A method and system for dynamic adjustment of load of a synchronous position loop ball screw pair

Abstract

The application discloses a kind of synchronous position ring under ball screw pair load dynamic adjustment method and system, by setting same position ring under corner difference loading mode, avoid the direction of current that needs to change frequently when current loop loading, while the screw on current loop belongs to reverse transmission contact state, not consistent with the working condition of screw, and accelerate its friction and wear, prone to cause the performance degradation and fatigue breakage of screw on current loop earlier than position ring on screw and other problems.On this basis, through static corner difference calibration experiment and verification, the static corner difference and load equation are accurately established.In the process of motion, load closed-loop control is introduced, effectively reducing the problem of large fluctuation of load existing in the dynamic motion of screw after static load calibration.The ability of dynamic variable load in the process of screw motion is realized.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of axial loading and load dynamic regulation in ball screw pair performance degradation experiment, and particularly relates to a synchronous position ring under ball screw pair load dynamic adjustment method and system. BACKGROUND

[0002] As a kind of precision positioning transmission components for converting rotary motion into linear motion, ball screw pair is widely used in manufacturing industry with the advantage of high-precision linear positioning. In the actual use process of ball screw pair, there are complex working conditions of variable speed and axial variable load. Load is one of the key factors affecting the comprehensive performance degradation of ball screw pair. In order to simulate the degradation law of ball screw pair under variable load conditions, it is crucial to stably control and adjust the load.

[0003] The current research on ball screw pair load adjustment method mainly includes two types: segmented constant loading method with stable loading capacity and existing current loop load adjustment method. The former mainly changes the mass of the added weight to achieve load adjustment, which has good load stability but cannot realize dynamic continuous variable load. In the case of double-motor torque, the latter adjusts the load size by combining the position loop and the current loop and adjusting the current. This adjustment method needs to frequently change the direction of the current when reversing, and the screw on the current loop is in reverse transmission contact state, which is inconsistent with the common working condition of the screw. Moreover, it accelerates the friction and wear of the screw on the current loop, which is prone to cause performance degradation and fatigue failure of the screw on the current loop earlier than the screw on the position loop. Therefore, a new ball screw load adjustment method is proposed. In the case of double-motor torque, the load is controlled at the target load based on the synchronous position ring external load closed loop without changing the transmission characteristics of the screw, which significantly reduces the load fluctuation problem in the movement process. This is of great significance to the performance degradation experiment of ball screw pair. SUMMARY

[0004] The technical problem to be solved by the application is to provide a synchronous position ring under ball screw pair load dynamic adjustment method and system to solve the technical problems of current loop loading causing reverse transmission of the screw, unreasonable load adjustment leading to abnormal wear of the screw, and large load fluctuation caused by static loading in the movement process.

[0005] The application adopts the following technical solutions:

[0006] A synchronous position ring under ball screw pair load dynamic adjustment method, comprising the following steps:

[0007] S1, control the double-motor to work under the position loop at the same time, and move at the same planned position and planned speed;

[0008] S2, based on the synchronous position loop mode of the dual-motor in step S1, independently adjusting the planned position of the secondary motor in the dual-motor, observing the force value, and carrying out a static angle difference and load calibration experiment, analyzing the calibration experiment data to establish a mapping relationship between the angle difference and the load;

[0009] S3, according to the mapping relationship between the angle difference and the load obtained in step S2, the two motors working in the synchronous position loop set in step S1, under the condition that both motors are enabled at zero position, inputting the target load to the load calibration equation to obtain the target angle difference pulse, planning the position of the secondary motor in the dual-motor to the target angle difference pulse, and issuing the planned position of the primary motor in the dual-motor to the far end point of the screw pair stroke and back to zero, the secondary motor following the planned position of the primary motor and biasing the target angle difference pulse based on the synchronous position loop, and observing the fluctuation of the target load in the static load during the movement;

[0010] S4, based on the fluctuation of the target load in the static load obtained in step S3, calculating the deviation between the real-time force feedback value and the current target load, based on the mapping relationship between the angle difference and the load obtained in step S2, establishing a dynamic closed-loop control model of the ball screw pair axial load, and realizing real-time dynamic variable load and load stability function based on the dynamic closed-loop control model of the ball screw pair axial load.

[0011] Preferably, in step S1, the primary motor and the secondary motor are both set to work in the position loop, the primary motor drives the primary ball screw pair for transmission, the secondary motor drives the secondary ball screw pair for transmission, the planned position of the primary motor is bound to the planned position of the secondary motor, and the planned position of the secondary motor is independently adjustable while realizing the synchronization of the planned position of the primary motor in the planned position of the secondary motor.

[0012] Preferably, step S2 is specifically:

[0013] S201, selecting m position points at equal intervals on the working stroke of the ball screw pair, and performing a static angle difference and load calibration experiment at each position point;

[0014] S202, repeating the static angle difference and load calibration experiment of the m position points in step S201, recording the force sensor value corresponding to all angle differences of all position points, and completing the static angle difference and load calibration experiment of the m position points;

[0015] S203, according to the force sensor value corresponding to all angle differences of all position points obtained in step S202, establishing a linear regression model of the load about the angle difference pulse, fitting the model by using the least square estimation method, and obtaining the equation of the angle difference pulse and the load.

[0016] Preferably, in step S201, the corner difference pulse is gradually increased from 0 to Pmax, then gradually decreased from Pmax to Pmin, Pmax=-Pmin, and then gradually increased from Pmin to 0, and the force sensor reading is recorded at each interval point during the process to complete the static corner difference and load calibration experiment of a position point.

[0017] Preferably, before each experiment, the planned positions of the main motor and the auxiliary motor are reset to zero to ensure that the initial corner difference is zero.

[0018] Preferably, in step S3, the load is approached at 300 r / min, 500 r / min, and 800 r / min for 500 N, 1000 N, and 1500 N, respectively.

[0019] Preferably, step S4 is specifically:

[0020] First, calculate the size of the axial force of the ball screw pair at time t , and input it into the corner difference calculation equation to obtain , according to the planned axial target load size of the ball screw pair at time t and the calculated axial force size of the ball screw pair at time t , determine whether to perform closed-loop adjustment, according to the calculated speed control instruction of shaft 2 controller , convert the time accumulation to corner difference and add it to the planned position of the shaft 2 controller.

