Method and system for dynamically adjusting load of ball screw pair under synchronous position ring

Abstract

The invention discloses a method and a system for dynamically adjusting the load of a ball screw pair under a synchronous position ring, which are used for avoiding the situation that the direction of current needs to be frequently changed when a current ring is loaded by setting a corner difference loading mode under the same position ring, and a lead screw on the current ring is in a reverse transmission contact state and is not consistent with the common working condition of the lead screw; and the friction wear is accelerated, so that the lead screw on the current ring is easy to generate performance degradation and fatigue ring damage earlier than the lead screw on the position ring. On the basis, a static lower corner difference and load equation is accurately established through static corner difference calibration experiment and verification. Load closed-loop control is introduced in the movement process, and the problem that the load fluctuates greatly in the dynamic movement of the lead screw after static load calibration is effectively solved. And the dynamic load changing capability in the movement process of the screw rod is realized.

Description

Background Art

[0002] As a precision positioning transmission component that converts rotational motion into linear motion, ball screw pairs are widely used in the manufacturing industry due to their high-precision linear positioning advantages. In actual use, ball screw pairs are subject to complex working conditions such as variable speed and axial variable load. Load is one of the key factors affecting the degradation of the comprehensive performance of ball screw pairs. In order to simulate the degradation law of ball screw pairs under variable load conditions, stable control and adjustment of load are essential.

[0003] At present, the research on the load adjustment method of ball screw pair is mainly divided into two categories, namely, the segmented constant loading method with stable loading capacity and the existing current loop load adjustment method. The former load adjustment is mainly achieved by changing the mass of the external weight, and the load stability is good, but there is a disadvantage that it cannot achieve dynamic continuous load change. In the case of dual motor torsion, the latter adjusts the load size by combining the position loop and the current loop and adjusting the current. This adjustment method requires frequent changes in the direction of the current when the current is reversed. At the same time, the screw on the current loop is in the reverse transmission contact state, which is inconsistent with the common working conditions of the screw, and accelerates its friction and wear, which easily causes the screw on the current loop to degrade and fatigue damage earlier than the screw on the position loop. Therefore, a new ball screw load adjustment method is proposed. In the case of dual motor torsion, based on the synchronous position loop external load closed loop, the load is controlled within the target load without changing the screw transmission characteristics, which significantly reduces the load fluctuation problem during the movement, which is of great significance to the performance degradation experiment of the ball screw pair. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a method and system for dynamically adjusting the load of a ball screw pair under a synchronous position ring in response to the above-mentioned deficiencies in the prior art, so as to solve the technical problems in the prior art that the current loop loading causes the screw to reverse transmit, unreasonable load adjustment easily leads to abnormal wear of the screw, and large load fluctuations caused by static loading during movement.

[0005] The present invention adopts the following technical solutions: A method for dynamically adjusting the load of a ball screw pair under a synchronous position ring comprises the following steps: S1, control the dual motors to work simultaneously under the position loop and move at the same planned position and planned speed; S2. Based on the synchronous position loop working mode of the dual motors in step S1, the planned position of the auxiliary motor in the dual motors is adjusted separately, the force indication is observed, and a static angular difference and load calibration experiment is carried out, and the calibration experiment data is analyzed to establish a mapping relationship between the angular difference and the load; S3. According to the mapping relationship between the angular difference and the load obtained in step S2, the two motors set in step S1 work in the synchronous position loop. When both motors are enabled at zero position, the target load is input into the load calibration equation to obtain the target angular difference pulse. The angular difference pulse planning position is given to the auxiliary motor in the dual motors. The planned position of the main motor in the dual motors is sent to the far end point of the screw pair stroke and back and forth to the zero point. The auxiliary motor follows the planned position of the main motor on the basis of the synchronous position loop and offsets the target angular difference pulse. The fluctuation of the static load on the target load is observed during the movement. S4. Based on the fluctuation of the target load due to the static load obtained in step S3, the deviation between the real-time force feedback value and the current target load is calculated; based on the mapping relationship between the angular difference and the load obtained in step S2, a dynamic closed-loop control model of the axial load of the ball screw pair is established; based on the dynamic closed-loop control model of the axial load of the ball screw pair, real-time dynamic load variation and load stabilization functions are realized.

[0006] Preferably, in step S1, the main motor and the auxiliary motor are both set to work in the position loop, the main motor drives the main ball screw pair for transmission, and the auxiliary motor drives the auxiliary ball screw pair for transmission. The planned position of the main motor is bound to the planned position of the auxiliary motor. The planned position of the auxiliary motor is independently adjustable while the planned position of the main motor is synchronized with the planned position of the auxiliary motor.

[0007] Preferably, step S2 specifically includes: S201, selecting m position points at equal intervals on the working stroke of the ball screw pair, and performing a static angular difference and load calibration experiment at each position point; S202, repeat the static rotation angle difference and load calibration experiment of m position points in step S201, record the force sensor indications corresponding to all rotation angle differences of all position points, and complete the static rotation angle difference and load calibration experiment of m position points; S203. According to the force sensor indications corresponding to all the rotation angle differences of all the position points obtained in step S202, a linear regression model of the load with respect to the rotation angle difference pulse is established, and the least squares estimation method is used to fit the model to obtain an equation of the rotation angle difference pulse and the load.

[0008] Preferably, in step S201, the angle difference pulse is set to gradually increase from 0 to Pmax, and then gradually decrease from Pmax to Pmin, Pmax=-Pmin, and then the angle difference pulse is gradually increased from Pmin to 0. During this process, the indication of the force sensor needs to be recorded at each interval point to complete the static angle difference and load calibration experiment at one position point.

[0009] Preferably, before each experiment, the planned positions of the main motor and the auxiliary motor are cleared to ensure that the initial rotation angle difference is zero.

