UR20 Added to Existing Robot Models

[vkzimmerman]

I want to create and test all of the functions of the toolbox with UR20's (the URs our lab has). Currently the toolbox only has the UR3, 5, and 10, and when I looked for the readme for the URDF steps for a new model it wasn't there (saw it for DH). Is there a way to add this easily to the toolbox? I have all of the parameters from UR, so I figured I'd ask.

[petercorke]

Hi @vkzimmerman, thank you for your interest in RTB, and apologies for the very long delay in replying. Various life events got in the way, and since May this year I've been doing a lot of work across RTB, Swift and SpatialGeometry.

This is now easy. The toolbox's URDF models are loaded from the robot_descriptions package, which includes the whole UR family, including the UR20. So you can define the model yourself in a few lines, the same way the UR10 is defined:

import numpy as np
from roboticstoolbox.models.URDF.URDFRobot import URDFRobot

class UR20(URDFRobot):
    def __init__(self):
        super().__init__("ur20", manufacturer="Universal Robots")
        self.qz = np.zeros(6)
        self.addconfiguration("qz", self.qz)

robot = UR20()
print(robot)
Tep = robot.fkine(robot.qz)
sol = robot.ik_LM(Tep)

The first time you use it, the description is downloaded from GitHub and cached. I tried this with a UR20: fkine, jacob0 and ik_LM all work, and the model has its geometry for plotting.

If you'd like it in the toolbox itself, adding it is a small change: a new class in roboticstoolbox/models/URDF/ modelled on UR10.py, plus an entry in the models index and a test. A pull request is very welcome, and I'm happy to help with it. If you hit any problems, please post an Issue rather than a discussion thread. Thanks for the question.