CN111897300A - A software/hardware co-simulation system based on OPC-UA and its adaptive collaboration method - Google Patents

Abstract

The invention discloses an OPC-UA-based software/hardware co-simulation system and an adaptive collaboration method thereof, and relates to the technical field of system simulation. The system includes an emulation unit, an emulation adapter, a communication module and a clock agent. The adaptive collaboration method of the system includes the following steps: 1. Create a co-simulation environment, and establish a simulation model of each simulation unit; 2. Configure the co-simulation environment, establish an information model, connect each simulation adapter to a corresponding simulation unit, and set up each simulation unit 3. According to the simulation step size of each simulation unit, determine the co-simulation step size according to the step size cooperative adaptive method; 4. Run the co-simulation; 5. After the co-simulation, evaluate the results. The co-simulation scheme of the present invention performs cooperative control of each simulation unit, optimizes the system structure, reduces the computational complexity, and can effectively deal with scenes with complex actual industrial network structures and frequent information exchanges.

Description

A software/hardware co-simulation system based on OPC-UA and its adaptive collaboration method

technical field

The invention relates to the technical field of system simulation, in particular to an OPC-UA-based software/hardware co-simulation system and an adaptive collaboration method thereof.

Background technique

The simulation system is a necessary means for the verification test and optimization and upgrading of the operation performance, efficiency and safety of the smart factory. Since the smart factory scenario covers a variety of production process scenarios and heterogeneous networks, and contains complex network topology, the simulation system in this scenario not only needs to involve software such as process simulation, logistics simulation, network simulation, and energy simulation, but also involves Dedicated real-time hardware simulators, physical test beds and other hardware simulators. Therefore, to establish a precise and accurate simulation test, it is necessary to co-simulate a mixed soft/hard multi-simulation system, in order to more comprehensively simulate the operation mechanism of the actual system and evaluate the design scheme of the system.

Each simulation unit (SU) participating in the co-simulation runs a part of the complete simulation and needs to be time-synchronized with other simulation units to realize the global simulation of the complete coupled system. Ideally, each module or device in the plant provides its own simulation model, which is created, communicated, and maintained using a systems engineering approach, and finally integrated into a complete system simulation model. However, the existing co-simulation standards are limited to specific industries or specific tools, and lack unified standards for integration, such as functional entity interface (Functional Mock-up Interface, FMI) and high-level architecture (High-Level Architecture, HLA), etc. .

In the joint simulation of multiple simulation units, it is necessary to carry out unified collaborative management of multiple simulation systems or equipment, and each simulator performs simulation data interaction according to the set step size. However, due to the complexity of solving the operation modes (discrete, continuous and mixed) of each simulation system and the difference of the system operation period, the operation step size of each simulator has a great difference. For example, the step size of communication and electrical categories is usually relatively short, ranging from microseconds to milliseconds, and the step size of processing and logistics categories is relatively long, ranging from minutes to hours. The difference in synchronization step size will reduce the efficiency of co-simulation, and if the setting is unreasonable, the simulation system will fail to converge, and the correct verification result cannot be obtained. Therefore, how to design the simulation step size of the co-simulation and ensure the safe and effective operation of the simulation system is a key technology that needs to be solved to realize the semi-physical simulation scheme of the complex system of the smart factory.

The domestic application number is 201610055323.X, the patent is entitled "A power communication system co-simulation platform based on variable time window synchronization method and its synchronization method", and the simulation synchronization module designed for the power communication system is switched according to the simulation data of the power system. The synchronous time window of the simulation controls two simulation tools, but the set time window can only be switched between the fixed wide and narrow time steps that have been set, and the appropriate time cannot be set according to the multiple simulation units of the complex system of the smart factory step size, the simulation accuracy is limited. The domestic application number is 201810498282.0 for a patent titled "A Multi-Simulator Collaborative Simulation Method, Simulation Main Control Platform and Simulation System", which uses Lagrangian polynomials to interpolate the simulators whose simulation step size is greater than the predicted collaborative step size. , and transfer the data to other simulators for co-simulation calculation, but its numerical prediction technology is only a theoretical approximation and cannot accurately describe the real response of the simulator. The domestic application number is 201810697108.9 and the patent is entitled "A method for realizing real-time synchronous control of multiple simulation devices". The real-time communication network is used to connect the simulation computer and multiple simulation devices. The simulation computer collects the feedback data of the corresponding simulation devices to complete the simulation. However, when the number of devices participating in the simulation is greater than a certain threshold, the communication and interaction mechanism cannot guarantee the real-time and reliable transmission of a large amount of data, and the simulation computer cannot guarantee the real-time feedback of control instructions and control data. The domestic application number is 201610988418.7, the patent is entitled "A method for automatic synchronization and reliable communication of simulation system", which encapsulates the network communication code into a class, and the objects of each class include a sending queue and a receiving queue. (Ensure that the data packets are received in order and only once), so that each simulation subsystem can achieve reliable communication through objects of this class, but when one or some subsystems fail and restart during the simulation operation, it is necessary to Restoring the communication relationship in the last run cannot guarantee the reliability and security of transmission when a communication error occurs.

