Power distribution method and system in dual-motor master-slave control

Abstract

The invention discloses a power distribution method and system in dual-motor master-slave control, and relates to the technical field of motor control, and the method comprises the following steps: determining the proportion of single-tooth meshing and dual-tooth meshing of a driving gear in a whole meshing period based on the overlap ratio of the driving gear and a load gear, and obtaining an initial assembly angle difference according to the proportion condition; a main motor and a slave motor are adopted to drive the two assembled driving gears correspondingly; the rotation speed of the main motor is set according to the actual load working condition, and the output torque function of the slave motor in one period is obtained according to the rotation speed of the main motor and the stress change characteristics of single-tooth meshing and double-tooth meshing; and dynamically distributing the power of the master motor and the slave motor according to the output torque function of the slave motor. The power of the two driving gears is dynamically adjusted by combining the single-tooth and double-tooth meshing characteristic, the problem of large stress caused by single-tooth meshing is reduced to the maximum extent, and therefore the service life of the driving system is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of gear life, and in particular to a power distribution method and system in dual-motor master-slave control. Background Art

[0002] Under high-power load conditions driven by electric motors, most transmission methods involve a motor connected to a reduction gear, a drive spur gear, and a load spur gear to drive the load. This is particularly true in nuclear power plant drum screens and shield machine tool rotating heads. The drive spur gear has a smaller rotation radius than the load spur gear. Therefore, under the same operating conditions, the drive gear experiences higher operating stresses and more cycles, resulting in greater fatigue wear and a shorter lifespan. Furthermore, harsh operating environments, such as increased friction caused by sand and gravel and increased localized stress concentrations caused by foreign matter, can negatively impact the gear's service life, directly impacting overall system operation. Furthermore, high loads can lead to excessive loads on individual gear meshes, accelerating fatigue damage and shortening service life. Given the high cost of downtime for maintenance, the requirements for efficient and stable gear operation are particularly stringent.

[0003] Existing methods extend gear life by manufacturing or designing gear pairs with different materials, but this approach offers limited improvement and cannot fundamentally address the issue of insufficient fatigue life under heavy loads. Adding multiple drive systems to multiple gears is an effective way to reduce gear loads. Multi-gear drives are widely used in heavy equipment such as slurry shield machines, heavy plate feeders, and gantry cranes. Master-slave control is a method for driving multi-gear drives.

[0004] Master-slave control performs target speed tracking control by configuring a master drive mechanism, and the slave drive mechanism uses the real-time position, speed or torque feedback of the master drive mechanism as the target for tracking control. This can easily complete the synchronous control deployment of the dual motors and solve the load balancing problem of the motors. From the perspective of load power distribution, the existing master-slave drive method evenly distributes power to different drive mechanisms, reducing the load and stress of each gear and improving the fatigue life to a certain extent. However, the even distribution of power cannot guarantee the optimal gear life. The overlap of the gear pairs is mostly in the range of 1.5-2. During the meshing process, there is a periodic switching phenomenon of single-tooth to double-tooth meshing, in which the stress in the single-tooth meshing stage is much greater than that in the double-tooth meshing stage. For dual-gear drive systems, the existing master-slave control method does not take into account the periodic meshing process of single-tooth to double-tooth switching, which may lead to the extremely harsh phenomenon that two gears are in the single-tooth meshing stage at the same time. This phenomenon will seriously affect the fatigue life of the gears. Summary of the Invention

[0005] Based on the defects of the above-mentioned prior art, the present invention provides a power distribution method and system in dual-motor master-slave control, which solves the problem that the existing master-slave control method does not take into account the periodic meshing process of single-tooth and double-tooth switching, which may lead to the extremely harsh phenomenon that two gears are in the single-tooth meshing stage at the same time, which will seriously affect the fatigue life of the gears.

[0006] The present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a power distribution method in dual-motor master-slave control, comprising the following steps:

[0008] Select the load gear and two drive gears based on the actual load working condition requirements, and obtain the overlap of the gear pair formed by the drive gear and the load gear according to the gear parameters of the two gears;

[0009] Based on the overlap of the gear pair, the proportion of single-tooth meshing and double-tooth meshing of the driving gear in a meshing cycle is determined, and the initial assembly angle difference of the two driving gears is obtained according to the proportion; the initial positions of the two driving gears are assembled according to the initial assembly angle difference;

[0010] A meshing cycle is divided into multiple stages according to the meshing state of the two driving gears after assembly. There are two meshing states: the first state is that one driving gear is in single-tooth meshing and the other driving gear is in double-tooth meshing; the second state is that both driving gears are in double-tooth meshing.

