Multi-axis multi-slave-station industrial control system

Abstract

The invention relates to the technical field of industrial control systems, and discloses a multi-axis multi-slave-station industrial control system, which comprises an upper computer; the master station is communicated with the upper computer through an Ethernet transmission control protocol; a plurality of extended slave stations, each of which is independently connected to the master station and communicates with the master station by using a CANFD communication protocol; wherein the master station and the extension slave station respectively comprise a multi-axis driving unit, and at least the master station comprises an IO control unit, so that the extension slave station can be in communication connection with the master station only through a CANFD transceiver chip. According to the invention, the master station communicates with the upper computer through an Ethernet transmission control protocol, the master station communicates with the slave station through a CANFD protocol, the slave station only needs a single CANFD transceiver chip, and both the master station and the slave station comprise a multi-axis driving unit, so that efficient communication with low cost is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of industrial control systems, and in particular to a multi-axis multi-slave industrial control system. Background Art

[0002] In the field of modern industrial automation, with the increasing complexity and sophistication of production processes, the requirements for industrial control systems continue to rise. Although traditional industrial bus solutions such as EtherCAT and PROFINET have shown certain advantages in some high-end industrial scenarios, their high hardware costs and complex configuration and maintenance processes have greatly limited their popularization and application in the vast number of low-end industrial enterprises, causing many companies to stay away from them. Although CANOPEN, MODBUS and other solutions are relatively low-cost, they have significant shortcomings in communication rate, data processing capabilities and real-time guarantee when dealing with complex working conditions of multi-axis motion control. They cannot meet the stringent requirements of equipment such as CNC machine tools and industrial robots for multi-axis high-precision synchronous motion control and rapid interaction of large amounts of data.

[0003] Nowadays, in the industrial environment of multi-axis and multi-slave stations, each slave station must not only accurately execute complex motion instructions, but also timely feedback rich status information. The existing bus solution is difficult to balance cost and performance, and cannot provide a cost-effective, stable and reliable solution, which seriously restricts the upgrading and development of the industrial automation industry. Therefore, it is necessary to improve the existing technology.

[0004] The above information is presented as background information only to assist with understanding the present disclosure and no determination or admission is made as to whether any of the above may be used as prior art with respect to the present disclosure. Summary of the invention

[0005] The invention provides a multi-axis multi-slave station industrial control system to solve the problems existing in the prior art.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A multi-axis multi-slave industrial control system, comprising:

[0008] Host computer;

[0009] A master station, the master station communicates with the host computer via an Ethernet transmission control protocol;

[0010] A plurality of extended slave stations, each of which is independently connected to a master station and communicates with the master station using a CAN_FD communication protocol;

[0011] The master station and the extended slave station respectively include a multi-axis drive unit, and at least the master station includes an IO control unit, so that the extended slave station can communicate with the master station only by relying on a CAN_FD transceiver chip.

[0012] Optionally, the host computer is an industrial computer, including an API library, and the API library includes a bus control module, a bus status query module, an axis control module, an axis status query module, an I0 analog control module, an I0 analog reading module, a bus configuration module, an axis configuration module and a safety function configuration module.

[0013] Optionally, the frame structure of the CAN_FD protocol communication includes a downlink frame structure for issuing control instructions and an uplink frame structure for bus data feedback.

[0014] Optionally, the downlink frame structure includes an instruction identifier, a slave station number, an axis number within the station, a function number and function data.

[0015] Optionally, the uplink frame includes a bus status and a slave data block, and the slave data block includes a slave status, I0 data, an axis status and axis motion information.

[0016] Optionally, the downlink frame structure further forms a complete frame with a protocol status bit, slave station data set according to the number of slave stations n, and checksum coordination data.

[0017] Optionally, the slave station data is divided into configuration frames, data frames and control frames according to functions;

[0018] The configuration frame includes a slave number bit, an axis number bit and m configuration numbers and configuration data;

[0019] The data frame includes a slave status bit, digital output data, digital input data, and j slave axis data;

[0020] The control frame includes a slave station number bit, k axis number bits, and k instruction numbers and instruction data;

[0021] Among them, n and m are not greater than 8, and j and k are not greater than 6.

[0022] Optionally, the master station sends slave station synchronization frames to extended slave stations No. 1 to n in sequence every p / n time. Upon receiving the synchronization frames, the extended slave stations immediately send local data to the bus and send local data again every p time.