[0010] Preferably, in step S3, loads of 500N, 1000N and 1500N are approached at 300r / min, 500r / min and 800r / min respectively.

[0011] Preferably, step S4 is specifically: First, calculate the axial force of the ball screw pair at time t , and input it into the angle difference calculation equation to obtain , according to the axial target load size of the ball screw pair planned at time t The axial force of the ball screw pair at time t calculated The difference in value determines whether to perform closed-loop adjustment, and the speed control instruction of axis 2 controller is obtained according to the calculation. , which is converted into an angle difference through time accumulation and added to the planned position of the axis 2 controller.

[0012] Preferably, according to , , Calculated axial force of the ball screw pair at time t , the angular difference corresponding to the difference between the axial target load of the ball screw pair planned at time t and the actual load , the speed command sent to the driver when the load is closed at time t The angle difference between the main motor and the auxiliary motor adjusted by closed loop at time t They are:

[0013] in, It is the analog voltage signal of the force sensor read by the acquisition system at time t. is the maximum value of the analog voltage signal of the force sensor, is the maximum measuring range of the force sensor, Based on , , The calculated axial force of the ball screw pair at time t is: is the target axial load of the ball screw pair planned at time t, is the load threshold value of load closed-loop control, is the angular difference between the main motor and the auxiliary motor in the previous closed-loop adjustment at time t, The period for adjusting the closed-loop control algorithm.

[0014] 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 hour, Set to zero, 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 of the load closed-loop control When Make planning adjustments. To control the execution time of instructions, It is the coefficient related to the planned speed in the point motion of the axis 2 controller.

[0015] In a second aspect, an embodiment of the present invention provides a ball screw pair load dynamic adjustment system under a synchronous position ring, comprising: The control module controls the dual motors to work simultaneously under the 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 dual motors, adjusts the planned position of the auxiliary motor in the dual motors separately, observes the force indication, and conducts static angular difference and load calibration experiments, and analyzes the calibration experiment data to establish the mapping relationship between angular difference and load; The loading module sets the two motors to work in the synchronous position loop according to the mapping relationship between the angular difference and the load. When both motors are enabled at zero position, the target load is input into the load calibration equation to obtain the target angular difference pulse. The angular difference pulse is planned to the auxiliary motor in the dual motors. The planned position of the main motor in the dual motors is sent to the far end point of the screw pair stroke and back and forth to the zero point. The auxiliary motor follows the planned position of the main motor on the basis of the synchronous position loop and offsets the target angular difference pulse. The fluctuation of the static load on the target load 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 due to static loading, establishes a dynamic closed-loop control model of the axial load of the ball screw pair based on the mapping relationship between the obtained angular difference and the load, and realizes real-time dynamic load variation and load stabilization functions based on the dynamic closed-loop control model of the axial load of the ball screw pair.

[0016] In a third aspect, a computer device comprises a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the above-mentioned method for dynamically adjusting the load of a ball screw pair under a synchronous position ring when executing the computer program.

[0017] In a fourth aspect, an embodiment of the present invention provides a computer-readable storage medium, including a computer program, which, when executed by a processor, implements the steps of the above-mentioned method for dynamically adjusting the load of a ball screw pair under a synchronous position ring.

[0018] Compared with the prior art, the present invention has at least the following beneficial effects: A method for dynamically adjusting the load of a ball screw pair under a synchronous position loop includes four main parts: dual-motor synchronous position loop setting, static angular difference and load calibration experiment and analysis, static load calibration verification during motion, and load closed-loop control under a synchronous position loop. By setting the angular difference loading mode under the same position loop, the need to frequently change the direction of the current when loading the current loop is avoided. At the same time, the screw on the current loop is in a reverse transmission contact state, which is inconsistent with the common working conditions of the screw, and accelerates its friction and wear, which easily causes the screw on the current loop to experience performance degradation and fatigue damage earlier than the screw on the position loop. On this basis, through the static angular difference calibration experiment and verification, the static angular difference and load equation is accurately established. The closed-loop load control is introduced during the motion process, which effectively reduces the problem of large load fluctuations in the dynamic motion of the screw after static load calibration. The ability to dynamically change the load during the motion of the screw is realized.

[0019] Furthermore, on the dual-motor torsion loading test bench, the main motor and the auxiliary motor are set to work under the position loop at the same time, and move at the same planned position and planned speed to ensure that both ball screw pairs are in a forward transmission state, to avoid reverse transmission of the screw pair and abnormal wear of the screw, and the planned position of the main motor is bound to the planned position of the auxiliary motor, to ensure that the planned position of the auxiliary motor is independently adjustable while achieving synchronization of the planned position of the main motor with the planned position of the auxiliary motor. In this way, it is possible to effectively adjust the offset planned position of the auxiliary motor to change the target load size, adjust the offset planned position of the auxiliary motor to observe the indication of the force sensor, carry out static static angular difference and load calibration experiments, and analyze the calibration experimental data to establish a mapping relationship between angular difference and load. By continuously adjusting the offset planned position, more force sensor data can be obtained to improve the accuracy of the calibration equation.

[0020] Furthermore, m positions are selected at equal intervals on the working stroke of the ball screw pair, and a static angular difference and load calibration experiment is performed at each position to eliminate the deviation of the angular difference and load mapping at different positions of the screw. The planned positions of the two motors are cleared before each experiment to ensure that the initial working conditions of each calibration experiment are the same.

[0021] Furthermore, the angular difference pulse is set to increase gradually from 0 to Pmax with an interval of k, and then decrease from Pmax to Pmin with an interval of k, where Pmax=-Pmin, and then the angular difference pulse is increased from Pmin to 0 with 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 compressive ball screw pair bears a compressive load. The positive and reverse calibration avoids the characteristic difference between the tensile load and the compressive load under different angular differences. The force sensor indications corresponding to all angular differences of all position points are obtained, and a linear regression model of the load on the angular difference pulse is established. The least squares estimation method is used to fit the model to obtain the equation of the angular difference pulse and the load. It is realized that the required angular difference size can be calculated in real time by inputting any target load.

