ModalAI Forum

jbiscan21

Thank you for the info. This is for the starling. Sounds great, is there a limit for the
backtrack_seconds value?

jbiscan21

Hello,

Just a generic question.

I was reading through the voxl-vision-hub docs and I was trying to understand how to use backtracking. Does that just require PX4 to be in offboard mode? How does one trigger the backtracking behavior?

mrawding

Hello,

I am looking to outfit this camera on our voxl2-mini platform vehicles; however, the lens FOV is too wide for the application we intend. Are there narrower lens options supported by ModalAI?

If not, what mount type and size is the lens so we can replace it with a lens from another vendor?

Lastly, if the lens cannot be changed, if we were to get the correct MIPI connectors and adapters - would the VOXL2 driver for the ov9281 still work if we used the same sensor from Vision Components - VC MIPI OV9281.

Thanks

김

We flew our first mapper-based path flight on a Starling 2 Max and the drone did follow the planned path. However, the local planner was unable to deliver a single trajectory for the entire flight, so the drone was flying on the one path computed before departure, with no replanning.

What happened

Global planning succeeded:

05:13:38  Client requested plan to location
05:13:38  Using start pose of: x: 1.67, y: -0.80, z: -1.46
05:13:38  Using goal pose of:  x: 5.16, y: -1.34, z: -0.89
05:13:38  Starting RRTConnect planner
05:13:38  Immediate collision free path found!

Then, from the instant we pressed Follow Path, this repeated continuously for 2 min 16 s until we took manual control:

05:14:10  Client requested to follow last path
05:14:10  Local Planner failed to send trajectory
05:14:10  ERROR: Cannot insert trajectory. Total segments = 20, Max segments = 20
...       (repeats at roughly 1-2 s intervals through 05:16:26)

Throughout those 2 min 16 s the planner itself was running normally — A* took = 0.07-0.14 ms for 13 iterations and Smoother took = 6-12 ms were interleaved with every failure. So it computes a trajectory and then cannot insert it.

The drone moved 2.68 m straight-line / 8.79 m total path at up to 1.04 m/s, which matches the pre-computed path. It stopped 0.81 m short of the goal only because the pilot intervened.

What we ruled out

Not a planning failure — the global path was found and reported collision-free.
Not a VIO problem — dt held at 33.3 ms for all 44 samples in flight, features 15-30, cs_ev_pos / cs_ev_yaw / cs_ev_hgt all True.
Not a map problem — voxl_mapper_aligned_ptcloud was producing 1,489-2,925 points at ~10 Hz before and during the flight.
Not CPU load — load average dropped from 7.75 on the ground to 4.5 in flight; governor was performance.
Not thermal throttling — 94-96 C, but scaling_cur_freq equalled cpuinfo_max_freq on all cores and dmesg showed no throttle events.
Not a config we changed — voxl-mapper.conf is stock; loco_num_segments is 10.

What we could not find

The limit of 20 does not appear in voxl-mapper.conf. loco_num_segments is 10, which is not the number in the error. We could not locate a setting that exposes Max segments.

One thing we suspect, but have not tested

Before the successful Go, we had two failed ones — both rejected with ERROR: End point is in collision because the goal came in at z: 0.00 (we were clicking in the 2D view, which puts the point at ground level). The Max segments = 20 error appeared immediately on the first Follow Path, which makes us wonder whether failed plans leave segments behind. We have not yet tested whether pressing Clear Paths first avoids it.

Questions

Where is the 20-segment limit set, and is it configurable?
What normally fills the segment buffer, and what clears it? Does a failed Go leave segments allocated?
Is Clear Paths the correct way to reset this state before Follow Path?
Is there a way to detect this condition other than reading the mapper journal? From the Portal UI everything looked correct — the path was drawn and Immediate collision free path found! was reported — so an operator has no indication that obstacle avoidance is not active.

Environment

Hardware: Starling 2 Max, SKU MRB-D0012-4-V4-C29-T8-M36
voxl-version: system-image 1.8.08-M0054-14.1a-perf, voxl-suite 1.6.4~beta5
voxl-mapper 0.2.4, voxl-vision-hub with offboard_mode: "trajectory"
Services active at the time: voxl-vision-hub, voxl-open-vins-server, voxl-mapper, voxl-px4, voxl-portal

We have the full mapper journal and the PX4 .ulg from this flight and can share either.

jbiscan21

Hello,

Just a generic question. For running PX4 on the DSP, I noticed that they typically come pre shipped on 1.14. However, I do see support for mainline in the docs. Is 1.14 still the most stable, or can I follow a process to upgrade?

Thank you,
John

oiler251

@alex-kushleyev
Now is back to normal setting as it used to be whereas i still see the drift issue after take off.
Can you support how to configure it to hold position once take off?
My demo will be inside the building in big 20' x 30' closed area and I can not run this with drift in any direction after take off and hit the boundary net.
Can you advise how i can resolve this drifting issue?

ZuraNeb

Potentially try to register using another email address.
Our public files (including CAD files) are located here
https://modalai.filecloudonline.com/ui/core/index.html#/

oiler251

I realized it would be mode 2 for Ghost joystick with left stick as throttle.
The drone arms with the controller now. The drone is tethered to a fixture inside our lab (GPS denied ambience) and when arm and takes off at manual mode, I can control less now. It use to be more controller with height adjustment and maneuvering clock wise or anti clock wise at 3 ft height. It is like jumping up and down and drift front, back, left and right.
Do I have to disable any sensors?

oiler251

Is it mode 1 or mode 2 for Ghost RC calibration? Mine is mode 1 by default.

oiler251

@alex-kushleyev
I followed the instruction steps and still arming issue. Below are the steps result.
Step 1: The RC=GHST
Step 2: Re-run Calibration as per the instruction as well as per the video. Calibration Successful.
Step 3: Manual arm gesture does not report any error but if I set arm to channel 7, I can see Arming denied: high throttle message.
I also tried tried clear all RC to Param and does not arm the drone.

Please, advise how can we troubleshoot further.

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