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How to interface arbotix_python package with a PhantomX Robot Arm (Trossen Robotics)

asked 2013-06-12 11:40:54 -0600

robbie.sharma gravatar image

I'm using the PhantomX_Reactor_IK.ino firmware that is uploaded to the Arbotix and creating a ROS version of the Commander code. I had a few questions.

1) Do I need to create my own ROS package/code to interface to the PhantomX or is there code already made? I was going to "copy/paste" the Commander.ino code into my own ROS package by creating the appropriate publisher/subscriber methods.

2) In the variable right_V = (1023 - analogWrite(RIGHT_V) -512)/5 + 128, what do the numbers/offset mean? What is it outputting? This is taken from Commander.ino

What is the easiest, and quickest way to do this?

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answered 2013-06-13 20:47:50 -0600

fergs gravatar image

We never created a ROS interface to the commander protocol, as it really is designed for handheld joysticks. There is an arbotix_ros bindings, but it uses the standard Dynamixel protocol. If you loaded the arbotix_ros firmware onto your ArbotiX, you could create a config/launch file for moving the robot arm around, but this would not have the IK.

As for the variables, the commander protocol only has one byte for each variable. So, we basically are taking the analog reading of the joystick (which is 10-bit, or 0-1023) and mapping it onto approximately -100 to 100 and then shifting it up 128, so values transmitted are approximately 28-228 (we really don't want to be transmitting values near 0 or 255).

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I'm making a ROS Port of the Commander.ino though I'm running into a typecasting issue. I've posted the problem on the Trossen forums:

robbie.sharma gravatar image robbie.sharma  ( 2013-06-24 08:53:58 -0600 )edit

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Asked: 2013-06-12 11:40:54 -0600

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Last updated: Jun 13 '13