[0022] Furthermore, when both motors are enabled at zero position, the target rotation angle difference pulse is calculated by the calibration equation according to the input target load, the target rotation angle difference pulse is superimposed on the planned position of the auxiliary motor, and the planned position of the main motor is sent to the far end point of the screw auxiliary stroke and back and forth to the zero point. The fluctuation of the static load on the target load is observed during the movement, which can effectively verify the effectiveness of the static loading close to the target load during the movement.

[0023] Furthermore, the deviation between the real-time force sensor feedback value and the current target load is calculated. On this basis, a dynamic closed-loop control model of the axial load of the ball screw pair is established based on the angular difference load calibration equation to suppress the load fluctuation problem during movement, realize real-time dynamic load change and load stabilization functions, and perform point movement at the planned position and planned speed. The force sensor between the actuators of the two axes outputs the real-time load to the adjustment model. The adjustment model calculates the output pulse increment according to the input target load, and superimposes the pulse increment on the axis 2 controller as a speed command to avoid the problem of control instructions being occupied during point movement.

[0024] Furthermore, The absolute value setting does not exceed the maximum range of the force sensor , avoiding the problem of sensor damage caused by overload, and calculating the axial force of the ball screw pair at time t , and input it into the angle difference calculation equation to obtain , the angular difference can be calculated in real time, according to the axial target load size of the ball screw pair planned at time t The axial force of the ball screw pair at time t calculated The difference in value determines whether to make a closed-loop adjustment, thus avoiding invalid adjustments after the load becomes stable.

[0025] Furthermore, the coefficients related to the planned speed in the point motion of the axis 2 controller are set , and conduct multiple experiments at different speeds. The larger the value, the smaller the load oscillation. The smaller the control speed, the greater the load oscillation. By adjusting the load response oscillation problem at different speeds, To control the execution time of instructions, For the closed-loop control algorithm adjustment cycle, set , to avoid the abnormal load problem during closed-loop adjustment caused by the large difference between the current target load and the next target load, to ensure the stability of control, and to obtain the speed control command of axis 2 controller according to the calculation , which is converted into the angular difference through time accumulation and superimposed on the planned position of the axis 2 controller. Dynamic closed-loop adjustment of the axial load of the ball screw pair is achieved.

[0026] It can be understood that the beneficial effects of the second aspect mentioned above can be found in the relevant description of the first aspect mentioned above, and will not be repeated here.

[0027] In summary, the present invention can avoid the reverse transmission of the ball screw pair when the current loop is loaded, which accelerates its 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, the angular difference and load calibration experiment is carried out on the basis of the control of the same position loop, and the relationship between the angular difference and the load under static conditions is accurately established and verified during the movement. Based on the angular difference load calibration equation, a dynamic closed-loop control model of the axial load of the ball screw pair is established to suppress the load fluctuation problem during the movement, and realize the real-time dynamic load change and load stabilization functions.

[0028] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings to be used in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0030] Figure 1 Schematic diagram of the dual-motor ball screw test bench Figure 2 This is the control block diagram for dynamic adjustment of the ball screw pair load under the synchronous position ring; Figure 3 It is the result of the first calibration of the ball screw pair angular difference and load under the synchronous position ring; Figure 4 The static and dynamic control effect diagrams of different target loads at 300r / min; Figure 5The static and dynamic control effect diagrams of different target loads at 500r / min; Figure 6 The static and dynamic control effect diagrams of different target loads at 800r / min; Figure 7 A schematic diagram of a computer device provided by an embodiment of the present invention; Figure 8 The present invention is a block diagram of an electronic device provided according to an embodiment.

[0031] Among them, 1. main motor; 2. main fixed end assembly; 3. main ball screw pair; 4. first actuator; 5. main support end assembly; 6. secondary support end assembly; 7. secondary ball screw pair; 8. second actuator; 9. force sensor; 10. secondary fixed end assembly; 11. secondary motor. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] In the description of the present invention, it should be understood that the terms “include” and “comprises” indicate the presence of described features, wholes, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or collections thereof.

[0034] It should also be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0035] It should be further understood that the term "and / or" used in the present specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes these combinations. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in the present invention generally indicates that the associated objects are in an "or" relationship.

[0036] It should be understood that, although the terms first, second, third, etc. may be used to describe preset ranges, etc. in the embodiments of the present invention, these preset ranges should not be limited to these terms. These terms are only used to distinguish preset ranges from each other. For example, without departing from the scope of the embodiments of the present invention, the first preset range may also be referred to as the second preset range, and similarly, the second preset range may also be referred to as the first preset range.

[0037] The word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrases "if it is determined" or "if (stated condition or event) is detected" may be interpreted as "when it is determined" or "in response to determining" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)", depending on the context.

[0038] Various structural schematic diagrams of the embodiments disclosed in the present invention are shown in the accompanying drawings. These figures are not drawn to scale, and some details are magnified and some details may be omitted for the purpose of clear expression. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships therebetween are only exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0039] The present invention provides a method for dynamically adjusting the load of a ball screw pair under a synchronous position loop, including four steps: dual-motor synchronous position loop setting, static angular difference and load calibration experiment and analysis, static load calibration verification during motion, and load closed-loop control under a synchronous position loop. A closed-loop load control logic is established under the synchronous position loop based on the angular difference load calibration result and real-time sensor force feedback to achieve a dynamic control function for any input target load, thereby ensuring that the load is dynamically stable and adjustable during the ball screw pair loading experiment.