[0011] A master motor and a slave motor are used to drive the two assembled drive gears respectively, wherein the driving mode of the master motor is a speed control mode, and the driving mode of the slave motor is a torque control mode;

[0012] The rotation speed of the main motor is set according to the actual load conditions, and the running time of each stage is obtained according to the rotation speed of the main motor and the overlap of the gear pair; the output torque function of the slave motor within one meshing cycle is obtained based on the running time of each stage and the stress change characteristics of single-tooth meshing and double-tooth meshing; the power of the main motor and the slave motor is dynamically allocated according to the output torque function of the slave motor in each stage.

[0013] Preferably, the step of obtaining the initial assembly angle difference of the two driving gears according to the proportions specifically includes the following steps:

[0014] When the overlap is between 1.5 and 2, the single tooth meshing accounts for 2-ε in the entire meshing cycle, and the double tooth meshing accounts for ε-1, where ε is the overlap;

[0015] The initial assembly angle difference of the two driving gears is set based on the proportion, and the initial assembly angle difference is specifically as follows:

[0016] Δθ=θ0+θ n ;

[0017] in,

[0018]

[0019] Where Δθ is the initial assembly angle difference, θ0 is the angle to avoid overlap between the two drive gears, and θ n To avoid the angle of single tooth meshing of two driving gears at the same time, C is a positive integer, θ n_min and θ n_max is θ n The maximum and minimum values of r a1 is the radius of the tooth top circle of the driving gear, a is the center distance between the driving gear and the load gear, and z2 is the number of teeth of the load gear.

[0020] Preferably, the meshing state of the two drive gears after assembly divides a meshing cycle into multiple stages, wherein the multiple stages include a first stage, a second stage, a third stage and a fourth stage, and the two drive gears are defined as a main drive gear and a slave drive gear. In the first stage, the main drive gear is single-tooth meshing, and the slave drive gear is double-tooth meshing; in the second stage, the main drive gear is double-tooth meshing, and the slave drive gear is double-tooth meshing; in the third stage, the main drive gear is double-tooth meshing, and the slave drive gear is single-tooth meshing; in the fourth stage, the main drive gear is double-tooth meshing, and the slave drive gear is double-tooth meshing.

[0021] Preferably, the running time of each stage is obtained according to the rotation speed of the main motor and the overlap of the gear pair. The running time of each stage is specifically as follows:

[0022]

[0023] Where, T1 is the running time of the first stage, T2 is the running time of the second stage, T3 is the running time of the third stage, T4 is the running time of the fourth stage, z1 is the number of teeth of the driving gear, ω 从 is the rotation speed of the slave motor, which is the same as the rotation speed of the master motor.

[0024] Preferably, the output torque function of the slave motor in each stage is obtained according to the control time of each stage and the stress change characteristics of single-tooth meshing and double-tooth meshing. The output torque function of the slave motor in each stage is specifically as follows:

[0025]

[0026] f(t)=f(t+T);

[0027] T=T1+T2+T3+T4

[0028] Where, τ 从 (t) is the output torque function, f(t-t0) is a periodic function starting from the initial time t0, with a period of T and a maximum amplitude of 1, and ρ is the output torque amplitude of the double-tooth meshing gear in the first or third stage and the total output torque τ 总 The ratio is less than 1 and greater than 0.5.

[0029] Preferably, the dynamic distribution of the power of the master motor and the slave motor according to the output torque function of the slave motor in each stage specifically includes the following steps:

[0030] Obtain the power of the slave motor according to the output torque function and the rotation speed of the slave motor at each stage;

[0031] Obtain the total power of the load, and subtract the total power of the load from the slave motor power to obtain the power of the master motor.

