Set time step in MoveIt trajectories
Hi to everyone, I'm writing my first script on python to command Franka Emika Panda arm.
Mine configuration is: ROS Melodic, Gazebo 9, Ubuntu 18.04LTS.
I'm starting by move_group_python_interface.py (http://docs.ros.org/kinetic/api/movei...) and I'm using the function "go_to_joint_state()" to move my robot but I'm looking for a solution that can allow me to set a prefixed integration step (time deltas or dt). At the moment I modified the "go_to_joint_state()" function with the following code:
*for i in range(0, 600):
#move_group.set_planning_time(0.005) [this function can help me??]
joint_goal[0] = joint_goal[0] + 0.002618
move_group.go(joint_goal, wait=True)*
I want to rotate the joint0 of 90 degrees in 3sec with dt=0.005sec=5ms. For this reason I have 600 step (3sec = 3000ms -> 3000ms/5ms = 600 step). The 0.002618(rad) value is the result of 90 degrees = 1.5708 rad -> 1.5708 rad/600 step = 0.002618 rad.
Someone can help me to set the dt value in the correct way? At the moment I can only manage the increments equal to each iteration but I cannot intervene on the time (time deltas) that the system will take to move the joint0.
I'm not going to say you shouldn't do this, but it seems like a strange thing to do with MoveIt.
MoveIt is not a low-level trajectory generator, but a fully fledged, free-space motion planner (with support for multiple planners) and on-line collision avoidance and motion optimisation functionality built-in. Asking it to generate tiny trajectories of 5ms length each seems like a mismatch with what it normally does and I'm not surprised that would lead you to not be able anything about doing this.
Your use of
move_group.go(..)in aforloop reminded me of #q261368. That's not exactly the same situation or use-case, but I believe it touches upon similar points.perhaps you can tell us why you want to do this, as this is not normally the responsibility ...(more)
I am writing a university thesis project and my professor wants that in the simulation the robot performs a rotation of the joint0 of 90 ° and the simulator must do this in 3 seconds and I must set the new waypoint every 5ms. I must also assign, within the cycle, a position and a speed calculated on the basis of the polynomial function but for now I'm trying a configuration with constant position increase and constant speed. Can you advise me one way to write a code as I am asked? I mean with position and speed assignment based on the polynomial function and setting of time deltas at 5ms. I know that maybe I ask a lot but I'm new to ROS and simulation and online I still haven't been able to find anything interesting besides the tutorial I linked previously.
I'm sorry, but I don't understand enough of your assignment to recommend anything.
It does sound more like you are doing something which I would associate with Control Engineering. If that is the case, and you're supposed to write a controller which takes a robot joint from current state to a setpoint while running at a certain frequency then MoveIt is not what you want to use.