[0040] The principle of the present invention is: for the dual-motor torsion ball screw pair experimental system, a synchronous position loop control method 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 independently issue speed instructions to control the bias pulse of the auxiliary motor. When there is a bias pulse, the main motor will cause an interaction force between the main screw and the auxiliary screw in order to maintain its planned position. From the relationship between the action force and the reaction force, it can be seen that the size of the force sensor reflects the axial load applied to the main screw and the auxiliary screw. By continuously adjusting the bias pulse, different load sizes can be obtained, based on which a calibration equation for the angle difference and load can be established; however, there will still be load fluctuation problems during movement. In order to solve this problem, a load closed loop is added on the basis of the position loop, and a load adjustment model based on the calibration equation is established. By real-time detection of the difference between the force sensor indication and the target load, the difference is input into the adjustment model, and the angle difference increment will be output. At the same time, the angle difference increment will be sent to the auxiliary motor offset planning position in the form of a speed command. The control adjustment can achieve that the force sensor indication and the target load are less than the load threshold. By inputting different target loads, real-time variable load adjustment function can be achieved. The present invention provides a method for dynamically adjusting the load of a ball screw pair under a synchronous position ring, comprising the following steps: S1. The dual motor synchronous position loop setting mainly ensures 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 positive transmission of the two ball screw pairs; See also Figure 1 The main motor 1 is connected to one end of the main ball screw pair 3 through the main fixed end assembly 2, and the other end of the main ball screw pair 3 is connected to the main support end assembly 5. The main ball screw pair 3 is provided with a first actuator 4; the auxiliary motor 11 is connected to one end of the auxiliary ball screw pair 7 through the auxiliary fixed end assembly 10, and the other end of the auxiliary ball screw pair 7 is connected to the auxiliary support end assembly 6. The auxiliary ball screw pair 7 is provided with a second actuator 8, and the first actuator 4 and the second actuator 8 are connected through a force sensor 9.

[0041] The main motor 1 drives the main ball screw pair 3 for transmission, and the auxiliary motor 11 drives the auxiliary ball screw pair 7 for transmission. The main motor 1 and the auxiliary motor 11 are both set to work in the position loop, and the planned position of the main motor 1 is bound to the planned position of the auxiliary motor 11, ensuring that the planned position of the auxiliary motor 11 is independently adjustable while achieving synchronization of the planned position of the main motor 1 with the planned position of the auxiliary motor 11.

[0042] S2, according to the synchronous position loop working mode of the main motor 1 and the auxiliary motor 11 set in step S1, the planned position of the auxiliary motor 11 is adjusted separately to observe the indication of the force sensor 9, and on this basis, a static angular difference and load calibration experiment is carried out, and the calibration experiment data is analyzed to establish a mapping relationship between the angular difference and the load; S201. Select m positions at equal intervals on the working stroke of the ball screw pair, and conduct a static angular difference and load calibration experiment at each position. Before each experiment, clear the planned positions of the two motors to ensure that the initial angular difference is zero; set the angular difference pulse to gradually increase from 0 to Pmax, and then gradually decrease from Pmax to Pmin, where Pmax=-Pmin, and then gradually increase from Pmin to 0. During this process, the indication of the force sensor needs to be recorded at each interval point, including the loading data of the positive tension and negative pressure. In this way, the static angular difference and load calibration experiment of a position point is completed one by one; S202, repeat the static rotation angle difference and load calibration experiment of m position points in step S201, record the force sensor indications corresponding to all rotation angle differences of all position points, and complete the static rotation angle difference and load calibration experiment of m position points.

[0043] S203. According to the force sensor indications corresponding to all the rotation angle differences of all the position points obtained in step S202, a linear regression model of the load with respect to the rotation angle difference pulse is established, and the least squares estimation method is used to fit the model to obtain an equation of the rotation angle difference pulse and the load.

[0044] See also Figure 3 , is the result of a static angle difference and load calibration experiment, which shows that the angle difference pulse is highly linear with the load. In this example, =0.625, =-1.875.

[0045] S3. According to the equation of the angular difference and the load obtained in step S2, verification is performed during the movement process to ensure the ability to approach the target load during the movement process; according to the setting of step S1, the two motors work in the synchronous position loop. When both motors are enabled at zero position, the target load is input into the load calibration equation to obtain the target angular difference pulse, and the angular difference pulse is planned to the auxiliary motor 2. The planned position of the main motor 1 is sent to the far end point of the screw pair stroke and back and forth to the zero point. The auxiliary motor will follow the planned position of the main motor 1 on the basis of the synchronous position loop and offset the target angular difference pulse, and observe the fluctuation of the static load on the target load during the movement; See also Figure 3 , 4, 5, the approach situation of loads of 500N, 1000N and 1500N at 300r / min, 500r / min and 800r / min respectively, indicating that static loading at different speeds can effectively approach the target load.

[0046] S4. Calculate the deviation between the real-time force sensor feedback value and the current target load. On this basis, establish a dynamic closed-loop control model for the axial load of the ball screw pair based on the angular difference load calibration equation to suppress the load fluctuation problem during movement and realize real-time dynamic load change and load stabilization functions.

[0047] The result of step S3 shows that the calibration equation of the angle difference and the load is effective, but the force sensor indication always has a large fluctuation near the target load during the dynamic motion process.

[0048] See also Figure 2 , which is a dynamic closed-loop control block diagram of the axial load of the ball screw pair. Both the axis 1 controller and the axis 2 controller work under the synchronous position loop and perform point motion at the planned position and planned speed. The force sensor between the actuators of the two axes outputs the real-time load to the adjustment model. The adjustment model calculates the output pulse increment according to the input target load, and superimposes the pulse increment to the axis 2 controller with a speed command to realize dynamic closed-loop adjustment of the load.

