Hacktoberfest 2026: the issues maintainers tagged for October, open and beginner-friendly. Browse Hacktoberfest issues

PX4 parameter setting problem

Open
  • Is something wrong?
#109 1 comment 0 reactions 0 assignees View on GitHub

Maintainers usually reply within 1 day

Nobody has claimed this yet.

Assessment

Difficulty
4/5
Estimated time
3-5 days
Newbie friendliness
25/100
Issue type
Bug
Clarity
Mostly clear
Activity status
Stale
Tech stack
cpp, unreal-engine
Domain
backend

Research direction

Start by reading the px4_sitl.md documentation and comparing its PX4 1.12.3 reference with the reported PX4 1.16.1 setup and the parameters in the provided config. Clarify whether unsupported parameter names should be reported and whether configured values are applied; the issue does not identify a code entry point or test.

Written by the indexing model from the issue text.

Description

px4 question

Question

What's your question?

When using PX4 as the controller, I get the following error in the Unreal Editor console:

SimPlugin: [PX4Api] Exception sending parameters to vehicle
SimPlugin: [PX4Api] Error: parameter name 'COM_OBL_ACT' was not found

Because of this error, I suspect other parameters are also not being sent correctly, as the values shown in PX4 (checked with param show) do not match what I set in the config. When I list all parameters on my PX4 console with param show -a, I do not see COM_OBL_ACT. The closest parameter name I see is COM_OBL_RC_ACT.

Is this error due to a version mismatch? My PX4 version is 1.16.1, whereas px4_sitl.md in the documentation refers to version 1.12.3. Could this be the cause?

Additionally, I tried adding a completely invalid parameter (for example: "SADasdjmlafkıafjalofaf": 2) in the parameters section, but did NOT get any error related to that in the logs.

px4 config:

  "parameters": {
    "NAV_RCL_ACT": 0,
    "NAV_DLL_ACT": 0,
    "LPE_LAT": 47.6414680,
    "LPE_LON": -122.1401650,
    "COM_OF_LOSS_T": 5,
    "COM_OBL_ACT" : 1,
    "EKF2_MAG_CHECK": 0, 
    "EKF2_MAG_TYPE": 5,
    "SADasdjmlafkıafjalofaf": 2
  },

PX4 shell output:

pxh> param show NAV_RCL_ACT
Symbols: x = used, + = saved, * = unsaved
x   NAV_RCL_ACT [662,1139] : 2
Sample Unreal Editor log
SimPlugin: [PX4Api] Sending params
SimPlugin: [PX4Api] ProcessMavMessages: received heartbeat message. count: 2
SimPlugin: [PX4Api] ProcessMavMessages: setting HIL mode
SimPlugin: [PX4Api] SetHILMode: putting PX4 in simulation mode via cmd
SimPlugin: [PX4Api] ProcessMavMessages: received heartbeat message. count: 3
SimPlugin: [PX4Api] ProcessMavMessages: message from PX4: [logger] ./log/2026-01-28/10_36_27.ulg   
SimPlugin: [PX4Api] ProcessMavMessages: message from PX4: Preflight: GPS fix too low
SimPlugin: [PX4Api] ProcessMavMessages: Got GPS lock
SimPlugin: [PX4Api] ProcessMavMessages: Got GPS Home Location
SimPlugin: [PX4Api] Exception sending parameters to vehicle
SimPlugin: [PX4Api] Error: parameter name 'COM_OBL_ACT' was not found
Include context on what you are trying to achieve

I want to set PX4 parameters from my AirSim settings file and ensure they are correctly applied in the simulated PX4 flight stack.

Context details
  • PX4 version: 1.16.1
  • Unreal Engine 5.2 used as simulation host
Include details of what you already did to find answers
  • Verified the existence of allegedly missing parameters using param show -a on the PX4 console
  • Tried invalid parameter names but no error was thrown for them

Any help or clarification on handling parameter version mismatches is appreciated.

Dominant language
C++
Stars
890
Forks
170
Avg merge
17h 15m
Merged PRs (30d)
8

Getting set up

  • No Dockerfile or Docker Compose file
  • Has a pull request template
  • No contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

More from iamaisim/ProjectAirSim

All issues in iamaisim/ProjectAirSim

Similar issues

More C++ issues

Get new issues in your inbox

A short digest of beginner-friendly GitHub issues.