[0021] Preferably, according to , , the axial force size of the ball screw pair at time t , the corresponding corner difference size of the difference between the planned axial target load and the actual load of the ball screw pair at time t , the speed instruction sent to the driver at time t when the load is closed loop , and the corner difference size between the main motor and the auxiliary motor at time t when the closed loop is adjusted are respectively:

[0022]

[0023] wherein, is the voltage analog signal of the force sensor read by the acquisition system at time t, is the maximum value of the voltage analog signal of the force sensor, is the maximum range of the force sensor, is the axial force size of the ball screw pair at time t calculated according to , , , a target load size of the ball screw pair at time t, a load threshold size of the load closed-loop control, an angle difference size between the main motor and the auxiliary motor at the previous closed-loop adjustment at time t, a period of the closed-loop control algorithm adjustment.

[0024] Preferably, when the absolute value of the difference between the target load and the actual load at time t is less than or equal to the load threshold size of the load closed-loop control, the difference is set to zero, and no planned adjustment is performed; when the absolute value of the difference between the target load and the actual load at time t is greater than the load threshold size of the load closed-loop control, the planned adjustment is performed at . is the execution time of the control instruction, is a coefficient related to the planned speed in the point motion of the shaft 2 controller.

[0025] In a second aspect, an embodiment of the present application provides a ball screw pair load dynamic adjustment system under a synchronous position loop, comprising:

[0026] a control module, which controls the two motors to work under the position loop at the same time and move at the same planned position and planned speed;

[0027] an analysis module, which adjusts the planned position of the auxiliary motor in the two motors separately based on the synchronous position loop working mode of the two motors, observes the indication of the force, and carries out a static angle difference and load calibration experiment to analyze the calibration experimental data and establish a mapping relationship between the angle difference and the load;

[0028] a loading module, which, according to the mapping relationship between the angle difference and the load, sets the two motors to work under the synchronous position loop, inputs the target load to the load calibration equation to obtain a target angle difference pulse, plans the position of the target angle difference pulse to the auxiliary motor in the two motors, issues the planned position of the main motor in the two motors to the far end point of the ball screw pair stroke and returns to the zero point, and the auxiliary motor follows the planned position of the main motor and is offset by the target angle difference pulse on the basis of the synchronous position loop, and observes the fluctuation of the target load under static loading in the movement process;

[0029] an adjustment module, which calculates the deviation between the real-time force feedback value and the current target load based on the fluctuation of the target load under static loading, establishes a ball screw pair axial load dynamic closed-loop control model based on the obtained mapping relationship between the angle difference and the load, and realizes real-time dynamic load variation and load stability functions based on the ball screw pair axial load dynamic closed-loop control model.

[0030] ​In a third aspect, a computer device includes a memory, a processor, and a computer program stored in the memory and executable on the processor, and the processor implements the steps of the method for dynamically adjusting load of a ball screw pair under a synchronous position ring when executing the computer program.

[0031] In a fourth aspect, an embodiment of the present application provides a computer readable storage medium including a computer program, and the computer program implements the steps of the method for dynamically adjusting load of a ball screw pair under a synchronous position ring when executed by a processor.

[0032] Compared with the prior art, the present application has at least the following beneficial effects:

[0033] A method for dynamically adjusting load of a ball screw pair under a synchronous position ring includes four main parts: synchronous position ring setting of a double motor, static angle difference and load calibration experiment and analysis, static load calibration verification in a motion process, and load closed-loop control under a synchronous position ring. By setting the angle difference loading mode under the position ring, the need to frequently change the direction of the current in the current loop loading is avoided. At the same time, the screw on the current loop belongs to a reverse transmission contact state, which is inconsistent with the normal working condition of the screw, and accelerates the friction and wear of the screw, which can easily cause the screw on the current loop to degrade and fatigue failure earlier than the screw on the position ring. On this basis, the static angle difference and load equation is accurately established through the static angle difference calibration experiment and verification. The load closed-loop control is introduced in the motion process, which effectively reduces the large load fluctuation problem existing in the dynamic motion of the screw after the static load calibration. The dynamic variable load capability of the screw in the motion process is realized.

[0034] Further, on the double motor torsion loading test bench, the main motor and the auxiliary motor are set to work under the position ring at the same time, and the motion is carried out at the same planned position and planned speed, so as to ensure that both ball screw pairs are in a forward transmission motion state and avoid the reverse transmission phenomenon of the screw pair to cause abnormal wear of the screw. The planned position of the main motor is bound to the planned position of the auxiliary motor, so as to ensure that the planned position of the auxiliary motor is independently adjustable while realizing the synchronization of the planned position of the main motor with the planned position of the auxiliary motor. In this way, the bias planned position of the auxiliary motor can be effectively adjusted to change the target load size, and the bias planned position of the auxiliary motor can be adjusted to observe the value of the force sensor, so as to carry out the static static angle difference and load calibration experiment, analyze the calibration experiment data, and establish the mapping relationship between the angle difference and the load. By continuously adjusting the bias planned position, more force sensor data can be obtained, and the accuracy of the calibration equation can be improved.

[0035] Further, m position points are selected on the working stroke of the ball screw pair at equal intervals, and a static rotation angle difference and load calibration experiment is performed at each position point to eliminate the deviation of the rotation angle difference and load mapping at different position points of the screw. The planned positions of the two motors are reset before each experiment to ensure that the initial working conditions of each calibration experiment are the same.

[0036] Further, the rotation angle difference pulse is set to gradually increase from 0 to Pmax at an interval of k, then gradually decrease from Pmax to Pmin at an interval of k, where Pmax=-Pmin, and then gradually increase from Pmin to 0 at an interval of k. When the load is positive, it reflects that the ball screw pair bears a tensile load, and when the load is negative, it reflects that the ball screw pair bears a compressive load. The calibration in the positive and negative directions avoids the characteristic differences of the tensile load and the compressive load under different rotation angle differences. The force sensor indications corresponding to all the position points and all the rotation angle differences are obtained, a linear regression model of the load with respect to the rotation angle difference pulse is established, the model is fitted by using the least square estimation method, and the equation of the rotation angle difference pulse and the load is obtained. The required rotation angle difference can be calculated in real time when any target load is input.

[0037] Further, in the case that both motors are enabled at zero position, the target rotation angle difference pulse is calculated from the calibration equation according to the input target load, the target rotation angle difference pulse is superimposed on the planned position of the secondary motor, and the planned position of the primary motor is issued to the far end point of the ball screw pair and returned to zero. In the movement process, the fluctuation of the static load to the target load is observed, which can effectively verify the effectiveness of the static load close to the target load in the movement process.

[0038] Further, the deviation of the real-time force sensor feedback value and the current target load is calculated, and on this basis, a ball screw pair axial load dynamic closed-loop control model is established based on the rotation angle difference load calibration equation to suppress the load fluctuation problem in the movement process and realize the functions of real-time dynamic variable load and load stability. Point position movement is performed under the planned position and speed, the real-time load output by the force sensor between the actuators of the two shafts is input to the adjustment model, the adjustment model calculates the pulse increment according to the input target load, and the pulse increment is superimposed on the speed command in the shaft 2 controller to avoid the problem that the control command is occupied in the point position movement.

[0039] Further, The absolute value is set to be not more than the maximum range of the force sensor to avoid the problem of sensor damage caused by overloading The axial force of the ball screw pair at time t is calculated and input into the rotation angle difference calculation equation to obtain The axial target load of the ball screw pair planned at time t is calculated The difference between the current target load and the next target load is determined to determine whether to perform closed-loop adjustment, thereby avoiding invalid adjustment when the load tends to be stable.

[0040] Further, a coefficient related to the planned speed in the shaft 2 controller point motion is set , a plurality of experiments are performed at different speeds, The greater the control load oscillation is smaller, The smaller the control load oscillation is greater, and through adjustment, the load response oscillation problem at different speeds can be effectively reduced, The execution time of the control instruction, The period of the closed-loop control algorithm adjustment is set , to avoid the abnormal load problem caused by the large difference between the current target load and the next target load during closed-loop adjustment, and to ensure the stability of the control, the shaft 2 controller speed control instruction , is converted into an angle difference through time accumulation and added to the planned position of the shaft 2 controller. The dynamic closed-loop adjustment of the ball screw pair axial load is realized.

[0041] It can be understood that the beneficial effects of the above-mentioned second aspect can be referred to the related description in the above-mentioned first aspect, which will not be described here.

[0042] In summary, the application can avoid the reverse transmission of the ball screw pair during current loop loading, which accelerates the friction and wear, and easily causes the performance degradation and fatigue failure of the screw on the current loop earlier than the screw on the position loop. At the same time, on the basis of the control of the same position loop, the angle difference and load calibration experiment is carried out, the relationship between the angle difference and the load under static state is accurately established and verified in the motion process. Based on the angle difference load calibration equation, a dynamic closed-loop control model of the ball screw pair axial load is established, the load fluctuation problem in the motion process is suppressed, and the real-time dynamic variable load and load stability function is realized.

[0043] The technical solutions of the application will be further described in detail below with the help of the drawings and examples. BRIEF DESCRIPTION OF DRAWINGS

[0044] In order to more clearly illustrate the technical solutions in the embodiments of the application, the drawings used in the following comparative example description are briefly introduced. Obviously, the drawings in the following description are only some embodiments of the application, and those skilled in the art can obtain other drawings according to these drawings without creating any creative labor.

[0045] Figure 1 The schematic diagram of the double-motor ball screw pair test bench

[0046] Figure 2 The load dynamic adjustment control block diagram of the ball screw pair under the synchronous position loop;

[0047] Figure 3 For the synchronous position ring under the ball screw pair rotation angle difference and load once calibration results;

[0048] Figure 4 For 300r / min under different target load static and dynamic control effect diagram;

[0049] Figure 5 For 500r / min under different target load static and dynamic control effect diagram;

[0050] Figure 6 For 800r / min under different target load static and dynamic control effect diagram;

[0051] Figure 7 For the schematic diagram of the computer equipment provided by the embodiment of the application is provided;

[0052] Figure 8 For the block diagram of the electronic device provided by the embodiment of the application is provided.

[0053] Wherein, 1. main motor;2. main fixed end assembly;3. main ball screw pair;4. first actuator;5. main support end assembly;6. vice support end assembly;7. vice ball screw pair;8. second actuator;9. force sensor;10. vice fixed end assembly;11. vice motor. DETAILED DESCRIPTION

[0054] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are some of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the application.

[0055] In the description of the application, it should be understood that the terms "include" and "contain" indicate the existence of described features, whole, steps, operations, elements and / or components, but do not exclude the existence or addition of one or more other features, whole, steps, operations, elements, components and / or sets thereof.

[0056] It should also be understood that the terms used in the specification of the application are only for the purpose of describing specific embodiments and are not intended to limit the application. As used in the specification and the appended claims of the application, unless otherwise clear from the context, the singular forms "a", "an" and "the" are intended to include plural forms.

[0057] It should be further understood that the term "and / or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items, and that the term "and / or" as used herein allows for the inclusion of only a single item, or the use of some items in combination with other items. In addition, the character " / " as used in the present application generally represents an "or" relationship between the objects before and after the " / ".

[0058] It should be understood that, although the terms first, second, third, etc. can be used in embodiments of the present application to describe a certain range, etc., these ranges should not be limited to these terms. These terms are only used to distinguish one range from another. For example, a first range can also be referred to as a second range, and similarly, a second range can also be referred to as a first range, without departing from the scope of embodiments of the present application.

[0059] Depending on the context, the word "if" as used herein can be interpreted to mean "when" or "while" or "in response to determining" or "in response to detecting." Similarly, the phrase "if it is determined" or "if [a stated condition or event] is detected" can be interpreted to mean "upon determining" or "in response to determining" or "upon detecting [the stated condition or event]" or "in response to detecting [the stated condition or event]."

[0060] Various structural diagrams according to the disclosed embodiments of the present application are shown in the accompanying drawings. These drawings are not drawn to scale, in which certain details are exaggerated for the purpose of clarity and certain details can be omitted. The shapes of various regions, layers, and their relative sizes and positional relationships shown in the drawings are only exemplary, and in actuality, they can deviate due to manufacturing tolerances or technical limitations, and a person skilled in the art can additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0061] The present application provides a synchronous position ring under ball screw pair load dynamic adjustment method, including double motor synchronous position ring setting, static angle difference and load calibration experiment and analysis, static load calibration verification in motion process, synchronous position ring load closed loop control, etc. Four steps. Based on the angle difference load calibration results and real-time sensor force feedback in the synchronous position ring, the closed loop load control logic is established, the dynamic control function of any input target load is realized, and the dynamic stability of the ball screw pair load experiment is ensured.

