establish a finite element model of the pitch mechanism, set different articulated fulcrum positions based on the finite element model of the pitch mechanism, and record the coordinates of the articulated fulcrum positions, wherein the articulated fulcrum includes an articulated fulcrum between the lower lug of the electric cylinder and the front lug of the working platform, an articulated fulcrum between the upper lug of the electric cylinder and the front lug of the landing gear, and an articulated fulcrum between the rear lug of the landing gear and the rear lug of the working platform; Based on the finite element model of the pitch mechanism at different articulated fulcrum positions, a force analysis is performed on the finite element model of the pitch mechanism, and corresponding performance parameters of the pitch mechanism are calculated as optimization target parameters, wherein the performance parameters of the pitch mechanism include the pitch load moment, the axial thrust of the electric cylinder, and the output torque requirement of the pitch motor; Establish a plane coordinate system with the vertical working platform upward as the positive direction of the y-axis and the horizontal working platform to the right as the positive direction of the x-axis, and calibrate the hinge fulcrum between the lower support ear of the electric cylinder and the front support ear of the working platform as The hinge point between the upper support ear of the electric cylinder and the front support ear of the landing gear is The hinge point between the rear lug of the landing gear and the rear lug of the working platform is ,but The initial position coordinates are , The initial position coordinates are , The initial position coordinates are ; The specific logic for calculating the performance parameters of the pitch mechanism is: The formulas for calculating the pitch load moment, electric cylinder axial thrust and pitch motor output torque requirements are: In the formula, is the pitching load moment at time t, is the total mass of the landing gear and the load, is the acceleration due to gravity, represents the hinge point at time t The distance to the center of gravity of the load on the landing gear, is the landing gear pitch angle at time t, is the landing gear and its effective load at the hinge point at time t The moment of inertia, is the angular acceleration of the landing gear at time t, is the friction force at time t, is the axial thrust of the electric cylinder at time t, The hinge point and The distance between represents the angle between the electric cylinder and the horizontal plane at time t, is the output torque requirement of the pitch motor at time t, is the pitch motor transmission ratio; The hinge point and The distance between The calculation is based on the formula: Friction It is composed of Coulomb friction, viscous friction and friction index terms. The specific calculation formulas include: In the formula, is the maximum static friction, is the friction index term at time t, is the viscous friction at time t, where the friction exponential term The calculation is based on the formula: In the formula, is the kinetic friction, is the angular velocity constant; Viscous friction The calculation is based on the formula: In the formula, is the viscous friction coefficient; A constraint function is set, and an optimization objective function is established based on the optimization objective parameter and the constraint function, and the optimization objective function is used as the fitness function, and an optimal hinge fulcrum position is solved by a genetic algorithm, wherein the optimal hinge fulcrum position is the hinge fulcrum position corresponding to the individual with the maximum fitness after satisfying the iteration condition; The constraint function includes: the pitch angle range of the landing gear, the height range of the landing gear movement, the total mass of the landing gear and the load, and the length range of the working platform; the formula for establishing the optimization objective function based on the optimization objective parameters and the constraint function is: In the formula, Indicates the hinge point , and The corresponding optimization objective function is Indicates the landing gear movement height, and Respectively represent the minimum and maximum values ​​of the total mass of the landing gear and the load, is the total mass of the landing gear and the load, is the landing gear pitch angle, Indicates the maximum pitch angle of the landing gear, is the length of the working platform, and They represent the minimum and maximum lengths of the working platform, respectively. n is the movement cycle time of the landing gear, that is, the working cycle time of the landing gear moving from the minimum elevation angle to the maximum elevation angle. The established optimization objective function is used as the fitness function, and the optimal hinge fulcrum position is obtained through the genetic algorithm. , , and are the weight coefficients of the total pitch load moment, the electric cylinder axial thrust, the pitch motor output torque requirement, and the total mass of the landing gear and the load; and , , and All are greater than 0; The motion error and environmental error of the pitch mechanism are analyzed, and based on the obtained error value, the optimal hinge fulcrum position is corrected to obtain the precise value of the optimal hinge fulcrum position. The motion error includes geometric error and vibration error, and the environmental error is temperature error.

2. The pitch mechanism hinge point layout optimization design method according to claim 1, characterized in that: A total of m groups of hinged fulcrum combinations are set as the initial population, and the hinged fulcrum combination includes hinged fulcrum , and The initial position of the hinge point is determined by optimizing the objective function as the fitness function, and the optimal hinge point position is solved by genetic algorithm. The optimal hinge point position includes Initial position , Initial position and Initial position .

3. The pitch mechanism hinge point layout optimization design method according to claim 1, characterized in that: The analysis of the pitch mechanism motion error and environmental error is based on the following logic: obtain the geometric error, which includes the processing error and the assembly error, and calibrate the processing horizontal error as , the machining vertical error is , the assembly level error is , the vertical error of the assembly is ; Based on the vibration acceleration of the electric cylinder, the displacement data of the landing gear is calculated. The specific formula is: In the formula, represents the ideal displacement of the electric cylinder in the time period from 0 to n, is the vibration acceleration at time t; The horizontal and vertical offsets caused by the vibration error are calculated based on the ideal displacement of the landing gear. The horizontal and vertical offsets caused by the vibration error are calculated based on the following formula: In the formula, is the horizontal offset caused by vibration error, is the vertical offset caused by vibration error, is the difference between the simulated displacement and the ideal displacement of the landing gear at time n, represents the pitch angle of the landing gear at time n; The calculation is based on the formula: In the formula, represents the simulated displacement of the landing gear, obtained by analyzing the finite element model of the pitch mechanism; The environmental error includes a temperature error, and the temperature deformation of the pitch mechanism hinge support at the working environment temperature is calculated, wherein the deformation amount of the hinge support caused by the temperature change is calculated based on the formula: In the formula, is the deformation of the hinge support, is the linear thermal expansion coefficient of the electric cylinder material, is the initial length of the hinge support; The maximum temperature difference of the environment.

4. The pitch mechanism hinge point layout optimization design method according to claim 3, characterized in that: Based on the error value obtained, the optimal hinge fulcrum position is corrected to obtain the optimal hinge fulcrum position accurate value, where and Considering geometric errors and temperature errors, for the hinge point Considering geometric error, vibration error and temperature error, the corrected hinge support The exact value of the optimal hinge fulcrum position is expressed as: Corrected hinge point The exact value of the optimal hinge fulcrum position is expressed as: Corrected hinge point The exact value of the optimal hinge fulcrum position is expressed as: In the formula, and Indicates the hinge point The optimal hinge point position coordinates obtained by genetic algorithm, and The hinge point The optimal hinge fulcrum position coordinates, and The hinge point The optimal hinge fulcrum position coordinates.

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