Robotics + Automation OPC UA Demonstrator
Interoperable, vendor-independent, capability-based
VDMA Robotics + Automation: Three working groups. One target!
In early 2017, VDMA Robotics + Automation launched several initiatives to develop data models for the uniform and open OPC UA communication standard. OPC UA stands for Open Platform Communication Unified Architecture and offers the possibility to provide platform- and manufacturer-independent communication over different levels of the automation pyramid and to resolve the strictly hierarchical data flow. This communication standard is also preferred by VDMA to achieve the interoperability required for the Industry 4.0/ Smart Factory approach, including machine-to-machine (M2M) communication. To make this vision a reality, several VDMA working groups are working on so-called Companion Specifications for OPC UA, which define the industry- and application-specific data models. This determines which concrete information (e.g. measured values, alarms, states, etc.) is provided in which form (e.g. data types, units, etc.).
To ensure that the networking possibilities with OPC UA are not just an abstract construct, VDMA Robotics + Automation has decided to build an OPC UA demonstrator which will be presented for the first time at automatica 2018 and shows a vision of how OPC UA can be used in production technology in the future. The chances and the potential of OPC UA should thus be made public and visible to all interested visitors.
Two use cases will be shown on the OPC UA demonstration area: control and condition monitoring.
Use Case capability-based control: The demonstrator has the task of assembling a product consisting of several individual parts together. In this case it is a fidget spinner, as you find it in (almost) every children's room. One major advance is that the production cell is not built by a single company, but by over 20 component manufacturers, system integrators and software specialists. Each of the participants integrates its own automation components and describes their functionalities with the help of so-called skills, which are standardized across manufacturers within the scope of the project. Such a description is an important prerequisite for the implementation of the changeability required in the context of Industry 4.0. In addition to the rotary indexing table, axes and grippers, image processing systems and robots are integrated in the cell.
Use Case Condition Monitoring: Several robot manufacturers show how condition monitoring can be implemented independently of manufacturer and robot type in the cloud. Here the visitor sees all relevant condition data clearly on the dashboard.
The VDMA Robotics + Automation Association consists of the three sub-groups: Robotics, Integrated Assembly Solutions (IAS) and Machine Vision (MV). The OPC UA approaches are described below:
In the first step, a motion device system is described in the form of an OPC UA Companion Specification, in which in turn individual motion devices, such as industrial robots and their controllers, can be processed to individual axes. Essentially, both a rough physical structure and condition, setpoint and actual values recorded by the components are displayed. In the first version, the declared goal of the specification is to provide a standardized and manufacturer-independent self-description of the Motion Device System's superimposed IT systems. In the next step, notification mechanisms and a state machine will be integrated and the information model extended to include geometric descriptions.
The machine vision working group would like to control the machine vision system with the first part of the Companion Specification. For this purpose, the activities of an machine vision system must be synchronized with the mechanics. For this purpose, a capability-based modelling approach was chosen which abstracts the system behavior by means of a state machine (status machine) and thus controls the machine vision system via method calls.
Integrated Assembly Solutions
The IAS working group aims to develop a concept for the generic description and control of processes, which can be used both in the engineering phase and during operation. The device functionalities, for example of grippers, linear axes or rotary indexing tables, are described in the form of standardized and manufacturer-independent skills. These enable both a resource-neutral design of the process flow and uniform control. Using the "Move object" capability, a handling process can be described without first determining which combination of robot and gripper will ultimately execute it. This can also result in composed skills, with whose help it is also possible for users to describe and encapsulate the processes within entire machines (cf. Figure 1).
During operation, these capabilities can then be executed via OPC UA, which leads to a corresponding movement of the components. It is only crucial that the selected resource meets the corresponding process requirements. The control of the capability, however, is identical for all components. Thus, it is also possible to easily meet the requirements of Industry 4.0 for changeability. Quick and easy integration is made possible by adding capabilities to the control process and using resources they also provide. In addition, in the event of a defect or a change in requirements, existing resources can be exchanged in existing processes in the shortest possible time.
Figure 1: IAS approach: Skill-based engineering with function blocks
VDMA Robotics + Automation wants to make the industry fit for interoperable and manufacturer-independent communication. Communication barriers between the hierarchy levels of the classical automation pyramid are to be resolved piecewise with OPC UA.
The R+A demonstrator illustrates how a uniform and semantic description of a production plant can be modeled - provided interoperable communication with OPC UA is possible. All three sub-groups will present their industry-specific approach at the booth at automatica 2018.
What benefits do we see for the machinery industry?
- Less integration effort and time saving
- A unified interface, instead of many proprietary interfaces, increases interface quality and reduces the time and cost of developing and commissioning an interface.
- Interoperability via OPC UA as a uniform language in which systems, machines and components speak directly to each other without the information having to be translated via a gateway.
- Greater flexibility
- Control sequences can be adapted more easily and components can be replaced more easily across manufacturers.
- Product improvement
- Due to the formation of a manufacturer-independent understanding, the industries reinvent themselves to a certain extent, which are the prerequisite for synergies and product improvements.
- Reusability through standardized description
- For the first time, manufacturers have stopped using object-oriented information modeling to develop their products in information technology.
Visit us at automatica (19 to 22 June 2018) at hall B4 and get your custom-made fidget spinner.