To sum up, the disadvantages of the prior art solutions are:

(1) Most of the existing co-simulation systems are aimed at full software simulation or full hardware simulation, and do not consider the complex coupled system coexisting with software and hardware, and are not suitable for the semi-physical system simulation scheme of smart factories.

(2) Most of the existing co-simulations assume that real-time and reliable communication between simulation units can be achieved, and rarely involve specific communication architectures and specifications, as well as communication and interaction mechanisms to ensure effective interaction between co-simulation units.

(3) The existing simulation scheme of multiple simulation systems adopts the client/server architecture based on the OPC-UA protocol, and builds a coupled network for data interaction by establishing a point-to-point session, and integrates data processing into the general controller. The unit only receives instructions from the general controller and feeds back relevant data, which results in a large computational load under this architecture. When the number of simulation units is too large, the reliability of data transmission cannot be guaranteed.

(4) When designing the co-simulation step size of multiple simulation units in the prior art, switching is usually performed in a fixed time step size. For the simulation unit whose time step size is longer than the co-simulation step size, interpolation is used to predict the feedback data. Time step and interpolation prediction cannot guarantee the accuracy of the simulation of complex coupled systems.

Therefore, those skilled in the art are committed to developing a software/hardware co-simulation system based on OPC-UA and an adaptive collaboration method thereof, and use the co-simulation scheme of the subscription/publishing architecture based on the OPC-UA protocol to perform the simulation of each simulation unit. Collaborative control can further optimize the system structure, reduce the computational complexity, and can effectively deal with the actual industrial network structure complex and frequent information interaction scenarios.

SUMMARY OF THE INVENTION

In view of the above-mentioned defects of the prior art, the technical problems to be solved by the present invention include:

(1) How to construct a software/hardware hybrid simulation scheme in a complex coupled system of a smart factory;

(2) How to design a specific communication and interaction mechanism to ensure the reliability of the data interaction of each simulation unit of the co-simulation;

(3) How to design an adaptive step size adjustment scheme for the complex coupled system of the smart factory under the problem that the time steps of the simulation units participating in the co-simulation are inconsistent, so that the co-simulation can be carried out accurately and effectively.

To achieve the above object, the present invention provides a software/hardware co-simulation system based on OPC-UA, including an emulation unit, an emulation adapter, a communication module and a clock agent;

The simulation unit includes software such as process simulation, logistics simulation, network simulation, and energy simulation, as well as hardware simulators such as dedicated real-time hardware simulators and physical test beds;

Described simulation adapter comprises OPC-UA client end and simulation unit interface, described simulation adapter adopts OPC-UA agreement, is set as the interface of simulation unit and middleware agent to carry out data interaction, to complete the data interaction of co-simulation;

The communication module sets a transmission protocol according to the transmission requirements of the simulation unit, and for the simulation unit with low latency requirements, the communication module adopts the unified architecture datagram protocol (OPC UA Datagram Protocol, UADP); The simulation unit of the non-real-time transport stream, the communication module adopts any one of UADP or UDP protocol;

The clock agent controls the co-simulation step size setting of the co-simulation. During the co-simulation, each simulation unit sends a report message to the clock agent through the simulation adapter after each simulation step is executed to report that the simulation step has been completed. Complete, when all the simulation units report that the current simulation step has been completed, the clock agent sends a simulation step confirmation message or configuration adjustment information message to each of the simulation units to start the next simulation step. Simulation step: if the subsequent simulation step size needs to be adjusted, the configuration adjustment information is sent, and if the subsequent simulation step size remains unchanged, the simulation step size confirmation information is sent.

