The human-machine interface represents the analog or digital interaction interface between a person, i.e., a user, and a machine. It is part of human-machine communication (also known as human-machine interaction). In its simplest form, this interface can be a simple on/off switch; in a more sophisticated form, it can be the software interface of a company-wide IT system. With increasing digitalization in all areas of life, especially in industry, the interface to technology and its ease of use are becoming increasingly important.

The processes in industrial software systems have become very complex. Industry 4.0, the digital networking of the entire supply chain, and the use of cyber-physical systems in production are leading to the high-tech automation of formerly manual fields of work. For employees in operational business, this also means that they have to find their way around digital working environments. Logically, it would be far too time-consuming for them to have to familiarize themselves with the program code and programming language of the underlying system in order to operate a machine. That is why visual and audio-based dialog systems have been developed to form an interface between humans and machines.

Graphical user interfaces (GUI)

In industry, a widespread form of user interaction with an IT system is communication via graphically visualized software interfaces, known as graphical user interfaces (GUI). Since humans cannot interact directly in the language of the IT system, all information is translated (encoded or decoded) into a language that the other side can understand. Extensive computing operations and database queries take place in the background, invisible to the user. The results of these computing processes are ultimately visible to the user as visual information in a dialog. The employee can then respond or interact with the system. These user dialogs can be made available to the user via various end devices such as PCs, stationary terminals, smartphones, tablets, mobile industrial terminals, or data glasses. To ensure smooth operation, it is important that all processes and data required for a system process are recorded in full. This is done partly automatically, and partly the user must provide data manually.

Human-machine interfaces in intralogistics

In intralogistics, there are interfaces between humans and machines at various points. Essential communication points are the logistics control center and order picking.

Interface: Warehouse control center

In simple terms, the control center is the operations center of a distribution center – this is where all information about throughput, personnel deployment, key figures, facility statuses, and any problems that arise converge. Monitoring takes place via PC, tablet, or smartphone, and the information is presented to the responsible employee in graphical form so that they can quickly gain an overview. If necessary, they can interact with the warehouse management system and make fine adjustments to the process. In the background, the machine processes a large amount of data, and in the best case scenario, human intervention at the control center is minimal.

Interface: Order picking

The order picking business process is probably the area in the warehouse that involves the most two-way human-machine communication. On the one hand, the order picker receives information about the pick orders from the warehouse management system, and on the other hand, he continuously reports the status of his tour, missing quantities, and the confirmation of completed picks back to the system. In addition, picking is usually the area in the warehouse with the highest number of personnel. It is therefore not surprising that efficiency and accuracy are constantly being put to the test here and that new technologies and processes are continuously being introduced.

Visually via displays (pick-by-MDE)

The most common picking method in distribution centers is user-guided picking via a mobile device. This is usually an industry-standard mobile data collection device (MDC) that has both a display (data output) and a scanner and various buttons (data input). The picker is guided by instructions on the display and confirms order fulfillment by scanning or manual entry on the device. The MDC is connected directly to the IT system via Wi-Fi. In addition to MDEs, smartphones and tablets are also increasingly being used in industry.

Visually via light signals (pick-by-light)

In pick-by-light picking, the employee receives the picking instruction via signal lamps and numeric displays attached to the corresponding shelf compartment. The employee confirms the removal manually via a button or automatically via sensors.

Visually via head-mounted displays (pick-by-vision)

Pick-by-vision is a form of picking that is still in the early stages of development. Data glasses project the information about the pick order directly into the picker’s field of vision. Depending on the design of these augmented reality solutions, navigation support can also be provided. The employee interacts with the system either via buttons on the glasses or an additional device, via voice, or via gestures that are captured by a camera integrated into the glasses.

Acoustically via voice instructions (pick-by-voice)

In pick-by-voice picking, the picker is guided by voice instructions. They wear either headphones or a special vest with integrated speakers, which tell them the position and quantity of the items to be picked. They confirm the removal either by voice command or by pressing buttons on the associated hardware.

For more information on handling data in intralogistics, see the article Smart Data.

Teaser image: geralt