Model-based function design method in system engineering

Abstract

The invention discloses a model-based function design method in system engineering. The method comprises the following steps: respectively designing system functions in a conceptual design stage, a logic design stage and a physical design stage; wherein in the conceptual design stage, the system is used as a whole object, and system functions are identified in a predefined scene; in the logic design stage, the identified system functions are decomposed into sub-functions which can be realized by a single device, and specific devices used for undertaking the sub-functions are identified; in the physical design stage, the implementation mode of each sub-function and the implementation mode of the system are concerned. According to the technical scheme, the design problem of system functions in model-based system engineering is solved, namely, the problem of how to decompose the top-layer functions of the system into a plurality of specific devices is required to be solved due to the emergencies of the system functions.

Description

Technical Field

[0001] The present invention relates to the field of system engineering technology, but is not limited to it, and in particular to a function design method in system engineering based on a model. Background Art

[0002] System engineering is an engineering technology for developing complex systems and has been widely used in the aviation field. Traditional system engineering uses documents to design system functions. These functions are designed by different designers in different documents. During the function design process, designers need to maintain the coordination between functions. Since the functions are recorded in different documents, a lot of manpower is required to maintain the coordination of functions. With the increase in system complexity and integration, the traditional system engineering set in the form of documents can no longer meet the development needs of modern complex systems.

[0003] The design of system functions in system engineering is the core work of system architecture design. Most of the system functions cannot be realized by a single device. Usually, multiple devices work together to realize complex system functions. This characteristic of the system is called the emergence of the system, and emergence is the focus of system design. How to decompose the top-level functions of the system into specific devices is the main problem to be solved in the design of complex system functions. Summary of the invention

[0004] The purpose of the present invention is: in order to solve the above-mentioned problem, an embodiment of the present invention provides a function design method in model-based system engineering to solve the design problem of system functions in model-based system engineering, that is, due to the emergent nature of system functions, it is required to solve the problem of how to decompose the top-level functions of the system into multiple specific devices.

[0005] The technical solution of the present invention is:

[0006] An embodiment of the present invention provides a method for designing functions in a model-based system engineering, including:

[0007] Step 1, in the conceptual design phase, consider the system as a whole object and identify the system functions in a predefined scenario;

[0008] Step 2: In the logic design phase, the system functions identified in step 1 are decomposed into sub-functions that can be implemented by a single device, and the specific devices used to undertake each sub-function are identified;

[0009] Step 3, in the physical design phase, focus on how each sub-function is implemented and how the system is implemented.

[0010] Optionally, in the functional design method in the model-based system engineering as described above, step 1 comprises:

[0011] Step 11, develop the system's operating concept, including: setting various scenarios for system operation, defining the execution logic of each activity in each scenario, and assigning each activity to each participating part of the scenario;

[0012] Step 12, for each activity assigned to the system in the activity diagram corresponding to each scenario, set these activities as system functions;

[0013] Step 13: for each set system function, a unified modeling language is used to express each system function in the form of a function with an input variable s and an output variable F.

[0014] Optionally, in the functional design method in model-based system engineering as described above, each scenario in step 11 is described using an activity diagram, the activity diagram includes various activities in this scenario, and the activity diagram is used to express the interactive activities between the system and the operating environment.

[0015] Optionally, in the functional design method in the model-based system engineering as described above, step 2 comprises:

[0016] Step 21, decomposition of system functions, including: decomposing the system functions layer by layer into various sub-functions of the system according to the principle of functional integrity, and further decomposing the decomposed sub-functions according to the principle of functional integrity until all sub-functions can be implemented by a single device;

[0017] Step 22, allocation of sub-functions, includes: allocating the sub-functions decomposed in step 21 to corresponding devices for undertaking each sub-function.

[0018] Optionally, in the functional design method in the model-based system engineering as described above, in step 21, according to the principle of functional integrity, the system function is decomposed layer by layer into various sub-functions of the system in the following manner:

[0019] According to the principle of functional integrity, the system functions are decomposed into sub-functions such as execution, transmission, power, monitoring, and control, and the interaction between people and the system is defined; if the decomposed sub-functions of execution, transmission, power, monitoring, and control cannot be realized by specific equipment, the sub-functions that cannot be realized by specific equipment will be further decomposed downwards, and the decomposition of sub-functions is also carried out according to the principle of functional integrity until all the lowest-level sub-functions can be realized by specific equipment.