[0062] The principle of the application is that for a double-motor torsion ball screw pair experimental system, a synchronous position loop control mode is adopted to ensure that the main motor and the auxiliary motor run at the same planned position and planned speed, wherein the main motor binds its planned position to the planned position of the auxiliary motor, and the auxiliary motor can separately issue a speed instruction for controlling the bias pulse of the auxiliary motor, when the bias pulse exists, the main motor will cause an interaction force between the main screw and the auxiliary screw in order to maintain its planned position, according to the relationship between the action force and the reaction force, the size of the force sensor reflects the axial load applied on the main screw and the auxiliary screw. By continuously adjusting the bias pulse, different load sizes can be obtained, and based on this, a calibration equation of the rotation angle difference and the load can be established; but there is still a load fluctuation problem in the movement process, in order to solve this problem, a load closed loop is added on the basis of the position loop, a load adjustment model based on the calibration equation is established, the difference between the force sensor indication value and the target load is detected in real time and input into the adjustment model, which will output the rotation angle difference increment, at the same time, the rotation angle difference increment is issued to the auxiliary motor bias planning position in the form of a speed instruction, and the force sensor indication value and the target load are controlled to be less than the load threshold value through control adjustment, and different target loads can achieve the real-time variable load adjustment function

[0063] The application discloses a synchronous position loop ball screw pair load dynamic adjustment method, which comprises the following steps:

[0064] S1, the double-motor synchronous position loop is set to mainly ensure that the two motors work in the position loop at the same time, move at the same planned position and planned speed, and ensure the forward transmission of the two ball screw pairs;

[0065] Please refer to Figure 1 The main motor 1 is connected with one end of the main ball screw pair 3 through the main fixed end assembly 2, the other end of the main ball screw pair 3 is connected with the main support end assembly 5, and the first actuator 4 is arranged on the main ball screw pair 3; the auxiliary motor 11 is connected with one end of the auxiliary ball screw pair 7 through the auxiliary fixed end assembly 10, the other end of the auxiliary ball screw pair 7 is connected with the auxiliary support end assembly 6, the second actuator 8 is arranged on the auxiliary ball screw pair 7, and the first actuator 4 and the second actuator 8 are connected through the force sensor 9.

[0066] The main motor 1 drives the main ball screw pair 3 to transmit, the auxiliary motor 11 drives the auxiliary ball screw pair 7 to transmit, the main motor 1 and the auxiliary motor 11 are arranged to work in the position loop, the planned position of the main motor 1 is bound to the planned position of the auxiliary motor 11, and the planned position of the auxiliary motor 11 is independently adjustable while the planned position of the main motor 1 is synchronized with the planned position of the auxiliary motor 11.

[0067] S2, according to the step S1 in which the synchronous position loop working mode of the main motor 1 and the auxiliary motor 11 is set, the indication of the planned position force sensor 9 of the auxiliary motor 11 is adjusted alone, on the basis of which the static angle difference and load calibration experiment is carried out, and the mapping relationship between the angle difference and the load is analyzed and established according to the calibration experiment data;

[0068] S201, m position points are selected at equal intervals on the working stroke of the ball screw pair, and a static angle difference and load calibration experiment is carried out at each position point, the planned positions of the two motors are cleared before each experiment to ensure that the initial angle difference is zero; the angle difference pulse is set to gradually increase from 0 to Pmax, and then gradually decrease from Pmax to Pmin, wherein Pmax=-Pmin, and then gradually increase from Pmin to 0, and the indication of the force sensor is recorded at each interval point in this process, including the loading data of the positive tension and the negative pressure. Thus, a static angle difference and load calibration experiment is completed at one position point;

[0069] S202, the static angle difference and load calibration experiment of the m position points in step S201 is repeated, and the force sensor indications corresponding to all angle differences of all position points are recorded, and the static angle difference and load calibration experiment of the m position points is completed.

[0070] S203, according to the force sensor indications corresponding to all angle differences of all position points obtained in step S202, a linear regression model of the load about the angle difference pulse is established, and the least square estimation method is used to fit the model to obtain the equation of the angle difference pulse and the load.

[0071] Please refer to Figure 3 , which is the result of a static angle difference and load calibration experiment, indicating that the angle difference pulse and the load have a high linear relationship, and the fitting obtains , in this example, = 0.625, = -1.875.

[0072] S3, according to the equation of the angle difference and the load obtained in step S2, the verification is carried out during the movement to ensure the approaching ability to the target load during the movement; according to the step S1 in which the two motors are set to work in the synchronous position loop, the target load is input to the load calibration equation to obtain the target angle difference pulse under the condition that the two motors are enabled at zero position, the angle difference pulse is planned to the position of the auxiliary motor 2, and the planned position of the main motor 1 is fed to the far end point of the screw pair and returned to the zero point, and the auxiliary motor will follow the planned position of the main motor 1 and offset the target angle difference pulse on the basis of the synchronous position loop, and the fluctuation of the static load to the target load is observed during the movement;

[0073] Please refer to Figure 3 , 4, 5, respectively, in 300 r / min, 500 r / min, 800 r / min to 500N, 1000N, 1500N load close to the case, show that in different speed static loading can effectively close to the target load.

[0074] S4, calculate the deviation of real-time force sensor feedback value and current target load, on this basis, based on the angle difference load calibration equation to establish the dynamic closed-loop control model of ball screw pair axial load, suppress the load fluctuation problem in the process of motion, realize the function of real-time dynamic variable load and load stability.

[0075] According to the results of step S3, the calibration equation of the angle difference and the load is effective, but the force sensor indication value always has a large fluctuation near the target load in the dynamic motion process.

[0076] Please refer to Figure 2 , the dynamic closed-loop control block diagram of ball screw pair axial load, the shaft 1 controller and the shaft 2 controller work in the synchronous position loop, and the point motion is carried out under the planned position and the planned speed. The force sensor output real-time load between the actuators of the two shafts is input to the adjustment model, which calculates the output pulse increment according to the input target load, and the pulse increment is superimposed into the shaft 2 controller with the speed command to realize the dynamic closed-loop adjustment of the load.

[0077] First, calculate the size of the axial force of the ball screw pair at time t , and input it into the angle difference calculation equation to get , according to the planned axial target load size of the ball screw pair at time t , and the difference between the calculated axial force size of the ball screw pair at time t , determine whether to carry out closed-loop adjustment, according to the calculated speed control command of shaft 2 controller , through time accumulation conversion to angle difference and superimposed into the planned position of shaft 2 controller.

[0078]

[0079] Among them, is the force sensor voltage analog signal read by the acquisition system at time t, is the maximum value of the force sensor voltage analog signal, is the maximum range of the force sensor, is the axial force size of the ball screw pair at time t calculated according to , , .

