Real-time servo control system

Abstract

The invention discloses a real-time servo control system, which is characterized by comprising a plurality of nodes, the plurality of nodes comprise at least one controller node, at least one sensor node and at least one actuator node, and the plurality of nodes form a bidirectional ring network. The two-way ring network adopts time-sharing network transmission of real-time control information and non-real-time control information which are set according to a preset transmission time proportion; each node comprises an FPGA chip, a first network interface used for being connected with a previous node and a second network interface used for being connected with a next node. The FPGA chip comprises a network distribution module, and the network distribution module is used for compiling an application layer communication protocol, a UDP communication protocol and an IP communication protocol, packaging the protocols to generate a DCP netlist file, and calling the DCP netlist file to establish a communication link with adjacent nodes so as to realize real-time servo control.

Description

Technical Field

[0001] The present invention relates to the field of servo control, and more particularly to a real-time servo control system. Background Art

[0002] With the continuous advancement of servo control technology, servo control has gradually developed from early single-axis, dual-axis and three-axis control to multi-axis control. The control instructions and sensor data of the axes have real-time requirements, and there are requirements for collaborative work between multi-axis controls.

[0003] Early servo control systems often employed a centralized control architecture, where signals from all sensors and actuators were aggregated and processed by a controller. This controller then generated control instructions and sent them to the actuators for execution. This centralized control architecture involves numerous switching, analog, and point-to-point signals, resulting in complex wiring, poor scalability, and reliability. Furthermore, a controller failure could result in the loss of the servo system's overall functionality. Traditional centralized control architectures struggle to achieve synchronized multi-axis control, especially when deployed in a distributed system. Summary of the Invention

[0004] The present invention provides a real-time servo control system to solve at least one of the problems existing in the prior art.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] The present invention provides a real-time servo control system, comprising a plurality of nodes, wherein the plurality of nodes comprises at least one controller node, at least one sensor node and at least one actuator node, and the plurality of nodes form a bidirectional ring network.

[0007] The bidirectional ring network adopts a time-sharing network transmission in which real-time control information and non-real-time control information are transmitted according to a preset transmission time ratio;

[0008] The node includes an FPGA chip, a first network interface for connecting to a previous node, and a second network interface for connecting to a next node;

[0009] The FPGA chip includes a network allocation module, which is used to write application layer communication protocols, UDP communication protocols and IP communication protocols and package them to generate DCP netlist files, call the DCP netlist files to establish communication links with adjacent nodes, and realize real-time servo control.

[0010] Optionally, the node further includes a PHY chip for implementing a transmission physical layer.

[0011] Optionally, the FPGA chip further includes a network monitoring module for monitoring the bidirectional ring network, and switching to a communication link in the other direction for communication after detecting that the communication link in one direction is open.

[0012] Optionally, the network monitoring module is further configured to output communication link fault information after detecting that the communication link is open for a preset period of time, wherein the communication link fault information includes fault node information.

[0013] Optionally, nodes in the bidirectional ring network are configured to be hot-replaceable.

[0014] Optionally, the transmission time ratio of the real-time control information to the non-real-time control information is set to 7:3-9:1.

[0015] Optionally, the plurality of nodes further include at least one expander node.

[0016] Optionally, the network allocation module is further configured to perform time alignment on multiple nodes in the bidirectional ring network.

[0017] Optionally, the multiple nodes are dispersedly arranged.

[0018] Optionally, the real-time servo control system is used to achieve multi-axis synchronous control.

[0019] The beneficial effects of the present invention are as follows:

[0020] In the present invention, multiple nodes form a bidirectional ring network, and each node can directly send data to the next node in the network, avoiding the problem of having to pass through multiple nodes to reach the destination node in the traditional topology structure, improving data transmission efficiency and having higher stability; arranging real-time control information and non-real-time control information for time-sharing transmission ensures real-time data interaction between nodes, improves control accuracy, and increases the response speed of the system; and generating a DCP netlist file through a network allocation module facilitates the reuse of existing layout and wiring, thereby improving reuse efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0022] Figure 1 Shows a schematic structural diagram of the real-time servo control system of the present invention;

[0023] Figure 2 A schematic diagram showing the control principle of a node in an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0024] In order to more clearly illustrate the present invention, the present invention is further described below in conjunction with preferred embodiments and accompanying drawings. Similar components in the accompanying drawings are represented by the same reference numerals. It should be understood by those skilled in the art that the following detailed description is illustrative rather than restrictive and should not be used to limit the scope of protection of the present invention.