[0020] Optionally, in the above-mentioned method for functional design in model-based systems engineering, step 21 comprises:

[0021] Divide the system functions into multiple functional domains according to the division of labor, assign the system functions identified in the conceptual design phase to each functional domain, and the engineer responsible for developing the functional domain completes the decomposition of the system functions; if a sub-function after the decomposition of a system function cannot be realized by a specific device, it will continue to be decomposed, and the sub-function is called a derived function; the derived function is first assigned to the corresponding functional domain, and continues to be decomposed in the functional domain until all underlying sub-functions can be realized by specific equipment.

[0022] Optionally, in the functional design method in the model-based system engineering as described above, step 22 comprises:

[0023] According to the emergent functions realized, the system is divided into multiple subsystems and subsystems.

[0024] Adopting the three-level integration principle, each sub-function in the system is divided into subsystems, subsystems and devices in descending order of hierarchy.

[0025] Optionally, in the above-mentioned function design method in model-based system engineering, the allocation method of sub-functions in step 22 includes:

[0026] Allocate the sub-functions after decomposition of system functions to subsystems, subsystems and equipment levels to integrate the same sub-functions in the corresponding levels; integrate the sub-functions allocated to subsystems into subsystems and equipment; integrate the sub-functions allocated to subsystems into equipment.

[0027] Optionally, in the functional design method in the model-based system engineering as described above, step 3 comprises:

[0028] During the physical design phase, the interfaces between devices are identified based on the relationships between the sub-functions after the system function decomposition, and the interface connections are implemented using mechanical, piping, cable or bus methods.

[0029] The beneficial effects of the present invention are as follows: the embodiment of the present invention provides a method for functional design in model-based system engineering, which designs system functions in the conceptual design stage, the logical design stage and the physical design stage respectively; wherein, in the conceptual design stage, the system is regarded as a whole object, and the system functions are identified in a predefined scenario; in the logical design stage, the identified system functions are decomposed into sub-functions that can be implemented by a single device, and the specific devices used to undertake each sub-function are identified; in the physical design stage, attention is paid to the implementation method of each sub-function and the implementation method of the system. The technical solution provided by the present invention adopts activity diagrams to develop and operate conceptual scenarios, and derives system functions according to the activities assigned to the system in the scenarios; Operation in the SysML language is used to express system functions and sub-functions; SysML activity diagrams are used to express functional logic, and sub-functions are defined on this basis; the functional integrity principle is used to decompose system functions; the functional domain method is used to implement the collaborative development process of functions; and the three-level integration principle of functions is used to implement the allocation of functions. The technical solution provided by the present invention has the following beneficial effects:

[0030] A series of problems related to function definition in the process of applying MBSE method to the development of complex systems are solved. First, the concept scenario of operation is developed by using activity diagram, and the specific activities in the activity diagram are abstracted into system functions, which solves the problem of system function identification; secondly, the system functions and sub-functions are defined by Operation, which can effectively distinguish high-level activities from system functions; thirdly, the activity diagram functional logic is used to associate the activities in the diagram with Operation, which can effectively express the logical relationship between system functions; thirdly, the system functions are gradually developed by using the principle of functional integrity, which can effectively solve the problem of inability to fully define functions in the process of complex function development; in addition, the proposed collaborative development of functions by using functional domains can solve the problem of collaborative development of functions in different professional fields; further, the proposed three-level functional integration principle can effectively solve the problem of multi-level system function allocation. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The accompanying drawings are used to provide a further understanding of the technical solution of the present invention and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the technical solution of the present invention and do not constitute a limitation on the technical solution of the present invention.

[0032] Figure 1 A flowchart of a method for designing functions in system engineering provided by an embodiment of the present invention;

[0033] Figure 2 An activity diagram of a helicopter ground taxiing scene in an embodiment of the present invention;

[0034] Figure 3This is a schematic diagram of using Operation to define system functions in an embodiment of the present invention;

[0035] Figure 4 A schematic diagram of the functional integrity principle in an embodiment of the present invention;

[0036] Figure 5 An activity diagram for expressing the decomposition of brake functions in an embodiment of the present invention;

[0037] Figure 6 A schematic diagram of a collaborative design strategy for system functions in an embodiment of the present invention;

[0038] Figure 7 A schematic diagram of implementing sub-function allocation by adopting the three-level integration principle of functions in an embodiment of the present invention;

[0039] Figure 8 Schematic diagram of the physical interface between devices in an embodiment of the present invention. DETAILED DESCRIPTION

[0040] The accompanying drawings are used to provide a further understanding of the technical solution of the present invention and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the technical solution of the present invention and do not constitute a limitation on the technical solution of the present invention.