[0080] is the planned axial target load size of the ball screw pair at time t, The absolute value of the difference between the target load and the actual load at the t time cannot exceed the maximum range of the force sensor Otherwise, overload will occur, causing damage to the sensor. The planned position angle difference between the main motor and the auxiliary motor at the t time, The derivative of the angle difference with respect to the load in the calibration equation is used to calculate the angle difference corresponding to the difference between the planned axial target load and the actual load of the ball screw pair at the t time .

[0081] The speed instruction sent to the driver at the t time when the load is closed loop, because the two motors work under the synchronous position ring, the position planning is carried out in point motion, and the position can only be planned in speed mode. Therefore, the control instruction accepted by the system is , unit: plus / ms; The load threshold value of the load closed loop control, when the absolute value of the difference between the target load and the actual load at the t time is less than or equal to , Set to zero, no planning adjustment.

[0082] When the absolute value of the difference between the target load and the actual load at the t time is greater than , the planning adjustment needs to be carried out , wherein The execution time of the control instruction, The coefficient related to the planning speed in the point motion of the shaft 2 controller. This coefficient needs to be adjusted through multiple experiments, The greater the control load shock is smaller, The smaller the control load shock is greater.

[0083] The angle difference between the main motor and the auxiliary motor at the t time of the previous closed loop adjustment, The period of the closed loop control algorithm adjustment, in order to avoid the problem of abnormal load caused by the large difference between the current target load and the next target load during closed loop adjustment, it is necessary to satisfy To ensure the stability of the control. The angle difference between the main motor and the auxiliary motor at the t time of the closed loop adjustment, which is the cumulative value from the initial time to the current time.

[0084] Those skilled in the art can understand that various aspects of the present application can be implemented as a system, a method or a program product. Therefore, various aspects of the present application can be implemented in the form of a complete hardware implementation, a complete software implementation (including firmware, microcode, etc.), or a combination of hardware and software aspects, which can be collectively referred to as "circuit", "module" or "platform" here.

[0085] In another embodiment of the present application, a synchronous position loop under ball screw pair load dynamic adjustment system is provided, which can be used to implement the synchronous position loop under ball screw pair load dynamic adjustment method. Specifically, the synchronous position loop under ball screw pair load dynamic adjustment system comprises a control module, an analysis module, a loading module, and an adjustment module.

[0086] The control module controls the two motors to work under the position loop simultaneously and move at the same planned position and planned speed.

[0087] The analysis module adjusts the planned position of the secondary motor in the two motors based on the synchronous position loop working mode of the two motors, observes the indication of the force, and carries out static angle difference and load calibration experiments to analyze the calibration experimental data and establish a mapping relationship between the angle difference and the load.

[0088] The loading module inputs the target load into the load calibration equation to obtain the target angle difference pulse according to the mapping relationship between the angle difference and the load, plans the position of the secondary motor in the two motors with the target angle difference pulse, and issues the planned position of the primary motor in the two motors to the far end point of the screw pair stroke and back to the zero point. The secondary motor follows the planned position of the primary motor and is offset by the target angle difference pulse based on the synchronous position loop, and observes the fluctuation of the target load during the movement.

[0089] The adjustment module calculates the deviation between the real-time force feedback value and the current target load based on the fluctuation of the target load under static loading, establishes a ball screw pair axial load dynamic closed-loop control model based on the obtained mapping relationship between the angle difference and the load, and realizes real-time dynamic variable load and load stability function based on the ball screw pair axial load dynamic closed-loop control model.

[0090] In another embodiment of the present application, a terminal device is provided, which comprises a processor and a memory, the memory being configured to store a computer program, the computer program comprising program instructions, and the processor being configured to execute the program instructions stored in the computer storage medium. The processor can be a central processing unit (CPU), and can also be other general-purpose processors, digital signal processors (DSP), application specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc., which are the computing core and control core of the terminal, and are suitable for implementing one or more instructions, and are particularly suitable for loading and executing one or more instructions to implement a corresponding method flow or a corresponding function; the processor in the embodiments of the present application can be used for the operation of the synchronous position loop under the ball screw pair load dynamic adjustment method, comprising:

[0091] The two motors are controlled to work in the position loop at the same time, and move at the same planned position and planned speed; based on the synchronous position loop working mode of the two motors, the planned position of the secondary motor in the two motors is adjusted individually, the force indication is observed, and the static angle difference and load calibration experiment is carried out, and the mapping relationship between the angle difference and the load is analyzed and calibrated. According to the obtained mapping relationship between the angle difference and the load, the two motors are set to work in the synchronous position loop, and in the case that the two motors are enabled at zero position, the target load is input to the load calibration equation to obtain the target angle difference pulse, the angle difference pulse is planned to the secondary motor in the two motors, and the planned position of the primary motor in the two motors is issued to the far end point of the screw pair stroke and returns to zero point. The secondary motor follows the planned position of the primary motor on the basis of the synchronous position loop and offsets the target angle difference pulse, and the fluctuation of the target load under static loading is observed during the movement. Based on the obtained fluctuation of the target load under static loading, the deviation between the real-time force feedback value and the current target load is calculated, the mapping relationship between the angle difference and the load is established based on the obtained mapping relationship between the angle difference and the load, and the ball screw pair axial load dynamic closed-loop control model is established. Based on the ball screw pair axial load dynamic closed-loop control model, the real-time dynamic variable load and load stability function are realized.

[0092] In still another embodiment of the present application, a storage medium, specifically a computer readable storage medium (Memory) is also provided. The computer readable storage medium is a memory device in the terminal equipment, for storing programs and data. It can be understood that the computer readable storage medium herein can include the built-in storage medium in the terminal equipment, and of course can also include the expansion storage medium supported by the terminal equipment, and can be any tangible medium containing or storing programs, which can be used by or in combination with the instruction execution system, device or apparatus. The computer readable storage medium provides a storage space, which stores the operating system of the terminal. Moreover, one or more instructions suitable for being loaded and executed by the processor are also stored in the storage space, and the instructions can be one or more computer programs (including program codes). It should be noted that more specific examples (non-exhaustive list) of the computer readable storage medium herein include: an electrical connection with one or more conductive wires, a portable disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above.

