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I’m trying to demonstrate pick and place in gazebo by using moveit to plan trajectory.

Here is the code which i’m using, this is code is very much inline with moveit pick-n-place tutorials.

I’m not able to understand the impact of time_from_start parameter used in open_gripper and close_gripper functions. I have read about this previous queston on community but it couldn’t solve my queries.

my questions are as follows:

  1. What is the exact meaning and importance of parameter time_from_start in trajectory_msgs used in above pointed tutorial?

  2. what significant the parameter time_from_start has on when the gripper is opened and closed?

  3. Why the value of duration is hardcoded and how can i make it generic if it is possible?

  4. Can i relate his time_from_start with sim_time or real_time parameters seen in gazebo??

i’ll appreciate any leads as it will help me to solve the problems about gripper opening and closing!

Thanks, Vishal

Originally posted by mvish7 on ROS Answers with karma: 104 on 2019-03-20

Post score: 1


1 Answer 1


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Hello Vishal, I would like to share some knowledge on the "time_from_start" variable in trajectory_msgs. Trajectory msgs from moveit or any controller would generally be a list of points that the robot should follow. This parameter defines the time instance at which the robot should be at that particular trajectory point. (i.e, it serves as an instantaneous goal for that exact time instance after the start of trajectory)

Originally posted by RoboHack04 with karma: 16 on 2022-05-27

This answer was ACCEPTED on the original site

Post score: 0


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