The high complexity of industrial systems,the diversity and variability of production environment and working conditions,and the fragmentation of industrial knowledge accumulation make it more difficult to carry out the application of various new technologies.In order to avoid detours,enterprises must avoid these common misunderstandings before entering the”race track”of digital twins:
Mistake 1:3D simulation data display≠digital twins!
When people refer to digital twins,they often associate directly with 3D simulation display,especially some data displayed in the background of 3D simulation.This understanding is one-sided.
“The real core of digital twins lies in the near-real-time calculation of the data collected at the production site to obtain an accurate understanding of the working conditions at the production site,so as to make decisions in line with the event.The core lies in the data and calculation.”
The 3D simulation display is only the mapping of 3D space,and the result is to make the display of data,status or events and the browsing of the system more intuitive.The display in large screen mode can give visitors a cool look.However,this is only a human-computer interface expression,without the support of digital twins’data and algorithms,these displays have little significance.
Of course,if the digital twins have rich data and powerful algorithms,and the corresponding industrial APP is also powerful,most of the production operation and maintenance operations can be solved automatically without manual intervention,then the necessity of 3D simulation display will also be weakened.And if there is an algorithm that can effectively monitor,alarm,record and process the equipment status,the existing”virtual patrol”will have little effect.
Of course,in addition to meeting the previous process requirements,3D simulation,as a kind of digital twin model,will continue to play a unique role in the design,equipment disassembly and maintenance operation guidance,as well as in the replay of operational events of moving equipment,by establishing a visual model based on the actual spatial parameters of physical entities and the topological relationship of space,especially in combination with AR.
Mistake 2:Traditional analog simulation model≠digital twins!
Simulation is to establish a model in a computer,reproduce the essential process occurring in a physical system,and conduct experimental calculations by adjusting the input and control parameters of the model,which is used to study and evaluate the existing or design system characteristics and behaviors,and to find feasible or optimal designs.It is widely used in the manufacturing industry.
“But generally speaking,the cost of building the actual system is high,and some tests take a long time or are dangerous.Using computer simulation to carry out experiments is obviously a means to get twice the result with half the effort.”
And the actual system is generally very complex,and is limited by the current technology.When establishing the simulation model,most of them need to be simplified.Only focusing on the key factors,ignoring the secondary factors,or only simulating some aspects of the system can meet the requirements of verifying whether the design results meet certain design requirements(such as safety production)during the design process,but the accuracy of calculation is not easy to meet the requirements of supervision and optimization during the production process.
In addition,most of the simulation model software used in the design process is based on the simulation data,which is used in batches and is not connected with the real-time data of the production site.In terms of computing performance,it is not easy to support continuous streaming computing,and it is difficult to support the control and optimization of the production and operation process in the digital twins.
In general,analog simulation is an important supporting technology for digital twins.The simulation model in the design process is only an important part of the digital twin algorithm model,not equal to the digital twin itself.
Myth 3:Digital twins≠”alchemy”!
“Digital twins are not alchemy,but opportunities for continuous improvement.”
The effectiveness of digital twinning depends on the complexity of the equipment or production process,the difficulty of mode determination,state prediction or optimization strategy calculation,and the completeness and accuracy of the sensor data collected from the site for calculation.Just as people’s cognition of the real world has a continuous learning process,the digital twins’grasp of the physical world also has a process of upgrading from rough to fine.
As a methodology,a framework technology system,or even a middleware oriented to the digital architecture of the production and operation environment,digital twinning is not a magic trick that can be achieved overnight.
Enterprises should not regard digital twinning as a golden touch technology,and unrealistic expectation is that digital twinning can solve difficult problems in one step.The core of digital technology is software.In essence,it is a technology of continuous improvement,and software without continuous iterative improvement is lifeless.
The true meaning of”digital twins”
“Digital twinning is an idea,methodology,technical system and technical capability of industrial digitalization.”
●As a basic concept,the core of Digital Twin is to use sensor data and computing to realize deep understanding and intelligent decision-making of physical entities,effectively control and manage these physical entities,and better serve human beings;
●As a technical concept,digital twinning is the mapping of physical entities in the computer,which belongs to the problem of computer engineering and also belongs to the category of software engineering.To map physical entities,it is necessary to carry out mode determination,root cause analysis,state prediction and other calculations for its state,and there can be many implementation methods.
