View Full Version : [Question(s)] yaml file with 2 parallel servos

02-05-2014, 04:56 PM

i have bought a PhantomX Reactor robotic arm that i am using in a ROS environment with the arbotix_python package and i need a YAML file to define my robot.
I got a problem because in order to be stronger, two of my joints have two servos in parallel, they are then dependent each other. How do I describe this feature in my yaml file? It seems that each servo has each its own controller and i do not want to take a risk of breaking the robot trying movements.

Every advice is welcome!
Thanks in advance.

02-06-2014, 12:00 PM
What are you using to send a trajectory to the arbotix_python follow_controller node?

fergs would know for certain, but my limited, and far from current, ros experience says the easiest way to implement this would be to: 1) create a node to grab the arm trajectory sent by whatever node is producing it, 2) have the new node modify the trajectory to add the second servo under a new joint name to each joint that was doubled up (if 'shoulder_lift' is the doubled joint, then it becomes 'shoulder_lift_1' and 'shoulder_lift_2'), 3) add the additional servos to the yaml using the joint names added by the new node and flip the 'invert' setting of the appropriate joint, 4) publish the modified trajectory under a new name, 5) have the arbotix_python follow_controller node listen to the modified trajectory. If it works as I expect, you would get one joint goal position under two names for the doubled joints and the invert option will cause the follow_controller node to flip the goal position on the required servo.