[0093] The computer readable storage medium also includes a data signal carrying the readable program code in a baseband or as a part of a carrier, where the readable program code is carried by the data signal. Such a propagated data signal can take any of a variety of forms, including but not limited to electro-magnetic, optical, or any suitable combination thereof. The readable storage medium can also be any readable medium that can be used to carry the readable program code in any suitable manner, and the readable program code can be executed by or in combination with an instruction execution system, device or apparatus. The readable program code contained in the readable storage medium can be transmitted in any suitable manner, including but not limited to wireless, wired, optical, RF, or any suitable combination thereof.

[0094] The program code for carrying out operations of the present application can be written in any combination of one or more programming languages, including an object oriented programming language such as Java, C++, or the like, and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The program code can execute entirely on the user's computing device, partly on the user's computing device, as a stand-alone software package, partly on the user's computing device and partly on a remote computing device or entirely on the remote computing device or server. In the latter scenario, the remote computing device can be connected to the user's computing device through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection can be made to an external computing device, such as through the Internet using an Internet Service Provider.

[0095] The one or more instructions stored in the computer readable storage medium can be loaded and executed by the processor to implement the corresponding steps of the method for dynamically adjusting load of a ball screw pair under a synchronous position loop in the above embodiments. The one or more instructions stored in the computer readable storage medium are loaded and executed by the processor to implement the following steps:

[0096] The two motors are controlled to work under the synchronous position loop and move at the same planned position and planned speed. Based on the synchronous position loop working mode of the two motors, the planned position of the secondary motor in the two motors is adjusted, the force indication is observed, and the static angle difference and load calibration experiment is carried out to analyze the calibration experiment data and establish the mapping relationship between the angle difference and the load. According to the obtained mapping relationship between the angle difference and the load, the two motors are set to work under the synchronous position loop, the target load is input to the load calibration equation to obtain the target angle difference pulse, the angle difference pulse is planned to the secondary motor in the two motors, the planned position of the primary motor in the two motors is issued to the far end point of the screw pair stroke and returns to the zero point, and the secondary motor follows the planned position of the primary motor and offsets the target angle difference pulse on the basis of the synchronous position loop. The fluctuation of the target load under static loading is observed during the movement. Based on the obtained fluctuation of the target load under static loading, the deviation between the real-time force feedback value and the current target load is calculated, the dynamic closed-loop control model of the axial load of the ball screw pair is established based on the obtained mapping relationship between the angle difference and the load, and the real-time dynamic variable load and load stability function are realized based on the dynamic closed-loop control model of the axial load of the ball screw pair.

[0097] Please refer to Figure 7 , the terminal device is a computer device, the computer device 60 of the embodiment includes a processor 61, a memory 62, and a computer program 63 stored in the memory 62 and executable on the processor 61, and the computer program 63 is executed by the processor 61 to implement the method for dynamically adjusting load of a ball screw pair under a synchronous position loop in the embodiment. To avoid repetition, details are not repeated here. Alternatively, the computer program 63 is executed by the processor 61 to implement the functions of each model / unit in the ball screw pair load dynamic adjustment system under the synchronous position loop in the embodiment. To avoid repetition, details are not repeated here.

[0098] The computer device 60 can be a desktop computer, a notebook computer, a palm computer, and a cloud server, etc. The computer device 60 can include, but is not limited to, a processor 61 and a memory 62. Those skilled in the art can understand that Figure 7 is only an example of the computer device 60 and does not constitute a limitation on the computer device 60, and can include more or fewer components than shown, or combine certain components, or different components, for example, the computer device can also include an input / output device, a network access device, a bus, etc.

[0099] The processor 61 can be a central processing unit (CPU), and can also be other general-purpose processors, central processing units, graphics processing units, digital signal processors (DSPs), application specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs) or other programmable logic devices, discrete gates or transistor logic components, quantum computing-based data processing logic components, discrete hardware components, etc. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor.

[0100] The memory 62 can be an internal storage unit of the computer device 60, such as a hard disk or a memory of the computer device 60. The memory 62 can also be an external storage device of the computer device 60, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc. equipped on the computer device 60.

[0101] Further, the memory 62 can include both an internal storage unit and an external storage device of the computer device 60. The memory 62 is used to store computer programs and other programs and data required by the computer device. The memory 62 can also be used to temporarily store data that has been output or will be output.

[0102] Any reference to storage, databases or other media used to store data in the embodiments provided herein is intended to include at least one of volatile and non-volatile storage. Non-volatile storage can include, for example, optical, floppy disks, hard disks, or solid state drives. Volatile storage can include, for example, random access memory (RAM). A basic input / output system (BIOS), containing the basic routines that help to transfer information between elements within the electronic device, such as during startup, can typically be stored in non-volatile memory. By way of illustration, and not limitation, a basic input / output system based on the BIOS, can include a BIOS, a unified extensible firmware interface (UEFI), or the like, including open firmware, firmware option ROM, flash BIOS, or the like. RAM typically contains data and / or program modules that are immediately accessible to and / or being operated on by the processing unit(s) and can include, for example, operating system, application programs, other program modules, and program data.

[0103] The database referred to in the embodiments provided herein can include at least one of a relational database and a non-relational database. The non-relational database can include a distributed database based on a blockchain, and the like, but is not limited thereto. The processor referred to in the embodiments provided herein can be a general processor, a central processing unit, a graphics processing unit, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, and the like, but is not limited thereto.

[0104] Referring to Figure 8 , the terminal device 600 is an electronic device, which is manifested in the form of a general computing device. The components of the electronic device can include, but are not limited to, at least one processing unit 610, at least one storage unit 620, a bus 630 connecting different platform components including the storage unit 620 and the processing unit 610, a display unit 640, and the like.

[0105] The storage unit stores program codes, which can be executed by the processing unit 610, so that the processing unit 610 performs the steps according to various exemplary embodiments of the present application described in the method part of the present specification. For example, the processing unit 610 can perform the steps as shown in Figure 1 .

[0106] The storage unit 620 can include a readable medium in the form of volatile storage such as random access memory (RAM) 6201 and / or cache memory 6202, and also can include a non-volatile storage such as read only memory (ROM) 6203.

[0107] The storage unit 620 also can include a program / utility 6204 having a set of program modules 6205 such as an operating system, one or more application programs, other program modules, and program data, each of which can govern, as is known, the operation of the electronic device 600 and / or the network environment.

[0108] The bus 630 can represent one or more of several types of bus structures, including a storage bus or bus for storage controller, peripheral bus, graphics bus, processor or local bus using any of a variety of bus architectures.

