Control method applied to dual-motor propulsion system

Abstract

The invention relates to the field of efficient motor control systems, in particular to a control method applied to a dual-motor propulsion system, which comprises the following steps: acquiring load weight, table surface diameter, table surface friction coefficient and table surface operating parameters; obtaining a table top estimation angle according to the height of the table top reference point and the table top diameter; obtaining an estimation reasonability according to the table top estimation angle, the table top pressure, the height of the reference point and the load weight; fitting the table top estimation angle in combination with the estimation reasonability to obtain a table top inclination angle; according to the table top inclination angle and the table top friction coefficient, compensation friction force is obtained; and according to the compensation friction force, the friction force between the table top of the dual-motor propulsion system and the load is controlled. The friction force between the table top and the load of the dual-motor propulsion system is compensated by compensating the friction force, and the operation stability of the dual-motor propulsion system is improved.

Description

Technical Field

[0001] The present invention relates to the field of high-efficiency motor control systems, and in particular to a control method applied to a dual-motor propulsion system. Background Art

[0002] A dual-motor propulsion system refers to a system that uses two electric motors to provide power. The dual-motor propulsion system is mainly used on a turntable with one motor controlling rotation and one motor controlling tilt, thereby providing a wider observation angle and facilitating comprehensive monitoring or photography of the load. This dual-degree-of-freedom (i.e. rotation and tilt) design makes the turntable more flexible and adaptable, and can meet the needs of complex application scenarios.

[0003] Generally, when the turntable is tilted with dual motors, the gravity component of the load parallel to the table surface will increase, causing the load to slide downward. If the friction provided by the table surface is not enough to offset the increased gravity component, the load will slide. Therefore, friction is the key to ensure safe and stable operation. Too much friction will lead to operational difficulties and increased energy consumption; too little friction will make the system unstable, reduce control accuracy, and even cause the load to slide. Summary of the invention

[0004] The present invention provides a control method applied to a dual-motor propulsion system to solve the existing problems.

[0005] A control method for a dual-motor propulsion system of the present invention adopts the following technical solution:

[0006] An embodiment of the present invention provides a control method for a dual-motor propulsion system, the method comprising the following steps:

[0007] Obtaining the load weight, table diameter, table friction coefficient, and table operation parameters at each moment; the table operation parameters include the heights of several table reference points and table pressure;

[0008] According to the height of all table reference points and table diameter at each moment, the estimated angle of the table at each moment is obtained;

[0009] According to the estimated table angle and table pressure at each moment, the estimated load weight at each moment is obtained; according to the distribution of the height of the reference point at each moment, the rationality of the reference distribution at each moment is obtained; according to the difference between the load weight and the estimated load weight at each moment and the rationality of the reference distribution, the rationality of the estimate at each moment is obtained;

[0010] The estimated angles of the table top at all times are fitted according to the reasonableness of the estimation corresponding to each time, and the tilt angle of the table top at each time is obtained;

[0011] According to the inclination angle of the table at the current moment, combined with the friction coefficient of the table, the compensation friction force at the current moment is obtained; according to the compensation friction force at the current moment, the friction force between the table and the load of the dual-motor propulsion system is controlled.

[0012] Furthermore, the method of obtaining the estimated angle of the table at each moment according to the heights of all table reference points and the table diameter at each moment includes the following specific steps:

[0013] For any moment, obtain the maximum and minimum values ​​of the heights of all reference points, and record the difference between the maximum and minimum values ​​as the table height at that moment; record the inverse sine function value of the ratio of the table height to the table diameter at that moment as the estimated table angle at that moment.

[0014] Furthermore, the method of obtaining the estimated load weight at each moment according to the estimated tabletop angle and tabletop pressure at each moment includes the following specific steps:

[0015] The cosine value of the estimated table angle at any moment is calculated, and the ratio of the table pressure at that moment to the cosine value is recorded as the estimated load weight at that moment.