[0032] Preferably, the step of obtaining the degree of contact of the gear pair formed by the driving gear and the load gear according to the gear parameters of the driving gear and the load gear comprises the following steps:

[0033] Obtaining gear parameters of the load gear and two driving gears, and obtaining corresponding addendum circle radius, base circle radius, and addendum circle pressure angle based on the gear parameters; the load gear and the two driving gears are all involute gears;

[0034] The contact ratio of the gear pair is obtained based on the tooth tip circle radius, base circle radius and tooth tip circle pressure angle.

[0035] In a second aspect, the present invention provides a power distribution system for dual-motor master-slave control, comprising:

[0036] A selection module is used to select a load gear and two drive gears based on operating parameters of an actual load condition, and obtain the degree of contact of a gear pair formed by the drive gear and the load gear according to the gear parameters of the drive gear and the load gear;

[0037] An assembly module is used to determine the proportion of single-tooth meshing and double-tooth meshing of the driving gear in a meshing cycle based on the overlap of the gear pair, obtain the initial assembly angle difference of the two driving gears based on the proportion, and assemble the initial positions of the two driving gears based on the initial assembly angle difference;

[0038] A division module is used to divide a meshing cycle into multiple stages according to the meshing state of the two driving gears after assembly; wherein the meshing states include two states, a first state in which one driving gear is in single-tooth meshing and the other driving gear is in double-tooth meshing; a second state in which both driving gears are in double-tooth meshing;

[0039] A drive module, configured to drive the two assembled drive gears using a master motor and a slave motor, wherein the master motor is driven in a speed control mode and the slave motor is driven in a torque control mode;

[0040] The distribution module is used to set the rotation speed of the main motor according to the actual load conditions, obtain the operating time of each stage according to the rotation speed of the main motor and the overlap of the gear pair; obtain the output torque function of the slave motor within one meshing cycle according to the operating time of each stage and the stress change characteristics of single-tooth meshing and double-tooth meshing; and dynamically distribute the power of the main motor and the slave motor according to the output torque function of the slave motor in each stage.

[0041] Compared with the prior art, the at least one technical solution adopted by the present invention can achieve the following beneficial effects:

[0042] The present invention first determines the proportion of single-tooth and double-tooth meshing between the load and drive gears in the entire meshing cycle based on the contact ratio of their gear pairs. The initial assembly angle difference between the two drive gears is then determined based on this proportion. By adjusting the initial relative positions of the gears, the two drive gears are prevented from simultaneously engaging in single-tooth meshing during assembly, reducing the stress of single-tooth meshing and achieving more balanced load distribution between the two drive gear systems.

[0043] In order to avoid the situation where the two drive gears are in a state of single tooth meshing at the same time during operation, and to further reduce the stress during single tooth meshing and extend the life of the drive gears, the present invention adopts a dual-motor master-slave control strategy in which the main motor is in speed control mode and the slave motor is in torque control mode to drive the two drive gears, and divides the meshing cycle of the two drive gears into multiple stages. By controlling the output torque of the slave motor in each stage, the power of the main motor and the slave motor is dynamically distributed. Specifically, the present invention gives the rotation speed of the drive gear corresponding to the main motor through the speed control mode, and divides the meshing cycle into multiple stages in combination with the overlap of the gear pair, and gives the torque of the drive gear corresponding to the slave motor in combination with the single and double tooth meshing characteristics, so as to achieve dynamic adjustment of the power of the two drive gears, thereby achieving reasonable power distribution between the two gear systems, minimizing the problem of high stress caused by single tooth meshing, thereby extending the service life of the drive system, and at the same time improving the load adaptability of the system under different working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. 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 any creative work.

[0045] Figure 1 This is a flow chart of a power distribution method in dual-motor master-slave control according to the present invention;

[0046] Figure 2 is a schematic diagram of the initial assembly angle difference of the present invention;

[0047] Figure 3 A master-slave control strategy diagram for a speed-torque control mode in a dual-drive system of the present invention;

[0048] Figure 4 Schematic diagram of tracking target output torque in the torque control mode of the slave motor of the present invention;

[0049] Figure 5 A three-dimensional model diagram of the drum filter gear drive system of the present invention;

[0050] Figure 6 Schematic diagram of the difference in single-tooth and double-tooth meshing areas of the two driving gears of the present invention;

[0051] Figure 7 This is a field application diagram of the present invention in a drum filter gear drive system. DETAILED DESCRIPTION

[0052] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only 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 making creative efforts are within the scope of protection of the present invention.