[0041] As described in the above background technology, since most functions of the system cannot be implemented by a single device, multiple devices usually collaborate to implement complex system functions, which brings difficulties to the design of system functions in model-based system engineering (MBSE).

[0042] MBSE uses a unified modeling language to build a system model and define the elements in the system model and the relationships between the elements. On this basis, design errors introduced by coordination problems can be reduced and system development efficiency can be improved. SysML, as the core part of MBSE, has been widely used in the development of complex systems such as aviation and aerospace. There are 9 views in SysML, namely package diagram, requirement diagram, activity diagram, sequence diagram, state machine diagram, use case diagram, block definition diagram, internal block diagram and parameter diagram. These 9 views can be used to express the structure and behavior of the system. The SysML language does not clearly define the expression of system functions and functional logic.

[0043] Some existing MBSEs do not clearly propose a method suitable for multi-level system function design. The existing MBSE only explains the concepts of function decomposition and integration, but does not propose the principles of design function decomposition and integration. In the actual work process, it is difficult to clearly define the function logic because the system functions are too complex, and omissions often occur. These omitted functions will eventually cause system errors. For complex systems, the development process of their functions involves many professional fields, and it is difficult for a single person to complete the design of system functions. The design of system functions requires the collaboration of personnel from multiple professional fields. The existing MBSE method does not provide a method for collaborative function development.

[0044] As mentioned above, the present invention aims to solve the problem of designing system functions in model-based system engineering, that is, to solve the problem of how to decompose the top-level functions of the system into multiple specific devices. Specifically, the application of MBSE in multi-level complex systems specifically needs to solve the following problems:

[0045] 1. Clarify the expression of functions and propose a method for decomposing functions;

[0046] 2. Solve the problem of collaborative design of functions;

[0047] 3. Clarify the rules of system integration, realize the allocation of functions, and achieve the layer-by-layer transmission of functions within multi-level complex systems.

[0048] The present invention provides the following specific embodiments which can be combined with each other. The same or similar concepts or processes may not be described in detail in some embodiments.

[0049] The system development process is the process of turning the needs of stakeholders into product realization. In this process, it is necessary to identify system functions and decompose and distribute the functions layer by layer to each device. Based on this, the embodiment of the present invention provides a functional design method in model-based system engineering, which designs system functions in the conceptual design stage, logical design stage and physical design stage respectively; the system architecture is divided into five levels: task system, system, subsystem, subsystem and device; as shown in Table 1 below, the corresponding relationship between each design stage and system level in the embodiment of the present invention is:

[0050] Table 1 Correspondence between design phases and system levels

[0051]

[0052] It can be seen that the task system layer defines the boundaries of the system, corresponding to the conceptual design stage. The logical design stage corresponds to three system levels, namely the system layer, subsystem layer and subsystem layer, and defines the process of function decomposition and allocation. The physical design stage corresponds to the device layer, defining the implementation methods of functions and systems.

[0053] For a multi-level complex system, the embodiment of the present invention provides a functional design method in system engineering, such as Figure 1 FIG. 1 is a flowchart of a method for designing a function in a system engineering according to an embodiment of the present invention. The method for designing a function includes the following steps:

[0054] Step 1, in the conceptual design phase, consider the system as a whole object and identify the system functions in a predefined scenario;

[0055] Step 2: In the logic design phase, the system functions identified in step 1 are decomposed into sub-functions that can be implemented by a single device, and the specific devices used to undertake each sub-function are identified;

[0056] Step 3, in the physical design phase, focus on how each sub-function is implemented and how the system is implemented.

[0057] In one implementation of the embodiment of the present invention, the implementation process of step 1 may include:

[0058] Step 11, develop the system's operating concept, including: setting various scenarios for system operation, defining the execution logic of each activity in each scenario, and assigning each activity to each participating part of the scenario;

[0059] Step 12, for each activity assigned to the system in the activity diagram corresponding to each scenario, set these activities as system functions;

[0060] Step 13: for each set system function, a unified modeling language is used to express each system function in the form of a function with an input variable s and an output variable F.