[0025] One embodiment of the present invention provides a real-time servo control system, comprising a plurality of nodes, the plurality of nodes being distributed, the plurality of nodes including at least one controller node, at least one sensor node, and at least one actuator node, the plurality of nodes forming a bidirectional ring network,

[0026] The bidirectional ring network adopts a time-sharing network transmission in which real-time control information and non-real-time control information are transmitted according to a preset transmission time ratio;

[0027] The node includes an FPGA chip, a first network interface for connecting to a previous node, and a second network interface for connecting to a next node;

[0028] The FPGA chip includes a network allocation module, which is used to write application layer communication protocols, UDP communication protocols and IP communication protocols and package them to generate DCP netlist files, call the DCP netlist files to establish communication links with adjacent nodes, and realize real-time servo control.

[0029] This embodiment provides a real-time servo control system that forms a bidirectional ring network through multiple nodes. Each node can directly send data to the next node in the network, avoiding the problem of having to pass through multiple nodes to reach the destination node in traditional topology structures, improving data transmission efficiency, and having higher stability. Real-time control information and non-real-time control information are arranged for time-sharing transmission to ensure real-time data interaction between nodes, improve control accuracy, and enhance system response speed. High-speed data transmission is achieved through the network allocation module in the FPGA chip, providing high bandwidth and low latency, and realizing parallel processing. DCP netlist files are generated by various protocols written by the network allocation module, so that each process can reuse the results of existing layout and routing, reducing recompilation time. Reusing existing layout and routing improves the predictability of re-layout and routing, thereby improving design efficiency.

[0030] In a specific example, for example Figure 1As shown, the real-time servo control system in this example includes multiple nodes, and the multiple nodes are dispersedly arranged. The multiple nodes include at least one controller node, at least one sensor node and at least one actuator node. The multiple nodes form a bidirectional ring network to achieve synchronous control between the servo system nodes, ensure the real-time control between the controller nodes, sensor nodes and actuator nodes in the system, and perform dual-path hot backup through the bidirectional ring network.

[0031] The bidirectional ring network adopts time-sharing network transmission with real-time control information and non-real-time control information set according to the preset transmission time ratio. The real-time control information and non-real-time control information are set for time-sharing transmission to ensure real-time data interaction between nodes, improve control accuracy, and enhance the response speed of the system.

[0032] In this example, the node includes an FPGA chip, a first network interface for connecting to the previous node, and a second network interface for connecting to the next node. Figure 2 The schematic diagram of the node in this example is shown. The FPGA chip includes a network distribution module. Figure 2 NET_ALLOC is the network allocation module, used to allocate network resources. Application layer communication protocols, UDP communication protocols, and IP communication protocols are compiled and packaged into a DCP netlist file, which is then called to establish communication links with adjacent nodes. The network allocation module in the FPGA chip enables high-speed data transmission, providing high bandwidth, low latency, and parallel processing. Packaging the application layer communication protocols, UDP communication protocols, and IP communication protocols into a DCP netlist file allows each process to reuse existing layout and routing results, reducing recompilation time. Reusing existing layout and routing improves the predictability of re-layout and routing, thereby increasing design efficiency.

[0033] The real-time servo control system in this example is highly versatile and portable. It adopts the scheduling-based time-sharing transmission principle and is scheduled through a network allocation module. Specifically, network addresses are allocated to the FPGA chip, each node is configured as a bidirectional network port, two transmission addresses are allocated, a bidirectional ring network is established, and the network allocation module of the FPGA chip is called to constrain the transmission time of real-time control information and non-real-time control information, thereby improving the system's response speed, reducing system failures caused by transmission delays, and enhancing the system's fault tolerance and security.

[0034] In one possible implementation, the node further includes a PHY chip for implementing a transmission physical layer.

[0035] Continuing with the previous example, Figure 2As shown in the figure, the MAC layer is the media access control layer, which controls communication with the physical layer (PHY) and manages physical addresses. The PHY layer is the physical layer, which handles signal transmission on the physical medium. The RJ-45 is the network interface used to connect the network cable to achieve physical connection. ARP is the address resolution protocol used to resolve IP addresses to MAC protocols. The MAC layer IP core is called to establish the RGMII communication interface between the MAC layer and the PHY chip.

[0036] In one possible implementation, the FPGA chip further includes a network monitoring module for monitoring the bidirectional ring network and switching to a communication link in the other direction for communication upon detecting that a communication link in one direction is open.

[0037] The network monitoring module is further configured to output communication link fault information after detecting that the communication link is open for a preset period of time. The communication link fault information includes faulty node information, and the faulty node information includes node faults and inter-node communication medium faults.