[0053] To improve the stability and service life of multi-gear systems, existing technologies use a master-slave control scheme in multi-gear drive systems. The master motor controls the target speed, and the slave motor synchronously tracks the master motor through torque control to achieve load balance. In this scheme, the speed control of the master motor and the torque control of the slave motor are coordinated to achieve motor synchronization through torque following. However, this method does not analyze from the perspective of improving gear life, and fails to fully consider the impact of different gear meshing states (single-tooth meshing and double-tooth meshing) on load distribution. As a result, the fatigue life of the gears has not been significantly improved under high loads or extreme working conditions.

[0054] To solve the above problems, refer to Figure 1 The present invention provides a power distribution method in dual-motor master-slave control, which specifically includes the following steps:

[0055] Step 1: According to the load torque τ 负载需求 , load power p负载 and load speed ω 负载需求 Choose the appropriate size of involute spur gears based on the working conditions, so that two small drive gears drive the large load gear. Compared with circular arc and cycloid tooth profiles, involute gear tooth profiles are more suitable for large load transmission environments, and have a constant transmission ratio, which makes the transmission more stable.

[0056] Step 2: Calculate the addendum radius r of the drive gear and the load gear based on the number of teeth z1 of the drive gear, the number of teeth z2 of the load gear, and the module m. a , base circle radius r b and the tooth tip pressure angle α a :

[0057]

[0058] α a =arccos(r a / r b ).

[0059] The contact ratio formula is widely used in gear design. It refers to the average number of tooth pairs in contact on a gear tooth surface during one meshing cycle. The contact ratio of a gear pair (meshing the drive gear and the load gear) is calculated using the above results:

[0060] ε=[z1(tanα a1 -tanα)+z2(tanα a2 -tanα)] / (2π);

[0061] Where, α is the pressure angle (usually the standard value is 20°) a1 and α a2 are the addendum pressure angles of the drive and load gears, respectively. When the gear pair's contact ratio ε is mostly between 1.5 and 2, the meshing process involves both double-tooth and single-tooth meshing. Single-tooth meshing accounts for 2-ε of the entire meshing cycle, while double-tooth meshing accounts for ε-1.

[0062] Reference Figure 2 , so that the two driving gears are in different meshing states, and the initial assembly angle difference is calculated. The initial assembly angle difference consists of two parts. The initial angle should also consider its own size to avoid overlap and avoid the two gears being in single-tooth meshing at the same time, where 1.5≤ε≤2.

[0063] The initial assembly gear angle difference of the two driving gears is set based on the proportion. The initial assembly angle difference is as follows:

[0064] Δθ=θ0+θ n ;

[0065]

[0066] Where Δθ is the initial assembly angle difference, which consists of two parts. The first part θ0 is the angle to avoid the overlap of the two drive gears, and the second part θ n To avoid the angle of single tooth meshing of two driving gears at the same time; C is a positive integer, and θ n_min and θ n_max is θ n The maximum and minimum values of Define n as θ n and θ n_min The ratio of r a1 is the radius of the tooth top circle of the driving gear, a is the center distance between the driving gear and the load gear, and z2 is the number of teeth of the load gear.

[0067] At this time, the two driving gear systems are divided into two meshing situations. The first situation is that one gear is in single-tooth meshing and the other gear is in double-tooth meshing; the second situation is that both gears are in double-tooth meshing. The two driving gears (i.e. gear 1 and gear 2) are assembled according to the initial assembly angle difference θ. When the gear angle difference n is greater than 1, see Figure 6 , its meshing cycle can be divided into four stages: the first stage: {gear 1 (single tooth meshing), gear 2 (double tooth meshing)}, the second stage: {gear 1 (double tooth meshing), gear 2 (double tooth meshing)}, the third stage: {gear 1 (double tooth meshing), gear 2 (single tooth meshing)}, the fourth stage: {gear 1 (double tooth meshing), gear 2 (double tooth meshing)}.