[0109] The electronic device 600 also can communicate with one or more external devices 700 such as a keyboard or pointing device, a Bluetooth device, etc., using the I / O interface 650. Additionally, the electronic device 600 can communicate with one or more devices that enable a user to interact with the electronic device 600 using the I / O interface 650, and / or with one or more devices that enable the electronic device 600 to communicate with one or more other computing devices. Such communication can occur via an I / O interface 650. Still yet, the electronic device 600 can communicate with one or more networks (such as a local area network (LAN), a wide area network (WAN), and / or the Internet) through a network adapter 660. The network adapter 660 can communicate with the other components of the electronic device 600 via the bus 630. It should be understood that, although not shown explicitly, other hardware and / or software components could be used in conjunction with the electronic device 600. These include, but are not limited to, microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data archival storage systems, etc.

[0110] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some embodiments of the present application but not all embodiments of the present application. The components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative efforts belong to the scope of protection of the present application.

[0111] Please refer to Figure 3 In the corner difference and load calibration process, it can be seen that the ball screw pair has a strong linear relationship between the corner difference and the load whether it is a positive tension load or a negative pressure load, which shows that the calibration method is linearly adjustable for the load, and through the static loading, the target load can be effectively approached. In the load closed-loop adjustment process, please refer to Figure 4 Reflects the results of static and dynamic adjustment of the target load of the ball screw pair to 500N, 1000N, 1500N at 300r / min, from the results it can be seen that the static load can quickly approach the target load, but there is still a large fluctuation, when the load closed-loop adjustment model is added, the dynamic load can effectively reduce the fluctuation while quickly approaching the target load, so that the load control is within a small threshold range, which shows that the method has effective variable load stable control ability.

[0112] Embodiment

[0113] In order to illustrate the use scene and effectiveness of the load adjustment method, for example, there is a download load control task:

[0114] On the double-motor torsion ball screw test bench, low-load 500N, medium-load 1000N, heavy-load 1500N performance degradation experiments of the ball screw pair need to be carried out at low speed 300r / min, medium speed 500r / min, high speed 800r / min, and the actual load and target load control deviation should not exceed ±4% at different running speeds.

[0115] According to the above requirements, the main motor and the auxiliary motor are set as a synchronous position ring, and are run at 300r / min, 500r / min, and 800r / min respectively, the target load is input into the ball screw real-time dynamic load adjustment model in turn, the corner difference offset pulse is calculated and judged in each closed-loop control period, and is issued to the offset planning position of the auxiliary motor in the form of speed command, and this is repeated until the movement stops. Thus, dynamic adjustment of different target loads during movement is realized. Please refer to Figure 4 Reflects the results of static and dynamic adjustment of the target load of the ball screw pair to 500N, 1000N, 1500N at 300r / min, 500r / min, 800r / min, from the results it can be seen that the actual load and target load control deviation of the dynamic adjustment model at different running speeds does not exceed ±4%, which meets the control requirements.

[0116] In summary, the load dynamic adjustment method and system of the ball screw pair under the synchronous position ring can avoid the reverse transmission of the ball screw pair during the current loop loading, accelerate the friction and wear of the ball screw pair, and easily cause the performance degradation and fatigue failure of the screw on the current loop earlier than the screw on the position loop. Meanwhile, the angle difference and load calibration experiments are carried out on the basis of the control of the same position ring, the relationship between the angle difference and the load under the static state is accurately established, and the verification in the movement process is carried out. Based on the angle difference load calibration equation, the axial load dynamic closed-loop control model of the ball screw pair is established, the load fluctuation problem in the movement process is inhibited, and the real-time dynamic variable load and load stability functions are realized.

[0117] Those skilled in the art can clearly understand that, for the convenience and brevity of description, only the division of the above functional units and modules is exemplified, and in actual application, the above functions can be completed by different functional units and modules according to needs, that is, the internal structure of the device is divided into different functional units or modules to complete all or part of the functions described above. Each functional unit and module in the embodiment can be integrated in one processing unit, or each unit can be physically present separately, or two or more units can be integrated in one unit. The integrated unit can be realized in the form of hardware or in the form of software functional unit. In addition, the specific names of each functional unit and module are only for easy distinction, and do not limit the protection scope of the application. The specific working process of the units and modules in the system can refer to the corresponding process in the foregoing method embodiments, which will not be repeated here.

[0118] In the above embodiments, the description of each embodiment has its own emphasis, and the parts not described or recorded in detail in a certain embodiment can be referred to the relevant description of other embodiments.

[0119] Those skilled in the art can realize that the units and algorithm steps of each example described in combination with the embodiments disclosed in the present application can be realized by electronic hardware or a combination of computer software and electronic hardware. Whether the functions are executed in hardware or software depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0120] In the embodiments of the present application, it should be understood that the disclosed apparatus / terminal and method can be implemented in other manners. For example, the embodiments of the apparatus / terminal described above are merely schematic, and the division of the modules or units is merely logical function division, and there can be another division manner in actual implementation. For example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the displayed or discussed mutual couplings or direct couplings or communication connections between different units, can be indirect couplings or communication connections through some interfaces, devices or units, and can be electrical, mechanical or in other forms.

[0121] The units described as separate components can or can not be physically separate, and the components shown as units can or can not be physical units, i.e., can be located in one place, or can be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the embodiments.

[0122] In addition, each functional unit in the various embodiments of the present application can be integrated into a processing unit, or each unit can be a physically independent unit, or two or more units can be integrated into a unit. The integrated unit can be implemented in the form of hardware or in the form of a software functional unit.

[0123] The integrated module / unit, if implemented in the form of a software functional unit and sold or used as an independent product, can be stored in a computer readable storage medium. Based on such understanding, all or part of the flow of the above-mentioned embodiment methods can be completed by a computer program instructing related hardware, and the computer program can be stored in a computer readable storage medium. When the processor executes the computer program, the steps of each method embodiment described above can be implemented. The computer program includes computer program code, which can be in the form of source code, object code, executable file or some intermediate form. The computer readable medium can include any entity or device capable of carrying the computer program code, recording medium, U disk, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signal, telecommunication signal and software distribution medium, etc. It should be noted that the computer readable medium can include or exclude content according to the requirements of legislation and patent practice in the jurisdiction, for example, in some jurisdictions, according to legislation and patent practice, the computer readable medium does not include electrical carrier signals and telecommunication signals.