[0016] Further, the method of obtaining the reasonableness of the reference distribution at each moment according to the distribution of the height of the reference point at each moment, and obtaining the estimated reasonableness at each moment according to the difference between the load weight and the estimated load weight at each moment and the reasonableness of the reference distribution, comprises the following specific steps:

[0017] Starting from any reference point on the edge of the table, the reference points are numbered from 1 to N in a clockwise direction, where N is the number of preset references;

[0018] At any moment, a rectangular coordinate system is established with the number of the reference point as the horizontal axis and the height of the reference point as the vertical axis, all the reference points are mapped to the rectangular coordinate system, and the least square method is used to fit the curve to the data points in the rectangular coordinate system with the cosine function as the fitting model; for any reference point, the value on the fitting curve corresponding to the number of the reference point in the rectangular coordinate system is recorded as the fitting height of the reference point; the absolute value of the difference between the height of the reference point and the fitting height is recorded as the fitting error of the reference point; the inverse proportional normalization result of the sum of the fitting errors of all the reference points is recorded as the reasonableness of the reference distribution at that moment;

[0019] w t =(1-norm(|GG t ′ |))×U t

[0020] In the formula, w tis the estimated rationality at the tth moment; G is the load weight; G t ′ is the estimated weight of the load at the tth moment;

[0021] U t is the rationality of the benchmark distribution at the tth moment; norm() is the linear normalization function; || is the absolute value function.

[0022] Furthermore, the estimated angles of the table top at all times are fitted according to the estimated rationality corresponding to each time to obtain the tilt angle of the table top at each time, and the specific steps include the following:

[0023] During the operation of the dual-motor propulsion system, the estimated angle and reasonableness of the table surface at each moment are obtained;

[0024] The objective function of the least square method is constructed based on the estimated angle of the table surface at all times and the reasonableness of the estimation; the estimated angle of the table surface at all times is fitted multiple times using the least square method and the constructed objective function to obtain the fitting straight line for each fitting, and the value corresponding to the fitting straight line at each time is recorded as the angle obtained by each fitting at each time; the optimal solution of the objective function is obtained, and the corresponding fitting straight line is used as the final fitting straight line of the table surface estimation angle; a linear function model is constructed:

[0025] θ t =k×t+b

[0026] In the formula, θ t is the tilt angle of the table at the tth moment; t represents the order value at the tth moment; k and b are the parameters to be fitted, representing the slope and intercept of the final fitting line of the estimated angle of the table, respectively.

[0027] Furthermore, the objective function is obtained by:

[0028]

[0029] Where S(t) is the output value of the objective function of the least squares method; M is the number of all moments; W t is the reasonableness of the estimate at the tth moment; θ t ′ is the estimated angle of the table at the tth moment; θ t is the angle obtained by the fitting at the tth moment.

[0030] Furthermore, the method of obtaining the compensating friction force at the current moment according to the inclination angle of the table surface at the current moment and the friction coefficient of the table surface includes the following specific steps:

[0031] Record the last moment as the current moment;

[0032] The product of the sine value of the table top inclination angle at the current moment and the load weight is recorded as the required friction force at the current moment;

[0033] According to the load weight, the friction coefficient of the table surface and the inclination angle of the table surface at the current moment, the existing friction force at the current moment is obtained;

[0034] The difference between the required friction force at the current moment and the existing friction force at the current moment is recorded as the compensation friction force at the current moment.

[0035] Furthermore, the existing friction force includes the following specific steps:

[0036] The product of the cosine value of the table top inclination angle at the current moment, the table top friction coefficient and the load weight is recorded as the existing friction force at the current moment.

[0037] Furthermore, the friction between the table and the load of the dual-motor propulsion system is controlled according to the compensation friction at the current moment, and the specific steps include the following:

[0038] The current moment's compensation pressure is obtained according to the current moment's compensation friction force and the table surface friction coefficient;

[0039] The electric motor is connected to the control unit, and the motor output is adjusted by the PWM signal. The compensation pressure at the current moment is then used as the compensation pressure applied to the friction surface. The control unit continuously adjusts the output of the electric motor according to the feedback from the pressure sensor on the turntable to achieve the required friction force at the current moment.

