Today, digital twin (DT) concepts can be applied in a variety of different fields including the manufacturing sector. DTs can for example help design assets or expand existing assets. DTs do that by allowing different applications access to the assets’ information. One such application that could be DT-driven is virtual commissioning, which is covered as a practical application in an DTA learning activity.
Virtual commissioning validates control code before it is uploaded onto the real machine. This can be carried out using the real controller with a simulated machine or using both a simulated machine and a simulated controller. In this way, control code can already be debugged and verified before any hardware is manufactured and/ or bought. This cuts back tremendously on the real commissioning time of machines, where traditionally control code has been debugged for the first time.
This DTA learning activity provides a hands-on introduction into virtual commissioning and its connection to the digital twin. The usage of software tools like Siemens NX, PLCSIM Advanced, and TIA Portal is described step by step. In the context of virtual commissioning, a physics-based model of the Lucas Nülle assembly line will be created and used to verify the PLC control code.
- You will carry out a virtual commissioning application.
- You will get to apply your knowledge of the basics of Siemens NX MCD.
- You will create a physics-based model.
- You will get familiar with the TIA Portal environment.
- You will be able to program Siemens PLCs using FBD, LAD, and SCL programming languages.
- You will be able to simulate 15xx Siemens PLCs.
The Industrial Mechatronics System (IMS), which is shown below, is a small production plant used for training purposes. It consists of five modular stations that serve the purpose of assembling a variable product.
The IMS1 is made up of simply a Programmable Logic Controller (PLC) and a conveyor belt. This station provides the bases for all other IMS stations (i.e., all other IMS stations include a PLC and a conveyor belt). The IMS1 functions as a simple conveyor belt to transport the work piece from one station to the other in our IMS production line configuration. The IMS3 station’s goal is to drop the base part of the product onto the workpiece carrier. This is the first step of the mounting process. This is done by actuating a pneumatic cylinder, which pushes a rotational latch to separate the parts. The mounting is complete with the retraction motion of the pneumatic cylinder. The IMS4 station mounts the top part onto the pre-existing base part. This is the second step in the mounting process. This is done using two pneumatic cylinders (one on each side) and two corresponding rotational latches. The mechanism is similar to that of the IMS3 station. Depending on the ordered workpiece variant, a bolt may or may not be inserted between top and base parts. The IMS5 station’s goal is to insert that bolt. This is achieved using one pneumatic cylinder. Finally, the finished workpiece is handled by the IMS7 station. This station uses a vacuum gripper to lift the workpiece and place it on an attached platform.
Existing CAD models of the production line, provided by the DT as type data, will be imported into Siemens NX. Each station of the production line will be simulated separately. Using the MCD plugin, physical properties like weight, center of mass, and inertia are automatically assigned to the CAD models. Moreover, rigid bodies, collision bodies, joints, and springs are added to the existing CAD models to create a physics-based simulation. Signals will be created in Siemens NX that correspond to the signals from the PLC and that have identical names to their respective PLC counterparts. Following this name rule allows for auto-mapping, which saves the extra effort of mapping each two signals manually together.
Sensors from the physical layer will be simulated in the virtual layer using the collision sensor function. This function turns an object in the simulation into a collision sensor that triggers a boolean variable when it undergoes collision with another object during the simulation.
Previous knowledge in automation technology is a plus, but not a requirement for this course. The course consists of theoretical and practical activities. For the theoretical activities, no specific software or hardware is required. For the practical activities, the following software is required:
- Siemens NX version 1872 or newer
- TIA Portal V15 or newer
- PLCSIM Advanced V2.0 or newer
The DTA learning activity can be accessed here: