Angular Velocities Output goes wrong with D435i & D455 Camera

[HappySamuel]

---

Required Info
Camera Model	D435i / D455
Firmware Version	5.16.0.1
Operating System & Version	JetPack 5.1.3 (Ubuntu 20.04)
Kernel Version (Linux Only)	5.10.192-tegra
Platform	NVIDIA Jetson AGX Orin
Librealsense SDK Version	2.54.1
Language	ROS2
Segment	Robot
ROS Distro	Humble
RealSense ROS Wrapper Version	4.54.1

Issue Description

I have the realsense-ros installed following Realsense Camera with CUDA-enabled steps suggested here. However, when i tried to enable both the gyro and accel, and having the unite_imu_method=1 / 2 , which will output the imu topic /front_cam/imu . Although the camera is sitting still, for the accelerations portion, they are seems OK, but the angular velocities are awful, keep dramatically jumping around. For your info, the camera is sitting still. I tried both d435i and d455 cameras, both their angular velocities are unsable at all. And this phenomenon only observed in the realsense-ros, while angular velocities seems just fine in the realsense-viewer . Here i attached the bagfiles of both 435i and d455 cameras recorded with running realsense-ros.

d435i_rs_imu.zip

d455_rs_imu.zip

Here are the config i used for both d435i and d455 cameras. I only enable gyro and accel at the moment with else disabled. I also have enabled the enable_motion_correction

rgb_camera:
  profile: '1280x720x15'
  global_time_enabled: true
  enable_auto_exposure: true
  enable_auto_white_balance: true
  power_line_frequency: 2
color_info_qos: "SENSOR_DATA"
color_qos: "SENSOR_DATA"

depth_module:
  profile: '640x360x60'
  global_time_enabled: true
  enable_auto_exposure: true
  hdr_enabled: false
  emitter_always_on: true
  emitter_enabled: 1  #0=OFF | 1=enable laser | 2=enable laser auto
  emitter_on_off: false

infra1_qos: "SENSOR_DATA"
infra1_info_qos: "SENSOR_DATA"
infra2_qos: "SENSOR_DATA"
infra2_info_qos: "SENSOR_DATA"

motion_module:
  global_time_enabled: true
  enable_motion_correction: true
  frames_queue_size: 16
gyro_fps: 200
accel_fps: 63
unite_imu_method: 2  #0=none | 1=copy | 2=linear_interpolation

enable_color: false
enable_depth: false
enable_infra1: false
enable_infra2: false
enable_sync: false
enable_accel: true
enable_gyro: true

pointcloud:
  enable: false
  filter_magnitude: 2  #1=OFF | 2=ON
  ordered_pc: false
  pointcloud_qos: "SENSOR_DATA"

decimation_filter:
  enable: false
  filter_magnitude: 4

clip_distance: 3.0

Any solution for this?

Best, Samuel

[MartyG-RealSense]

Hi @HappySamuel Does gyro stability improve if you set global_time_enabled for the motion module to false, please? Having global time enabled is less important in ROS than it is in the RealSense Viewer because ROS has its own timing sync mechanism.

I would also recommend confirming in the Viewer's Motion Module section the FPS speeds that are supported for your cameras. RealSense cameras with an IMU supported 63 Accel and 200 Gyro prior to mid 2022, and after that the IMU component in the cameras was changed to one that supports 100 Accel and 200 Gyro, with the '63' accel speed no longer supported.

[HappySamuel]

Hi @MartyG-RealSense

I just tried to disable the global_time_enabled , however the gyro outcome is still dramastically jumping around for all 3 axes.

Besides, i checked my D435i camera for their available FPS for both gyro and accel via realsense-viewer

Gyro: 200 / 400
Accel: 63 / 250

What shall i do next?

[MartyG-RealSense]

How does gyro behave if you set enable_sync to true?

[HappySamuel]

I tried having the enable_sync:=true, but the gyro outcome is still dramastically jumping around for all 3 axes.

The weird thing is, why would gyro outcome becoming like this ? while the accel still remain normal.

[MartyG-RealSense]

There is a similar sounding ROS case at https://github.com/IntelRealSense/realsense-ros/issues/2745 where the gyro was fluctuating continuously and using motion correction or setting unite_imu_method to copy made no difference.

Eventually they described at https://github.com/IntelRealSense/realsense-ros/issues/2745#issuecomment-1571241211 how they minimized rotation with something called /cmd_vel. Apparently it is a command used with robots such as turtlebots though, so may not be applicable to how you are using the camera.

http://wiki.ros.org/Robots/TIAGo/Tutorials/motions/cmd_vel

[MartyG-RealSense]

Hi @HappySamuel Do you require further assistance with this case, please? Thanks!

[HappySamuel]

Hi @MartyG-RealSense

Sorry for the late reply. I will look forward for the next upgrade on the realsense Firmware, perhaps this issue will be resolved when it comes.

[MartyG-RealSense]

It's no problem at all. Thanks very much for the update!