[0040] Furthermore, the pressure compensation comprises the following specific steps:

[0041] The ratio of the current compensation friction force to the table surface friction coefficient is recorded as the current compensation pressure.

[0042] The beneficial effects of the technical solution of the present invention are as follows: for the problem of inaccurate acquisition of the table angle, the present invention analyzes the height of the table reference point to obtain the estimated table angle, and evaluates the estimated rationality of the table angle according to the table pressure and the load weight, and determines the weight of the estimated table angle in the fitting process, providing a basis for the subsequent fitting process; for the problem of accurately obtaining the table tilt angle at the current moment, the present invention accurately obtains the current table tilt angle by fitting the estimated table angle at all moments according to the estimated rationality corresponding to each moment; for the problem of compensating the friction between the table and the load contact surface during the operation of the dual-motor propulsion system, the present invention obtains the compensation friction through the current table tilt angle, and controls the friction between the table and the load of the dual-motor propulsion system. So far, the present invention compensates for the friction between the table and the load of the dual-motor propulsion system by accurately and reliably compensating the friction, thereby improving the stability of the operation of the dual-motor propulsion system. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. 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 paying creative work.

[0044] Figure 1 A flow chart of the steps of a control method applied to a dual-motor propulsion system of the present invention;

[0045] Figure 2 A schematic diagram of the turntable structure of a dual-motor propulsion system provided in this embodiment. DETAILED DESCRIPTION

[0046] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following is a detailed description of a control method for a dual-motor propulsion system proposed by the present invention, its specific implementation method, structure, features and effects, in combination with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "another embodiment" does not necessarily refer to the same embodiment. In addition, specific features, structures or characteristics in one or more embodiments may be combined in any suitable form.

[0047] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0048] A specific scheme of a control method for a dual-motor propulsion system provided by the present invention is described in detail below with reference to the accompanying drawings.

[0049] See also Figure 1 , which shows a flow chart of a control method for a dual-motor propulsion system provided by an embodiment of the present invention, the method comprising the following steps:

[0050] Step S001: Obtain the load weight, table diameter, table friction coefficient, and table operation parameters at each moment.

[0051] It should be noted that the purpose of this embodiment is to determine the compensation friction force at the current moment by analyzing the tilt angle of the table, and then control the friction force between the table and the load of the dual-motor propulsion system to maintain the stability of the dual-motor propulsion system. The schematic diagram of the turntable structure of the dual-motor propulsion system is shown in Figure 2 As shown, the load weight and table parameters are first obtained.

[0052] Specifically, the load is placed on an electronic platform scale for weighing to obtain the load weight; the friction coefficient of the table surface is obtained according to the material of the contact surface between the table surface and the load (based on the material and directly obtained by the existing method, which is not the focus of this embodiment and will not be repeated in this embodiment); the table surface of the turntable is circular, and the diameter information of the table surface is obtained;

[0053] A pressure sensor is installed on the turntable; N reference points are evenly set on the edge of the table, and each reference point is marked; N is the preset reference number, N=30, and this embodiment is described as an example;

[0054] The load is placed on the table of the dual-motor propulsion system. After the system is running, the table pressure is collected in real time using a pressure sensor. The reference points on the edge of the table are scanned using laser scanning to obtain the height of each reference point in real time. The frequency of the pressure sensor and laser scanning is 10 Hz.

[0055] It should be noted that during the operation of the dual-motor propulsion system, the table will rotate according to the direction set by the system. During each rotation, it rotates in the direction given by the system. When controlling the friction between the table and the load of the dual-motor propulsion system, the control method is real-time control, so the table operation parameters during the last rotation are recorded, and the table operation parameters include the height of several table reference points and the table pressure.

[0056] Step S002: Obtain the estimated angle of the table at each moment according to the heights of all table reference points and the table diameter at each moment.

[0057] It should be noted that during the operation of the dual-motor propulsion system, as the inclination angle of the table changes, in order to ensure the stability of the load on the table, it is necessary to adjust the friction between the table and the load so that the maximum friction that can be provided between the table and the load is greater than or equal to the gravity component of the load parallel to the table. Therefore, it is necessary to first estimate the angle between the table and the horizontal plane.