Further, the clock agent is set to realize the distributed interaction of each of the simulation units; the working state and feedback data of each of the simulation units pass through the corresponding simulation adapter, according to the subscription rules of the data between the simulators. It is sent to the corresponding simulation adapter and the simulation unit through the communication module.

The present invention also provides a kind of adaptive collaboration method based on OPC-UA software/hardware co-simulation system, comprising the following steps:

Step 1: the user creates a co-simulation environment, and establishes a simulation model of each of the simulation units;

Step 2: configure the co-simulation environment, establish an information model, each of the simulation adapters is connected to the corresponding simulation unit, and set the quality of service QoS requirements required by each of the simulation units in the co-simulation environment, establishing the underlying co-simulation environment;

Step 3: According to the simulation step size of each of the simulation units, the co-simulation step size of the co-simulation is determined according to the step size cooperative adaptive method; the co-simulation step size can ensure that an emergency occurs in one or some simulation units. (such as failure, etc.) the stable operation of the overall co-simulation system;

Step 4: Run the co-simulation;

Step 5: The co-simulation ends, and the simulation results are evaluated.

Further, in the step 2, when the co-simulation environment is constructed, the simulation adapter of the simulation unit uses the OPC-UA protocol to perform data interaction with the simulation unit.

Further, in the step 2, when constructing the co-simulation environment, a publish/subscribe (Pub/Sub) mechanism based on the OPC-UA protocol is used to complete the distributed interaction of the simulation units.

Further, in the step 3, the co-simulation step size is determined as one of the following three situations:

Case 1: When each simulation unit is running normally, the co-simulation is based on time sequence division, and all the simulation units need to complete their own simulation calculations before proceeding to the next time sequence step; the co-simulation step size of the co-simulation is selected to be close to the communication interaction the least common multiple of the smallest possible simulation time step Ti (i=1, .

Situation 2: When one or more of the simulation units are added, after the co-simulation completes the simulation of the current time step, that is, after the clock agent receives the messages from all the simulation units reporting that the current simulation step has been completed , the clock agent recalculates the co-simulation step size of the co-simulation; at this time, the co-simulation step size of the co-simulation selects the co-simulation step size of the original normal operation and the minimum possible simulation time of the newly added simulation unit the least common multiple of the step size;

Scenario 3: When the emergency detection mechanism detects an emergency in one or some simulation units, the co-simulation adaptively switches to the event-triggered operation mode. Executed sequentially, the co-simulation at this time is aperiodic. If the emergency event has been preset in the clock agent (Clock Agent), the event-triggered mode can be entered in advance of the previous time synchronization point, otherwise each of the simulation units rolls back to the previous simulation synchronization point. The co-simulation step size of the co-simulation is determined according to the least common multiple of the triggering time point of all the current emergency events and the simulation time step size of the remaining normal running simulation units.

Further, in the step 3, each simulation unit performs simulation and data interaction according to its own simulation step size, and the co-simulation step size is only used as the minimum interval basic step size.

Further, the step 4 includes the following steps:

Step 4.1: in each simulation time step, each simulation unit updates its own simulation output according to the simulation model established in step 1;

Step 4.2: each simulation unit sends the updated simulation configuration output to the simulation adapter;

Step 4.3: Each of the simulation adapters, as a publisher, forms a data set with the output of the corresponding simulation unit for the preparation of data publishing; the data set is connected to the nodes of the OPC-UA information model, including the published data set and dataset domain;

Step 4.4: The data set released by each simulation unit is passed into the write group; the write group is the producer of the message in the data interaction, and the user can add the data set write function by himself;

Step 4.5: the communication module performs data transmission at the selected transport layer with the corresponding transport protocol according to the delay requirement of the simulation unit;

Step 4.6: After the corresponding simulation adapter receives the message data of the subscribed topic as a subscriber, it obtains the subscription data set by reading in the group, and sends the data to the corresponding simulation unit; the reading group is: The receiver of the message in the data interaction, the user can add the data set reading function;

