Multi-rotor transmission control method and multi-rotor transmission control system

Abstract

The invention discloses a multi-rotor transmission control method and a multi-rotor transmission control system, and the method achieves the autonomous cascade control between different drivers corresponding to different linear motor modules when rotors cross the different linear motor modules, and greatly reduces the workload of an upper controller. The upper controller does not need to carry out real-time control scheduling on all the drivers, and only needs to issue a high-level control instruction, so that the complexity and cost of system development are reduced. Data interaction and control cooperation are carried out among the drivers through the special inter-stage communication bus, the bus communication bottleneck is avoided, and the communication real-time performance of the system is improved. Therefore, the rotor can stably and continuously move between the linear motor modules, the problems of unstable thrust and speed fluctuation when the rotor crosses the joint of the linear motor modules in the prior art are solved, and the control performance and the operation reliability of the system are remarkably improved.

Description

Technical Field

[0001] The present application relates to the technical field of transmission system control, and in particular to a multi-motor transmission control method and a multi-motor transmission control system. Background Art

[0002] As the application of assembly line operation on production and assembly lines becomes more and more important, the multi-motor flexible production transmission line has become an important production transmission line on production and assembly lines. The multi-motor flexible production transmission line adopts multi-motor control technology, which realizes the continuous operation of the mover on the cascade guide rail through the control cascade of multiple linear motor modules. Among them, each linear motor module is equipped with a driver, a linear motor and a linear encoder, and is mainly used in industrial transmission production lines. Compared with the existing belt transmission technology, it has the advantages of high transmission speed, good positioning performance, high reliability and flexible functions.

[0003] The multi-motor control technology is achieved by the host controller controlling and scheduling multiple drives and their supporting linear motor modules through a communication bus. One control scheme of the host controller for multiple drives and their supporting linear motor modules is: the position control loop is controlled by the host controller, and the speed loop and current loop are controlled by the drive; another control scheme of the host controller for multiple drives and their supporting linear motor modules is: the position control loop and speed loop are controlled by the host controller, and the current loop is controlled by the drive.

[0004] In the prior art, a single driver can only realize the control of the mover on the linear motor module connected to the driver. When the mover spans across two linear motor modules, the two linear motor modules will independently control the mover and cause conflicts. When the mover spans across the connection between the two linear motor modules, it will cause problems such as unstable mover thrust and speed fluctuations, affecting the reliability of the use of the multi-motor flexible production transmission line. Summary of the invention

[0005] To this end, the present application provides a control method and system for a multi-motor transmission system to solve the problem in the prior art that when the mover crosses the connection between two linear motor modules, the mover thrust is unstable and the speed fluctuates.

[0006] In order to achieve the above objectives, this application provides the following technical solutions:

[0007] In a first aspect, a control method for a multi-motor transmission system is characterized in that it is applied to a multi-motor transmission system, wherein the multi-motor transmission system comprises an upper controller, M drivers and M linear motor modules; the M drivers correspond one to one to the M linear motor modules, the M drivers are cascaded in series, and two adjacent drivers among the M drivers are connected through an inter-stage communication bus; the multiple slaves are also connected to the host through a first communication bus respectively; wherein M is a positive integer, and M≥2;

[0008] The method comprises:

[0009] When the mover moves from the N-1th linear motor module to the N-1th linear motor module and the mover is located before the first preset position, the position adjustment of the N-1th driver corresponding to the N-1th linear motor module, the speed adjustment of the N-1th driver and the current adjustment of the N-1th driver are all effective; wherein N is a positive integer, and 1<N≤M, and the N-1th linear motor module is adjacent to the N-1th linear motor module along the series cascade direction;

[0010] Generate a first current instruction and a second current instruction through the N-1th driver; wherein the first current instruction is the current instruction of the N-1th driver, and the second current instruction is the current instruction of the Nth driver corresponding to the Nth linear motor module;

[0011] When the mover is located after the first preset position and before the second preset position, the N-1th driver is controlled to send a main control instruction to the Nth driver through the inter-stage communication bus, and the position adjustment of the N-1th driver and the speed adjustment of the N-1th driver are controlled to fail;