[0038] Continuing with the previous example, Figure 2 As shown, NET_DIAG is a network monitoring module used to monitor and diagnose bidirectional ring networks. It also outputs communication link fault information if it detects an open communication link for a preset duration. This information includes faulty node information, which could indicate a node failure or a failure in the communication medium between nodes. The network monitoring module monitors the bidirectional ring network links in real time. If an open communication link is detected in one direction, communication is switched to the other direction, the link failure is reported, and monitoring of the faulty branch continues, implementing redundant backup functionality for the servo control system.

[0039] If a link failure is detected in one direction, the faulty node can be replaced without powering down the entire system. The replaced node can then be configured. Once the network monitoring module detects link recovery, communication in that direction resumes, with the faulty link serving as a redundant backup link. Based on redundant backup requirements, communication is enabled in both directions of the bidirectional ring network, with one direction selected as the data backup branch. This allows for real-time switching if the other direction fails.

[0040] If the fault in one direction lasts longer than the preset time and communication is not restored, a serious link fault will be reported, and the location of the faulty node will be reported.

[0041] This example uses the network monitoring module to monitor the status of data transmission in real time and detect anomalies in the bidirectional ring network, which helps to promptly detect and handle network anomalies and improve system reliability. Real-time monitoring of data transmission efficiency and quality helps to optimize data transmission paths, reduce transmission delays, and improve data transmission efficiency. The network monitoring module provides detailed network status information, which helps engineers to debug and maintain in a timely manner, quickly locate problems, and reduce the time and cost of debugging and maintenance. The bidirectional ring network is monitored to ensure that any node in the bidirectional ring network can communicate with other nodes through multiple paths. After the communication link on one side is opened, data transmission will not be interrupted, ensuring the stability of data transmission.

[0042] In one possible implementation, nodes in the bidirectional ring network are configured to be hot-replaceable.

[0043] Continuing with the previous example, Figure 1 As shown, each node in the bidirectional ring network has two network interfaces connected to other nodes. If a fault occurs in one direction of the bidirectional ring network, communication is switched to the other direction. This redundant design greatly improves the reliability of the system. The node configuration in the bidirectional ring network is set to hot swap, and the faulty node can be replaced without interrupting the system operation, thereby enhancing the stability and reliability of the system.

[0044] Traditional node configuration methods are typically manual. Replacing a faulty node requires shutting down the entire system or part of it, which can cause system downtime, be time-consuming, labor-intensive, and error-prone. The bidirectional ring network in this example incorporates a protection mechanism. When replacing node configurations, hot replacement is used to ensure the proper functioning of the bidirectional ring network's protection mechanism, preventing network interruptions or failures during the configuration update process. This reduces downtime and improves the network's availability and flexibility.

[0045] In a possible implementation, the transmission time ratio of the real-time control information to the non-real-time control information is set to 7:3-9:1.

[0046] Continuing with the previous example, Figure 2 As shown in the figure, the hardware uses an FPGA chip and a PHY chip that support Gigabit Ethernet. The UDP_IP protocol and MAC protocol are both implemented by the FPGA, and the PHY layer is implemented by the physical PHY chip. The servo control system implemented in this example adopts the time-sharing transmission principle based on scheduling, and is scheduled by the network allocation module. The network transmission in the bidirectional ring network includes real-time control information and non-real-time control information. Figure 2In this example, RT_NET_SEND is a real-time network send function, used to prepare to send real-time control information, and RT_NET_RECV is a real-time network receive function, used to receive real-time control information. NRT_NET_SEND is a non-real-time network send function, used to prepare to send non-real-time control information, and NRT_NET_RECV is a non-real-time network receive function, used to receive non-real-time control information. Real-time control information includes information that requires strict time synchronization, such as the angle, length, control value, critical fault, and emergency braking information of the controlled object. Non-real-time control information does not require strict time synchronization, such as general fault information, video, and health monitoring information. In this example, the network allocation module is used to constrain the transmission time of real-time and non-real-time control information. The transmission time ratio of real-time control information to non-real-time control information is set at 8:2. The real-time control limit period is 1ms, the number of servo function nodes is 100, and the real-time data of each node is no less than 100 bytes. That is, the transmission time of real-time control information allocated to each functional node is 8μs, and 100 bytes are transmitted within 8μs; the transmission time of non-real-time control information is 2μs. If the non-real-time control information cannot be completely transmitted within 2μs, the non-real-time control information will continue to be transmitted in the next scheduling cycle.