[0061] In this implementation, each scenario in step 11 is described using an activity diagram, which includes various activities in this scenario. The activity diagram is used to express the interactive activities between the system and the operating environment.

[0062] In one implementation of the embodiment of the present invention, the implementation process of the above step 2 may include:

[0063] Step 21, decomposition of system functions, including: decomposing the system functions layer by layer into various sub-functions of the system according to the principle of functional integrity, and further decomposing the decomposed sub-functions according to the principle of functional integrity until all sub-functions can be implemented by a single device;

[0064] Step 22, allocation of sub-functions, includes: allocating the sub-functions decomposed in step 21 to corresponding devices for undertaking each sub-function.

[0065] In this implementation, in step 21, according to the principle of functional integrity, the system function is decomposed layer by layer into the sub-functions of the system as follows:

[0066] According to the principle of functional integrity, the system functions are decomposed into sub-functions such as execution, transmission, power, monitoring, and control, and the interaction between people and the system is defined; if the decomposed sub-functions of execution, transmission, power, monitoring, and control cannot be realized by specific equipment, the sub-functions that cannot be realized by specific equipment will be further decomposed downwards, and the decomposition of sub-functions is also carried out according to the principle of functional integrity until all the lowest-level sub-functions can be realized by specific equipment.

[0067] In this implementation, the functional decomposition of step 21 includes:

[0068] Divide the system functions into multiple functional domains according to the division of labor, assign the system functions identified in the conceptual design phase to each functional domain, and the engineer responsible for developing the functional domain completes the decomposition of the system functions; if a sub-function after the decomposition of a system function cannot be realized by a specific device, it will continue to be decomposed, and the sub-function is called a derived function; the derived function is first assigned to the corresponding functional domain, and continues to be decomposed in the functional domain until all underlying sub-functions can be realized by specific equipment.

[0069] In this implementation, step 22 includes:

[0070] According to the emergent functions realized, the system is divided into multiple subsystems and subsystems.

[0071] Adopting the three-level integration principle, each sub-function in the system is divided into subsystems, subsystems and devices in descending order of hierarchy.

[0072] In this implementation, the allocation method of the sub-functions in step 22 includes:

[0073] Allocate the sub-functions after decomposition of system functions to subsystems, subsystems and equipment levels to integrate the same sub-functions in the corresponding levels; integrate the sub-functions allocated to subsystems into subsystems and equipment; integrate the sub-functions allocated to subsystems into equipment.

[0074] In an implementation of the embodiment of the present invention, the implementation of the above step 3 may include:

[0075] During the physical design phase, the interfaces between devices are identified based on the relationships between the sub-functions after the system function decomposition, and the interface connections are implemented using mechanical, piping, cable or bus methods.

[0076] The functional design method in model-based system engineering provided by the embodiment of the present invention designs system functions in the conceptual design stage, the logical design stage and the physical design stage respectively; wherein, in the conceptual design stage, the system is regarded as a whole object, and the system functions are identified in a predefined scenario; in the logical design stage, the identified system functions are decomposed into sub-functions that can be realized by a single device, and the specific devices used to undertake each sub-function are identified; in the physical design stage, attention is paid to the implementation method of each sub-function and the implementation method of the system. The technical solution provided by the present invention adopts activity diagrams to develop and operate conceptual scenarios, and derives system functions according to the activities assigned to the system in the scenarios; Operation in the SysML language is used to express system functions and sub-functions; SysML activity diagrams are used to express functional logic, and sub-functions are defined on this basis; the functional integrity principle is used to decompose system functions; the functional domain method is used to realize the collaborative development process of functions; and the three-level integration principle of functions is used to realize the allocation of functions. The technical solution provided by the present invention has the following beneficial effects:

[0077] A series of problems related to function definition in the process of applying MBSE method to the development of complex systems are solved. First, the concept scenario of operation is developed by using activity diagram, and the specific activities in the activity diagram are abstracted into system functions, which solves the problem of system function identification; secondly, the system functions and sub-functions are defined by Operation, which can effectively distinguish high-level activities from system functions; thirdly, the activity diagram functional logic is used to associate the activities in the diagram with Operation, which can effectively express the logical relationship between system functions; thirdly, the system functions are gradually developed by using the principle of functional integrity, which can effectively solve the problem of inability to fully define functions in the process of complex function development; in addition, the proposed collaborative development of functions by using functional domains can solve the problem of collaborative development of functions in different professional fields; further, the proposed three-level functional integration principle can effectively solve the problem of multi-level system function allocation.