[0012] After the Nth driver receives the main control instruction sent by the N-1th driver, the position adjustment of the Nth driver and the speed adjustment of the Nth driver are controlled to be effective, and a third current instruction and a fourth current instruction are generated by the Nth driver; wherein the third current instruction is the current instruction of the Nth driver, and the fourth current instruction is the current instruction of the N-1th driver;

[0013] When the mover is located behind the second preset position, a fifth current instruction is generated by the Nth driver, so that the Nth driver controls the mover based on the fifth current instruction; wherein the fifth current instruction is the current instruction of the Nth driver.

[0014] In a second aspect, a multi-motor transmission system is characterized in that the system includes a host controller, M drivers and M linear motor modules;

[0015] The M drivers correspond to the M linear motor modules one by one, the M drivers are cascaded in series, and two adjacent drivers among the M drivers are connected via an inter-stage communication bus; the multiple slaves are also connected to the host via a first communication bus respectively; wherein M is a positive integer, and M≥2;

[0016] Each of the drivers is connected to the linear motor module corresponding to the driver via a three-phase power cable and a linear encoder cable;

[0017] Wherein, the upper controller is used to execute the method described in claim 1.

[0018] In the above solution, optionally, each of the drivers includes a global position and speed reconstruction module, a cascade control scheduling module, a cascade position control module, a cascade speed control module and a cascade thrust current control module.

[0019] In the above scheme, optionally, the global position and speed reconstruction module includes a module crossing state determination unit, a global position generation control unit and a global speed generation control unit;

[0020] Among them, the global position and speed reconstruction module is used to calculate the global position P of the mover in the multi-motor transmission system according to the topological station address of the linear motor module corresponding to the driver and the feedback value of the linear encoder; and according to the global position value P of the mover, after differentiation and filtering, the actual speed V of the mover is obtained.

[0021] When the mover is located on a single linear motor module, the global position P1 of the linear motor module is the global position value P of the mover;

[0022] When the mover crosses the connection between two adjacent linear motor modules, the global positions P1 and P2 generated by the two linear motor modules are comprehensively corrected to the global position value P of the mover.

[0023] In the above scheme, optionally, the cascade position control module includes a proportional control unit and a speed feedforward control unit;

[0024] The cascade position control module is used to obtain a position error by subtracting the global position command of the mover issued by the upper controller from the global position value P of the mover, and input the position error into the position controller to generate a speed control command.

[0025] In the above scheme, optionally, the cascade speed control module includes a proportional-integral control unit and an acceleration feedforward control unit;

[0026] The cascade speed control module is used to obtain a speed error by subtracting the speed control instruction issued by the upper controller from the actual speed V of the mover, and input the speed error into the speed controller to generate a current control instruction.

[0027] In the above solution, optionally, the cascade thrust current control module includes a thrust current instruction distribution unit and a compensation control unit;

[0028] Among them, the cascade thrust current control module is used to give the thrust control instructions to the current instructions of the two linear motor modules respectively when the mover crosses the linear motor module, so as to jointly realize the thrust control; and, when the mover is in a single linear motor module, give the thrust control instructions to the current instructions of the current linear motor module.

[0029] In the above solution, optionally, the linear motor module includes a linear motor winding stator and a linear sensor detection unit fixed on the stator.

[0030] Compared with the prior art, this application has at least the following beneficial effects:

[0031] 1. This application significantly reduces the workload of the host controller by realizing autonomous cascade control between different drivers corresponding to different linear motor modules when the mover crosses different linear motor modules. The host controller no longer needs to perform real-time control scheduling of all drivers, but only needs to issue high-level control instructions, thereby reducing the complexity and cost of system development.

[0032] 2. The drivers of this application exchange data and coordinate control through a dedicated inter-stage communication bus, avoiding the bus communication bottleneck and improving the real-time communication of the system. It ensures that the mover moves smoothly and continuously between the linear motor modules, solves the thrust instability and speed fluctuation problems that occur when the mover crosses the connection of the linear motor module in the prior art, and significantly improves the control performance and operation reliability of the system.

