I have a robot where the 2 ousters(blue circles) are mounted on a robot on the front and back. red line indicating the wire connector/ 0°. I want all the lidar points to be aligned and both the ousters to publish their frame at the same time when the scan reaches yellow. how do i do it?
I’ve tried phase locking them and phase lock offset to align them, but the timestamp is delayed and it means that that portion of the points that i need to use for DLIO will be in a previous message.
So I need a way to align the points and have them publish at the same time (no timestamp delay). Thank you in advance!
This is a timely question because Ouster just released firmware 3.2 along with ouster SDK 0.16 which can solve your problem. FW3.2 is not posted on Datasheets, CAD files, and guides for our lidar sensor | Ouster yet, it will be up next week, so please message me directly with contact info so we can send you the firmware image.
Phase locking affects where the lidar is pointing relative to the absolute time base, but not where the physical frame boundary is that dictates when the frame id rolls over. Up until FW3.2, the frame boundary was not modifiable and it was always the 0° mark - the red marked connector in your drawing.
FW3.2 introduces a lidar_frame_azimuth_offset config parameter that allows a user to rotate the physical angle where frame id’s rollover. By default the frame boundary (lidar_frame_azimuth_offset) is 0° to maintain backwards compatibility.
In your case, you should:
Time sync the lidars: timestamp_mode=TIME_FROM_PTP_1588
Phase lock the lidars: phase_lock_enable=True
Set phase_lock_offset=0 on each lidar, which is the default
Apply a 60° lidar_frame_azimuth_offset=60 to the top lidar, and a 360°-30° = 330° offset to the bottom lidar. The angle is defined in millidegrees so 60000 and 330000.
This should result in the two lidars generating frames simultaneously, with the frame boundary aligned with the yellow line. It’s possible my math is wrong so you may need to experiment to get this just right.
Please reply if this solves your problem given that this is a brand new feature and we want to ensure it’s properly working and document the solution for others.
Thank you for your reply, this functionality sounds like it will fix my issue. What Is the best way to reach you to get a copy of the firmware? Maybe linkedin and then I can share you my email?