Computing is the core of”digital twins”
In the early stage of computer development,we only had assembly language,which is almost to use the machine language of the computer processor to program.It is a long series of instructions without any structure.It is laborious,time-consuming,error-prone,difficult to troubleshoot,and can not be reused.
Later,high-level languages,such as Fortran and C,introduced logic and data structures,and were able to organize code by task in the form of functions.Since functions can be called in multiple places as a code unit,code reuse was also realized.
However,these programming languages belong to the process programming paradigm.For large program systems,there are many functions that need to be decomposed,and the call relationship is complex.The difficulty of design,development and maintenance will become very high.Reuse is difficult,and the cost of software development and maintenance will become very high.
The later object-oriented programming paradigm(OOP),such as the earliest Smalltalk,and later widely used C++and Java,introduced the concept of object.Corresponding to the”object”or”logic body”in real life in the form of object,its characteristic data(attribute)and operation logic(behavior)are encapsulated in the object body as data and functions respectively.
This way makes the design of software more in line with the way of thinking in real life,not only makes the design more structured,but also enhances the reusability and maintainability of software,improves the quality of software,and reduces the cost of software development.
As a set of methodology
As a methodology,object-oriented programming paradigm(OOP)can be used for reference and reference in the design of digital twins.The design of digital twins can extend the object-oriented programming paradigm to the entities in the physical world,represent the physical entities in the form of objects in software,and establish corresponding software objects for each physical entity.
In digital twinning,data is used to represent the attributes and states of physical entities,and algorithm models are used to simulate their behaviors.In addition,the object-oriented design method can support the use of unit objects to build more and more complex systems in the way of building blocks.Starting from the number of components,building equipment,units,production lines,workshops,and even the digital twins of the whole factory become the digital representation of the whole factory.
The construction of digital twins in this way reflects the attributes,states and behaviors of physical entities structurally,shields the complexity of the site,and simplifies the construction of digital industrial applications.
As a technical framework system
Digital twinning maps entities in the real world,and calculates their states through pattern determination,root cause analysis,state prediction,etc.-For this purpose,digital twinning is generally not suitable as an application of terminals for users,but as a supporting technology for digital chemical industry applications,and can even be built as middleware in these application architectures.
To map the status and behavior of devices in the production site,digital twins need to establish corresponding image objects in the software.If we use OOP for reference,we need to set the parameters corresponding to the device in the digital twin.These parameters include attributes,states,instructions and other types.
On this basis,connect these parameters with the data collected from the device one by one.If a certain operating parameter of the device changes,it will also be reflected on the corresponding digital twins in almost real time.This is a process of sorting out equipment data,and also a process of settling industrial knowledge into software.
After that,the algorithm model is used to analyze and calculate these data and map the behavior of physical entities.For example,to determine or predict the operation status of the equipment,whether it is abnormal operation,whether it meets the process requirements,whether it meets the energy efficiency requirements,etc.If the abnormality is determined,the root cause analysis of the abnormality,as well as the solution strategy,will use the mechanism model and data algorithm model.
However,the final solution must take the operation characteristics and behavior of the equipment mapped by the digital twins as input,make appropriate decisions and implement them in combination with the business logic and production rules of production operation management,especially the principles and methodologies of lean management.These logic can generally be implemented in the way of App.
This is the role of Digital Twin as a technical framework system and as the middleware of the digital industrial application architecture:it can lower the IOT data and connect the site;It carries on the industrial APP,conveys the insight and cognition of the site status and behavior,and supports the decision-making of controlling the site.
Characteristics and functions of digital twins
At the level of digital production and operation,after more than 20 years of information development,manufacturing enterprises have adopted various design software and CAD in the process of product and process design.On the basis of the original automated production,they have realized the automation and informatization of business management processes.
However,most industrial software is used to manage business processes and plan production under normal conditions.In the production process,there is still a lot of work to be done to make full use of the large amount of equipment data on the production site,further reduce the equipment failure rate,improve the overall equipment efficiency,improve product quality,reduce energy and material consumption,and ensure the compliance of the production process.