[0033] 3. When the mover crosses the connection between two linear motor modules, the N-1th driver and the Nth driver jointly generate current instructions to jointly control the thrust and speed of the mover. By transmitting control instructions and position adjustment in real time, the thrust of the mover is stable and the speed does not fluctuate during the process of crossing the module, ensuring the precise motion trajectory of the mover and improving the positioning performance and reliability of the production line.

[0034] 4. The present invention simplifies the architecture design of the multi-motor transmission system through autonomous cascade control between drivers, which does not require complex upper controller scheduling, greatly reduces the difficulty of designing and implementing the control system, and makes the system architecture more concise and efficient. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more intuitively illustrate the prior art and the present application, exemplary drawings are given below. It should be understood that the specific shapes and structures shown in the drawings should not generally be regarded as limiting conditions for implementing the present application; for example, those skilled in the art are capable of easily making conventional adjustments or further optimizations to the addition / reduction / attribution division, specific shapes, positional relationships, connection methods, dimensional ratios, etc. of certain units (components) based on the technical concepts and exemplary drawings disclosed in the present application.

[0036] Figure 1 A schematic flow chart of a control method for a multi-motor transmission system provided in one embodiment of the present application;

[0037] Figure 2 This is a schematic diagram of a specific flow chart of a multi-actuator driver cascade control method in one embodiment of the present application;

[0038] Figure 3 A block diagram of the module architecture of a control model of a servo drive provided in one embodiment of the present application. DETAILED DESCRIPTION

[0039] The present application is further described below in detail through specific embodiments in conjunction with the accompanying drawings.

[0040] In the description of this application: unless otherwise specified, the meaning of "plurality" is two or more. The terms "first", "second", "third", etc. in this application are intended to distinguish the objects referred to, and do not have special meanings in terms of technical connotations (for example, they should not be understood as emphasizing the importance or order, etc.). Expressions such as "including", "comprising", "having", etc. also mean "not limited to" (certain units, components, materials, steps, etc.).

[0041] The terms such as "upper", "lower", "left", "right", "middle", etc. cited in this application are usually used to indicate the general relative position relationship for the purpose of intuitive understanding by referring to the drawings, and are not absolute limitations on the position relationship in the actual product.

[0042] The multi-motor flexible production transmission line is realized by controlling and cascading multiple linear motor drivers and modules. The actual system composition has dozens to hundreds of motor modules. With the existing multi-motor control technology, a single driver can only realize the control of the driver on the corresponding connected module. When the driver runs continuously between different modules, the upper controller is required to realize real-time control scheduling and position closed-loop control of all drivers on the bus. This method has very high requirements on the upper controller, and due to the large number of driver modules on the bus, the communication interaction speed is generally not high, the communication real-time performance is poor, and the control performance is low. The present invention significantly reduces the functional performance requirements of the upper controller by realizing autonomous cascade control between the driver modules, and can be replaced by a general upper controller, thereby reducing the technical difficulty of system development and significantly improving the driver control performance.

[0043] With the existing multi-motor control technology, a single driver can only realize the control of the motor on the corresponding connected module. When the motor crosses two modules, the two modules will conflict when they independently control the motor. Therefore, when the motor crosses the connection between the two modules, the upper level needs to control and schedule the two drivers of the motor crossing the module to ensure that only one module controls the motor normally at the same time. At this time, since the motor has been partially separated from the module, the thrust of the motor will decrease. In addition, since the position sensor of a single module can only reflect its own local position information, in order to realize the positioning of the motor on the cascade guide rail, the upper level controller needs to reconstruct the global position value of the motor according to the position information fed back by the driver and the cascade position of the driver in the system. Moreover, the position control loop can only be realized in the upper level controller, which is complex to control. Its response speed is affected by the bus communication speed and the total number of online driver modules. Therefore, high requirements are placed on the upper level controller, and the realized control performance is relatively low.

[0044] The purpose of the present invention is to design a method that can avoid the disadvantages of the existing methods, significantly improve the control performance of the mover, and reduce the functional performance requirements of the upper controller.

