IMU problems for the D455

louislelay commented 1 month ago

Issue Description

Required Info	Details
Camera Model	D455
Firmware Version	5.15.0.2
Operating System & Version	Ubuntu 22.04
Kernel Version (Linux Only)	6.8.0-40
Platform	PC
Librealsense SDK Version	2.55.1
Language	N/A
Segment	Robot
ROS Distro	Humble
RealSense ROS Wrapper Version	4.55.1

Hello, I’m working with a RealSense D455 camera and encountered some issues when trying to use the IMU topic.

Steps to Reproduce:

I launched the rs_launch.py file without any arguments. I noticed that the expected /camera/camera/imu topic doesn't appear. From my inspection, it seems that this topic is not enabled by default. If this is intended behavior, I suggest updating the README to reflect the change.

I then tried to enable the IMU by running the following command:

ros2 launch realsense2_camera rs_launch.py enable_accel:=true enable_gyro:=true unite_imu_method:=2

Issues Observed:

Frames Timeout Warning: After running the above command, I started encountering the following delay warnings:

[realsense2_camera_node-1] 22/09 21:52:30,461 WARNING [133606110398016] (backend-v4l2.cpp:1649) Frames didn't arrive within 5 seconds
[realsense2_camera_node-1] [WARN] [1727056350.461886004] [camera.camera]: XXX Hardware Notification: Frames didn't arrive within 5 seconds,1.72706e+12,Warn,Frames Timeout

Partial IMU Data: After launching with the enable_accel, enable_gyro and unite_imu_method options, new topics, including /camera/camera/imu, appeared. However, when echoing this topic, I noticed that only the angular_velocity and linear_acceleration fields were receiving updates, while the orientation field remained at all zeros:
```
header:
stamp:
sec: 1727056330
nanosec: 371350528
frame_id: camera_imu_optical_frame
orientation:
x: 0.0
y: 0.0
z: 0.0
w: 0.0
orientation_covariance:
```
-1.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0 angular_velocity: x: -0.005235987715423107 y: -0.003490658476948738 z: 0.005235987715423107 angular_velocity_covariance:
0.01
0.0
0.0
0.0
0.01
0.0
0.0
0.0
0.01 linear_acceleration: x: 0.45110589265823364 y: -9.090764045715332 z: 1.0296982526779175 linear_acceleration_covariance:
0.01
0.0
0.0
0.0
0.01
0.0
0.0
0.0
0.01

Confusion:

Why am I receiving updates for angular velocity and linear acceleration even though I'm getting "frames didn't arrive" warnings?
Why is the orientation field not being updated, and why does it show all zeros?

Thanks in advance!

IRONCROWY commented 1 month ago

If what i remembered is not wrong, D455 has no orientation output.

MartyG-RealSense commented 1 month ago

Hi @louislelay Thanks very much for your questions.

You are correct, the accel and gyro IMU topics are disabled by default, because not everyone has a RealSense camera equipped with an IMU.

The IMU streams being disabled by default is referenced in the following line of the documentation on the wrapper's main page.

enable_: Choose whether to enable a specified stream or not. Default is true for images and false for orientation streams.

The recollection of @IRONCROWY above regarding orientation values not being provided is correct, at least for the ROS1 wrapper - please see https://github.com/IntelRealSense/realsense-ros/issues/1210#issuecomment-634465607

One ROS1 user at https://github.com/IntelRealSense/realsense-ros/issues/1694#issuecomment-779736012 installed an additional package to obtain the orientation.

In regard to IMU support in the ROS2 wrapper, it also only supports gyro, accel and the unite_imu_method parameter that publishes the /imu topic.

louislelay commented 1 month ago

Hi @MartyG-RealSense, thank you so much for the detailed response!

I’ll go over everything in the next few days, but I do think the README might need a small update. It seems to suggest that the IMU topic is published without any parameters, which isn’t accurate from what you say. It’s a minor change, but it would make things clearer. Also, I now understand why the other messages in the topic aren't updating. That said, do you think it would be a good idea to add a node in the repository to publish orientation if needed?

MartyG-RealSense commented 1 month ago

You are very welcome!

If you would like to suggest a change to the documentation or create and submit a mechanism to publish orientation then contributions to the RealSense wrapper from users via a Pull Request (PR) are welcomed. Please see https://github.com/IntelRealSense/realsense-ros/pulls

louislelay commented 1 month ago

I'll experiment with a few approaches and, if I find a promising solution, I'll be sure to propose it! Since all my questions have been answered, I'll close this issue. Thanks again @MartyG-RealSense!

MartyG-RealSense commented 1 month ago

You are very welcome, @louislelay - thanks very much for the update. Good luck!

IntelRealSense / realsense-ros