[0078] The implementation of the function design method in model-based system engineering provided by the present invention is schematically described below through a specific implementation example.

[0079] Implementation Example

[0080] This implementation example provides a functional design method in model-based system engineering, which designs system functions in the conceptual design stage, logical design stage, and physical design stage. The conceptual design stage studies the system as a whole and identifies system functions in predefined scenarios. The logical design stage further decomposes the identified system functions into sub-functions that can be implemented by a single device, and finally identifies the specific devices that undertake each sub-function. The physical design stage focuses on the implementation methods of specific sub-functions and the implementation methods of the system.

[0081] The architecture of a multi-level complex system is divided into five levels: task system, system, subsystem, subsystem, and equipment. The task system level defines the boundaries of the system and corresponds to the conceptual design stage. The logical design stage corresponds to three system levels, namely the system level, subsystem level, and subsystem level, and defines the process of functional decomposition and allocation. The physical design stage corresponds to the equipment level and defines the implementation methods of functions and systems; see the corresponding relationship shown in Table 1.

[0082] like Figure 1 As shown, the functional design method in model-based system engineering provided by this implementation example is implemented through the following steps:

[0083] Step 1: Develop the system's concept of operation;

[0084] First, the concept of system operation is developed in the conceptual design phase, including: various scenarios of system operation are defined in the conceptual design phase. Each scenario is described by an activity diagram, including various activities. The activity diagram expresses the interaction between the system and the operating environment (including users, operators, equipment, facilities, natural environment, etc.). The execution logic of each activity in each scenario is defined, and the swimlane diagram is used to allocate each activity to each participating part of the scenario (including the system, other equipment and people interacting with the system).

[0085] Identify system functions in each scenario of the developed operational concept. The activities assigned to the system in the activity diagram of each scenario are the functional behaviors of the system and can be further abstracted into system functions. For example, Figure 2 This is an activity diagram of a helicopter ground taxiing scene in an embodiment of the present invention. The activity diagram defines activities such as brake and park. These activities define the functional behavior of the helicopter. On this basis, the brake activity is set as the brake function, and the park activity is set as the park function. Figure 2 Operating the brake and operating the parking brake are functional behaviors of the operator and will not be defined as system functions.

[0086] The present invention adopts Operation to express function. Figure 3 FIG. 1 is a schematic diagram of using Operation to define system functions in an embodiment of the present invention. Figure 3 In the example, a helicopter is represented by a block, and the Operation property under the "Helicopter block" defines the brake function. In engineering, functions can be abstracted into functions that conform to specific physical laws. Functions that can be represented as functions have input and output parameters. The input parameters correspond to the input variables of the function, and the output parameters correspond to the output variables of the function. Figure 3In the figure, the function is represented by Operation under the "helicopter block". The Operation that expresses the brake function through Operation has an input variable s and an output variable F. S expresses the control signal of the brake function, and F expresses the brake force output by the brake function.

[0087] Step 2: Decomposition of system functions and allocation of sub-functions;

[0088] Most system functions need to be realized through the cooperation of multiple devices. In the logic design stage, the system functions are decomposed layer by layer into sub-functions that can be realized by a single device, and then allocated to specific devices layer by layer. Figure 4 As shown, it is a schematic diagram of the functional integrity principle in an embodiment of the present invention. The functional decomposition of the present invention is as follows Figure 4 The functional integrity principle shown in the figure is implemented. The realization of system functions can be divided into execution, transmission, power, control, monitoring and other parts. The interaction between people and the system is part of the control and is parallel to the control. The parts of the system function decomposed according to the functional integrity principle are called sub-functions of the system. The sub-functions are also decomposed according to the functional integrity principle until all sub-functions can be realized by a single device.

[0089] 2.1, in this step, the system function decomposition is carried out according to the principle of functional integrity as follows:

[0090] A system function first adopts Figure 4 The functional integrity principle decomposition shown in the figure decomposes the system functions into sub-functions such as execution, transmission, power, monitoring, and control, and defines the interaction between people and the system; if the decomposed sub-functions such as execution, transmission, power, monitoring, and control cannot be implemented by specific equipment, it is still necessary to further decompose the sub-function. The decomposition of sub-functions is still carried out in accordance with the functional integrity principle, and so on, until all the bottom-level sub-functions can be implemented by specific equipment. Decomposing functions or sub-functions according to the functional integrity principle can ensure that there will be no missing sub-functions after each decomposition. The method of gradually applying the functional integrity principle to decompose functions can ensure that there will not be too many sub-functions decomposed each time, which is conducive to the smooth implementation of functional decomposition.