[0068] Reference Figure 3 In the dual-motor drive, the control mode of the motor connected to the drive gear 1 is set to speed control mode in the servo drive. This motor is regarded as the main motor, and its speed tracking target is ω 主 ,ω 主 The target required speed of the loaded gear condition multiplied by the gear ratio iω 负载需求 The other motor is regarded as a slave motor, and the rotation speed of the slave motor is the same as that of the master motor. It is set to torque / current tracking mode, and the target τ is tracked by adjusting the torque / current. 从 To adjust the power distribution of the slave motor. Without considering the power loss during the transmission process, the power distribution of the main drive gear satisfies:

[0069]

[0070] Among them, the main drive gear speed ω 主 Set to ω 主 =iω 负载需求 , the speed of the driving gear due to the meshing relationship with the load gear is ω 从 =iω负载需求 =ω 主 , the total power of the load P 负载 P 负载 =ω 负载需求 τ 负载需求 , τ 负载需求 is the target required load torque of the load gear working condition, the main motor power P 主 and slave motor P 从 The sum of the powers is the total power P of the load 负载 , the speed of the main motor ω 主 According to the speed condition setting, the power distribution at this time is related to the torque of the master and slave motors, and the target output torque τ of the slave motor is 从 and the target speed of the main motor ω 主 Can be set via host motion controller or PLC, see Figure 3 Dynamically adjust the slave motor torque τ on the host computer 从 , can achieve the adjustment of τ 主 The purpose is to realize the power distribution of the master and slave motors.

[0071] In order to improve the service life of the gears, the present invention starts from reducing the stress on the gears and designs the following control strategy based on the four different stages in the process of two gear meshing.

[0072] After the calculated angle difference is assembled, the main motor is connected to the main drive gear, and the slave motor is connected to the slave drive gear. The rotation speed of the slave motor ω 从 The time of each stage is calculated based on the gear pair contact ratio ε:

[0073]

[0074] Where, T1 is the time of the first stage, T2 is the time of the second stage, T3 is the time of the third stage, T4 is the time of the fourth stage, and the time unit is seconds (s); z1 is the number of teeth of the driving gear, ω 从 The rotation speed of the slave motor is the same as the rotation speed of the master motor, and the unit is revolutions per minute (r / min).

[0075] The two driving gears can be divided into four stages based on different meshing states of the same period, namely the first and third stages where one gear is single-tooth meshing and the other gear is double-tooth meshing, and the second and fourth stages where both driving gears are double-tooth meshing. The output torque of the slave driving gear needs to be adjusted according to different meshing states. Since the directions of the contact force and bending force are constantly changing during the meshing process, the equivalent stresses in the single-tooth meshing stage and the double-tooth meshing stage are not simply in a fixed proportional relationship. A transformed torque function is required to distribute the torque between the master and slave driving gears. The peak value of the function exists in the first and third stages. The output torque τ of the slave gear 从 for:

[0076]

[0077] f(t)=f(t+T);

[0078] Where f(t-t0) is a periodic function starting at t0 and with a period of T, f(t)∈[-1,1]; the function can be a triangular wave, trapezoidal wave, sine function, etc.; T=T1+T2+T3+T4; ρ is the output torque amplitude of the first / third stage double-tooth meshing gear (master gear or slave gear) and the total output torque τ 总 The ratio is less than 1 and greater than 0.5. t0 can be a certain time point within a cycle. When one of the driving gears enters single-tooth meshing, its allocated output torque is gradually reduced. Strain gauges can be attached to the gears, and other high-precision visual or laser sensors can be used to calibrate the position angles at the beginning of the first and third stages, and then calculate t0. If half of the fourth stage time is used as the initial time point t0, an example of using a sine wave or a triangle wave as the periodic function of f(t) is as follows. Figure 4 As shown. ρ has a maximum value ρ max . This system is considered as a second-order system for dynamic analysis. It is not limited to this dynamic analysis method and can be calculated as ρ max See the following formula:

[0079]

