Fiber Node "Rolling Wrapper" KUKA End Effector

The idea of our project is to develop an end effector for a KUKA robot that wraps fiber around a node, reinforcing it. This idea addresses the common problem of delamination at points where fibers intersect, and it overcomes the challenge of wrapping fiber around a node using a single robotic arm.

Fabrication with fibers often encounters the issue of delamination at points where fibers cross each other. To address this, our end effector reinforces these critical points, improving the structural integrity of the fabricated material. Additionally, when using a robotic arm, such as the KUKA robot, it is challenging to have one end effector wrap around a fiber node. Furthermore, passing the fiber from one robot arm to another for wrapping purposes is also difficult. Our project aims to overcome these limitations and enable efficient and effective fiber wrapping around nodes.

This project was made during the summer semester 2023 at ITECH, University of Stuttgart.

HARDWARE

• 2x NEMA-17 Stepper Motors
• 1x Arduino Uno Board
• Jumper Cables
• Diode
• Mosfet
• DC Motor
• External Power Supply (at least 5V and 2 Amp)
• Kinect 360 Camera V1 with Kinect Adapter for Xbox 360 (USB to AC Power Supply PC)
• Plywood
• 9x Bearings 608-ZZ 22mm Diameter
• 2 x wheels with strong grip

The DC-motor, Mosfet, Bread Board and Diode can be purchased as a Arduino Starter kit. This includes more then the necessary amount of components, however it is a very recommendable starter pack if you want to do other projects with it.

SOFTWARE

• Rhinoceros 3D Programm
• Grashopper inside Rhino3D
• Firefly for Grashopper (Firefly Software)
• Simulacrum, KukaVarProxy plugin for grasshopper (Simulacrum Software)
• Bitmap+ Plugin (Bitmap+ Software)

Hardware overview of the components and assembly.

a.      Order the necessary sensors and actuators.

b.      Refer to the supply list to ensure that you order the correct components.

c.     We recommend getting the Arduino Starter Kit because it has great circuit explanations and examples .

a.      Lay out all the components on a clean and flat desk.

b.      Make sure to have several different jumper cables on hand, especially male-male and female-male.

c.      Use the electronic schematic representation to connect the sensors and actuators.

a.      Download the 3D Rhino file and prepare the plywood parts for CNC milling. The Geometry is designed to fit perfectly two NEMA-17 Stepper motors, as well as holding the holes for the 3D printed bearings footers.

b.      Once milled sand all the rough edges in order to avoid having splinters looking out which could make problems with the bearings later on.

c.      Download the File for 3D printing, use PLA with an 40% infill when slicing the objects.

d.      When the 3D printed objects are done remove all the supports and clean the objects.

e.      Glue the bearings with the bearing footers and rail holders. Eight bearings are for the rails and one for the spool holder. Once dry, glue all of the pieces in their respective positions onto the cnc milled timber components as it is shown in the 3D file.

f.      Place the rotary disc carefully into the bearings, it is easier to slide it clock/counterclockwise into the rails. One in its position try to slide it manually and make sure that it rotates freely without any friction. If it does, take the rotary disc out and sand it more on the edges. Try rotating it again until it works properly.

g.      Once done, place the stepper motors into their position with the shaft sticking through the plywood board facing the rotary disc. Then attach the wheels to the ends so that the wheels are pushing the rotary disc against the bearings.

a.      Plug in the external power supply

b.      Run the Arduino Code, once the motors start rotating, make sure that the wrapper stays in the rails. It helps to reduce the stepper motor speed for the beginning.

c.      Calibrate the rotation time of the stepper motors in the arduino code. Because it can vary depending on the components precision, test how many seconds it need to do a full rotation. Once you have the time, you can store it as a variable in the arduino code and use it multiplied by x(time the amount of rotations that you want) in the main code loop.

for( uint32_t tStart = millis();  (millis()-tStart) < period;  ){ //Main Loop}

a.      Drill holes into the Plywood interface plate with the needed dimensions (varies for every robot). Attach it firmly with bolts to the robot.

b. Use Firefly firmata and KUKA Var Proxy in order to synchronize the KUKA with the end effector and Kinect camera.

By following these instructions, you should be able to successfully assemble your end effector and ensure that it is functioning properly. If you have any further questions or concerns, don't hesitate to reach out for assistance.