[0023] Optionally, when the master station communicates with the extended slave station, the master station uses time-division multiplexing to complete the data transmission of each extended slave station.

[0024] Optionally, the multiple extended slave stations are connected to the master station via the same twisted shielded pair cable.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The present invention provides a multi-axis multi-slave industrial control system, in which the master station communicates with the host computer through the Ethernet transmission control protocol, the master and slave stations communicate with each other using the CAN_FD protocol and the slave station only needs a single CAN_FD transceiver chip, and both the master station and the slave station contain multi-axis drive units, thereby achieving low-cost and efficient communication.

[0027] The present invention has other features and advantages, which will be apparent from or will be described in detail in the accompanying drawings and the following detailed description incorporated herein, which together serve to explain the specific principles of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] 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.

[0029] Figure 1 It is a structural schematic diagram of a multi-axis multi-slave industrial control system provided by an embodiment of the present invention;

[0030] Figure 2 This is a topological diagram of a multi-axis multi-slave industrial control system provided by an embodiment of the present invention.

[0031] Figure numerals: 10, host computer; 20, master station; 21, Ethernet communication module; 22, first power supply module; 23, first CAN_FD communication module; 24, first multi-axis drive unit; 30, extended slave station; 31, second power supply module; 32, second CAN_FD communication module; 33, second multi-axis drive unit; 40, twisted shielded pair cable. DETAILED DESCRIPTION

[0032] In order to explain in detail the possible application scenarios, technical principles, specific schemes that can be implemented, and the purposes and effects that can be achieved, the following is a detailed description of the specific embodiments listed in conjunction with the accompanying drawings. The embodiments described herein are only used to more clearly illustrate the technical solutions of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0033] Reference to "embodiment" herein means that the specific features, structures or characteristics described in conjunction with the embodiment may be included in at least one embodiment of the present application. The term "embodiment" appearing in various places in the specification does not necessarily refer to the same embodiment, nor does it particularly limit its independence or association with other embodiments. In principle, in the present application, as long as there is no technical contradiction or conflict, the various technical features mentioned in the embodiments can be combined in any way to form a corresponding implementable technical solution.

[0034] Unless otherwise defined, the technical terms used in this document have the same meanings as those generally understood by those skilled in the art to which this application belongs; the use of relevant terms in this document is only for describing specific embodiments and is not intended to limit this application.

[0035] In the description of this application, the term "and / or" is an expression used to describe the logical relationship between objects, indicating that three relationships may exist, for example, A and / or B, which means: A exists, B exists, and A and B exist at the same time. In addition, the character " / " in this article generally indicates that the objects before and after are in an "or" logical relationship.

[0036] In the present application, terms such as “first” and “second” are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship of quantity, priority or sequence between these entities or operations.

[0037] Without further limitations, in this application, the words "include", "comprises", "has" or other similar expressions used in the sentences are intended to cover non-exclusive inclusion. These expressions do not exclude the presence of additional elements in the process, method or product including the elements, so that the process, method or product including a series of elements may include not only those limited elements, but also other elements not explicitly listed, or also include elements inherent to such process, method or product.

[0038] Similar to the understanding in the Examination Guidelines, in this application, expressions such as "greater than", "less than", "exceed" and the like are understood to exclude the number itself; expressions such as "above", "below", "within" and the like are understood to include the number itself. In addition, in the description of the embodiments of this application, "multiple" means more than two (including two), and similar expressions related to "multiple" are also understood in this way, such as "multiple groups", "multiple times", etc., unless otherwise clearly and specifically limited.

[0039] In the description of the embodiments of the present application, space-related expressions used, such as "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "vertical", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicate the orientation or position relationship based on the orientation or position relationship shown in the specific embodiments or drawings, and are only for the convenience of describing the specific embodiments of the present application or facilitating the reader's understanding, and do not indicate or imply that the referred device or component must have a specific position, a specific orientation, or be constructed or operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0040] Unless otherwise expressly specified or limited, in the description of the embodiments of the present application, the terms such as "install", "connect", "connect", "fix", "set", etc. used should be understood in a broad sense. For example, the "connection" can be a fixed connection, a detachable connection, or an integrated setting; it can be a mechanical connection, an electrical connection, or a communication connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. For technicians in the technical field to which the present application belongs, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0041] Please refer to Figure 1 The embodiment of the present invention provides a multi-axis multi-slave industrial control system, including:

[0042] Host computer 10;

[0043] A master station 20, which communicates with the host computer 10 via an Ethernet transmission control protocol;

[0044] A plurality of extended slave stations 30, each extended slave station 30 is independently connected to the master station 20, and communicates with the master station 20 using the CAN_FD communication protocol;

[0045] The master station 20 and the extended slave station 30 respectively include a multi-axis drive unit, and at least the master station 20 includes an IO control unit, so that the extended slave station 30 can communicate with the master station 20 only by relying on a CAN_FD transceiver chip. The IO control unit of the master station 20 is connected to a solenoid valve, a sensor and an indicator light.

[0046] Please refer to Figure 2 Further, the master station 20 includes an Ethernet communication module 21, a first power supply module 22, a first CAN_FD communication module 23 and a first multi-axis drive unit 24; the extended slave station 30 includes a second power supply module 31, a second CAN_FD communication module 32 and a second multi-axis drive unit 33.

[0047] In this embodiment, the master station 20 communicates with the host computer 10 using ETHERNETTCP, no additional hardware is required, and the requirements for the industrial computer are simple. The master station 20 communicates with the slave station using the CAN_FD protocol, which is easy to expand.

[0048] At the same time, multiple extended slave stations 30 are independently connected to the master station 20. Both the master station 20 and the extended slave station 30 have built-in multi-axis drive units, and the master station 20 is additionally equipped with an IO control unit, so that the extended slave station 30 can communicate smoothly with the master station 20 with only one CAN_FD transceiver chip, which greatly simplifies the hardware structure, reduces costs, and effectively solves the problems of existing industrial bus solutions in terms of cost and multi-axis motion control adaptability, meeting the needs of industrial control equipment such as printers and dispensing machines for precise control and signal acquisition of multiple groups of distributed axes and IO. The design of the master and slave stations with multi-axis drive units and IO control units improves system integration, reduces the number of slave stations, and improves communication efficiency.

[0049] In this embodiment, the host computer 10 is an industrial computer, including an API library, which includes a bus control module, a bus status query module, an axis control module, an axis status query module, an I0 analog control module, an I0 analog reading module, a bus configuration module, an axis configuration module and a safety function configuration module.

[0050] It can be understood that when executing industrial control tasks, the bus control module coordinates bus resource allocation based on the system real-time load and task priority, obtains bus status information from the bus status query module, and the axis control module adjusts the axis motion parameters in combination with the feedback from the axis status query module after receiving the bus control module instructions. The I0 analog control module and the reading module collaborate to complete the analog input and output processing, and interact with the bus configuration module and the axis configuration module to realize dynamic setting of system parameters. The safety function configuration module monitors the system operation status in real time to ensure safe operation, and the modules work together through shared memory and event triggering mechanism.

[0051] In this embodiment, the frame structure of the CAN_FD protocol communication includes a downlink frame structure for issuing control instructions and an uplink frame structure for bus data feedback.

[0052] Furthermore, the downlink frame structure includes a command identifier, a slave station number, an axis number within the station, a function number, and function data. It is understandable that in multi-axis motion control, the command identifier is used to distinguish different types of control commands, the slave station number specifies the target slave station, the axis number within the station accurately locates the control axis, the function number determines the specific control function, such as speed setting, position zeroing, etc., and the function data carries the parameter values ​​required to execute the command, and they work together to achieve accurate axis motion control command issuance.

[0053] In this embodiment, the uplink frame includes the bus status and the slave data block, and the slave data block includes the slave status, I0 data, axis status and axis motion information.

[0054] Among them, the slave status reflects the slave connection, operation and abnormal conditions, the I0 data covers the real-time values ​​of digital input and output, the axis status includes the axis power-on, enable, fault and other status information, and the axis motion information records the axis speed, position, acceleration and other dynamic data, providing the host computer 10 and the master station 20 with comprehensive slave and axis operation status feedback for system monitoring and decision-making.

[0055] In this embodiment, the downlink frame structure further adapts to the overall frame structure setting of the CAN_FD communication protocol, and cooperates with the 4-byte protocol status bit, the slave data set according to the number of slaves n, and the 2-byte checksum to form a complete frame.