[0080] Where, J 主 、J 从 and J 负 Represents the moment of inertia of the main drive gear, the slave drive gear and the load gear, b 主 、b 从 and b 负 Represent the damping coefficients of the main drive gear, the slave drive gear and the load gear, k 主 、k 从 and k 负 Respectively represent the stiffness coefficients of the main drive gear, the slave drive gear and the load gear, τ 主负 represents the torque applied by the load gear to the drive gear, τ 从负 The torque applied by the load gear to the driven gear, τ 从 and τ 负 They represent the torque of the slave drive gear and the load gear respectively, and i is the transmission ratio between the drive gear and the load gear. Considering the main motor is controlled in speed control mode, its output torque is K pv K Iv are the speed loop and current loop gain coefficients in the system respectively, and Represent the reference angular velocity of the main motor and the current angular velocity of the system respectively. For the gear system, since there is basically no elastic deformation, the rigid part is ignored. After the speed of the system tends to be stable, θ and is 0, we can deduce τ 从 The expression:

[0081]

[0082] Which must meet At this time, the system will follow the speed of the main drive gear. If the output torque from the drive system is too large, The speed of the two drive gears is not synchronized. Due to the characteristics of the motor speed control mode, the main motor will do negative work, forcing the speed of the slave drive gear to be reduced to the same speed as the main drive gear. Select the critical value When τ 从 is the maximum value τ 从max , at this time ρ also has a maximum value The parameters of this kinetic model can be obtained through parameter identification method, and finally ρ can be calculated. max If the entire meshing cycle starts from the middle of the fourth stage, the target output torque is tracked from the motor torque control mode. Figure 4 , where the load power from the motor satisfies p 从 =ω 从 τ 从 , the main motor speed tracking target is always ω 主 =iω 负载需求 , where ω 从 =ω 主 =iω 负载需求 Its power distribution satisfies P 主 =P 负载 -P 从 ,As the target tracking torque of the slave motor changes, the master and slave motors complete ,dynamic power distribution after the optimized setting based on the meshing ,characteristics.

[0083] The present invention fully considers the single-tooth and double-tooth meshing characteristics of gears, and by optimizing the assembly position of the driving gear, effectively avoids the adverse situation that the two driving gears are in single-tooth meshing at the same time during the meshing process, thereby significantly improving the stability and reliability of the drive system.

[0084] The present invention determines the initial assembly conditions of a gear system based on the geometric parameters and meshing characteristics of the gears. In actual production, by adjusting the initial relative positions of the gears, the two drive gears are prevented from being in single-tooth meshing at the same time, reducing the stress of single-tooth meshing and achieving more optimal load distribution between the two drive gear systems. Especially under high-load and high-power operating conditions, optimizing assembly conditions can effectively reduce maximum gear stress and reduce gear wear, thereby extending the gear service life and improving the overall reliability of the system.

[0085] In the two drive gear systems, the master-slave control strategy adopted by the present invention is relatively simple to implement and has high practicality. The speed control mode is used to give the rotation speed of the speed gear, the torque control mode is used to give the torque of the torque gear, and the input torque of the torque gear is dynamically adjusted in combination with the single and double tooth meshing characteristics, thereby achieving a reasonable distribution of power between the two gear systems. This control method can effectively avoid the situation where the single tooth meshing stress is large by accurately adjusting the torque distribution, and can reduce the fatigue loss of the gear and extend the service life of the gear. The control strategy is simple to operate, easy to implement, and has strong adaptability. It can flexibly adjust the load distribution not only according to the single and double tooth meshing characteristics, but also according to the actual working environment. It is widely used in gear drive systems with various complex working conditions, such as drum filter drive systems (refer to Figure 5 and Figure 7 ), shield machine cutter head drive system, etc., with high engineering application value.

[0086] This invention proposes a rule for the assembly angle difference of the dual drive gears in a two-gear drive system. When the two drive gears are in different relative assembly positions, they will be in different initial meshing states. This rule effectively prevents the two drive gears from being in single-tooth meshing at the same time during actual operation, thereby ensuring smooth system operation and improving transmission efficiency and reliability.

[0087] Based on the characteristics of single and double tooth meshing, this paper proposes a speed-torque master-slave control power dynamic distribution strategy. Dynamically adjusting the power distribution ratio based on the gear meshing state minimizes the high stress caused by single tooth meshing, thereby extending the service life of the drive system. It also improves the system's load adaptability under different operating conditions.

[0088] In the drum filter power system, two driving gear systems are used. By applying this method, the service life of the driving gears can be effectively extended, so that the driving gears can reach the major overhaul period of the drum filter drive system.