Step 4.7: the simulation unit completes the current simulation step, and sends a report message to the clock agent through the simulation adapter to report that the current simulation step has been completed;

Step 4.8: After the clock agent confirms that it has received the message report that all the simulation units have completed the current time step, it sends a simulation step confirmation message or configuration adjustment message to all the current simulation units, notifying them that they can proceed to the next step. One-step simulation step; if the subsequent simulation step needs to be adjusted, the configuration adjustment information is sent, and if the subsequent simulation step remains unchanged, the simulation step confirmation information is sent;

Step 4.9: Return to step 4.1.

Further, in the step 4.3, the published data set is a container for publishing information, consisting of published variables and meta-information, including a set of variables, event filtering, application-specific information and meta-data; the data set domain A description of the distribution variable, including the selected information model node and additional information such as distribution, sampling, error handling, etc.

Further, in the step 4.5, the data transmission includes the following two situations: for a data stream with low latency requirements, use UADP to directly map to the second layer of the reference model, and the message is packaged in an Ethernet frame; For non-real-time data streams, the UADP datagram is directly mapped to UDP, and the message is packaged in a UDP packet; the message needs to be securely sealed by the security key server for transmission;

The security key server is constructed based on the OPC-UA protocol, manages the security keys of the publisher and the subscriber, and establishes a connection with the publisher and the subscriber through the OPC-UA client-server form.

Compared with the prior art solutions, the beneficial technical effects of the present invention are:

(1) The co-simulation system is adopted, so that each simulation unit participating in the co-simulation only runs a part of the complete simulation, and realizes the global simulation of the complete coupling system through data interaction with other simulation units, thus solving the problem of multiple software/hardware in the smart factory. The problems brought about by the simulation system mixing more comprehensively simulate the operation mechanism of the actual system.

(2) The co-simulation scheme of subscription/publishing architecture based on OPC-UA protocol is used to carry out cooperative control of each simulation unit, and a flat industrial simulation system is established. Compared with the centralized master controller and multiple slave controllers The present invention further optimizes the system structure, so that the computational complexity is greatly reduced, and each simulation unit can interact in a distributed manner, which significantly improves the reliability of the simulation system, and can effectively deal with the complex structure of the actual industrial network and frequent information interaction. scene.

The concept, specific structure and technical effects of the present invention will be further described below in conjunction with the accompanying drawings, so as to fully understand the purpose, characteristics and effects of the present invention.

Description of drawings

Fig. 1 is a soft/hard hybrid co-simulation system architecture diagram of a preferred embodiment of the present invention;

2 is a flowchart of a cooperative adaptive control method according to a preferred embodiment of the present invention;

3 is a schematic diagram of the quality of service QoS requirements for configuring a co-simulation environment according to a preferred embodiment of the present invention;

4 is a schematic diagram of a data interaction process between a publisher and a subscriber according to a preferred embodiment of the present invention;

FIG. 5 is a schematic diagram of a process of a communication module transmitting data published by an emulation adapter according to a preferred embodiment of the present invention.

Among them, 1-communication module, 2-emulation adapter, 3-emulation unit, 4-clock agent, 21-OPC-UA client, 22-emulation unit interface.

Detailed ways

The following describes several preferred embodiments of the present invention with reference to the accompanying drawings, so as to make its technical content clearer and easier to understand. The present invention can be embodied in many different forms of embodiments, and the protection scope of the present invention is not limited to the embodiments mentioned herein.

The purpose of the present invention is to overcome the defects of the existing co-simulation scheme, and to provide a soft/hard hybrid co-simulation system and a collaborative adaptive method for the smart factory scene, which can realize the semi-physical complex system simulation of the smart factory.

As shown in Figure 1, an OPC-UA-based software/hardware co-simulation system includes a communication module 1, several simulation adapters 2 (Simulation Adaptors, SA), a simulation unit 3 (Simulation Unit, SU), and a clock agent 4 (Clock Agent, CA). The emulation adapter 2 includes an OPC-UA client 21 and an emulation unit interface 22 .

