Commanding velocity to the arm and lift

Knowledge Base
1

Hello,

Is there a way to send velocity commands to the joints (i.e. not the base) with the python
library or with ROS ?

Thank you

2

Hi @sguysc, welcome to the forum! Yes, you can send velocity commands to the arm and lift joints using the set_velocity() API in Stretch Body. Here’s an example script of what using this API would look like:

import stretch_body.robot

r = stretch_body.robot.Robot()
r.startup()
assert(r.is_calibrated()) # the robot must be homed

# move the arm out at 0.05 m/s
r.arm.set_velocity(0.05)
r.push_command()

[...]

# some time later, move the lift up at 0.05 m/s
r.lift.set_velocity(0.05)
r.push_command()

Let me know if you have any questions.

3

Ahh, cool. I should’ve checked the code. I based my question on the
docs where the arm and lift did not specify set_velocity while the base did …

4

Thanks for pointing that out. The API ref is relatively new. It was missing methods that are undocumented in the code, but I’ve changed that now. set_velocity() now shows in the API ref as a member of the arm and lift classes.