[0049] First, calculate the axial force of the ball screw pair at time t , and input it into the angle difference calculation equation to obtain , according to the axial target load size of the ball screw pair planned at time t The axial force of the ball screw pair at time t calculated The difference in value determines whether to perform closed-loop adjustment, and the speed control instruction of axis 2 controller is obtained according to the calculation. , which is converted into an angle difference through time accumulation and added to the planned position of the axis 2 controller.

[0050]

[0051] in, It is the analog voltage signal of the force sensor read by the acquisition system at time t. is the maximum value of the analog voltage signal of the force sensor, is the maximum measuring range of the force sensor, Based on , , Calculate the axial force of the ball screw pair at time t.

[0052] is the target axial load of the ball screw pair planned at time t, The absolute value cannot exceed the maximum range of the force sensor , otherwise it will cause overload and damage the sensor; is the planned position angle difference between the main motor and the auxiliary motor at time t, It is the derivative of the angular difference with respect to the load in the calibration equation, and is used to calculate the angular difference corresponding to the difference between the axial target load of the ball screw pair planned at time t and the actual load. .

[0053] is the speed command sent to the driver when the load is closed at time t. Because the two motors work under the synchronous position loop, the position is planned by point motion. The position can no longer be planned separately. The axis 2 controller can only be planned in speed mode. Therefore, the control command accepted by the system is , the unit is plus / ms; is 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 time t is less than or equal to hour, Set to zero to make no planning adjustments.

[0054] When the absolute value of the difference between the target load and the actual load at time t is greater than When Make planning adjustments, including: To control the execution time of instructions, This is the coefficient related to the planned speed in the point motion of the axis 2 controller. This coefficient needs to be adjusted through multiple experiments. The larger the value, the smaller the load oscillation. The smaller the control load, the greater the oscillation.

[0055] is the angular difference between the main motor and the auxiliary motor in the previous closed-loop adjustment at time t, The cycle of closed-loop control algorithm adjustment. In order to avoid abnormal load during closed-loop adjustment caused by a large difference between the current target load and the next target load, it is necessary to meet , ensuring the stability of control. It is the rotation angle difference between the main motor and the auxiliary motor in the closed-loop adjustment at time t, which is the cumulative value from the initial moment to the current moment.

[0056] It will be appreciated by those skilled in the art that various aspects of the present invention may be implemented as systems, methods or program products. Therefore, various aspects of the present invention may be specifically implemented in the following forms, namely: complete hardware implementation, complete software implementation (including firmware, microcode, etc.), or a combination of hardware and software implementations, which may be collectively referred to herein as "circuits", "modules" or "platforms".

[0057] In another embodiment of the present invention, a system for dynamically adjusting the load of a ball screw pair under a synchronous position ring is provided. The system can be used to implement the above-mentioned method for dynamically adjusting the load of a ball screw pair under a synchronous position ring. Specifically, the system for dynamically adjusting the load of a ball screw pair under a synchronous position ring includes a control module, an analysis module, a loading module and an adjustment module.

[0058] Among them, the control module controls the dual motors to work simultaneously under the 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 dual motors, adjusts the planned position of the auxiliary motor in the dual motors separately, observes the force indication, and conducts static angular difference and load calibration experiments, and analyzes the calibration experiment data to establish the mapping relationship between angular difference and load; The loading module sets the two motors to work in the synchronous position loop according to the mapping relationship between the angular difference and the load. When both motors are enabled at zero position, the target load is input into the load calibration equation to obtain the target angular difference pulse. The angular difference pulse is planned to the auxiliary motor in the dual motors. The planned position of the main motor in the dual motors is sent to the far end point of the screw pair stroke and back and forth to the zero point. The auxiliary motor follows the planned position of the main motor on the basis of the synchronous position loop and offsets the target angular difference pulse. The fluctuation of the static load on the target load 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 due to static loading, establishes a dynamic closed-loop control model of the axial load of the ball screw pair based on the mapping relationship between the obtained angular difference and the load, and realizes real-time dynamic load variation and load stabilization functions based on the dynamic closed-loop control model of the axial load of the ball screw pair.

[0059] In another embodiment of the present invention, a terminal device is provided, which includes a processor and a memory, wherein the memory is used to store a computer program, the computer program includes program instructions, and the processor is used to execute the program instructions stored in the computer storage medium. The processor may be a central processing unit (CPU), or 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. It is the computing core and control core of the terminal, which is suitable for implementing one or more instructions, and is specifically suitable for loading and executing one or more instructions to implement the corresponding method flow or corresponding function; the processor described in the embodiment of the present invention can be used for the operation of the dynamic adjustment method of the load of the ball screw pair under the synchronous position ring, including: The dual motors are controlled to work simultaneously under the position loop and move at the same planned position and planned speed; based on the synchronous position loop working mode of the dual motors, the planned position of the auxiliary motor in the dual motors is adjusted separately, the force indication is observed, and static angular difference and load calibration experiments are carried out, and the mapping relationship between angular difference and load is established by analyzing the calibration experimental data; according to the obtained mapping relationship between angular difference and load, the two motors are set to work in the synchronous position loop, and when both motors are enabled at zero position, the target load is input into the load calibration equation to obtain the target angular difference pulse, and the angular difference pulse planned position is given to the auxiliary motor in the dual motors. The motor sends the planned position of the main motor in the dual motors to the far end point of the screw pair travel and back and forth to the zero point. The slave motor follows the planned position of the main motor on the basis of the synchronous position loop and offsets the target angular difference pulse. The fluctuation of the static load on the target load is observed during the movement. The deviation between the real-time force feedback value and the current target load is calculated based on the obtained fluctuation of the static load on the target load. The dynamic closed-loop control model of the axial load of the ball screw pair is established based on the mapping relationship between the angular difference and the load. The real-time dynamic load change and load stabilization functions are realized based on the dynamic closed-loop control model of the axial load of the ball screw pair.

