# PX4 Community Q&A: May 24, 2023 **URL:** \ **Category:** PX4 Autopilot\ **Created:** [May 17, 2023, 5:00pm UTC](https://discuss.px4.io/t/px4-community-q-a-may-24-2023/32263 "2023-05-17T17:00:32Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![rroche](https://discuss.px4.io/user_avatar/discuss.px4.io/rroche/32/17635_2.png) [@rroche](https://discuss.px4.io/u/rroche)\ **Post date:** [May 17, 2023, 5:00pm UTC](https://discuss.px4.io/t/px4-community-q-a-may-24-2023/32263/1 "2023-05-17T17:00:32Z")
# May 24, 2023 ## Join us > **[Discord - Group Chat That’s All Fun & Games](https://discord.com/channels/1022170275984457759/1022185721450213396/1065287189791002776)** > > Discord is great for playing games and chilling with friends, or even building a worldwide community. Customize your own space to talk, play, and hang out. ## Agenda - Community Announcement - Community Q&A - General Discussions ## 📢 Community Announcement * * * ### A.1 : Release branch for 1.14 has been cut New things merged to the main branch do not necessarily end up in the release. Additional bug fixes will be ported. Release date is not clear yet. We’re hunting after the last issues. We’re feeling good about the release. A lot of successful flight tests were conducted. We worked through multiple reported bugs. One things still hanging at the moment is the PWM calibration: [[WIP] PWM calibration problem · Issue #21634 · PX4/PX4-Autopilot · GitHub](https://github.com/PX4/PX4-Autopilot/issues/21634) Feel free to chime in and cooperate on this. ## 🧑‍🤝‍🧑 Community Q&A (No deep technical discussions) * * * ### ❗ Guideline for asking a Question 1. Specify what you are trying to **achieve** 2. Specify what environment / **platform** you are using 3. Prepare a **Link** or **Document** to help understand if possible 4. First, ask the question on **Discord** or [create a **Github Issue**](https://github.com/PX4/PX4-Autopilot/issues/new/choose)! 5. If you take over 5 minutes for the question, please continue in Discord or a Github Issue. ### Q.1 : Aly/ @princealy ROS2 launch script From below: > [@PX4 Community Q&A: May 24, 2023](https://discuss.px4.io/t/px4-community-q-a-may-24-2023/32263/5): > > Hey everyone! I am trying to create a launch file that will start PX4, so we can send commands from ROS2 to PX4 using the microDDs bridge. I have read the following examples: While these launch ROS2 and connect to PX4 using the bridge, we need a way to first connect the drones to PX4. The use case is to implement the following using a launch file: As the multi-vehicle simulation requires gazebo garden, which is not compatible with our environment. How can we get this to work? Are there a… Is it supported to run ROS2, microDDS, and PX4 using one common launch script? Is there an example for that? Answer: There’s currently no go-to example that works with the latest versions. Once the release is out we want to move back to improving the entire ROS2 workflow. Since Aly is interested to help and contribute we’ll get a forum thread started and already have a draft running. TheotimeBlg is also interested and wants to cooperate. ### Q.2 : @farhang Apple M based toolchain experience Does someone else use Apple M-silicon and use the toolchain and has experience with it? Who is the maintainer? @ThomasDebrunner was making it work in the first place. The Homebrew toolchain setup script works for farhang and jMAVsim works ok after installing both OpenJDKs. ### Q.3 : ayham\_allarbat No log files available Making logs by arming, disarming or `logger on`, `logger off` there is no log available afterwards. The logger seems to trigger as expected. Board: Holybro pixhawk 6C The suggested next thing to try is back up the SD card content, format it on e.g. a Windows computer and then try again. ### Q.4 : ayham\_allarbat MAVLink stream configuration Using a startup script from 1.11/1.12 releases that adjust the message frequency of a MAVLink telemetry stream for odometry from 30Hz to 100Hz on 1.13 results in a higher message rate seen in MAVLink inspector on the round station but not in mavros. This could be because the USB MAVLink instance is started in a different way only when something is connected via USB and sends a heartbeat. Depending on the timing when having the stream adjustment command during bootup it could not have an effect. The suggestion is to adjust/add a MAVLink stream mode that has full rate odometry feedback for the use case. In general, having a companion computer connected over USB is a use case that also @AlexKlimaj is working with. It would be useful to have a configuration option to have a fixed MAVLink instance on the USB port and not have it fail the preflight check when connected (the last part already available in a circuit breaker `CBRK_USB_CHK`). ### Q.5 : SalimTerryLi Apple jMAVsim issue Some library in [jMAVSim/lib at main · PX4/jMAVSim · GitHub](https://github.com/PX4/jMAVSim/tree/main/lib) doesn’t work properly for him on an ARM-based computer. @farhang is trying to reproduce the issue and shares what the necessary additional steps are. ### Q.6 : SalimTerryLi Tested his PR for the PWM extender Now it needs to be reviewed. > > > This PR fixes \`pca9685\_pwm\_out\`. Now it should works again. > > Blocker #20594 go…t merged. > > \#### Fixed things: > > \- Parameters for setting PWM frequency > \- May looks better now, comparing to what I've done years before... > > \#### Imporvements > > \- Move scheduling rate from cmdline argument into parameters > \- Support output duty-cycle signals per channel > \- Support configuring CLK