[0045] Embodiment 1: Figure 1 As shown, a control method for a multi-motor transmission system is provided, characterized in that it is applied to a multi-motor transmission system, wherein the multi-motor transmission system comprises an upper controller, M drivers and M linear motor modules; the M drivers correspond one to one to the M linear motor modules, the M drivers are cascaded in series, and two adjacent drivers among the M drivers are connected through an inter-stage communication bus; the multiple slaves are also respectively connected to the host through a first communication bus; wherein M is a positive integer, and M≥2;

[0046] The method comprises:

[0047] When the mover moves from the N-1th linear motor module to the N-1th linear motor module and the mover is located before the first preset position, the position adjustment of the N-1th driver corresponding to the N-1th linear motor module, the speed adjustment of the N-1th driver and the current adjustment of the N-1th driver are all effective; wherein N is a positive integer, and 1<N≤M, and the N-1th linear motor module is adjacent to the N-1th linear motor module along the series cascade direction;

[0048] Generate a first current instruction and a second current instruction through the N-1th driver; wherein the first current instruction is the current instruction of the N-1th driver, and the second current instruction is the current instruction of the Nth driver corresponding to the Nth linear motor module;

[0049] When the mover is located after the first preset position and before the second preset position, the N-1th driver is controlled to send a main control instruction to the Nth driver through the inter-stage communication bus, and the position adjustment of the N-1th driver and the speed adjustment of the N-1th driver are controlled to fail;

[0050] After the Nth driver receives the main control instruction sent by the N-1th driver, the position adjustment of the Nth driver and the speed adjustment of the Nth driver are controlled to be effective, and a third current instruction and a fourth current instruction are generated by the Nth driver; wherein the third current instruction is the current instruction of the Nth driver, and the fourth current instruction is the current instruction of the N-1th driver;

[0051] When the mover is located behind the second preset position, a fifth current instruction is generated by the Nth driver, so that the Nth driver controls the mover based on the fifth current instruction; wherein the fifth current instruction is the current instruction of the Nth driver.

[0052] This embodiment realizes autonomous cascade control between different drivers corresponding to different linear motor modules when the mover crosses different linear motor modules, which greatly reduces the workload of the upper controller. The upper controller no longer needs to perform real-time control scheduling of all drivers, but only needs to issue high-level control instructions, thereby reducing the complexity and cost of system development.

[0053] In this embodiment, the drivers exchange data and coordinate control via a dedicated inter-stage communication bus, avoiding the bus communication bottleneck and improving the real-time communication of the system. This ensures that the mover moves smoothly and continuously between the linear motor modules, solves the thrust instability and speed fluctuation problems that occur when the mover crosses the connection of the linear motor module in the prior art, and significantly improves the control performance and operation reliability of the system.

[0054] In this embodiment, when the mover crosses the connection between two linear motor modules, the N-1th driver and the Nth driver jointly generate current instructions to jointly control the thrust and speed of the mover. By transmitting control instructions and position adjustment in real time, the thrust of the mover is stable and the speed does not fluctuate during the process of crossing the module, ensuring the precise motion trajectory of the mover and improving the positioning performance and reliability of the production line.

[0055] This embodiment simplifies the architecture design of the multi-motor transmission system through autonomous cascade control between drivers, which does not require complex upper controller scheduling, greatly reduces the difficulty of control system design and implementation, and makes the system architecture more concise and efficient.

[0056] Embodiment 2: A multi-motor transmission system is provided, characterized in that the system comprises an upper controller, M drivers and M linear motor modules;

[0057] The M drivers correspond to the M linear motor modules one by one, the M drivers are cascaded in series, and two adjacent drivers among the M drivers are connected via an inter-stage communication bus; the multiple slaves are also connected to the host via a first communication bus respectively; wherein M is a positive integer, and M≥2;

[0058] Each of the drivers is connected to the linear motor module corresponding to the driver via a three-phase power cable and a linear encoder cable;

[0059] Wherein, the upper controller is used to execute the method described in claim 1.