[0058] It should be further explained that when estimating the angle between the table top and the horizontal plane, it is mainly determined by using the proportional relationship between the distance between the highest point to the lowest point on the table top and the diameter of the turntable.

[0059] Preferably, in one embodiment of the present invention, the estimated angle of the table at each moment is obtained according to the heights of all table reference points and the table diameter at each moment, which specifically includes:

[0060] For any moment, obtain the maximum and minimum values ​​of the heights of all reference points, and record the difference between the maximum and minimum values ​​as the table height at that moment; record the inverse sine function value of the ratio of the table height to the table diameter at that moment as the estimated table angle at that moment.

[0061] Step S003: Obtain the estimated load weight at each moment based on the estimated table angle and table pressure at each moment; obtain the benchmark distribution rationality at each moment based on the distribution of the height of the benchmark point at each moment; obtain the estimated rationality at each moment based on the difference between the load weight and the estimated load weight at each moment and the benchmark distribution rationality.

[0062] It should be noted that since the table height is obtained using the height of the reference points, and the reference points are evenly and discretely set on the table, the highest point among the reference points is not necessarily located at the highest position of the table at this moment, and the lowest point among the reference points is not necessarily located at the lowest position of the table at this moment, so the obtained table height deviates from the actual value; and since during the laser scanning process, the load may block the highest reference point at some moments, resulting in a deviation between the obtained table height and the actual value, and thus a deviation in the estimated angle of the table, it is necessary to analyze the rationality of the estimated angle of the table.

[0063] Specifically, starting from any reference point on the edge of the table top, the reference points are numbered from 1 to N in a clockwise direction, where N is the preset reference number.

[0064] It should be noted that at a certain moment when the table rotates, when the inclination angle of the table is a constant, if the clockwise angle between the line connecting the center of the table to the reference point and the line connecting the center of the table to the top of the table is recorded as the state angle of the reference point, then the state angle of the reference point and the height of the reference point present a trigonometric function relationship, where the trigonometric function relationship is specifically z i ′ =R(1+cosθ i )sinα, where z i ′ is the height of the ith reference point, R is the table radius, θ i is the state angle of the ith reference point, and α is the inclination angle of the table. Since the positions of the reference points are evenly distributed on the edge of the table, as the number of the reference points increases, the state angle of the reference points also increases with a fixed step size. Therefore, the number of the reference point and the height of the reference point present a trigonometric function relationship. Therefore, the fitting error of the reference point number and the measured height of the reference point is used to judge the rationality of the reference distribution at each moment.

[0065] Specifically, at any moment, a rectangular coordinate system is established with the number of the reference point as the horizontal axis and the height of the reference point as the vertical axis, all reference points are mapped to the rectangular coordinate system, and the least squares method is used to fit the curve to the data points in the rectangular coordinate system with a cosine function as a fitting model; for any reference point, the value on the fitting curve corresponding to the number of the reference point in the rectangular coordinate system is recorded as the fitting height of the reference point; the absolute value of the difference between the height of the reference point and the fitting height is recorded as the fitting error of the reference point; the inverse proportional normalization result of the sum of the fitting errors of all the reference points is recorded as the reasonableness of the reference distribution at that moment; wherein, the least squares method of fitting curves is a well-known technology, and the specific method is not introduced here.

[0066] It should be further explained that the weight of the load can be estimated based on the estimated table angle combined with the table pressure, and the rationality of the estimated table angle can be evaluated based on the difference between the estimated weight of the load and the actual weight of the load.

[0067] Preferably, in one embodiment of the present invention, the estimated load weight at each moment is obtained according to the estimated tabletop angle and tabletop pressure at each moment, specifically including:

[0068] The cosine value of the estimated table angle at any moment is calculated, and the ratio of the table pressure at that moment to the cosine value is recorded as the estimated load weight at that moment.

