The KUKA Youbot is an AGV (automated guided vehicle) with a KUKA robot arm mounted on top. The AGV has omni wheels so it can move in X and Y direction without turning. Our Youbot works with 2 Hokuyo URG-04LX-UG01 laser scanners, a robot arm with 2 gripper claws and a Logitech camera for vision detection. The platform is created and manufactured by KUKA and can be bought at the Youbot Store.
One of the requirements is to pick up objects vertical with the KUKA arm outside of the frame from the youBot. This is possible at the original position, but just 2 cm outside the youBot. For this reason, there is chosen to replace the standard KUKA baseplate with a new base plate for making it possible to manually reposition the location of the arm relative to the drivetrain.
It was decided to use the design from the original plate, which can be delivered by KUKA, and make a redesign. Here the arm is mounted above a wheel from the youBot to make it possible to pick up objects 270 degrees outside the robot. Because the base is around 20 kg and the arm is 5.3 kg there is no problem with the center of gravity. The remaining area of the plate is used to place an embedded computer with a strong graphics processor called Jetson TX1, an emergency button and an object storage plate. It was decided to install the graphics card on the back of the baseplate, as far as possible outside of the KUKA arm range.
For this project, there are two laser scanners needed which are available at the mechatronics development department (2x Hokuyo UBG-04LX-F1, scan angle 240 degrees) to create a map that can be used for localization of the robot. These scanners need to be mounted at a maximal height of 15cm, else the robot isn’t able to detect the pick and drop points.
Because it is most desired to pick up all the objects, at all times, the translating movement is chosen. The mechatronics development department has the following servomotor available: Dynamixel type AX-12+.With this servo, it is possible to read out the load, velocity, temperature and position. Because the many advantages with respect to the standard DC motor, there has been chosen to use the servo motor. It was decided to test the fingers by 3D printing them self to get a feeling for the flexibility and force they can apply. This means that the servo motor can deliver around 12 kg of pressing force. This is more than enough to pick up all the objects because the heaviest object is below 1 kg. On the endcap, a milled part is mounted, and two linear guides are mounted on this part. On each guide, there is a bracket which are also connected to the toothed belt. Because the two brackets are both connected to the toothed belt they will always move symmetrically to each other.