## 4 Event-Based Programming Model With Geometric Spatial Semantics
### Semantic
#### 4.3.2 **ea** Execution Semantic in GeFB
## 6 Conclusions

The PTIDES model uses the time semantic mechanism to guarantee the deterministic of the execution of the CPS system and can describe the computational and time attributes of CPPS. Similarly, an enhanced FB model [16] has been proposed for the same purpose. However, the geometric property of physical dynamic are ignored. In this paper, an event-based programming model based on IEC 61499 with geometric spatial semantics, GePro, has been proposed for integrated programming framework of CPPS to bridge the gap of lacking geometric property. The GePro framework considers the representation of geometric information in space and the semantic transformations among different geometric coordinate systems for multirobot coordination. We have defined the syntax and semantics for GePro and have used a prototype operating in a reconfigurable collaborative scenario to verify the practicability of the proposed model in reducing design effort. Adding new robots to the system and performing contact-rich-and-collaborative manipulation actions in Cartesian space requires a new software development life cycle, but the programming diagram with geometric spatial semantics does not need extra development time just drag the correspond software components and connections. The comparison of use cases in this paper shows that GePro enables a programming time savings of an development life cycle time compared to traditional one. A limitation of this programming model is that it assumes that the robot components have a certain degree of autonomy and can adjust the trajectory or timing of actions according to changes in geometric information. However, the robot programming of the current assembly production line relies heavily on robot teaching methods, which means that the geometric information of its collaborator is \begin{table}
\begin{tabular}{l l l} \hline
**Item** & **Extra Development for Collaboration** & **Extra Design Effort** \\ \hline Scenario without GePro & Scheduling, Spatial conversion, Collision avoiding & A new development life cycle \\ Scenario with GePro & None, Ge event connections & No extra development \\ \hline \end{tabular}
\end{table} 
Table 1: Comparison of different programming models. meaningless and the robot controller cannot automatically modify it's trajectory responding to changes in geometry. However, advances in robot programming technology will alleviate this limitation in the future. **Author Contributions:** Conceptualization and methodology, G.W. and P.Z. ; software, validation, formal analysis, investigation, data curation, and writing and original draft preparation, G.W. ; resources, supervision, project administration, and funding acquisition, P.Z. All authors have read and agreed to the published version of the manuscript. **Funding:** This research was funded by the National Key Research and Development Program of China (2018 YFB1700200) and National Natural Science Foundation of China (61903356). **Conflicts of Interest:** The authors declare no conflicts of interest. ## References

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