[0069] It should be noted that the smaller the difference between the estimated load weight and the actual load weight is, and the greater the rationality of the reference distribution is, the greater the estimated rationality of the table top estimated angle is.

[0070] Specifically, the calculation method of the estimated rationality at the tth moment is:

[0071] w t =(1-norm(|GG t ′ |))×U t

[0072] In the formula, w t is the estimated rationality at the tth moment; G is the load weight; G t ′ is the estimated weight of the load at the tth moment; U t is the rationality of the benchmark distribution at the tth moment; norm() is a linear normalization function, and the normalized object is (|GG t ′ |);|| is the absolute value function.

[0073] Step S004: fitting the estimated angles of the table top at all times according to the estimated rationality corresponding to each time, to obtain the tilt angle of the table top at each time.

[0074] It should be noted that due to the error in the estimated angle of the table, the compensation friction force directly obtained based on the estimated angle of the table has deviations, which will cause the dual-motor propulsion system to operate unstable, so it is necessary to obtain an accurate table tilt angle. During the operation of the dual-motor propulsion system, the table will rotate according to the direction set by the system. During each rotation, the system will rotate in the direction given by the system. During a single rotation, the motor controls the turntable to slowly tilt, so the time and the table angle show a linear relationship, so the estimated angle of the table is fitted according to the linear relationship.

[0075] Preferably, in one embodiment of the present invention, the estimated angles of the table top at all times are fitted according to the estimated rationality corresponding to each time to obtain the tilt angle of the table top at each time, which specifically includes:

[0076] During the operation of the dual-motor propulsion system, the estimated angle and reasonableness of the table surface at each moment are obtained;

[0077] The objective function of the least squares method is constructed according to the estimated angle of the table surface at all times and the estimated rationality; the estimated angle of the table surface at all times is fitted multiple times using the least squares method and the constructed objective function to obtain the fitting straight line for each fitting, and the numerical value corresponding to the fitting straight line at each moment in each fitting is recorded as the angle obtained by each fitting at each moment; the optimal solution of the objective function is obtained, and the corresponding fitting straight line is used as the final fitting straight line for the estimated angle of the table surface; wherein, the fitting process of the least squares method is a well-known technology, the objective function is the fitting parameter of the least squares method, and the specific fitting method is not introduced here.

[0078] Construct a linear function model:

[0079] θ t =k×t+b

[0080] In the formula, θ t is the tilt angle of the table at the tth moment; t represents the order value at the tth moment; k and b are the parameters to be fitted, representing the slope and intercept of the final fitting line of the estimated angle of the table, respectively.

[0081] Specifically, the method for obtaining the objective function of the least squares method includes:

[0082]

[0083] Where S(t) is the output value of the objective function of the least squares method; M is the number of all moments; W t is the reasonableness of the estimate at the tth moment; θ t ′ is the estimated angle of the table at the tth moment; θ t is the angle obtained by the fitting at the tth moment.

[0084] It should be noted that in order to reduce the impact of the table top estimation angle with too low estimation rationality on the fitting process, the smaller the estimation rationality of the table top estimation angle, the smaller its weight in the fitting process, making the fitting result more accurate.

[0085] Step S005: According to the table top inclination angle at the current moment, combined with the table top friction coefficient, the current moment compensation friction force is obtained; according to the current moment compensation friction force, the friction force between the table top and the load of the dual-motor propulsion system is controlled.

[0086] It should be noted that during the operation of the dual-motor propulsion system, in order to maintain the stability of the load, the friction between the table and the load contact surface needs to be adjusted in real time, so that the maximum friction that can be provided between the table and the load is greater than or equal to the gravity component of the load parallel to the table. After obtaining the inclination angle of the table at each moment, the gravity component of the load parallel to the table is obtained.

[0087] It should be further explained that the table top inclination angle can accurately reflect the current inclination angle between the table top and the horizontal plane, so the gravity component of the load parallel to the table top can be obtained from the table top inclination angle.

