## 4 Digital Twin and Control System Design
### Geometry and Kinematics Model
This database can be local, created as an eM Server \"System Root\", or hosted externally on a server. To facilitate structured team collaboration, project data in Tecnomatix Process Simulate are centrally managed in an Oracle database on the server. Within this eM Server, each project has a dedicated \"System Root\", serving as an interface between client computers and the database, ensuring efficient data management and synchronization across the development environment. The import of individual equipment models is only possible after defining the component type within the simulation (\"Define Component Type\"). Assigning this classification to a model in the database enables or restricts specific functionalities based on the component type (e.g., robot, clamp, workpiece, device, sensor, human, tool, gripper, etc.). These functionalities become accessible only after the project is created. A Tecnomatix Process Simulate project primarily consists of a database of virtual models and simulation studies. Within the database, a distinction is made between production resources (Resources) and workpieces (Parts), ensuring a structured organization of manufacturing components for simulation and validation. If all conditions for inserting a model into the project are met (JT file format, database creation, and component definition), the model is classified within the project database upon insertion. Its categorization depends on whether it represents a workpiece (Part) or a production resource (Resource), ensuring proper organization and functionality within the simulation environment. The kinematic model of the resource is created in the Kinematics Editor by defining joints, motion axes, degrees of freedom, and movement limits. A reference base is assigned, linking model parts to their respective axes (\"Link\"). Joints (\"Joints\") can be prismatic or revolute, with defined limits, speed, and acceleration (Figure 8). More complex structures can be generated using \"Create Crank\". Figure 7: Pneumatic cylinder DSNU-8-100-PPV-A (19182), Festo AG & Co. KG, Esslingen, Germany and the generated pneumatic cylinder model and subsequent export in the Festo Design Tool 3D environment. Modelling kinematics for complex geometries is a manual process that requires expertise and time. Once completed and confirmed via \"End Modelling\", the kinematic data are stored in the database for reuse in other projects. In this study, the pneumatic cylinder of the MPS \"Distribution\" station was modelled, converted to JT format, and imported into the project database, where kinematics was assigned. Actuating the pneumatic cylinder extends the feeding mechanism, releasing the cylinder into the working position, as shown in Figure 9.  
Figure 8: Insertion of the pneumatic cylinder as a production resource into the project database and creation of its kinematic model with defined joint properties. Finally, motion positions are defined in the \"Pose Editor\", either as predefined limits or manually. Here, two positions are set: \"push_home\" and \"push_extract\", essential for automation, as they are controlled by signals and verified by sensors. The HOME position is pre-configured. For digital twin models, mechanisms are restricted to generating either translational or rotational motion, as all complex movements can be decomposed into these fundamental types. Translational motion involves movement along a straight path, typically achieved through linear actuators, pneumatic cylinders, or guide rails. Rotational motion occurs around a fixed axis and is implemented using rotary joints, servo motors, or gears. In digital twin simulations, these motions are modelled and parameterized to reflect real-world system behaviour, ensuring accurate representation of kinematic properties. The combination of linear and rotational elements allows for the simulation of more complex robotic and automation systems while maintaining a structured and computationally efficient model. Linear motion is characterized by translational displacement along a single axis.