When running the co-simulation, the simulation step size of the co-simulation is controlled by the clock agent 4 to realize the distributed interaction of each simulation unit 3, and the working state and feedback data of each simulation unit 3 pass through the corresponding simulation adapter 2, according to the subscription of the data between the simulators. The rules are sent to the corresponding simulation adapter 2 and the simulation unit 3 through the communication module 1 to complete effective co-simulation.

The communication module 1 sets the transmission protocol according to the transmission requirements of the simulation unit 3. For the simulation unit 3 with low latency requirements, the unified architecture datagram protocol (OPC UA Datagram Protocol, UADP) can be used to directly map the datagram to the OSI (Open System Interconnection (OSI) reference model layer 2, thus ensuring low cycle time requirements for messages; for simulation units that only require non-real-time transport streams, the former method can be used, or the UADP datagram can be mapped to the user datagram protocol (User Datagram Protocol, UDP) for transmission in UDP packets.

The emulation adapter 2 adopts an OPC-UA-based emulation adapter, including: an OPC-UA client 21 and an emulation unit interface 22 . The OPC-UA client 21 is based on the OPC Unified Architecture (OPC Unified Architecture, OPC-UA), which provides a consistent and complete address space and service model, can communicate across platforms, and has higher security and reliability. Using the OPC-UA protocol for software/hardware hybrid co-simulation in smart factory scenarios can achieve seamless access to metadata, help improve the scalability of the simulation system, and meet the precise simulation requirements of the production environment of flexible industrial manufacturing . The simulation unit interface 22 corresponds to the simulation unit 3 one-to-one, and performs data connection according to the physical characteristics of the simulation unit 3 .

The simulation unit 3 includes software/hardware simulators in the smart factory scenario, including software such as process simulation, logistics simulation, network simulation, and energy simulation, as well as hardware simulators such as dedicated real-time hardware simulators and physical test beds.

The clock agent 4 controls the setting of the co-simulation step size of the co-simulation. During the co-simulation, each simulation unit 3 sends a report message to the clock agent 4 through the simulation adapter 2 after each simulation step is performed to report that the simulation step has been completed. When all the simulation units 3 report that the current simulation step has been completed, The clock agent 4 sends to each simulation unit 3 a simulation step size confirmation message or a configuration adjustment information message to start the simulation step of the next simulation step size. If the subsequent simulation step size needs to be adjusted, the configuration adjustment information is sent, and if the subsequent simulation step size remains unchanged, the simulation step size confirmation message is sent.

Figure 2 is a flowchart of a collaborative adaptive method of a software/hardware co-simulation system based on OPC-UA, including the following steps:

Step 1: The user creates a co-simulation environment and establishes a simulation model of each simulation unit (mixed software and hardware).

Step 2: Configure the co-simulation environment and establish an information model.

Step 2.1: The emulation adapter is connected to the corresponding emulation unit.

Step 2.2: If the simulation adapter does not receive a connection request from the simulation unit within a reasonable time, the network connection is closed, and the simulation unit exits the co-simulation. The reasonable time depends on the type of application service, the communication infrastructure, and the like.

Step 2.3: Set the quality of service (Quality of Service, QoS) requirements of each simulation unit in the co-simulation environment, including requirements such as bandwidth guarantee (Bandwidth Guarantee) and maximum delay (Maximum Latency). The bottom layer needs to read the corresponding QoS requirements and configure the corresponding parameters.

Step 3: According to the simulation step size of each simulation unit, the co-simulation step size of the co-simulation is determined according to the step size cooperative adaptation method.

The step size cooperative adaptive method can adaptively adjust the step size when one or more simulation units are added, or when an unexpected event (such as a fault, etc.) occurs in one or some simulation units, resulting in a need for a more refined simulation step size. Adjust the co-simulation step size of the co-simulation system, including the following three cases:

①When each simulation unit is running normally, the co-simulation is based on time sequence division, and all simulation units need to complete their own simulation calculations before proceeding to the next time sequence step. The co-simulation step size of the co-simulation selects the least common multiple of the smallest possible simulation time step Ti (i=1,...,N, N is the number of simulation units participating in the co-simulation) of all simulation units close to the communication interaction period T;