[0056] The number of slave stations n is determined according to the system scale and control complexity, and n is not greater than 8.

[0057] In this embodiment, slave station data is subdivided into configuration frames, data frames and control frames according to functions.

[0058] Specifically, the configuration frame includes a slave number bit, an axis number bit and m configuration numbers and configuration data, which are used to initialize and adjust the working parameters of the slave and the axis, such as motor drive parameters, sensor calibration values, etc.; m is set according to the functional characteristics and control requirements of the axis, where m is not greater than 8.

[0059] The data frame includes the slave status bit, digital output data, digital input data, and j slave axis data, which is responsible for real-time transmission of the operating status and data information of the slave and axis; j is determined based on the actual number of slave axes and real-time monitoring requirements, where j is not greater than 6.

[0060] The control frame includes the slave number bit, k axis number bits, and k instruction numbers and instruction data to realize the dynamic control instruction transmission for a specific axis. Among them, k is determined according to the number of axes involved in the current control task and the complexity of the instruction, and k is not greater than 6.

[0061] It can be understood that the frame structure of CAN_FD protocol communication is a rule system for data interaction between master and slave stations, including downlink frame structure and uplink frame structure. As a carrier for the release of control instructions, the downlink frame structure accurately carries the control intention of the master station 20 to the slave stations and each axis; the uplink frame structure is responsible for efficient feedback of the bus status and slave station data, ensuring that the master station 20 has real-time knowledge of the system operation status. The two work together to build an orderly and accurate data flow channel to meet the stringent requirements of the multi-axis and multi-slave system for issuing a large number of control instructions and status information feedback under complex working conditions, ensuring the continuity, stability and real-time performance of system communication, and providing solid support for precise control and real-time monitoring in the industrial production process, ensuring the precise coordination of the movement of each axis, and safe and reliable operation of the equipment.

[0062] In this embodiment, the master station 20 sends slave station synchronization frames to slave stations 1 to n in sequence every p / n time. The extended slave station 30 immediately sends local data to the bus upon receiving the synchronization frame, and sends local data again every p time. Among them, p is set according to the system bus cycle and data transmission volume, and n is the number of slave stations.

[0063] If synchronization fails, the master station 20 starts the resynchronization mechanism, adjusts the synchronization frame sending time interval and increases the number of synchronization attempts according to the preset backoff algorithm, and reports the synchronization abnormality information to the upper computer 10; if the slave station data sends a conflict, the master station 20 arbitrates based on the data priority and timestamp information, giving priority to high-priority and first-arrived data to ensure the orderliness and stability of data transmission.

[0064] It is understandable that the master station 20 estimates the communication delay by the time when the slave station feedbacks data, and compensates for the delay by the synchronization frame. The master station 20 should receive slave station data every p / n time. If the data feedback time of a slave station is abnormal, the master station 20 retransmits the synchronization frame of the slave station for compensation. If there is no slave station data feedback time drift, the master station 20 will no longer send the synchronization frame to save bus bandwidth.

[0065] For example, the process of bus synchronization is as follows: the master station 20 divides the bus cycle p into n slices, and waits for data from a slave station in each slice of p / n time. If data is received within p / n time, the slave station is considered normal. If not, the slave station synchronization is considered abnormal. At the beginning of the bus time slice of this slave station in the next bus cycle, a synchronization frame is sent to force the slave station to feedback data.

[0066] If the master station 20 does not receive feedback information from the slave station i within a plurality of time periods, the master station 20 modifies the slave station status bit in the slave station information of the slave station i to indicate that the slave station is offline.

[0067] For example, at time T, the time slice of slave station i starts. If the synchronization abnormality of slave station i has not been marked before, the master station 20 does nothing and waits for the data of slave station i. If the synchronization abnormality of slave station i has been marked before, the master station 20 sends a synchronization frame and then waits for the data of slave station i. The waiting time is p / n.

[0068] At time T+p / n, if data is received from slave i within the waiting time, then slave i has no abnormality and the master station 20 does not take any action. If data is not received from slave i within the waiting time, the master station 20 marks the synchronization abnormality of slave i and processes it in the next cycle.

[0069] In this embodiment, when the master station 20 communicates with the extended slave stations 30 , the master station 20 uses a time-division multiplexing method to complete the data transmission of each extended slave station 30 .