[0088] Preferably, in one embodiment of the present invention, the compensating friction force at the current moment is obtained according to the inclination angle of the table surface at the current moment and the friction coefficient of the table surface, which specifically includes:

[0089] Record the last moment as the current moment;

[0090] The product of the sine value of the table top inclination angle at the current moment and the load weight is recorded as the required friction force at the current moment;

[0091] According to the load weight, the friction coefficient of the table surface and the inclination angle of the table surface at the current moment, the existing friction force at the current moment is obtained;

[0092] The difference between the required friction force at the current moment and the existing friction force at the current moment is recorded as the compensation friction force at the current moment.

[0093] Specifically, the existing method for obtaining friction force includes:

[0094] The product of the cosine value of the table top inclination angle at the current moment, the table top friction coefficient and the load weight is recorded as the existing friction force at the current moment.

[0095] It should be noted that after obtaining the existing friction force at the current moment, it is necessary to control the friction force between the table and the load of the dual-motor propulsion system according to the existing friction force to maintain the stability of the load during the operation of the system.

[0096] Specifically, the compensation pressure at the current moment is obtained according to the compensation friction force at the current moment and the friction coefficient of the table surface;

[0097] The electric motor is connected to the control unit, and the motor output is adjusted by the PWM signal. The compensation pressure at the current moment is then used as the compensation pressure applied to the friction surface. The control unit continuously adjusts the output of the electric motor according to the feedback from the pressure sensor on the turntable to achieve the required friction force at the current moment.

[0098] Specifically, the method for obtaining the compensation pressure includes:

[0099] The ratio of the current compensation friction force to the table surface friction coefficient is recorded as the current compensation pressure.

[0100] This embodiment uses the exp(-A) model to present the inverse proportional relationship and normalization processing, A is the input of the model, and the implementer can set the inverse proportional function and normalization function according to actual conditions.

[0101] So far, the present invention is completed.

[0102] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A control method applied to a dual-motor propulsion system, characterized in that: The method comprises the following steps: Obtaining the load weight, table diameter, table friction coefficient, and table operation parameters at each moment; the table operation parameters include the heights of several table reference points and table pressure; According to the height of all table reference points and table diameter at each moment, the estimated angle of the table at each moment is obtained; According to the estimated table angle and table pressure at each moment, the estimated load weight at each moment is obtained; according to the distribution of the height of the reference point at each moment, the rationality of the reference distribution at each moment is obtained; according to the difference between the load weight and the estimated load weight at each moment and the rationality of the reference distribution, the rationality of the estimate at each moment is obtained; The estimated angles of the table top at all times are fitted according to the reasonableness of the estimation corresponding to each time, and the tilt angle of the table top at each time is obtained; According to the inclination angle of the table at the current moment, combined with the friction coefficient of the table, the compensation friction force at the current moment is obtained; according to the compensation friction force at the current moment, the friction force between the table and the load of the dual-motor propulsion system is controlled.

2. A control method for a dual-motor propulsion system according to claim 1, characterized in that: The specific steps of obtaining the estimated angle of the table at each moment according to the heights of all table reference points and the table diameter at each moment are as follows: For any moment, obtain the maximum and minimum values ​​of the heights of all reference points, and record the difference between the maximum and minimum values ​​as the table height at that moment; record the inverse sine function value of the ratio of the table height to the table diameter at that moment as the estimated table angle at that moment.

3. A control method for a dual-motor propulsion system according to claim 1, characterized in that: The method of obtaining the estimated load weight at each moment according to the estimated table surface angle and table surface pressure at each moment includes the following specific steps: The cosine value of the estimated table angle at any moment is calculated, and the ratio of the table pressure at that moment to the cosine value is recorded as the estimated load weight at that moment.

