Nikon Metrology

Robot Control Brings Aerospace Tolerances to Automotive Robots

Nikon Metrology, Optical Scanning

A major Airbus research project to develop greater levels of accuracy in automated drilling and riveting has led to the formation of a consortium to build a robotic platform incoporating a Nikon Metrology K-series Optical CMM.

Since industrial robots do not meet Airbus process specifications; Airbus, Nikon Metrology, KUKA and Delmia have formed a consortium to build a new aerospace grade robotic platform. This patent-applied-for solution establishes a dynamic on-line link between a KUKA robot and a Nikon Metrology K-series Optical CMM. This system will result in a robotic platform that features adaptive real-time motion control. Airbus expects that the robotic solution – operating on aerospace accuracy tolerance – will reduce cost, cut production time and improve build quality once deployed.

“Company-wide, we drill around 50 million holes per year and half of these are manually processed,” says Mark Summers, Engineering Group leader, Automation and Robotics, Airbus UK. “Our research is part of a drive to significantly reduce manual processing across current and future aircraft programs as our build rate increases to meet market demand. Standard industrial robots are not accurate enough for our process specifications, as absolute positional accuracy of ±0.2 mm is required in many application areas. Our team has brought together two developmental partners, KUKA UK and Nikon Metrology to address this problem. We believe we have come up with a winning solution, which could bring a flexible, low-cost robotic platform into the aerospace sector.”

A flexible, low cost robotic platform for the aerospace sector

Initially the system will be applied to two KUKA production robots that jointly pick up an unfinished large wing assembly, and present this part to a drilling/riveting station at a fixed location. Both the drilling/riveting machine and the part being manufactured (through its fixture) are tracked dynamically by means of infrared LEDs and the Nikon Metrology K-series Optical CMM station. As part of the control feedback loop, the position of the part with respect to the machine is systematically returned to the robot controller. This Nikon Metrology/KUKA robotic solution is responsible for positioning wing part holes and rivets at CAD-specified wing locations with accuracy levels 10 times higher than before.

“This project has been a real partnership between all involved parties,” explains Roger Holden, Managing Director of Nikon Metrology. “Everybody agreed that considering part programs being so large and accuracy requirements so high, an off-line robot programming solution was needed. DELMIA’s V5 and KUKA’s VRC software provide an excellent solution that – linked with Nikon Metrology interface and integration – is capable of consistently driving the robot to run programs accurately, by referencing back to the CAD master dynamically on-site. Nikon Metrology now has the order for the first production system to be put into action at Airbus, and we are now going live with the product at Filton, UK.”

Intelligent, real-time adaptive robot control driven by Nikon Metrology

The unique and fully integrated metrology system measures the virtual world first, and adapts the real world to fit. This intuitive system is called Adaptive Robot Control, as it makes the robot intelligent enough to make its own adaptations. This means that the robot can accurately compensate for robot deformation (under dynamic load), temperature fluctuations and mechanical play. The metrology system makes the robot aware of deflections by measuring the relative positions of the target and the robot as it moves toward it. The robot is able to coordinate that data on-line and make the necessary compensations instantaneously.
Since the robot(s) carry out tasks at great positional accuracy and faster than a person, they could be used for a range of tasks, such as sealant application, component handling, fastening and machining. Such robotic platforms could become truly multi-functional. The multi-functionality is generally agreed to become key for the aerospace industry, as single process automation tools are often under-utilized, owing to the long cycle times for each wing set, for example. Another benefit is that the robotic system, in effect, becomes an in-line CMM, which is capable of certifying jigs and products in real time. There is potential to re-certify jigs without taking them out of production at regular intervals.  Instead, geometry changes in the jig could be identified in the real-time production environment. Similarly, it could become unnecessary to divert products to a laboratory for QA, as the robot could measure them as they are being made via a multi-functional 3D scanning end effector.

Higher level of simulation prove-out and robot integration

Although beneficial to any robot configuration, the Adaptive Robot Control solution responds well to highly accurate robot operation requirements in the aerospace sector. One reason for this is the extensive use of lightweight materials like aluminum, which requires far more accurate drilling and riveting. Since the loads robots are asked to bear are too great for a single robot, load sharing among multiple cooperating robots has become common practice. The accurate robot solutions are designed to smoothly interact with one another, and are now made available through Nikon Metrology integration services.

Nikon Metrolgy/KUKA robot solutions can now be commissioned off-line, eliminating time consuming robot teach-in procedures. All of the robot programs being created off-line use the DELMIA V5 Robotics simulation solution. KUKA connects real-time information on the movements of its own Virtual Robotic Manipulator (VRC) into the second-generation Realistic Robot Simulation (RRS2) software it developed in conjunction with DELMIA. This results in a significantly higher level of simulation prove-out and integration into real robots. The Airbus project takes advantage of this solution, with the final full syntax programs being run on the KUKA VRC, enabling accurate cycle-times and clash detection.

Learn more about Adaptive Robot Control.

Click here to watch a video about Adaptive Robot Control.