[0091] The result of functional decomposition is expressed in an activity diagram. Figure 5 As shown, it is an activity diagram for expressing the decomposition of the braking function in an embodiment of the present invention. Figure 5 The activities in are sub-functions. Each functional behavior will eventually be abstracted into sub-functions, also expressed by Operation.

[0092] like Figure 5 As shown, Figure 5 Specifically Figure 2The result of the decomposition of the braking function in the lane. The concave pentagon in the landing gear lane indicates receiving the pilot's braking command, and the convex pentagon in the avionics lane indicates providing information to the pilot. The pilot is responsible for operating the brake. The concave pentagon and the convex pentagon only indicate the interaction with people, not the result of the functional decomposition. "Provide braking pressure", "generate braking signal", "distribute braking pressure", "generate braking torque", "transmit braking torque", "generate braking force" and "monitor speed" are the sub-functions after the decomposition of the braking function. The "provide braking pressure" sub-function outside the lane cannot be implemented by specific equipment and needs to be further decomposed. The sub-functions inside the lane indicate that they can be implemented by specific equipment of the landing gear and avionics system. The "provide braking pressure" sub-function is of the power type, the "generate braking signal" sub-function is of the control type, the "distribute braking pressure" and "transmit braking torque" sub-functions are of the transmission type, the "transmit braking torque" and "generate braking force" sub-functions are of the execution type, and the "monitor speed" is of the monitoring type.

[0093] The specific processing method of function decomposition in this step: the function decomposition process is a highly professional process and must be completed by senior engineers in various professional fields. In order to solve the problem of collaborative development of functions, the present invention proposes a collaborative design strategy for system functions, such as Figure 6 As shown, a schematic diagram of the collaborative design strategy of system functions in an embodiment of the present invention. First, the functional domains are divided according to the division of labor; the system functions identified in the conceptual design phase are assigned to each functional domain, and the engineers responsible for developing the functional domain complete the function decomposition; if the sub-functions after a system function decomposition cannot be implemented by a specific device, they need to be further decomposed. In this case, the sub-function is called a derived function; the derived function is first assigned to the corresponding functional domain, and the decomposition continues in the functional domain. And so on, until all underlying sub-functions can be implemented by specific devices.

[0094] 2.2, the specific processing method of function allocation in this step: the principle of function integration is the emergence of the system. The functions of the system layer, subsystem layer, and subsystem layer are all emergent functions. The subsystem layer and subsystem layer are divided according to the emergent functions they implement. Among them, the subsystem layer is allocated according to the functions it implements. For example, the hydraulic subsystem implements the functions related to providing hydraulic pressure, and the landing gear subsystem implements the functions related to ground movement. Functions such as providing hydraulic pressure and ground movement cannot be achieved by a single device and are emergent functions. Among the sub-functions of the braking function, generating braking signals, distributing braking pressure, generating braking torque, transmitting braking torque, and generating braking force are the main parts of the braking function. These functions are allocated to the landing gear subsystem, and emerge as the braking function of the landing gear subsystem.

[0095] like Figure 7 As shown in FIG. 1 , it is a schematic diagram of implementing sub-function allocation by adopting the three-level integration principle of functions in an embodiment of the present invention. Figure 7 As shown, the sub-functions after decomposition of each system function can be integrated into the subsystem, subsystem and equipment levels; each sub-function allocated to the subsystem can also be integrated into the subsystem and equipment; each sub-function allocated to the subsystem can be integrated into the equipment.

[0096] Step 3, the physical design phase focuses on how each sub-function is implemented and how the system is implemented;

[0097] In the physical design phase, we focus on the realization of the system and complete the realization of the interface between devices. Since the devices that realize each sub-function are arranged in different locations, each device needs to be connected together in a certain way. This way of connecting devices together is called a physical interface. In the physical design phase, according to the relationship between each sub-function after the system function is decomposed, the interface between each device is identified; and the interface connection is realized by mechanical, pipe, cable or bus.