4. A control method for a dual-motor propulsion system according to claim 1, characterized in that: The method of obtaining the reasonableness of the reference distribution at each moment according to the distribution of the height of the reference point at each moment, and obtaining the estimated reasonableness at each moment according to the difference between the load weight and the estimated load weight at each moment and the reasonableness of the reference distribution, comprises the following specific steps: Starting from any reference point on the edge of the table, the reference points are numbered from 1 to N in a clockwise direction, where N is the number of preset references; At any time, a rectangular coordinate system is established with the reference point number as the horizontal axis and the reference point height as the vertical axis. All reference points are mapped to a rectangular coordinate system, and curve fitting is performed on the data points in the rectangular coordinate system using the least square method with a cosine function as the fitting model; for any reference point, the value on the fitting curve corresponding to the number of the reference point in the rectangular coordinate system is recorded as the fitting height of the reference point; the absolute value of the difference between the height of the reference point and the fitting height is recorded as the fitting error of the reference point; the inverse proportional normalization result of the sum of the fitting errors of all reference points is recorded as the reasonableness of the reference distribution at that moment; w t =(1-norm(|G-G t ′ |))×U t In the formula, w t is the estimated rationality at the tth moment; G is the load weight; G t ′ is the estimated weight of the load at the tth moment; U t is the rationality of the benchmark distribution at the tth moment; norm() is the linear normalization function; || is the absolute value function.

5. A control method for a dual-motor propulsion system according to claim 1, characterized in that: The estimated table top angles at all times are fitted according to the estimated rationality corresponding to each time to obtain the table top tilt angle at each time, and the specific steps include the following: During the operation of the dual-motor propulsion system, the estimated angle and reasonableness of the table surface at each moment are obtained; The objective function of the least square method is constructed according to the estimated angle of the table surface at all times and the reasonableness of the estimation; the estimated angle of the table surface at all times is fitted multiple times using the least square method and the constructed objective function to obtain the fitting straight line of each fitting, and the value corresponding to the fitting straight line at each time is recorded as the angle obtained by each fitting at each time; Obtain the optimal solution for the objective function, and use the corresponding fitting straight line as the final fitting straight line for the estimated angle of the table surface; construct a linear function model: i t =k×t+b In the formula, θ t is the tilt angle of the table at the tth moment; t represents the order value at the tth moment; k and b are the parameters to be fitted, representing the slope and intercept of the final fitting line of the estimated angle of the table, respectively.

6. A control method for a dual-motor propulsion system according to claim 5, characterized in that: The method for obtaining the objective function is: Where S(t) is the output value of the objective function of the least squares method; M is the number of all moments; W t is the reasonableness of the estimate at the tth moment; θ t ′ is the estimated angle of the table at the tth moment; θ t is the angle obtained by the fitting at the tth moment.

7. A control method for a dual-motor propulsion system according to claim 1, characterized in that: The method of obtaining the compensating friction force at the current moment according to the inclination angle of the table surface at the current moment and the friction coefficient of the table surface includes the following specific steps: Record the last moment as the current moment; The product of the sine value of the table top inclination angle at the current moment and the load weight is recorded as the required friction force at the current moment; The existing friction force at the current moment is obtained according to the load weight, the friction coefficient of the table surface and the inclination angle of the table surface at the current moment; the difference between the required friction force at the current moment and the existing friction force at the current moment is recorded as the compensation friction force at the current moment.

8. A control method for a dual-motor propulsion system according to claim 7, characterized in that: The existing friction force includes the following specific steps: The product of the cosine value of the table top inclination angle at the current moment, the table top friction coefficient and the load weight is recorded as the existing friction force at the current moment.

9. A control method for a dual-motor propulsion system according to claim 7, characterized in that: The control of the friction between the table and the load of the dual-motor propulsion system according to the current compensation friction force includes the following specific steps: The current moment's compensation pressure is obtained according to the current moment's compensation friction force and the table surface friction coefficient; The electric motor is connected to the control unit, and the motor output is adjusted by the PWM signal. The compensation pressure at the current moment is then used as the compensation pressure applied to the friction surface. The control unit continuously adjusts the output of the electric motor according to the feedback from the pressure sensor on the turntable to achieve the required friction force at the current moment.

10. A control method for a dual-motor propulsion system according to claim 9, characterized in that: The pressure compensation comprises the following specific steps: The ratio of the current compensation friction force to the table surface friction coefficient is recorded as the current compensation pressure.

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