Robots are popular in automotive industry for a long time, but recently they also had a remarkable success in the aerospace industry, especially for Composites Manufacturing. Below my thoughts on this topic, I am waiting for your feedback!
Remark: This post has already been published in the CATIA Composites community:
https://swym.3ds.com/#post:24466
https://swym.3ds.com/#post:24785
Automation trend
In the Aerospace industry, the current challenge is to increase the production, keeping the quality and the costs under control. So the trend is to increase the level of automation in Manufacturing, especially in the domain of Composites, which traditionally involve a lot of manual operations: cutting, layup, drilling/riveting, handling, inspection etc.
Machines vs Robots
Automation doesn't mean robots: specific machines may be used for Automatic Tape Layout (ATL) or Fiber Placement (AFP), for drilling/riveting etc. Typically these machines are of made of a Cartesian gantry (3 translations) and a head (2 rotations). Due to this mechanical structure, such machines are very accurate, and can ensure a high production rate.
However, these machines are usually quite expensive, and difficult to adapt to a new workpiece with different dimensions, or to a new manufacturing process.
Industrial 6 axes robots from ABB, Kuka, Staubli etc are providing this flexibility, at a lower cost. They can be combined with additional devices: The robot itself can be mounted on a gantry, to increase the robot workspace, or the workpiece can be mounted on a positioner, so that the robot can reach a wider area on the workpiece. It has to be completed with dedicated devices such as the end-effector, the handling equipment, the creel that contains the bobbins (for AFP), the safety barriers etc. The total cost of the robotized workcell is much higher of the robot itself, but still remains competitive with respect to the dedicated machine solution. And it is easier to install in the shopfloor (no need for expensive foundations).
Challenges in Robotics
The first challenge to be addressed is the robot accuracy. Robot manufacturers provide dedicated “High Accuracy” robots, together with special software modules, that can help to meet the requirements from the aerospace industry. Another way to address this issue is to use specific end-effectors with sensors, to adapt on-line the theoretical robot trajectory to the real workpiece.
Other challenges are the cycle time, which may be higher with an industrial robot (vs a dedicated machine), and the limited payload and stress.
However the aerospace robotic integrators are able to address these challenges, with advanced technologies, especially for the end-effector.
Robotized Processes in Composites
In the aerospace industry today, here are the processes where we find more and more robots for Composites:
- Automatic Fiber Placement. For example, Dassault Aviation, EADS Composites Aquitaine or Bombardier Aerospace are using in production robotic workcells provided by Coriolis Composites. Mounted on the robot, the patented end-effector for fiber deposition has been designed to accommodate the limited robot payload. A special fiber guidance system is able to handle the fiber from the creel to the end-effector.
Robotized AFP (Courtesy of Coriolis Composites)
- Stitching. This process is used to reinforce the composite workpiece, by adding the fiber in the Z direction, before the RTM. The “sewing machine” (stitching head) can be mounted on an industrial robot. Such workcells are provided by Keilmann Sondermaschinenbau for example.
Robotized Stiching (courtesy of Keilmann Sondermaschinenbau)
- Filament winding. Use of robots is growing for this process. This is the case for example at Boeing to manufacture a new large Composite Cryogenic Fuel Tank for future NASA rockets and spacecraft.
Robotized Filament winding (courtesy of NASA & Boeing)
- Non Destructive Testing (NDT). This process is mandatory in Composites manufacturing, since the defects cannot be found by a simple visual inspection. NDT takes place at the end of the manufacturing line, on the finished product, so it is has to be performed very quickly. In this process, the ultrasound transducer in mounted on the robot, sending the pulse-waves to the workpiece with water coupling. The signal can be received with the same device (pulse-echo), or by a dedicated sensor mounted on another robot, moving in the same time on the other side of the workpiece. Note that a new technology is emerging, ultrasonic testing with laser (the advantage is that no contact is needed).
Robotized NDT (courtesy of Eurocopter)
Beside the typical processes for Composites listed above, robots may be used for the following “classical” processes in aerospace:
- Drilling/Riveting
- Cutting, Contouring
- Machining
- Painting
- Handling (Pick and Place)
Robots Off-Line Programming (OLP) with DELMIA Robotics
In the aerospace industry, robot programs are created off-line, with dedicated software tools such as DELMIA Robotics. The goal is to ensure:
- The quality and accuracy of the program (using directly the design data: digital continuity)
- The quick update of the robot program after a design modification in the workpiece
DELMIA Robotics from Dassault Systèmes is integrated in CATIA, using the same user interface and the same 3D data (no conversion needed). It provides a complete infrastructure for robotic simulation and programming. It includes a complete library of industrial robots. This library ("Robotlib") is organized by robot manufacturer (ABB, Kuka, Staubli etc). Each robot model contains the 3D, kinematics, travel limits, joint speed etc. This Robotlib is continuously updated by DELMIA to integrate the newest industrial robots. For a special robot not in the Robotlib, it is possible to create its own robot model, by defining the forward and inverse kinematics, in a special DELMIA workbench ("Device Building"). Any kind of complex robot can be created in this way.
Creating a robotic workcell in DELMIA Robotics means combining various devices: one or several (cooperative) robots, gantries, rails, end-effector... It is possible to define auxiliary axes (ex: when the robot is on a rail, the rail axis is driven by the robot controller, like the internal robot axes).
DELMIA Robotics can be used to check the feasibility, when designing the robotic workcell (which robot can do the task, in how much time, where to put the robot with respect to the workpiece, is there a collisions etc). The robot trajectory is created quickly using the workpiece defined in CATIA. The user will set additional parameters such as the robot arm solution (flipped wrist or no), the motion type (linear or cartesian), the velocity, the aux axes positions etc.
If the robot trajectory simulation in DELMIA Robotics is correct (no collision, no travel limits etc), then it is possible to download the simulation into a robot program to be used in production at the shopfloor (DELMIA Robotics include a library of translators for the main robot controllers).
On top of DELMIA Robotics, additional modules can be used, to address specific composites processes such as AFP, Stitching or NDT. Below a focus on 2 processes, AFP and NDT.
OLP for AFP
CATFIBER from Coriolis Software, is fully integrated in CATIA Composites Part Design (CPD) and DELMIA, and provides advanced producibility analysis, taking into account material constraints (ex: steering radius analysis) and the machine constraints (ex: minimum tape length, roller crush analysis etc).
CATFiber in DELMIA V6 (courtesy of Coriolis Software)
Beside the robot programming, it enables to optimize the design of the workpiece, taking into account at the early stage of the design the manufacturing constraints.
TruFIBER from Magestic Systems is another solution on top of CATIA CPD and DELMIA for Simulation and Programming of AFP workcells, taking into account the material constraints to ensure an accurate deposition.
OLP for NDT
On top DELMIA V5, it is possible to use the FastSURF module from Cenit. This module (part of the Fastsuite product) is dedicated to robotized surface processes. It enables to create automatically the robot trajectory from the surface, keeping the correct orientation for the NDT end-effector. The holes in the workpiece are automatically avoided.
FastSURF in DELMIA V5
Sources:
Coriolis Composites :
http://www.coriolis-composites.com/index.php
KSL Keilmann Sondermaschinenbau GmbH :
http://www.ksl-lorsch.de/en/products/aerospace/aviation/
Boeing:
Eurocopter:
http://www.ndt.net/article/wcndt2012/papers/391_wcndtabstract00391.pdf
Magestic Systems Incorporated:
Cenit Gmbh:
http://www.cenit.com/en_EN/plm/digital-factory/software/fastsurf.html