[0098] It should be noted that the physical interface does not implement specific functions, but only transmits information between devices, such as Figure 8 FIG. 1 is a schematic diagram of a physical interface between devices in an embodiment of the present invention. Figure 8 Device 1 implements function A1, device 2 implements function A2, interface 1 connects device 1 and device 2, and interface 1 only implements the transmission of information between function A1 and function A2; the devices and interface functions constitute the physical composition of the system.

[0099] Although the embodiments disclosed in the present invention are as above, the contents are only embodiments adopted to facilitate understanding of the present invention and are not intended to limit the present invention. Any technician in the field to which the present invention belongs can make any modifications and changes in the form and details of implementation without departing from the spirit and scope disclosed in the present invention, but the patent protection scope of the present invention shall still be subject to the scope defined in the attached claims.

Claims

1. A functional design method in model-based systems engineering, characterized in that: include: Step 1, in the conceptual design phase, consider the system as a whole object and identify the system functions in a predefined scenario; Step 2: In the logic design phase, the system functions identified in step 1 are decomposed into sub-functions that can be implemented by a single device, and the specific devices used to undertake each sub-function are identified; Step 3, in the physical design phase, focus on how each sub-function is implemented and how the system is implemented.

2. The functional design method in model-based system engineering according to claim 1, characterized in that: The step 1 comprises: Step 11, develop the system's operating concept, including: setting various scenarios for system operation, defining the execution logic of each activity in each scenario, and assigning each activity to each participating part of the scenario; Step 12, for each activity assigned to the system in the activity diagram corresponding to each scenario, set these activities as system functions; Step 13: for each set system function, a unified modeling language is used to express each system function in the form of a function with an input variable s and an output variable F.

3. The functional design method in model-based system engineering according to claim 2, characterized in that: Each scenario in step 11 is described using an activity diagram, which includes various activities in the scenario. The activity diagram is used to express the interactive activities between the system and the operating environment.

4. The method for functional design in model-based system engineering according to claim 2, characterized in that: The step 2 comprises: Step 21, decomposition of system functions, including: decomposing the system functions layer by layer into various sub-functions of the system according to the principle of functional integrity, and further decomposing the decomposed sub-functions according to the principle of functional integrity until all sub-functions can be implemented by a single device; Step 22, allocation of sub-functions, includes: allocating the sub-functions decomposed in step 21 to corresponding devices for undertaking each sub-function.

5. The method for functional design in model-based system engineering according to claim 4, characterized in that: In step 21, according to the principle of functional integrity, the system function is decomposed layer by layer into the sub-functions of the system as follows: According to the principle of functional integrity, the system functions are decomposed into sub-functions such as execution, transmission, power, monitoring, and control, and the interaction between people and the system is defined; if the decomposed sub-functions of execution, transmission, power, monitoring, and control cannot be realized by specific equipment, the sub-functions that cannot be realized by specific equipment will be further decomposed downwards, and the decomposition of sub-functions is also carried out according to the principle of functional integrity until all the lowest-level sub-functions can be realized by specific equipment.

6. The method for functional design in model-based system engineering according to claim 5, characterized in that: The functional decomposition of step 21 includes: Divide the system functions into multiple functional domains according to the division of labor, assign the system functions identified in the conceptual design phase to each functional domain, and the engineer responsible for developing the functional domain completes the decomposition of the system functions; if a sub-function after the decomposition of a system function cannot be realized by a specific device, it will continue to be decomposed, and the sub-function is called a derived function; the derived function is first assigned to the corresponding functional domain, and continues to be decomposed in the functional domain until all underlying sub-functions can be realized by specific equipment.

7. The method for functional design in model-based system engineering according to claim 5, characterized in that: The step 22 comprises: According to the emergent functions realized, the system is divided into multiple subsystems and subsystems. Adopting the three-level integration principle, each sub-function in the system is divided into subsystems, subsystems and devices in descending order of hierarchy.

8. The method for functional design in model-based system engineering according to claim 7, characterized in that: The allocation method of the sub-functions in step 22 includes: Allocate the sub-functions after decomposition of system functions to subsystems, subsystems and equipment levels to integrate the same sub-functions in the corresponding levels; integrate the sub-functions allocated to subsystems into subsystems and equipment; integrate the sub-functions allocated to subsystems into equipment.

9. The method for functional design in model-based system engineering according to any one of claims 4 to 8, characterized in that: The step 3 comprises: During the physical design phase, the interfaces between devices are identified based on the relationships between the sub-functions after the system function decomposition, and the interface connections are implemented using mechanical, piping, cable or bus methods.

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