[0070] The master station 20 divides time slices of fixed length according to the number of slave stations and data transmission requirements, and allocates an exclusive time slice to each slave station for data upload. The slave station monopolizes the bus resources within the time slice. If a data transmission timeout or error occurs, the master station 20 suspends the current slave station time slice, records the error information and attempts to retransmit or adjust the subsequent time slice allocation strategy.

[0071] It can be understood that the slave station sends local data to the bus in time-sharing mode, and the master station 20 controls the time interval and delay compensation to avoid frame collision and improve bus efficiency.

[0072] In this embodiment, multiple extended slave stations 30 are connected to the master station 20 through the same twisted pair shielded cable 40, which is easy to expand. The slave station only needs one CAN_FD transceiver chip, which is more economical, simpler in structure and easier to connect than various ETHRECAT / ETHERNET solutions.

[0073] It can be understood that in this embodiment, a specific shielding layer grounding method and impedance matching technology are used during connection to ensure the quality of signal transmission. For long-distance wiring or strong interference environment, anti-interference elements such as magnetic beads, filters, etc. are reasonably added to the line, and the signal driving strength and receiving sensitivity are automatically adjusted according to the line length to ensure reliable data transmission and improve the adaptability of the system in complex wiring environments.

[0074] Finally, it should be noted that although the above embodiments have been described in the specification and drawings of this application, this does not limit the scope of patent protection of this application. All technical solutions generated by replacing or modifying equivalent structures or equivalent processes based on the essential concept of this application using the contents recorded in the specification and drawings of this application, as well as directly or indirectly implementing the technical solutions of the above embodiments in other related technical fields, are included in the scope of patent protection of this application.

Claims

1. A multi-axis multi-slave industrial control system, characterized in that: include: Host computer; A master station, the master station communicates with the host computer via an Ethernet transmission control protocol; A plurality of extended slave stations, each of which is independently connected to a master station and communicates with the master station using a CAN_FD communication protocol; The master station and the extended slave station respectively include a multi-axis drive unit, and at least the master station includes an IO control unit, so that the extended slave station can communicate with the master station only by relying on a CAN_FD transceiver chip.

2. The multi-axis multi-slave industrial control system according to claim 1, characterized in that: The host computer is an industrial computer, including an API library, which includes a bus control module, a bus status query module, an axis control module, an axis status query module, an I0 analog control module, an I0 analog reading module, a bus configuration module, an axis configuration module and a safety function configuration module.

3. The multi-axis multi-slave industrial control system according to claim 1, characterized in that: The frame structure of the CAN_FD protocol communication includes a downlink frame structure for issuing control instructions and an uplink frame structure for bus data feedback.

4. The multi-axis multi-slave industrial control system according to claim 3, characterized in that: The downlink frame structure includes a command identifier, a slave station number, an axis number within the station, a function number and function data.

5. The multi-axis multi-slave industrial control system according to claim 3, characterized in that: The uplink frame includes a bus state and a slave data block, and the slave data block includes a slave state, I0 data, an axis state and axis motion information.

6. The multi-axis multi-slave industrial control system according to claim 3, characterized in that: The downlink frame structure further forms a complete frame with the protocol status bit, the slave station data set according to the number of slave stations n, and the checksum coordination data.

7. The multi-axis multi-slave industrial control system according to claim 6, characterized in that: The slave station data is divided into configuration frames, data frames and control frames according to their functions; The configuration frame includes a slave number bit, an axis number bit and m configuration numbers and configuration data; The data frame includes a slave status bit, digital output data, digital input data, and j slave axis data; The control frame includes a slave station number bit, k axis number bits, and k instruction numbers and instruction data; Among them, n and m are not greater than 8, and j and k are not greater than 6.

8. The multi-axis multi-slave industrial control system according to claim 7, characterized in that: The master station sends slave station synchronization frames to the extended slave stations No. 1 to n in sequence every p / n time. Upon receiving the synchronization frames, the extended slave stations immediately send local data to the bus and send local data again every p time.

9. The multi-axis multi-slave industrial control system according to claim 1, characterized in that: When the master station communicates with the extended slave station, the master station uses a time-division multiplexing method to complete the data transmission of each extended slave station.

10. The multi-axis multi-slave industrial control system according to claim 1, characterized in that: The plurality of extended slave stations are connected to the master station via the same twisted-pair shielded cable.

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