[0060] In another embodiment of the present invention, the present invention also provides a storage medium, specifically a computer-readable storage medium (Memory), which is a memory device in a terminal device for storing programs and data. It is understandable that the computer-readable storage medium here can include both the built-in storage medium in the terminal device and the extended storage medium supported by the terminal device, and can be any tangible medium containing or storing a program, which can be used by an instruction execution system, device or device or used in combination with it. The computer-readable storage medium provides a storage space, which stores the operating system of the terminal. In addition, one or more instructions suitable for being loaded and executed by the processor are also stored in the storage space, and these 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 here include: an electrical connection with one or more 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.

[0061] Computer readable storage media also include data signals propagated in baseband or as part of a carrier wave, which carry readable program codes. Such propagated data signals can take a variety of forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. The readable storage medium can also be any readable medium other than a readable storage medium, which can send, propagate, or transmit a program for use by or in conjunction with an instruction execution system, device, or device. The program code contained on the readable storage medium can be transmitted using any appropriate medium, including but not limited to wireless, wired, optical cable, RF, etc., or any suitable combination of the above.

[0062] Program code for performing the operations of the present invention may be written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Java, C++, etc., and conventional procedural programming languages ​​such as "C" or similar programming languages. The program code may be executed entirely on the user computing device, partially on the user device, as a separate software package, partially on the user computing device and partially on a remote computing device, or entirely on a remote computing device or server. In the case of a remote computing device, the remote computing device may be connected to the user computing device through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computing device (e.g., through the Internet using an Internet service provider).

[0063] The processor may load and execute one or more instructions stored in the computer-readable storage medium to implement the corresponding steps of the method for dynamically adjusting the load of the ball screw pair under the synchronous position ring in the above embodiment; the processor may load and execute the following steps: The dual motors are controlled to work simultaneously under the position loop and move at the same planned position and planned speed; based on the synchronous position loop working mode of the dual motors, the planned position of the auxiliary motor in the dual motors is adjusted separately, the force indication is observed, and static angular difference and load calibration experiments are carried out, and the mapping relationship between angular difference and load is established by analyzing the calibration experimental data; according to the obtained mapping relationship between angular difference and load, the two motors are set to work in the synchronous position loop, and when both motors are enabled at zero position, the target load is input into the load calibration equation to obtain the target angular difference pulse, and the angular difference pulse planned position is given to the auxiliary motor in the dual motors. The motor sends the planned position of the main motor in the dual motors to the far end point of the screw pair travel and back and forth to the zero point. The slave motor follows the planned position of the main motor on the basis of the synchronous position loop and offsets the target angular difference pulse. The fluctuation of the static load on the target load is observed during the movement. The deviation between the real-time force feedback value and the current target load is calculated based on the obtained fluctuation of the static load on the target load. The dynamic closed-loop control model of the axial load of the ball screw pair is established based on the mapping relationship between the angular difference and the load. The real-time dynamic load change and load stabilization functions are realized based on the dynamic closed-loop control model of the axial load of the ball screw pair.

[0064] See also Figure 7 , the terminal device is a computer device, and the computer device 60 of this embodiment includes: a processor 61, a memory 62, and a computer program 63 stored in the memory 62 and executable on the processor 61. When the computer program 63 is executed by the processor 61, the method for dynamically adjusting the load of the ball screw pair under the synchronous position ring in the embodiment is implemented. To avoid repetition, it is not described one by one here. Alternatively, when the computer program 63 is executed by the processor 61, the functions of each model / unit in the system for dynamically adjusting the load of the ball screw pair under the synchronous position ring in the embodiment are implemented. To avoid repetition, it is not described one by one here.

[0065] The computer device 60 may be a computing device such as a desktop computer, a notebook, a PDA, or a cloud server. The computer device 60 may include, but is not limited to, a processor 61 and a memory 62. Those skilled in the art will appreciate that Figure 7 This is only an example of the computer device 60 and does not constitute a limitation of the computer device 60. It may include more or fewer components than shown in the figure, or a combination of certain components, or different components. For example, the computer device may also include input and output devices, network access devices, buses, etc.

[0066] The processor 61 may be a central processing unit (CPU), or other general-purpose processors, central processing units, graphics processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, data processing logic based on quantum computing, discrete hardware components, etc. The general-purpose processor may be a microprocessor or the processor may be any conventional processor, etc.

[0067] The memory 62 may be an internal storage unit of the computer device 60, such as a hard disk or memory of the computer device 60. The memory 62 may 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.

[0068] Furthermore, the memory 62 may include both an internal storage unit of the computer device 60 and an external storage device. The memory 62 is used to store computer programs and other programs and data required by the computer device. The memory 62 may also be used to temporarily store data that has been output or is to be output.

[0069] Any reference to a memory, database or other medium used in the embodiments provided in the present application may include at least one of a non-volatile and a volatile memory. Non-volatile memory may include a read-only memory (ROM), a magnetic tape, a floppy disk, a flash memory, an optical memory, a high-density embedded non-volatile memory, a resistive random access memory (ReRAM), a magnetic random access memory (MRAM), a ferroelectric random access memory (FRAM), a phase change memory (PCM), a graphene memory, etc. Volatile memory may include a random access memory (RAM) or an external cache memory, etc. As an illustration and not limitation, RAM may be in various forms, such as a static random access memory (SRAM) or a dynamic random access memory (DRAM), etc.

[0070] The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. The non-relational database may include a distributed database based on blockchain, etc., but is not limited thereto. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., but is not limited thereto.

[0071] See also Figure 8 The terminal device 600 is an electronic device, and the electronic device is in the form of a general computing device. The components of the electronic device may 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, etc.

[0072] 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 invention described in the above method section of this specification. For example, the processing unit 610 can perform the following steps: Figure 1 Follow the steps shown in .