[0089] Based on the same concept, the present invention also provides a power distribution system in dual-motor master-slave control, including a selection module, an assembly module, a division module, a drive module and a distribution module.

[0090] The selection module is used to select the load gear and two driving gears based on the operating parameters of the actual load condition, and obtain the overlap of the gear pair formed by the driving gear and the load gear according to the gear parameters of the driving gear and the load gear.

[0091] The assembly module is used to determine the proportion of single-tooth meshing and double-tooth meshing of the driving gear in a meshing cycle based on the overlap of the gear pair, and obtain the initial assembly angle difference of the two driving gears according to the proportion; and assemble the initial positions of the two driving gears according to the initial assembly angle difference.

[0092] The division module is used to divide a meshing cycle into multiple stages according to the meshing state of the two driving gears after assembly; wherein, the meshing state includes two kinds, the first state is that one driving gear is in single-tooth meshing and the other driving gear is in double-tooth meshing; the second state is that both driving gears are in double-tooth meshing.

[0093] The driving module is used to drive the two assembled driving gears using a master motor and a slave motor respectively, wherein the driving mode of the master motor is a speed control mode, and the driving mode of the slave motor is a torque control mode.

[0094] The distribution module is used to set the rotation speed of the main motor according to the actual load conditions, and obtain the running time of each stage according to the rotation speed of the main motor and the overlap of the gear pair; obtain the output torque function of the slave motor within a meshing cycle according to the running time of each stage and the stress change characteristics of single-tooth meshing and double-tooth meshing; and dynamically distribute the power of the main motor and the slave motor according to the output torque function of the slave motor in each stage.

[0095] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0096] Obviously, those skilled in the art may make various modifications and variations to the present invention without departing from the spirit and scope of the present invention. Thus, if such modifications and variations fall within the scope of the claims and their equivalents, the present invention is intended to include such modifications and variations.

Claims

1. A power distribution method in dual motor master-slave control, characterized in that: The following steps are involved: Select the load gear and two drive gears based on the actual load working condition requirements, and obtain the overlap of the gear pair formed by the drive gear and the load gear according to the gear parameters of the two gears; Based on the overlap of the gear pair, the ratio of single-tooth meshing and double-tooth meshing of the driving gear in a meshing cycle is determined, and the initial assembly angle difference of the two driving gears is obtained according to the ratio; Assemble the initial positions of the two driving gears according to the initial assembly angle difference; A meshing cycle is divided into multiple stages according to the meshing state of the two driving gears after assembly. There are two meshing states: the first state is that one driving gear is in single-tooth meshing and the other driving gear is in double-tooth meshing; the second state is that both driving gears are in double-tooth meshing. A master motor and a slave motor are used to drive the two assembled drive gears respectively, wherein the driving mode of the master motor is a speed control mode, and the driving mode of the slave motor is a torque control mode; The rotation speed of the main motor is set according to the actual load conditions, and the running time of each stage is obtained according to the rotation speed of the main motor and the overlap of the gear pair; the output torque function of the slave motor within one meshing cycle is obtained based on the running time of each stage and the stress change characteristics of single-tooth meshing and double-tooth meshing; the power of the main motor and the slave motor is dynamically allocated according to the output torque function of the slave motor in each stage.

2. The power distribution method in dual-motor master-slave control according to claim 1, characterized in that: The method of obtaining the initial assembly angle difference between the two driving gears according to the proportion situation specifically includes the following steps: When the overlap is between 1.5 and 2, the single tooth meshing accounts for 2-ε in the entire meshing cycle, and the double tooth meshing accounts for ε-1, where ε is the overlap; The initial assembly angle difference of the two driving gears is set based on the proportion, and the initial assembly angle difference is specifically as follows: Δθ=θ0+θ n ; in, Where Δθ is the initial assembly angle difference, θ0 is the angle to avoid overlap between the two drive gears, and θ n To avoid the angle of single tooth meshing of two driving gears at the same time, C is a positive integer, θ n_min and θ n_max is θ n The maximum and minimum values of r a1 is the radius of the tooth top circle of the driving gear, a is the center distance between the driving gear and the load gear, and z2 is the number of teeth of the load gear.

