# Development of a Novel Open Control System Implementation Method under Industrial IoT
## 5 Conclusions and Future Work  
In order to break the closed architecture of modern control systems in industrial automation, this paper presents a new implementation method to construct open control systems in the environment of the industrial IoT. Current open control systems are reviewed according to the open system definition and the criteria of openness, and two key issues are summarized: the decoupling of control tasks between each other and the decoupling of control tasks from heterogeneous infrastructures. Regarding the first issue, in contrast to current open control prototypes that depend on defining a control task granularity standard, this paper suggests relying on the control domain's formal description to decouple control tasks. Given that modern control systems often have both discrete and continuous behaviors, a hierarchical semantic model based on an extended FSM and a dependency network model with the time property is proposed. Regarding the second issue, moreover, unlike current open control prototypes that mostly develop control tasks in the form of components or services to achieve openness, this paper decouples control tasks from infrastructures via virtualization technologies. By discussing the merits and limitations of different virtualization technologies, and given the heterogeneity of infrastructures and the complexity of control domain, this paper suggests a hybrid virtualization approach based on containers and wasn. An open CNC demonstration is constructed by the proposed implementation method and compared to current open control prototypes from the openness criteria point of view.  
In summary, from the control system perspective, the proposed implementation method allows the dynamic customization of control systems according to the production requirements, which contributes to responding to the mass customization challenge. From the infrastructure resource perspective, the proposed implementation method enables the improvement of the resource utilization rate, which contributes to green manufacturing.  
In the future, the following works will be studied in sequence:  
* The verification of the proposed hierarchical semantic model and the development of the control domain formal description application with a user interface.
* The study of unikernel-based control task virtualization to complement containers and wasn, and the theoretical analysis of the hybrid virtualization approach to maximize the utilization of infrastructure resources in the industrial IoT.
* A corresponding operation pattern will be designed to replace the traditional stand-alone operation pattern, and this new operation pattern will integrate the implementation of the scheduler task.  
**Author Contributions:** Conceptualization, L.L. and X.Q.; methodology, L.L.; investigation, L.L. and Z.X.; writing--original draft preparation, L.L.; writing--review and editing, X.Q.; funding acquisition, L.L. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This research was funded by the Science, Technology and Innovation Commission of Shenzhen Municipality No. 20220809175919001.  
**Data Availability Statement:** Data are contained within the article.  
**Conflicts of Interest:** [PERSON] has not received research grants from China Nuclear Power Technology Research Institute Co., Ltd. However, [PERSON] from China Nuclear Power Technology Research Institute Co., Ltd. has been involved in this study as a consultant.