[0073] The storage unit 620 may include a readable medium in the form of a volatile storage unit, such as a random access memory unit (RAM) 6201 and / or a cache memory unit 6202 , and may further include a read-only memory unit (ROM) 6203 .

[0074] The storage unit 620 may also include a program / utility 6204 having a set (at least one) of program modules 6205, such program modules 6205 including but not limited to: an operating system, one or more application programs, other program modules, and program data, each of which or some combination may include an implementation of a network environment.

[0075] Bus 630 may represent one or more of several types of bus structures, including a memory unit bus or memory unit controller, a peripheral bus, an accelerated graphics port, a processing unit, or a local bus using any of a variety of bus architectures.

[0076] The electronic device 600 may also communicate with one or more external devices 700 (e.g., keyboards, pointing devices, Bluetooth devices, etc.), may also communicate with one or more devices that enable a user to interact with the electronic device 600, and / or communicate with any device that enables the electronic device 600 to communicate with one or more other computing devices (e.g., routers, modems, etc.). Such communication may be performed via an input / output (I / O) interface 650. Furthermore, the electronic device 600 may also communicate with one or more networks (e.g., a local area network (LAN), a wide area network (WAN), and / or a public network, such as the Internet) via a network adapter 660. The network adapter 660 may communicate with other modules of the electronic device 600 via a bus 630. It should be understood that, although not shown in the figure, other hardware and / or software modules may be used in conjunction with the electronic device 600, including but not limited to: microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data backup storage platforms, etc.

[0077] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. The components of the embodiments of the present invention described and shown in the drawings here can usually be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0078] See also Figure 3 In the process of angular difference and load calibration, it can be seen that the angular difference and load of the ball screw pair are strongly linearly related, whether it is a positive tensile load or a negative compressive load. This shows that the calibration method is linearly adjustable for the load, and can effectively approach the target load under static loading. In the process of load closed-loop adjustment, please refer to Figure 4 The results reflect the static and dynamic adjustment of the ball screw pair to the target load of 500N, 1000N, and 1500N at 300r / min. It can be seen from the results that the load can quickly approach the target load under static loading, but there is still a large fluctuation. When the load closed-loop adjustment model is added, the dynamic loading can effectively reduce the fluctuation size while quickly approaching the target load, so that the load is controlled within a smaller threshold range, which shows that the method of the present invention has effective variable load stable control capability.

[0079] Example To illustrate the usage scenarios and effectiveness of the load adjustment method, for example, there are the following load control tasks: On the dual-motor torsion ball screw test bench, it is necessary to carry out performance degradation experiments on the ball screw pair at low speed 300r / min, medium speed 500r / min, and high speed 800r / min under low load 500N, medium load 1000N, and heavy load 1500N. It is required that the control deviation between the actual load and the target load should not exceed ±4% at different operating speeds.

[0080] According to the above requirements, the main motor and the auxiliary motor are set as synchronous position loops, running at 300r / min, 500r / min, and 800r / min respectively. The target load is input into the real-time dynamic load adjustment model of the ball screw in turn. The angle difference offset pulse is judged and calculated in each closed-loop control cycle, and sent to the offset planning position of the auxiliary motor in the form of speed command. This is repeated until the movement stops. In this way, dynamic adjustment of different target loads can be achieved during the movement. Please refer to Figure 4 The results reflect the static and dynamic adjustment of the ball screw pair to the target load of 500N, 1000N and 1500N at 300r / min, 500r / min and 800r / min. From the results, it can be seen that the control deviation between the actual load and the target load of the dynamic adjustment model at different operating speeds does not exceed ±4%, meeting the control requirements.

[0081] In summary, the present invention provides a method and system for dynamically adjusting the load of a ball screw pair under a synchronous position loop, which can avoid reverse transmission of the ball screw pair when the current loop is loaded and accelerate its friction and wear, which 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, based on the control of the same position loop, an angular difference and load calibration experiment is carried out to accurately establish the relationship between the angular difference and the load in static state and verify it during the movement. A dynamic closed-loop control model of the axial load of the ball screw pair is established based on the angular difference load calibration equation to suppress the load fluctuation problem during the movement and realize the real-time dynamic load change and load stabilization functions.

[0082] The technicians in the relevant field can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In practical applications, the above-mentioned function allocation can be completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiment can be integrated in a processing unit, or each unit can exist physically separately, or two or more units can be integrated in one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned method embodiment, which will not be repeated here.

[0083] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0084] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed in the present invention can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0085] In the embodiments provided by the present invention, it should be understood that the disclosed devices / terminals and methods can be implemented in other ways. For example, the device / terminal embodiments described above are only schematic. For example, the division of the modules or units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0086] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0087] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0088] If the integrated module / unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present invention implements all or part of the processes in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium, and the computer program can implement the steps of the above-mentioned various method embodiments when executed by the processor. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, U disk, mobile hard disk, disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electric carrier signal, telecommunication signal and software distribution medium, etc. It should be noted that the content contained in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable media do not include electric carrier signals and telecommunication signals.

[0089] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0090] These computer program instructions may also be stored in a computer readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture including an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0091] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process in the computer or other programmable device. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0092] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A method for dynamically adjusting the load of a ball screw pair under a synchronous position ring, characterized in that: The following steps are involved: S1, control the dual motors to work simultaneously under the position loop and move at the same planned position and planned speed; S2. Based on the synchronous position loop working mode of the dual motors in step S1, the planned position of the auxiliary motor in the dual motors is adjusted separately, the force indication is observed, and a static angular difference and load calibration experiment is carried out, and the calibration experiment data is analyzed to establish a mapping relationship between the angular difference and the load; S3. According to the mapping relationship between the angular difference and the load obtained in step S2, the two motors set in step S1 work in the synchronous position loop. When both motors are enabled at zero position, the target load is input into the load calibration equation to obtain the target angular difference pulse. The angular difference pulse planning position is given to the auxiliary motor in the dual motors. The planned position of the main motor in the dual motors is sent to the far end point of the screw pair stroke and back and forth to the zero point. The auxiliary motor follows the planned position of the main motor on the basis of the synchronous position loop and offsets the target angular difference pulse. The fluctuation of the static load on the target load is observed during the movement. S4. Based on the fluctuation of the target load due to the static load obtained in step S3, the deviation between the real-time force feedback value and the current target load is calculated; based on the mapping relationship between the angular difference and the load obtained in step S2, a dynamic closed-loop control model of the axial load of the ball screw pair is established; based on the dynamic closed-loop control model of the axial load of the ball screw pair, real-time dynamic load variation and load stabilization functions are realized.