[0060] In this embodiment, each of the drivers includes a global position and speed reconstruction module, a cascade control scheduling module, a cascade position control module, a cascade speed control module and a cascade thrust current control module.

[0061] In this embodiment, the global position and speed reconstruction module includes a module crossing state determination unit, a global position generation control unit and a global speed generation control unit;

[0062] Among them, the global position and speed reconstruction module is used to calculate the global position P of the mover in the multi-motor transmission system according to the topological station address of the linear motor module corresponding to the driver and the feedback value of the linear encoder; and according to the global position value P of the mover, after differentiation and filtering, the actual speed V of the mover is obtained.

[0063] When the mover is located on a single linear motor module, the global position P1 of the linear motor module is the global position value P of the mover;

[0064] When the mover crosses the connection between two adjacent linear motor modules, the global positions P1 and P2 generated by the two linear motor modules are comprehensively corrected to the global position value P of the mover.

[0065] In this embodiment, the cascade position control module includes a proportional control unit and a speed feedforward control unit;

[0066] The cascade position control module is used to obtain a position error by subtracting the global position command of the mover issued by the upper controller from the global position value P of the mover, and input the position error into the position controller to generate a speed control command.

[0067] In this embodiment, the cascade speed control module includes a proportional-integral control unit and an acceleration feedforward control unit;

[0068] The cascade speed control module is used to obtain a speed error by subtracting the speed control instruction issued by the upper controller from the actual speed V of the mover, and input the speed error into the speed controller to generate a current control instruction.

[0069] In this embodiment, the cascade thrust current control module includes a thrust current instruction distribution unit and a compensation control unit;

[0070] Among them, the cascade thrust current control module is used to give the thrust control instructions to the current instructions of the two linear motor modules respectively when the mover crosses the linear motor module, so as to jointly realize the thrust control; and, when the mover is in a single linear motor module, give the thrust control instructions to the current instructions of the current linear motor module.

[0071] In this embodiment, the linear motor module includes a linear motor winding stator and a linear sensor detection unit fixed on the stator.

[0072] Embodiment 3: A cascade control method for a multi-motor driver, which realizes cascade control based on the driver itself. The module drivers are connected in a cascade form using a dedicated communication interface, and the relevant control data of the movers are exchanged in real time. The master control driver of the module where the mover is located reconstructs the global position and speed of the mover. According to the position instruction issued by the upper controller, the current control instruction is generated through the cascade position control regulator, the cascade speed control regulator, and the cascade thrust current control module. When the mover crosses the connection between two modules, the thrust control instruction is given to the current instructions of the two modules respectively, and the thrust control is realized together; when the mover is in a single module, the thrust control instruction is given to the current instruction of the current module.

[0073] The cascade control scheduling module monitors the position of the actuator fed back by the Nth driver in real time. When it is determined that the actuator is crossing the module connection, the cascade control scheduling module makes a judgment and passes the main driver control token to the next driver in real time, realizing continuous switching of the main control driver between different drivers.

[0074] like Figure 2 As shown, it includes upper controller, servo drive, module, mover, Figure 3 It is the control model of the servo drive, including the global position and speed reconstruction module, cascade control scheduling module, cascade position control module, cascade speed control module, cascade thrust current control module and other structures. P1 and P2 are the positions output by module 1 and module 2 respectively, P is the global position value, V is the actual speed of the mover, Р* is ​​the position command issued by the upper level, V* is the speed command output by the cascade position control module, I* is the current command output by the cascade speed control module, I1* and I2* are the current commands of module 1 and module 2 respectively, and I1 and I2 are the actual values ​​of the output current of module 1 and module 2 respectively.

[0075] This control structure is mainly composed of module crossing state judgment, global position generation control, and global speed generation control. This control structure is mainly composed of proportional integral control and acceleration feedforward control. This control structure is mainly composed of proportional control and speed feedforward control. This control structure is mainly composed of thrust current command distribution and compensation control. This control structure is mainly composed of master drive token transfer control and regulator enable control. The module unit includes a linear motor winding stator and a linear sensor detection unit fixed on the stator. The mover is a motor mover module that runs continuously on the module guide rail. It is equipped with a motor permanent magnet and can realize continuous operation on multiple cascade guide rails.

