Driver Node publish topics at different Interval

[zhouzhiqian]

When I use MTI300 on Ubunty 16.04 + ROS kinetic， the intervals between every two topics don't keep 5ms (its frequency is 200 Hz).
Just like this figure:

But when I use it on Ubunty 14.04 + ROS indigo, it shows a totally different result.

)

[fcolas]

That's a new issue for me.
Does it happen consistently or just sometimes (and if so, in which condition)?
I assume you checked it was not a CPU performance issue and only run the mtnode to reduce outside influences.
Is it the same system with two different installs or are there differences in the CPU/USB bus?

[MichalNowicki]

I experienced this issue on a similar configuration and in our case, it was caused by the latency settings of the Ubuntu driver for FTDI. The solution was to set the low_latency mode of the driver and thus prevent it from accumulating multiple measurements.

The command to execute after the device was plugged in:
setserial /dev/<tty_name> low_latency

The setting resets once the device is disconnected but udev rules can be used to make it permanent.

[zhouzhiqian]

@MichalNowicki Thank you very much. I will try your solution quickly.

[artemiialessandrini]

Hi, I am having the same issue of publisjing with different interval partially:

image

While trying to setserial /dev/ttyUSB0 low_latency, I get:
Cannot get serial info: Inappropriate ioctl for device

[artemiialessandrini]

@zhouzhiqian was it a solution for you?

[artemiialessandrini]

Apparently, rosbag_validate displays the same ERROR:
E1008 14:32:31.060365 31665 rosbag_validate_main.cc:389] IMU data (frame_id: "imu_link") has a large gap, largest is 0.660078 s, recommended is [0.0005, 0.005] s with no jitter.