Due to the latest technological advances in the field of augmented reality (AR), there is increasing interest in the industrial environment. Augmented reality is characterized by the extension of reality with digital information in a spatial context to the environment in real time. The contextual provision of information and the associated possibilities for human-technology interaction offer potential from an industrial perspective, particularly in applications where complex knowledge is required in manual processes. This potential has already been exploited in applications (e.g. machine maintenance and servicing) in which the content to be displayed can be prepared once and reused several times.

On the other hand, applications with only one-time use of visualization content have so far represented an application limit of augmented reality, as the effort required for manual content generation prevents economical use. The Chair of Production Systems (LPS), in cooperation with the company Phoenix Contact, is focusing on the necessary elimination of this limitation in the field of terminal strip production in control cabinet construction. Due to high product complexity, a large number of variants and small batch sizes, this discipline has a high proportion of manual work. An assembly line for terminal block production serves as an industry-oriented research environment at the LPS. This consists of a total of seven stations where complete terminal strips can be assembled from individual components. An assembly assistance system was prototypically implemented for this process using the AR glasses HoloLens (Microsoft). The application currently consists of two software components: The first component is a central control system with a graphical user interface that runs on a PC and allows order-specific import of assembly information.

Assembled example terminal strip (top), AR application with overlay of real product and 3D CAD data with assembly target highlighted in green, indication of the removal container and textual instructions (bottom).

The second component is the AR software that runs on the HoloLens. The central controller communicates with the HoloLens application at runtime via a TCP/IP connection (via WLAN) and sends instructions to be visualized and information about parts to be assembled, for example. The functionality of the AR application currently includes marker-based tracking of the workstation and the assembled terminal strip, the display of removal containers, the display of textual instructions and the 3D CAD visualization of the installation position of components as an overlay to the real assembly object. The prototype worker assistance system will be expanded in the future to include the option of connecting additional systems for quality inspection and visualization.

For the applicability of the developed assembly assistance in terminal block production, the aim is to derive assembly sequences to be visualized automatically and order-specifically from existing product data without manual preparation. The digital product image should be available in the standardized intermediate format AutomationML (Automation Markup Language).

As an approach for the automated derivation of assembly information from the digital product image, the definition of rules is pursued with regard to two aspects: The first aspect comprises product-specific additional information that defines the assembly-side compatibility of components. The second aspect comprises system-specific additional information that defines a clear decision for a valid assembly sequence. The additional information is intended to enable the unambiguous, automated derivation of complete assembly instructions from the digital product image. The generated assembly instructions will then be transferred to the developed assembly assistance system. In this way, AR technologies should also be able to be used economically in various assembly areas with small batch sizes in the future.

Jürgen Kutschinski/as

The Chair of Production Systems (LPS) at the Ruhr University Bochum.

Briefly explained: The LPS:
The Chair of Production Systems (LPS) was founded in 1976 by Prof. Dr. Wolfgang Maßberg at the Ruhr University Bochum in the Faculty of Mechanical Engineering and has been headed by Prof. Dr. Bernd Kuhlenkötter since April 2015. The scientific focus of the LPS covers the fields of production management, production automation and industrial robotics. The LPS operates a pilot factory designed according to modern principles, in which the theoretical concepts are implemented and evaluated. By demonstrating the results in the pilot factory, the LPS promotes the transfer of technology to industry. The pilot factory also served as the basis for the learning factories developed at the chair. The various learning factories are used for student training and are also offered as a further training program for industrial employees. www. lps.ruhr-uni-bochum.de

Scientific Society for Assembly, Handling and Industrial Robotics (MHI e.V.)

Briefly explained: The MHI e.V.
The Wissenschaftliche Gesellschaft für Montage, Handhabung und Industrierobotik e.V. (MHI e.V.) is a network of renowned university professors - institute directors and chair holders - from German-speaking countries. The members conduct both fundamental and application-oriented research on a wide range of current topics in the fields of assembly, handling and industrial robotics. Further information on the society, its members and activities: www.wgmhi.de.