②When one or more simulation units are added, after the co-simulation completes the simulation of the current time step, that is, after the clock agent receives a message from all simulation units reporting that the current simulation step has been completed, the clock agent recalculates the co-simulation value. Cosimulation step size. At this time, the co-simulation step size of the co-simulation selects the least common multiple of the co-simulation step size in the original normal operation and the minimum possible simulation time step size of the newly added simulation unit;

③ When the emergency detection mechanism detects an emergency in one or some simulation units, the co-simulation adaptively switches to the event-triggered operation mode. Execution, the co-simulation at this time is aperiodic. If the emergency event has been preset in the clock agent (Clock Agent), the event trigger mode can be entered in advance of the previous time synchronization point, otherwise each simulation unit rolls back to the previous simulation synchronization point. The co-simulation step size of the co-simulation is determined according to the least common multiple of the trigger time point of all the current emergency events and the simulation time step size of the remaining normal running simulation units.

Step 4: Run the co-simulation.

Step 4.1: In each simulation time step, each simulation unit updates its own simulation output according to the simulation model established in the first step.

Step 4.2: Each simulation unit sends the updated simulation configuration output to the simulation adapter.

Step 4.3: Each simulation adapter (publisher) outputs its corresponding simulation unit to form a data set (Datasets), which is used for the preparation of data release. The data sets are connected with nodes (eg variables) of the information model of OPC-UA, including published data sets (Published Datasets) and data set fields (Dataset Fields).

The published data set is a container of published information, consisting of published variables and meta information, including a set of variables, event filtering, application specific information and meta data (Meta Data).

The dataset domain is the description of the release variable, including the selected information model node and additional information such as release, sampling, error handling, etc.

Step 4.4: The data set published by each simulation unit is transferred to the WriterGroup. The write group is a producer of messages in data interaction, and a user can add a DatasetWrite (dataset write) function.

Step 4.5: The communication module performs data transmission at the selected transport layer with the corresponding transport protocol according to the delay requirement of the simulation unit. The transmission process includes the following two cases: for data streams with low latency requirements, UADP is used to directly map to the second layer of the reference model, and messages are packaged in Ethernet frames; for non-real-time data streams, UADP datagrams are directly Mapped to UDP, messages are packaged in UDP packets. The message needs to be transmitted after being securely encapsulated (Secure Envelope) by a Security Key Server (Security Key Server).

The security key server is a server based on the OPC-UA protocol, manages the security keys of the publisher and the subscriber, and establishes a connection with the publisher and the subscriber through a client-server (Client-Server) form.

Step 4.6: After the corresponding simulation adapter receives the message data of the subscribed topic, it obtains the subscription data set by reading in the group (ReaderGroup), and sends the data to the corresponding simulation unit (subscriber). The read-in group is the receiver of the message in the data interaction, and the user can add the DatasetRead function.

Step 4.7: The simulation unit completes the current simulation step, and sends a message to the clock agent through the simulation adapter to report that the current simulation step has been completed.

Step 4.8: After confirming receipt of the message report that all simulation units have completed the current time step, the clock agent sends a message to all current simulation units, informing them that they can proceed to the next long simulation step. The message is confirmation information of the simulation step size or configuration adjustment information. If the subsequent simulation step size needs to be adjusted, the configuration adjustment information is sent, and if the subsequent simulation step size remains unchanged, the confirmation information of the simulation step size is sent.

Step 4.9: Go to Step 4.1.

Step 5: The co-simulation ends, and the simulation results are evaluated.

In the above step 2, the co-simulation environment is initialized and configured, and a schematic diagram of establishing an information model is shown in FIG. 3 .

In the above steps 4.3, 4.4 and 4.6, the schematic diagram of the data interaction process between the publisher and the subscriber is shown in Figure 4.

In the above step 4.5, a schematic diagram of the process of publishing data by the communication module transmission simulation adapter is shown in FIG. 5 .

The advantages of the present invention are:

1. The co-simulation system is adopted, so that each simulation unit participating in the co-simulation only runs a part of the complete simulation, and realizes the global simulation of the complete coupled system through data interaction with other simulation units, thus solving multiple software/hardware simulations in the smart factory. The problems brought about by system mixing more comprehensively simulate the operation mechanism of the actual system.

2. The co-simulation scheme based on the subscription/publishing architecture of the OPC-UA protocol is used to carry out the collaborative control of each simulation unit, and a flat industrial simulation system is established, compared with the centralized master controller and multiple slave controllers. Simulation scheme, the present invention further optimizes the system structure, so that the computational complexity is greatly reduced, each simulation unit can interact in a distributed manner, the reliability of the simulation system is significantly improved, and the actual industrial network structure is complex and the information is exchanged frequently. Scenes.

The preferred embodiments of the present invention have been described in detail above. It should be understood that many modifications and changes can be made according to the concept of the present invention by those skilled in the art without creative efforts. Therefore, all technical solutions that can be obtained by those skilled in the art through logical analysis, reasoning or limited experiments on the basis of the prior art according to the concept of the present invention shall fall within the protection scope determined by the claims.

Claims (10)

1. A software/hardware combined simulation system based on OPC-UA is characterized by comprising a simulation unit, a simulation adapter, a communication module and a clock agent;

the simulation unit comprises software such as process simulation, logistics simulation, network simulation, energy simulation and the like, and a hardware simulator such as a special real-time hardware simulator, a physical test bed and the like;

the simulation adapter comprises an OPC-UA client and a simulation unit interface, adopts an OPC-UA protocol and is set as an interface for data interaction between the simulation unit and the middleware agent so as to complete the data interaction of joint simulation;

the communication module sets a transmission Protocol according to the transmission requirement of the simulation unit, and for the simulation unit with a low delay requirement, the communication module adopts a unified architecture Datagram Protocol (OPC UA Datagram Protocol, UADP); for the simulation unit which only needs non-real-time transmission stream, the communication module adopts any one of UADP or UDP protocol;

the clock agent controls the setting of the collaborative simulation step length of the joint simulation, after each simulation unit executes a simulation step length in the joint simulation, the clock agent sends a report message to the clock agent through the simulation adapter to report that the simulation step is completed, and when all the simulation units report that the current simulation step is completed, the clock agent sends a simulation step length confirmation message or a configuration adjustment message to each simulation unit to start the simulation step of the next simulation step length; and if the subsequent simulation step length needs to be adjusted, sending the configuration adjustment information, and if the subsequent simulation step length is kept unchanged, sending the simulation step length confirmation information.

2. The OPC-UA based combined software/hardware emulation system of claim 1 wherein said clock agent is arranged to effect distributed interaction of respective ones of said emulation units; and the working state and feedback data of each simulation unit are sent to the corresponding simulation adapter and the corresponding simulation unit through the corresponding simulation adapter and the communication module according to the subscription rule of the data among the simulators.

3. An adaptive cooperation method of a software/hardware combined simulation system based on OPC-UA is characterized by comprising the following steps:

step 1: a user creates a joint simulation environment and establishes a simulation model of each simulation unit;

step 2: configuring the joint simulation environment, establishing an information model, connecting each simulation adapter to the corresponding simulation unit, setting the QoS (quality of service) requirement required by each simulation unit in the joint simulation environment, and establishing the basic joint simulation environment;

and step 3: determining the cooperative simulation step length of the joint simulation according to the simulation step length of each simulation unit and a step length cooperative adaptive method; the collaborative simulation step length can ensure the stable operation of the whole combined simulation system when an emergency (such as a fault) occurs in a certain simulation unit or some simulation units;

and 4, step 4: running the joint simulation;

and 5: and (5) after the joint simulation is finished, evaluating a simulation result.

4. The adaptive coordination method for OPC-UA based software/hardware co-simulation system according to claim 3, wherein in said step 2, when constructing said co-simulation environment, said simulation adapter of said simulation unit performs data interaction with said simulation unit using OPC-UA protocol.

5. The adaptive coordination method for OPC-UA based software/hardware co-simulation system according to claim 3, wherein in said step 2, when constructing said co-simulation environment, a publish/subscribe (Pub/Sub) mechanism based on OPC-UA protocol is used to complete distributed interaction of each simulation unit.