source of PCA9685 with Kconfig > \- Now it should be able to act as an alternative to the old \`pca9685\` module, which is deprecated in 0e2df5a > > \#### Test Coverage > > \- RPi 4B with my expansion board using PCA9685 as main output > \- CUAV pixhack v3 with PCA9685 connected to I2C1 and he’s also looking for feedback on > > > \### Changes > > \- bring the modified source of linenoise in-tree > \- server\_io.cpp… added new get\_stdin() method, which is primarily used by uorb top. Now uorb top can work with MavShell inputs > \- apps.cpp.in use PX4\_INFO\_RAW() to ensure all outputs go into thread stdout, which will be redirected to its real location > > \### Improvements > > \- MavlinkShell won't dup2() on original stdio, thus will not mess the real terminal > \- use of the linenoise makes it much easier to implement advanced terminal functionaliies > > Now the console can be gracefully shutdown, but further cleanups still can not be performed until per-thread graceful shutdown is implemented. > > \### Test coverage > > \- works on native arm64 RPi 4B > \- \`make px4\_sitl gz\_x500\` works on x64 with Linux Mint 21 > \- \`make px4\_sitl jmavsim\` and \`make px4\_sitl gz\_x500\`works on Intel MacBookPro 2017 with macOS 12.6.5 ---
**Author:** ![Matteo\_Mennea](https://discuss.px4.io/user_avatar/discuss.px4.io/matteo_mennea/32/13205_2.png) [@Matteo\_Mennea](https://discuss.px4.io/u/Matteo_Mennea)\ **Post date:** [May 17, 2023, 8:55pm UTC](https://discuss.px4.io/t/px4-community-q-a-may-24-2023/32263/2 "2023-05-17T20:55:39Z")
Hi! I’m developing my Master’s Thesis, and I’m using the PX4 toolbox in Simulink to design a customized controller for a quadcopter. I want to apply a model design approach, so I want to create the controller in Simulink and then through code generation, I want to perform SITL, PIL and HIL on Gazebo in order to validate my controller and then deploy the generated code on the real drone. I’m having problems with the simulator I want to use. Does anyone know how to perform SITL in Gazebo using the PX4 Toolbox in Simulink? I have just two simulators listed on the settings (jMAVsim and Simulink), how can I run my Simulink model on Gazebo? ---
**Author:** ![Matteo\_Mennea](https://discuss.px4.io/user_avatar/discuss.px4.io/matteo_mennea/32/13205_2.png) [@Matteo\_Mennea](https://discuss.px4.io/u/Matteo_Mennea)\ **Post date:** [May 22, 2023, 10:25am UTC](https://discuss.px4.io/t/px4-community-q-a-may-24-2023/32263/3 "2023-05-22T10:25:48Z")
Hi, I’m developing my Master’s Thesis, and I’m using the PX4 toolbox in Simulink to design a customized controller for a quadcopter. I have done a Simulink file where I’m injecting rotor velocities into the quadcopter simulated on jMAVsim, it is like an open loop system. I have to store the system states of the open loop system because I need them for further calculation (model validation with the mathematical models),but I have a problem. I need also to read and store the rotor velocities because I have to check if they are the equals to the injected one. How can I read the rotor velocities? I’m using the PX4 read block on Simulink using the esc\_report.msg and rpm.msg, but I read 0 as output which is impossible because the drone takes off. How can I fix this problem? ---
**Author:** ![rroche](https://discuss.px4.io/user_avatar/discuss.px4.io/rroche/32/17635_2.png) [@rroche](https://discuss.px4.io/u/rroche)\ **Post date:** [May 22, 2023, 9:49pm UTC](https://discuss.px4.io/t/px4-community-q-a-may-24-2023/32263/4 "2023-05-22T21:49:35Z")
hey @Matteo_Mennea please join us for the call! ---
**Author:** ![princealy](https://discuss.px4.io/user_avatar/discuss.px4.io/princealy/32/12558_2.png) [@princealy](https://discuss.px4.io/u/princealy)\ **Post date:** [May 23, 2023, 2:44pm UTC](https://discuss.px4.io/t/px4-community-q-a-may-24-2023/32263/5 "2023-05-23T14:44:48Z")
Hey everyone! I am trying to create a launch file that will start PX4, so we can send commands from ROS2 to PX4 using the microDDs bridge. I have read the following examples: > > **[Offboard Control | PX4 User Guide](https://docs.px4.io/main/en/ros/offboard_control.html)** > > PX4 is the Professional Autopilot. Developed by world-class developers from industry and academia, and supported by an active world wide community, it powers all kinds of vehicles from racing and cargo drones through to ground vehicles and... While these launch ROS2 and connect to PX4 using the bridge, we need a way to first connect the drones to PX4. The use case is to implement the following using a launch file: > **[Multi-Vehicle Simulation with Gazebo | PX4 User Guide](https://docs.px4.io/main/en/sim_gazebo_gz/multi_vehicle_simulation.html)** > > PX4 is the Professional Autopilot. Developed by world-class developers from industry and academia, and supported by an active world wide community, it powers all kinds of vehicles from racing and cargo drones through to ground vehicles and... As the multi-vehicle simulation requires gazebo garden, which is not compatible with our environment. How can we get this to work? Are there any examples? Here are some related threads: [Launch PX4 via ROS2 python launch file - #13 by befaro](https://discuss.px4.io/t/launch-px4-via-ros2-python-launch-file/20370/13) - uses RTPS not microDDS [ROS2 lidar integration - via python launch file?](https://discuss.px4.io/t/ros2-lidar-integration-via-python-launch-file/25763) - unasnwered Here is my discord question: [Discord](https://discordapp.com/channels/1022170275984457759/1030186476153085993/1108910429167697940) Thank you so much!!!