[0124] The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks. Figure 1 one or more flow or blocks Figure 1 means for functionally implementing the steps in one or more flow or blocks

[0125] These computer program instructions can also be stored in a computer readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture including instructions which implement the function specified in the flowchart block or blocks. Figure 1 one or more flow or blocks Figure 1 means for functionally implementing the steps in one or more flow or blocks

[0126] The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks. Figure 1 one or more flow or blocks Figure 1 means for functionally implementing the steps in one or more flow or blocks

[0127] The above merely provides the technical idea of the present application, and cannot be used to limit the protection scope of the present application. Any modification made according to the technical idea of the present application, on the basis of the technical solutions, falls within the protection scope of the claims of the present application.

Claims

1. A method for dynamic adjustment of load on a ball screw pair under a synchronous position loop, characterized in that, Comprising the following steps: S1, control the dual motor to work in the position loop and move at the same planned position and speed; S2, based on the synchronous position loop working mode of the dual motor in step S1, adjust the planned position of the secondary motor in the dual motor separately, observe the force indication, and carry out static angle difference and load calibration experiments, analyze the calibration experimental data to establish the mapping relationship between the angle difference and the load; S3, according to the mapping relationship between the angle difference and the load obtained in step S2, the dual motor works in the synchronous position loop set in step S1, and the target load is input to the load calibration equation to obtain the target angle difference pulse, the angle difference pulse is planned to the secondary motor in the dual motor, and the planned position of the primary motor in the dual motor is issued to the far end point of the screw pair stroke and returns to the zero point, the secondary motor follows the planned position of the primary motor and offsets the target angle difference pulse on the basis of the synchronous position loop, and the fluctuation of the target load under static loading is observed during the movement; S4, based on the fluctuation of the target load under static loading obtained in step S3, calculate the deviation between the real-time force feedback value and the current target load, establish a dynamic closed-loop control model of the ball screw pair axial load based on the mapping relationship between the angle difference and the load obtained in step S2, and realize real-time dynamic variable load and load stability function based on the dynamic closed-loop control model of the ball screw pair axial load.

2. The method of claim 1, wherein, In step S1, the primary motor and the secondary motor are set to work in the position loop, the primary motor drives the primary ball screw pair to transmit, the secondary motor drives the secondary ball screw pair to transmit, the planned position of the primary motor is bound to the planned position of the secondary motor, and the planned position of the secondary motor is independently adjustable while realizing the synchronization of the planned position of the primary motor in the planned position of the secondary motor.

3. The method of claim 1, wherein, Step S2 is specifically: S201, select m position points at equal intervals on the working stroke of the ball screw pair, and perform a static angle difference and load calibration experiment at each position point; S202, repeat the static angle difference and load calibration experiment of the m position points in step S201, record the force sensor indication value corresponding to all angle differences of all position points, and complete the static angle difference and load calibration experiment of the m position points; S203, according to the force sensor indication value corresponding to all angle differences of all position points obtained in step S202, a linear regression model of the load about the angle difference pulse is established, and the least square estimation method is used to fit the model to obtain the equation of the angle difference pulse and the load.

4. The method of claim 1, wherein, In step S201, the angle difference pulse is gradually increased from 0 to Pmax, then gradually decreased from Pmax to Pmin, Pmax=-Pmin, and then gradually increased from Pmin to 0. In this process, the indication value of the force sensor at each interval point needs to be recorded to complete the static angle difference and load calibration experiment of a position point.

5. The method of claim 4, wherein, Before each experiment, the planned positions of the primary motor and the secondary motor are cleared to ensure that the initial angle difference is zero.

6. The method of claim 3, wherein, In step S3, the load is approached at 300r / min, 500r / min and 800r / min respectively for 500N, 1000N and 1500N.

7. The method of claim 1, wherein, Step S4 is specifically: Firstly, the axial force of the ball screw pair at time t is calculated and input into the rotation angle difference calculation equation to obtain According to the axial target load size of the ball screw pair planned at time t and the difference between the calculated axial force size of the ball screw pair at time t , it is determined whether to perform closed-loop adjustment. According to the calculated speed control instruction of shaft 2 controller , the rotation angle difference is converted through time accumulation and added to the planned position of the shaft 2 controller.

8. The method of claim 7, wherein, According to , , The size of the ball screw pair axial force at time t calculated , The size of the angle difference corresponding to the difference between the ball screw pair axial target load planned at time t and the actual load , The speed instruction given to the driver when the load is closed at time t And the size of the angle difference between the main motor and the auxiliary motor adjusted at time t Respectively: wherein, is the force sensor voltage analog signal read by the acquisition system at time t, is the maximum value of the force sensor voltage analog signal, is the maximum range of the force sensor, is the force sensor voltage analog signal at time t according to , , is the size of the ball screw pair axial force at time t calculated, is the size of the ball screw pair axial target load planned at time t, is the size of the load threshold value of the load closed-loop control, is the size of the angle difference between the primary motor and the secondary motor adjusted by the previous closed-loop adjustment at time t, is the period of the closed-loop control algorithm adjustment.

9. The method of claim 7, wherein, When the absolute value of the difference between the target load and the actual load at time t is less than or equal to , , it is set to zero, and no planning adjustment is performed; when the absolute value of the difference between the target load and the actual load at time t is greater than the load threshold value of the load closed-loop control , planning adjustment is needed , is the execution time of the control instruction, is a coefficient related to the planning speed in the axis 2 controller point position movement.

10. A dynamic load adjustment system for a ball screw pair with a synchronous position ring, characterized in that, Comprising: The control module controls the two motors to work in a position loop and move at the same planned position and planned speed. The analysis module, based on the synchronous position loop working mode of the two motors, separately adjusts the planned position of the secondary motor in the two motors, observes the indication of the force, and carries out a static angle difference and load calibration experiment, analyzes the calibration experiment data, and establishes a mapping relationship between the angle difference and the load. The loading module, according to the mapping relationship between the angle difference and the load, sets the two motors to work in the synchronous position loop, enables the two motors at the zero position, inputs the target load into the load calibration equation to obtain a target angle difference pulse, plans the position of the angle difference pulse to the secondary motor in the two motors, and issues the planned position of the primary motor in the two motors to the far end point of the screw pair stroke and returns to the zero point, the secondary motor follows the planned position of the primary motor and is offset by the target angle difference pulse on the basis of the synchronous position loop, and the fluctuation of the target load under static loading is observed during the movement. The adjustment module calculates the deviation between the real-time force feedback value and the current target load based on the fluctuation of the target load under static loading, establishes a ball screw pair axial load dynamic closed-loop control model based on the mapping relationship between the angle difference and the load, and realizes real-time dynamic variable load and load stability function based on the ball screw pair axial load dynamic closed-loop control model.

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