6. The adaptive collaborative method for OPC-UA based co-simulation systems according to claim 3, wherein in step 3, the collaborative simulation step size is determined to be one of the following three cases:

the first condition is as follows: when each simulation unit normally operates, joint simulation is carried out based on time sequence division, and all simulation units need to complete self simulation calculation before the next time sequence step length; selecting the minimum common multiple of the minimum possible simulation time step length Ti (i is 1, …, N, N is the number of simulation units participating in the joint simulation) of all the simulation units which are close to the communication interaction period T by the joint simulation step length selection;

case two: when one or more simulation units are newly added, after the simulation of the current time step length is completed in the joint simulation, namely after the clock agent receives the information of all the simulation units reporting that the current simulation step is completed, the clock agent recalculates the cooperative simulation step length of the joint simulation; selecting the minimum common multiple of the joint simulation step length in the original normal operation and the minimum possible simulation time step length of the newly added simulation unit according to the joint simulation step length;

case three: when the emergency detection mechanism detects an emergency of one or some simulation units, the joint simulation is adaptively switched to an operation mode based on event triggering, all the emergency needs to be ensured to be sequentially executed according to a correct sequence, and the joint simulation is aperiodic. If the emergency event is preset in the Clock Agent (Clock Agent), the event trigger mode can be entered in advance of the previous time synchronization point, otherwise, each simulation unit returns to the previous simulation synchronization point. And determining the collaborative simulation step length of the joint simulation according to the triggering time points of all current emergency events and the least common multiple of the simulation time step lengths of the rest simulation units which normally operate.

7. The adaptive coordination method for OPC-UA based software/hardware co-simulation system according to claim 3, wherein in said step 3, each of said simulation units performs simulation and data interaction according to its own simulation step size, said co-simulation step size being only used as a minimum interval base step size.

8. The adaptive collaborative method for OPC-UA based combined software/hardware emulation system according to claim 3, wherein the step 4 comprises the steps of:

step 4.1: each simulation unit updates the own simulation output according to the simulation model established in the step 1 in each simulation time step;

step 4.2: each simulation unit sends the updated simulation configuration output to the simulation adapter;

step 4.3: each simulation adapter is used as a publisher to combine the output of the corresponding simulation unit into a data set for preparing data publishing; the nodes of the data set and the OPC-UA information model are connected and comprise a release data set and a data set domain;

step 4.4: the data sets issued by the simulation units are transmitted into a write group; the writing group is a producer of messages in data interaction, and a user can add a data set writing function by himself;

step 4.5: the communication module transmits data in a selected transmission layer by a corresponding transmission protocol according to the time delay requirement of the simulation unit;

step 4.6: after the corresponding simulation adapter serving as a subscriber receives message data of a subscribed topic, a subscription data set is obtained through a read-in group, and the data is sent to the corresponding simulation unit; the read-in group is a receiver of messages in data interaction, and a user can add a data set reading function;

step 4.7: the simulation unit completes the current simulation step, and sends a report message to the clock agent through the simulation adapter to report that the current simulation step is completed;

step 4.8: after confirming that all the simulation units complete the message report of the current time step, the clock agent sends a piece of simulation step length confirmation information or configuration adjustment information to all the current simulation units to inform the simulation units of going to the next long simulation step; if the subsequent simulation step length needs to be adjusted, sending the configuration adjustment information, and if the subsequent simulation step length is kept unchanged, sending the simulation step length confirmation information;

step 4.9: and returning to execute the step 4.1.

9. The adaptive collaborative method for OPC-UA based co-simulation system of claim 8 wherein in step 4.3, the release data set is a container of release information, consisting of released variables and meta information, including a set of variables, event filtering, application specific information and meta data; the data set domain is the description of the release variables and contains the selected information model nodes and additional information such as release, sampling, error processing and the like.

10. The adaptive coordination method for OPC-UA based combined software/hardware emulation system according to claim 8, wherein in said step 4.5, said data transmission comprises the following two cases: for the data stream with low delay requirement, directly mapping to the layer 2 of the reference model by using UADP, and packaging the message in the Ethernet frame; directly mapping the UADP datagram to UDP aiming at the non-real-time data stream, and packaging the message in a UDP packet; the message needs to be transmitted after being safely encapsulated by a safety key server;

the security key server is constructed based on an OPC-UA protocol, manages the security keys of the publisher and the subscriber, and establishes connection with the publisher and the subscriber through an OPC-UA client-server form.

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