Aruco Tag Information
Currently, RapidSense supports Aruco tags that are mounted off of the robot faceplate for camera calibration and tags mounted static in the scene to check calibration status against. If the tag cannot be permanently mounted off of the robot faceplate (such as being fixed on the end of arm tooling) and it must be removable, then it should be designed such that re-mounting the tag is accurate and repeatable. A Tool Center Point (TCP) location will need to be provided to the system for providing where the center of the tag is located relative to the robot faceplate origin.
If more than one calibration tag is required for a system, each tag must have a unique pattern. It may be required to utilize more than one calibration tag pattern per system such as if:
One robot with a calibration tag on the end effector cannot reach the field of view (FOV) of all of the cameras being utilized for the system.
Calibration tags mounted in the scene for camera calibration checking.
Fabrication/Ordering Information
The highest quality tags can be custom made purchased at: calib.io. The aruco_tags.pdf can be sent to calib.io and have the markers sized at least 10cm wide. The aruco_tags.pdf attached has 20 different targets made to RapidSense specs. It will depend on the system setup for how many tags will be required.
For quick iteration, Ponoko can be used; however, the tag is of a much lower quality. It is highly recommended to order from calib.io and only use Ponoko for prototyping as they typically have quicker turnaround time.
Requirements for Aruco tag fabrication:
Aruco pattern needs to be printed 9cm x 9cm size (in the future for larger robot systems, this size may need to be larger)
The pattern needs to be crisp and high contrast white and black
Material surface with Aruco pattern needs to be matte and non-reflective
This needs to be on a reliably rigid flat surface/material (plate) that will not flex during robot motion, but does not have to be so thick for anything load bearing (3mm thick is likely OK for an aluminum 9cm x 9cm tag)
There should be a mounting holes available for a user to be able to mount it on the robot end effector or in the scene
In the event a user needs to remove the Aruco tag/plate for a reason, the tag should be designed with a repeatable locating mechanism, such as utilizing dowel pins, to be easily replaced accurately.
Sample Aruco Tag Plate and Mounting Adapter Design
The below contains details of a sample fabricated Aruco tag for a system and a sample design for a mount to use to attach the tag to the robot. In this case, the tag is mounted to a plate that is mounted between the robot faceplate and the robot tooling. This mount works for the following robot models:
Mitsubishi RV7FR
FANUC LR Mate-200iD/7L
Kawasaki RS007N
Yaskawa GP8