[0076] The working principle of this embodiment is as follows: module drivers use a dedicated communication interface to exchange relevant control data of the mover in real time, and are connected in a cascade form. Each module driver is connected to the upper and lower drivers at the same time through its own two communication ports.

[0077] The working principle of the global position and speed reconstruction module is to calculate the global position of the mover in the system according to the topological station address of the module and the feedback value of the linear encoder; when the mover is located on a single module, the global position P1 of the module is the global position value P of the mover; when the mover spans the connection between two adjacent modules, the global positions P1 and P2 generated by the two modules are comprehensively corrected to the global position value P of the mover; according to the global position value P of the mover, the actual speed V of the mover is obtained after differentiation and filtering.

[0078] The working principle of the cascade position control module is: the global position command of the mover issued by the upper level is subtracted from the global position P of the mover to obtain the position error, which is input into the position controller to generate a speed control command.

[0079] The working principle of the cascade speed control module is: the speed control command is subtracted from the actual speed V of the mover to obtain the speed error, which is input into the speed controller to generate the current control command.

[0080] The working principle of the cascade thrust current control module is: when the mover crosses the module, the thrust control instruction is given to the current instructions of the two modules respectively, and the thrust control is jointly realized; when the mover is in a single module, the thrust control instruction is given to the current instruction of the current module.

[0081] The working principle of the cascade control scheduling control module is: when the mover starts to cross the module, before running to the appropriate middle position, the position, speed and current regulation of the N-1th driver are valid, and the N-1th driver current instruction is generated, and the Nth driver current instruction is generated at the same time; after running to the appropriate middle position, the N-1th driver transmits the main control signal to the Nth driver, and the position and speed regulation are invalidated. The current instruction is obtained from the lower-level main control driver. After receiving the main control signal, the position and speed regulation of the Nth driver is valid, and the current instruction of the current driver is generated, and the current instruction of the N-1th driver is generated at the same time, until the mover completely runs to the Nth driver, and the N-1th driver stops current output; when the mover is in a single module, the position and speed current regulation of the current driver is valid, and only the current driver current instruction is generated.

[0082] This embodiment designs a driver cascade control method for multiple movers, and the key points include:

[0083] A dedicated communication network is used between multiple mover drivers to realize information data exchange between the upper and lower drivers; according to the topological station address of the driver and the feedback value of the linear encoder, the global position and speed of the mover in the system are observed and reconstructed, and the upper controller does not need to participate in the reconstruction. The state of the master driver can be autonomously transmitted and automatically switched between different drivers, without the need for the upper controller to participate in the scheduling. Through cascaded position, speed, and current control, when the mover crosses the connection between two modules, the two drivers coordinate the output control to ensure that the combined thrust of the mover is continuous and stable, the speed does not fluctuate, and the system runs more smoothly. Due to the lack of communication delay, the position control and speed control cycles are significantly shorter than those of the existing technical solutions, with higher control performance and faster response; when the mover crosses the module connection, the mover output control performance will not decrease, and the mover speed will not fluctuate, which improves the motion smoothness and system stability. This embodiment does not require the upper controller to participate in control scheduling, reduces the controller function performance requirements and development costs, and can be implemented with a general controller.

[0084] The technical features of the above embodiments may be arbitrarily combined (as long as there is no contradiction in the combination of these technical features). To make the description concise, not all possible combinations of the technical features in the above embodiments are described; these embodiments that are not explicitly written should also be considered to be within the scope of this specification.