3. The power distribution method in dual-motor master-slave control according to claim 2, characterized in that: The meshing state of the two drive gears after assembly is used to divide a meshing cycle into multiple stages, wherein the multiple stages include a first stage, a second stage, a third stage and a fourth stage, and the two drive gears are defined as a main drive gear and a slave drive gear. In the first stage, the main drive gear is single-tooth meshing and the slave drive gear is double-tooth meshing; in the second stage, the main drive gear is double-tooth meshing and the slave drive gear is double-tooth meshing; in the third stage, the main drive gear is double-tooth meshing and the slave drive gear is single-tooth meshing; in the fourth stage, the main drive gear is double-tooth meshing and the slave drive gear is double-tooth meshing.

4. The power distribution method in dual-motor master-slave control according to claim 3, characterized in that: The running time of each stage is obtained according to the rotation speed of the main motor and the overlap of the gear pair. The running time of each stage is specifically as follows: Where, T1 is the running time of the first stage, T2 is the running time of the second stage, T3 is the running time of the third stage, T4 is the running time of the fourth stage, z1 is the number of teeth of the driving gear, ω 从 is the rotation speed of the slave motor, which is the same as the rotation speed of the master motor.

5. The power distribution method in dual-motor master-slave control according to claim 4, characterized in that: The output torque function of the slave motor in each stage is obtained according to the control time of each stage and the stress change characteristics of single-tooth meshing and double-tooth meshing. The output torque function of the slave motor in each stage is specifically as follows: f(t)=f(t+T); T=T1+T2+T3+T4; Where, τ 从 (t) is the output torque function, f(t-t0) is a periodic function starting from the initial time t0, with a period of T and a maximum amplitude of 1, and ρ is the output torque amplitude of the double-tooth meshing gear in the first or third stage and the total output torque τ 总 The ratio is less than 1 and greater than 0.

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6. The power distribution method in dual-motor master-slave control according to claim 1, characterized in that: The dynamic distribution of the power of the master motor and the slave motor according to the output torque function of the slave motor in each stage specifically includes the following steps: Obtain the power of the slave motor according to the output torque function and the rotation speed of the slave motor at each stage; Obtain the total power of the load, and subtract the total power of the load from the slave motor power to obtain the power of the master motor.

7. The power distribution method in dual-motor master-slave control according to claim 1, characterized in that: The step of obtaining the contact ratio of the gear pair formed by the driving gear and the load gear according to the gear parameters of the driving gear and the load gear comprises the following steps: Obtaining gear parameters of the load gear and two driving gears, and obtaining corresponding addendum circle radius, base circle radius, and addendum circle pressure angle based on the gear parameters; the load gear and the two driving gears are all involute gears; The contact ratio of the gear pair is obtained based on the tooth tip circle radius, base circle radius and tooth tip circle pressure angle.

8. A power distribution system in dual motor master-slave control, characterized in that: include: A selection module is used to select a load gear and two drive gears based on operating parameters of an actual load condition, and obtain the degree of contact of a gear pair formed by the drive gear and the load gear according to the gear parameters of the drive gear and the load gear; An assembly module is used to determine the proportion of single-tooth meshing and double-tooth meshing of the driving gear in a meshing cycle based on the overlap of the gear pair, and obtain the initial assembly angle difference between the two driving gears based on the proportion; Assemble the initial positions of the two driving gears according to the initial assembly angle difference; A division module is used to divide a meshing cycle into multiple stages according to the meshing state of the two driving gears after assembly; wherein the meshing states include two states, a first state in which one driving gear is in single-tooth meshing and the other driving gear is in double-tooth meshing; a second state in which both driving gears are in double-tooth meshing; A drive module, configured to drive the two assembled drive gears using a master motor and a slave motor, wherein the master motor is driven in a speed control mode and the slave motor is driven in a torque control mode; The distribution module is used to set the rotation speed of the main motor according to the actual load conditions, obtain the operating time of each stage according to the rotation speed of the main motor and the overlap of the gear pair; obtain the output torque function of the slave motor within one meshing cycle according to the operating time of each stage and the stress change characteristics of single-tooth meshing and double-tooth meshing; and dynamically distribute the power of the main motor and the slave motor according to the output torque function of the slave motor in each stage.

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