Assembly is a complicated, sometimes tedious process that often unfolds sequentially along a series of stations. In the manufacture of complex equipment such as jet engines and automobiles, technicians are guided through their work by referring to printed manuals, which document the various steps required. These processes usually demand the use of hand tools with little in the way of automation available either at the tool or verification level — in fact, all actions typically are performed manually. As a result, quality and performance times are dependent upon each technician’s technique and preferences, leaving room for individual differences and, at times, errors.
Recent developments in augmented reality technology offer a way to improve the assembly process. With an augmented reality advanced manufacturing system (AuRAM), technicians can be guided step-by-step through the assembly process with virtual overlays of system diagrams and directions, which are displayed on top of the physical components and equipment, eliminating the need to interrupt their assembly process to refer to paper documents or computer monitors. The essential components of an AuRAM system include a robust, accurate motion tracking system; an effective display capability; and visualization software appropriate to the application.
Today’s Assembly Process
The assembly process is tedious by nature, with a significant amount of time often spent preparing for, or “laying out,” a particular job. In the case of heavy equipment manufacturing, assembly technicians must identify and collect the appropriate tools, review the manual or diagrams to confirm the correct placement of a part, and perform other preparatory functions.
As an example, in the laying out of a core casing for a complex jet engine build-up, a technician’s first task might be to locate and label the 50 or more mounting holes in an engine casing. This process can take a technician as long as four hours, as they must manually identify and label each individual hole by physically mapping the hole to the correct location on a corresponding drawing. This step is repeated for each of the many mounting holes in each of the hemispherical casings that make up the core of the engine.
Subsequent assembly operations follow a similar pattern, in each case requiring the worker to cycle between assembly and reference to a manual or documentation. Furthermore, the assembly process contains a variety of time-consuming elements that can be prone to errors given the nature of the work. These errors can go undetected until much later in the assembly or test process, making their correction extremely expensive in terms of required rework and lost productivity.
Guiding Assembly with Augmented Reality
Augmented reality is the process of superimposing computer-generated data on real-world objects in order to provide the user with an improved understanding of his/her physical environment. This technology has been used to provide enhanced vision systems for military pilots, drivers of armored vehicles, and dismounted soldiers. For pilots in particular, enhanced or synthetic symbology is projected onto the pilot’s helmet visor and accurately registered to the corresponding object in the real world, allowing the pilot to view targeting information superimposed directly over the target. Over the past several years, the technology behind these systems has been extended to commercial applications in the construction, automotive, medical, and aerospace industries.
Particularly in the assembly of complex equipment, an AuRAM can significantly improve quality and productivity. Depending on the requirements of the specific assembly process, there are three potential options for displaying the virtual images for the technician — a safety-goggle-type Head- Mounted Display (HMD), a tablet PC, or an augmented reality projector (AR Flashlight).