Claims

1. A control method for a multi-motor transmission system, characterized in that: Applied to a multi-motor transmission system, the multi-motor transmission system comprises an upper controller, M drivers and M linear motor modules; the M drivers correspond one to one to the M linear motor modules, the M drivers are cascaded in series, and two adjacent drivers among the M drivers are connected via an inter-stage communication bus; The plurality of slaves are also connected to the host through the first communication bus respectively; wherein M is a positive integer, and M≥2; The method comprises: When the mover moves from the N-1th linear motor module to the N-1th linear motor module and the mover is located before the first preset position, the position adjustment of the N-1th driver corresponding to the N-1th linear motor module, the speed adjustment of the N-1th driver and the current adjustment of the N-1th driver are all effective; wherein N is a positive integer, and 1<N≤M, and the N-1th linear motor module is adjacent to the N-1th linear motor module along the series cascade direction; Generate a first current instruction and a second current instruction through the N-1th driver; wherein the first current instruction is the current instruction of the N-1th driver, and the second current instruction is the current instruction of the Nth driver corresponding to the Nth linear motor module; When the mover is located after the first preset position and before the second preset position, the N-1th driver is controlled to send a main control instruction to the Nth driver through the inter-stage communication bus, and the position adjustment of the N-1th driver and the speed adjustment of the N-1th driver are controlled to fail; After the Nth driver receives the main control instruction sent by the N-1th driver, the position adjustment of the Nth driver and the speed adjustment of the Nth driver are controlled to be effective, and a third current instruction and a fourth current instruction are generated by the Nth driver; wherein the third current instruction is the current instruction of the Nth driver, and the fourth current instruction is the current instruction of the N-1th driver; When the mover is located behind the second preset position, a fifth current instruction is generated by the Nth driver, so that the Nth driver controls the mover based on the fifth current instruction; wherein the fifth current instruction is the current instruction of the Nth driver.

2. A multi-motor transmission system, characterized in that: The system includes a host controller, M drivers and M linear motor modules; The M drivers correspond to the M linear motor modules one by one, the M drivers are cascaded in series, and two adjacent drivers among the M drivers are connected via an inter-stage communication bus; the multiple slaves are also connected to the host via a first communication bus respectively; wherein M is a positive integer, and M≥2; Each of the drivers is connected to the linear motor module corresponding to the driver via a three-phase power cable and a linear encoder cable; Wherein, the upper controller is used to execute the method described in claim 1.

3. The system according to claim 2, characterized in that Each of the drivers includes a global position and speed reconstruction module, a cascade control scheduling module, a cascade position control module, a cascade speed control module and a cascade thrust current control module.

4. The system according to claim 3, characterized in that The global position and speed reconstruction module includes a module crossing state determination unit, a global position generation control unit and a global speed generation control unit; The global position and speed reconstruction module is used to calculate the global position P of the mover in the multi-motor transmission system according to the topological station address of the linear motor module corresponding to the driver and the feedback value of the linear encoder; and obtain the actual speed V of the mover after differentiation and filtering according to the global position value P of the mover; When the mover is located on a single linear motor module, the global position P1 of the linear motor module is the global position value P of the mover; When the mover crosses the connection between two adjacent linear motor modules, the global positions P1 and P2 generated by the two linear motor modules are comprehensively corrected to the global position value P of the mover.

5. The system according to claim 4, characterized in that The cascade position control module includes a proportional control unit and a speed feedforward control unit; The cascade position control module is used to obtain a position error by subtracting the global position command of the mover issued by the upper controller from the global position value P of the mover, and input the position error into the position controller to generate a speed control command.

6. The system according to claim 3, characterized in that The cascade speed control module includes a proportional-integral control unit and an acceleration feedforward control unit; The cascade speed control module is used to obtain a speed error by subtracting the speed control instruction issued by the upper controller from the actual speed V of the mover, and input the speed error into the speed controller to generate a current control instruction.

7. The system according to claim 3, characterized in that The cascade thrust current control module includes a thrust current instruction distribution unit and a compensation control unit; Among them, the cascade thrust current control module is used to give the thrust control instructions to the current instructions of the two linear motor modules respectively when the mover crosses the linear motor module, so as to jointly realize the thrust control; and, when the mover is in a single linear motor module, give the thrust control instructions to the current instructions of the current linear motor module.

8. The system according to claim 3, characterized in that The linear motor module includes a linear motor winding stator and a linear sensor detection unit fixed on the stator.

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