2. The method for dynamically adjusting the load of the ball screw pair under the synchronous position ring according to claim 1, characterized in that: In step S1, the main motor and the auxiliary motor are both set to work in the position loop, the main motor drives the main ball screw pair for transmission, and the auxiliary motor drives the auxiliary ball screw pair for transmission. The planned position of the main motor is bound to the planned position of the auxiliary motor. The planned position of the auxiliary motor is independently adjustable while the planned position of the main motor is synchronized with the planned position of the auxiliary motor.

3. The method for dynamically adjusting the load of the ball screw pair under the synchronous position ring according to claim 1, characterized in that: Step S2 is specifically as follows: S201, selecting m position points at equal intervals on the working stroke of the ball screw pair, and performing a static angular difference and load calibration experiment at each position point; S202, repeat the static rotation angle difference and load calibration experiment of m position points in step S201, record the force sensor indications corresponding to all rotation angle differences of all position points, and complete the static rotation angle difference and load calibration experiment of m position points; S203. According to the force sensor indications corresponding to all the rotation angle differences of all the position points obtained in step S202, a linear regression model of the load with respect to the rotation angle difference pulse is established, and the least squares estimation method is used to fit the model to obtain an equation of the rotation angle difference pulse and the load.

4. The method for dynamically adjusting the load of the ball screw pair under the synchronous position ring according to claim 1, characterized in that: In step S201, the angle difference pulse is set to gradually increase from 0 to Pmax, and then gradually decrease from Pmax to Pmin, Pmax=-Pmin, and then the angle difference pulse is gradually increased from Pmin to 0. During this process, the indication of the force sensor needs to be recorded at each interval point to complete the static angle difference and load calibration experiment at one position point.

5. The method for dynamically adjusting the load of the ball screw pair under the synchronous position ring according to claim 4, characterized in that: Before each experiment, the planned positions of the main motor and the auxiliary motor were cleared to ensure that the initial rotation angle difference was zero.

6. The method for dynamically adjusting the load of the ball screw pair under the synchronous position ring according to claim 3, characterized in that: In step S3, loads of 500N, 1000N and 1500N are approached at 300r / min, 500r / min and 800r / min, respectively.

7. The method for dynamically adjusting the load of the ball screw pair under the synchronous position ring according to claim 1, characterized in that: Step S4 is specifically as follows: First, calculate the axial force of the ball screw pair at time t , and input it into the angle difference calculation equation to obtain , according to the axial target load size of the ball screw pair planned at time t The axial force of the ball screw pair at time t calculated The difference in value determines whether to perform closed-loop adjustment, and the speed control command of axis 2 controller is obtained according to the calculation. , which is converted into an angle difference through time accumulation and added to the planned position of the axis 2 controller.

8. The method for dynamically adjusting the load of the ball screw pair under the synchronous position ring according to claim 7, characterized in that: according to , , Calculated axial force of the ball screw pair at time t , the angular difference corresponding to the difference between the planned axial target load of the ball screw pair at time t and the actual load , the speed command sent to the driver when the load is closed at time t The angle difference between the main motor and the auxiliary motor adjusted by closed loop at time t They are: in, It is the analog voltage signal of the force sensor read by the acquisition system at time t. is the maximum value of the analog voltage signal of the force sensor, is the maximum measuring range of the force sensor, Based on , , The calculated axial force of the ball screw pair at time t is: is the target axial load of the ball screw pair planned at time t, is the load threshold value of load closed-loop control, is the angular difference between the main motor and the auxiliary motor in the previous closed-loop adjustment at time t, The period for adjusting the closed-loop control algorithm.

9. The method for dynamically adjusting the load of the ball screw pair under the synchronous position ring according to claim 7, characterized in that: When the absolute value of the difference between the target load and the actual load at time t is less than or equal to hour, Set to zero, 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 of the load closed-loop control When Make planning adjustments. To control the execution time of instructions, It is the coefficient related to the planned speed in the point motion of the axis 2 controller.

10. A ball screw pair load dynamic adjustment system under a synchronous position ring, characterized in that: include: The control module controls the dual motors to work simultaneously under the 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 dual motors, adjusts the planned position of the auxiliary motor in the dual motors separately, observes the force indication, and conducts static angular difference and load calibration experiments, and analyzes the calibration experiment data to establish the mapping relationship between angular difference and load; The loading module sets the two motors to work in the synchronous position loop according to the mapping relationship between the angular difference and the load. When both motors are enabled at zero position, the target load is input into the load calibration equation to obtain the target angular difference pulse. The angular difference pulse is planned to the auxiliary motor in the dual motors. The planned position of the main motor in the dual motors is sent to the far end point of the screw pair stroke and back and forth to the zero point. The auxiliary motor follows the planned position of the main motor on the basis of the synchronous position loop and offsets the target angular difference pulse. The fluctuation of the static load on the target load 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 due to static loading, establishes a dynamic closed-loop control model of the axial load of the ball screw pair based on the mapping relationship between the obtained angular difference and the load, and realizes real-time dynamic load variation and load stabilization functions based on the dynamic closed-loop control model of the axial load of the ball screw pair.

Images