Reducing delay at start of movement

[simonschmeisser]

We are currently trying to push a system to the limits and noticed that there is some delay between receiving a control_msgs/FollowJointTrajectoryActionGoal and seeing the joints move in /joint_states.

We already reduced the sleep in the MotomanJointTrajectoryStreamer::streamingThread()
isys-vision@3d47be3

from 250ms to 5ms

but we still see delays between 100ms and 200ms. I understand that the feedback is of course also delayed (we use 200hz update rate -> 5ms) but I'm just curious if there are other things that could be tuned?

callback received:
Trajectory Duration:  0.393297685     points:  9
137.43066787719727 ms for starting
Stopped motion. Complete actual duration:  705.3301334381104  ms
finished in mikado
callback received:
Trajectory Duration:  1.161717276     points:  25
137.2368335723877 ms for starting
Stopped motion. Complete actual duration:  1474.975347518921  ms
finished in mikado
callback received:
Trajectory Duration:  0.080922418     points:  2
83.02664756774902 ms for starting
Stopped motion. Complete actual duration:  406.0015678405762  ms
finished in mikado
Stopped motion. Complete actual duration:  598.8180637359619  ms
callback received:
Trajectory Duration:  1.024520684     points:  12
146.12674713134766 ms for starting
Stopped motion. Complete actual duration:  1327.4507522583008  ms
finished in mikado
callback received:
Trajectory Duration:  1.1278624800000001     points:  25
122.07555770874023 ms for starting
Stopped motion. Complete actual duration:  1427.854299545288  ms
finished in mikado
callback received:
Trajectory Duration:  0.083472203     points:  2
80.28817176818848 ms for starting
finished in mikado
Stopped motion. Complete actual duration:  413.1946563720703  ms
callback received:
Trajectory Duration:  0.99140924     points:  12
175.39501190185547 ms for starting
Stopped motion. Complete actual duration:  1317.8343772888184  ms
finished in mikado
callback received:
Trajectory Duration:  1.1464991119999999     points:  25
106.86349868774414 ms for starting
Stopped motion. Complete actual duration:  1447.6265907287598  ms
finished in mikado
callback received:
Trajectory Duration:  0.080995018     points:  2
92.2548770904541 ms for starting
Stopped motion. Complete actual duration:  399.22451972961426  ms
finished in mikado
Stopped motion. Complete actual duration:  580.5680751800537  ms
callback received:
Trajectory Duration:  0.989379824     points:  12
152.4033546447754 ms for starting
Stopped motion. Complete actual duration:  1294.548749923706  ms
finished in mikado
callback received:
Trajectory Duration:  1.01621366     points:  25
130.44309616088867 ms for starting
Stopped motion. Complete actual duration:  1346.4434146881104  ms
finished in mikado
callback received:
Trajectory Duration:  0.091512813     points:  2
112.86163330078125 ms for starting
Stopped motion. Complete actual duration:  409.62934494018555  ms
finished in mikado
callback received:
Trajectory Duration:  0.917212771     points:  12
149.92022514343262 ms for starting
Stopped motion. Complete actual duration:  1236.499547958374  ms
finished in mikado
callback received:
Trajectory Duration:  0.909805459     points:  12
110.77189445495605 ms for starting
Stopped motion. Complete actual duration:  1350.1110076904297  ms
finished in mikado
callback received:
Trajectory Duration:  0.201539985     points:  14
180.33313751220703 ms for starting
Stopped motion. Complete actual duration:  498.8265037536621  ms
finished in mikado
callback received:
Trajectory Duration:  0.084413037     points:  2
83.79244804382324 ms for starting
Stopped motion. Complete actual duration:  389.31846618652344  ms
finished in mikado
Stopped motion. Complete actual duration:  593.886137008667  ms
callback received:
Trajectory Duration:  1.004124684     points:  12
150.68960189819336 ms for starting
Stopped motion. Complete actual duration:  1314.835786819458  ms
finished in mikado
callback received:
Trajectory Duration:  1.29722745     points:  26
126.58143043518066 ms for starting
Stopped motion. Complete actual duration:  1610.3153228759766  ms
finished in mikado
callback received:
Trajectory Duration:  0.083471131     points:  2
108.67452621459961 ms for starting
Stopped motion. Complete actual duration:  403.9173126220703  ms
finished in mikado
Stopped motion. Complete actual duration:  587.7640247344971  ms
callback received:
Trajectory Duration:  1.015903883     points:  12
156.11886978149414 ms for starting
Stopped motion. Complete actual duration:  1334.991455078125  ms
finished in mikado
callback received:
Trajectory Duration:  0.969377502     points:  12
133.99958610534668 ms for starting

red is the action, blue the feedback, looking at axis 6 here, blueish vertical line is when industrial_msgs/RobotStatus changed, red vertical line is when action finishes, green is distance to goal with the right hand side y-axis

[gavanderhoorn]

Have you seen/read #458?

but we still see delays between 100ms and 200ms.

that would seem to fall in the range mentioned in #458.