[0047] Figure 2 IP_SEND is the sending data area, which is used to send real-time control information and non-real-time control information of the IP layer. IP_RECV is the receiving data area, which is used to receive and process real-time control information and non-real-time control information of the IP layer. SEND_BUF is the sending buffer, which is used to temporarily store the real-time control information and non-real-time control information to be sent. RECV_BUF is the receiving buffer, which is used to temporarily store the real-time control information and non-real-time control information to be received. Icmp echo data is the echo data used for network testing. It interacts between the sending data area and the receiving data area to detect network connectivity.

[0048] In a possible implementation, the network allocation module is further configured to perform time alignment on multiple nodes in the bidirectional ring network.

[0049] Continuing with the previous example, before constraining the transmission times of real-time control information and non-real-time control information, the network allocation module initiates network synchronization to align the time of each servo function node on the bidirectional ring network. The network allocation module then allocates the sending and receiving times for each node. For example, the first node occupies 0-10 μs of transmission time, of which 0-8 μs are used for sending and receiving real-time control information, and 8-10 μs are used for sending and receiving non-real-time control information. The second node occupies 10-20 μs of transmission time, of which 10-18 μs are used for sending and receiving real-time control information, and 18-20 μs are used for sending and receiving non-real-time control information. This process is repeated in this way, thus achieving time-sharing transmission of real-time control information and non-real-time control information in the bidirectional ring network.

[0050] In real-time servo control architectures, the accuracy and consistency of time at each node are crucial. Time alignment of each node through the network distribution module ensures the clock synchronization of each controller, sensor, and actuator node on a bidirectional ring network, aligning them to the same time base. This improves system synchronicity and avoids data distortion and control inaccuracies caused by time deviations during data exchange and collaborative work.

[0051] In a possible implementation, the plurality of nodes further include at least one expander node.

[0052] Continuing with the previous example, expander nodes can be used to easily add or reduce servo function nodes to adapt to different application scenarios and needs, achieving flexible system configuration. In a multi-node servo control system, if a node fails, the expander node can serve as a backup node to ensure normal system operation and improve system reliability.

[0053] In one possible implementation, the real-time servo control system is used to implement multi-axis synchronous control.

[0054] Continuing with the previous example, in this example, at least one controller node, at least one sensor node, and at least one actuator node are distributed, and the placement of multiple nodes is not restricted by space, realizing a distributed architecture of the servo control system. The nodes are distributed and have high-precision real-time control capabilities, realizing precise synchronous operation between multiple axes.

[0055] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "upper" and "lower" is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be internal communication between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0056] It should also be noted that, in the description of the present invention, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or device comprising the element.

[0057] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not limitations on the implementation methods of the present invention. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is impossible to list all the implementation methods here. All obvious changes or modifications derived from the technical solution of the present invention are still within the scope of protection of the present invention.

Claims

1. A real-time servo control system, characterized in that: The plurality of nodes includes at least one controller node, at least one sensor node and at least one actuator node, and the plurality of nodes form a bidirectional ring network. The bidirectional ring network adopts a time-sharing network transmission in which real-time control information and non-real-time control information are transmitted according to a preset transmission time ratio; The node includes an FPGA chip, a first network interface for connecting to a previous node, and a second network interface for connecting to a next node; The FPGA chip includes a network allocation module, which is used to write application layer communication protocols, UDP communication protocols and IP communication protocols and package them to generate DCP netlist files, call the DCP netlist files to establish communication links with adjacent nodes, and realize real-time servo control.

2. The system according to claim 1, wherein: The node also includes a PHY chip for implementing a transmission physical layer.

3. The system according to claim 1, wherein: The FPGA chip also includes a network monitoring module for monitoring the bidirectional ring network, and switching to a communication link in the other direction for communication after detecting that the communication link in one direction is open.

4. The system according to claim 3, characterized in that The network monitoring module is further configured to output communication link fault information after detecting that the communication link is open for a preset period of time, wherein the communication link fault information includes fault node information.

5. The system according to claim 4, characterized in that The nodes in the bidirectional ring network are configured to be hot-replaceable.

6. The system according to claim 1, wherein: The transmission time ratio of the real-time control information to the non-real-time control information is set to 7:3-9:

1.

7. The system according to claim 1, wherein: The plurality of nodes also includes at least one expander node.

8. The system according to claim 1, wherein: The network allocation module is further configured to perform time alignment on multiple nodes in the bidirectional ring network.

9. The system according to claim 1, wherein: The multiple nodes are dispersedly arranged.

10. The system according to claim 1, wherein: The real-time servo control system is used to realize multi-axis synchronous control.

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