At this stage,the determination of production anomalies,root cause analysis and coping strategies are mostly dependent on operating experience and manual operations.In the new round of digital development,whether in product and process design or in the production process,how to use data from the physical world to make accurate judgments,intelligent decisions and timely implementation of the actual situation has become the focus of enterprises.
Enterprises need to get through the efficient collaborative operation of multiple equipment upstream and downstream of the production process,and integrate the principles and methods of lean management into the digital production and operation management,and pursue the standardization,stability and continuous improvement of the production process.The birth of digital twinning technology can just use the digital virtual replication of physical entities to solve practical problems by computing.
There are many characteristics of digital twins(see the figure below),and OT and decoupling are worth emphasizing.
When we use the methodology of digital twins to establish a new technical framework,from the perspective of OT in structure,we take the equipment as the main object to model,define the characteristic data of the equipment,and establish an algorithm model to determine or predict the behavior of the equipment.In this way,the equipment experts can easily define the characteristic data of the equipment,and the experts who understand the equipment operation and production process can cooperate with the algorithm engineers to establish the algorithm model.The two sides can be integrated through the digital twin structure.
In this way,digital twins are built for various devices,and data definitions and algorithms are encapsulated into software components that can be reused in multiple plug-ins.Equipment suppliers familiar with equipment or industrial design institutes familiar with process can also independently build and provide digital twins of a certain type of equipment or production process,and can support multiple scenarios.
In addition,the digital twin itself decouples and separates the software structure from other business software components(such as production rules or user interfaces).When the algorithm of the digital twin is improved iteratively,such as improving the accuracy of a certain calculation,only the digital twin needs to be updated independently,and there is no need to modify and change the business software code.
In short,using digital twins,users have the opportunity to build a technical framework that can effectively support the integration of digital technology and industrial knowledge,promote the precipitation,accumulation and continuous improvement of industrial knowledge,and promote the extensive reuse and sharing of eco-industrial knowledge.
Make good use of”digital twins”:reuse and accumulation are the key
To realize the value of digital twins,it needs the integration of multiple technologies and knowledge,especially the integration of digital technology(IT)and industrial knowledge(OT).For manufacturing enterprises,they often encounter the dilemma of weak IT technology resources and weak OT knowledge accumulation.There are many obstacles to using digital twins alone to promote digital production and operation management.
To establish an effective digital twin in the industrial field,it needs the joint efforts of industrial ecological partners,including digital technology suppliers,equipment suppliers,industrial knowledge suppliers(such as industrial research institutes and design institutes)and enterprises as Party A to build and improve technologies and systems.
In this process,it is particularly important to promote the reuse of digital twins in the industry ecosystem.It can be imagined that in each enterprise scenario,software is used to deeply and accurately characterize and map the characteristic state and behavior of equipment and production process.The threshold of independent construction is high,the cost is high,and the accumulation and improvement are slow.
Tips：
At present,many enterprises still use the traditional software project-based implementation management mechanism to build digital application systems,which is a one-time project implementation.After the solution supplier wins the bid for implementation and delivery,there is generally no consideration or opportunity for subsequent maintenance or update after one year of warranty.Next time,it is difficult to accumulate and improve.
Enterprises need to maintain a long-term cooperative relationship with solution providers,provide corresponding inputs to support the maintenance and improvement of software applications,and leave a long-term path for the established digital solutions to avoid one-shot trading.At the same time,enterprises can also consider the use of third-party suppliers’products to avoid unnecessary self-built projects,which can leverage supplier products to maximize reuse and accumulate improved results.
If the corresponding digital twin sharing technology framework and value trading mechanism can be established in the industry to promote the reuse of the digital twin,it will reduce the start-up cost,accelerate the improvement of its effectiveness,quality and performance,and improve the cost performance of the digital twin application.
In a broader sense,software can be said to be used.With more users,more scenarios,and more problems solved for a software application,its functions will become rich and powerful,and its stability will be improved.This is the result of reuse and accumulation.
This is why third-party software products are generally better than self-developed ones.This is caused by the difference between space(scenario)and time accumulation,especially the advantage of cross-space reuse.
