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Repo info
Brian Amin
@jeprince Are you running gazebo standalone? How are you opening gazebo
@BAmercury gazebo ./iris.world --verbose
i've also tried just launch gazebo without a world
when i run with --verbose i get errors that it cannot find the plugins but i'm not sure how to fix it
Brian Amin
Oh word, so looks like you need to build the plugins and then install them. Have you looked at this? https://dev.px4.io/v1.9.0/en/setup/dev_env_linux.html#jmavsimgazebo-simulation
Sorry wrong link 1 sec
Brian Amin
And then for building the plugins check the readme on here: https://github.com/PX4/sitl_gazebo

@BAmercury I'm still having issues. I cloned the sitl_gazebo repo, tried "cmake .." and it failed (im on ubuntu 18.04 so maybe that's why?). I cloned the PX4/Firmware repo, and ran the following commands
cd Firmware
git checkout v1.8.2
git submodule update --init --recursive
make posix_sitl_default gazebo

It starts gazebo with a SITL PX4, but if i try gazebo ./iris.world --verbose it gives me errors that file paths are wrong, If i try with in the cloned sitl_gazebo you mentioned it says plugins cant be found and file paths are wrong.

Brian Amin
@jeprince when you ran cmake .. what did it say?
@BAmercury I just tried it again on Ubuntu 16.04 i got:
--   Found gstreamer-1.0 , version 1.8.3
-- Checking for module 'gstreamer-base-1.0 >= 1.0'
--   Found gstreamer-base-1.0 , version 1.8.3
-- Checking for module 'OGRE'
--   Found OGRE, version 1.9.0
CMake Error at CMakeLists.txt:70 (add_subdirectory):
  The source directory


  does not contain a CMakeLists.txt file.

-- Could NOT find MAVLink (missing:  MAVLINK_INCLUDE_DIRS) (found version "2.0")
-- catkin DISABLED
-- Found Protobuf: /usr/lib/x86_64-linux-gnu/libprotobuf.so  
-- Checking for module 'protobuf'
--   Found protobuf, version 2.6.1
-- Gazebo version: 9.11
-- Found GStreamer: adding gst_camera_plugin
-- Found GStreamer: adding gst_video_stream_widget
CMake Error: The following variables are used in this project, but they are set to NOTFOUND.
Please set them or make sure they are set and tested correctly in the CMake files:
looks like its looking for _MAVLINK_INCLUDE_DIR and its value

I saw this comment but I don't know how to "use pymavlink to generate header files"


i copied the "mavlink" folder from PX4/Firmware into the SITL_gazebo cloned repo and everything compiled. Now, when i run gazebo with gazebo worlds/iris.world it says:
abuser@labuser-VBox:~/src/sitl_gazebo$ gazebo worlds/iris.world 
Error Code 11 Msg: Unable to find uri[model://iris]

made changes to ~/.bashrc file per the README, now it works on Ubuntu 16.04, still no luck on 18.04


Brian Amin
@jeprince I'll try to find some time this week and run it on my 18.04 I'll get back to you
McKay Whight
Hey everyone, I'm trying to understand how motor actuation takes place in PX4. As far as I can see, the controller (rover_pos_control in my case) publishes control information to _t_actuator_controls_0, then the PX4FMU class calls the OutputMixer's mix operation in its run method which retrieves control values from _t_actuator_controls_0, mixes the values, and then the OutputMixer class calls the PX4FMU's updateOutputs function which directly sets PWM duty cycle inside pwm_servo.c. What I don't understand is if we are connecting our motors to the PX4IO chip, at what point does the PX4FMU code send the duty cycle information to the PX4 IO board? Does it somehow use px4io.cpp to send the information over UART? At the moment, it looks like the code inside px4io.cpp just gets information directly from _t_actuator_controls_0 and sends it straight to the IO chip, without ever talking to PX4FMU and without ever mixing the control values. Does mixing take place on the IO chip itself? Any help would be amazing
İsmail Emre Canpınar
Hi, how can I change a parameter in flighttask?
hi guys
happy new year to all!
do you guys have any experience with mounting companion computer connected to Pixhawk 4?

Hi guys
While I 'm looking into the ~/src/Firmware/CMakeLists.txt, I'm wondering where the reservation words such as PX4_PLATFORM and PX4_BOARD are come from.
Would anyone tell me where those keywords are located?

Thank you.

@Guohao91 -- nope but about to do that pretty soon -- theres some awesome instructions here:
@jeprince thanks for posting all them comments dude! Was gonna install 18.04 but now know better not to
There is enyone who worked with matlab to change px4 firmware
@islamdib What do you mean by changing px4 firmware? Do you mean something like uploading offboard mission through matlab? Actually, i'm working with simulink(ROS Toolbox) to upload offboard mission on px4 firmware.
Im new , i can't use scientific terms
@latebecomer Im new , i can't use scientific terms
@latebecomer I m using similink blocks to generate commands
@latebecomer then embedded coder support package for px4
@latebecomer build and deploy flight control algorithms to px4 autopilots i want to control a quadrotor using the radio control
Hi guys, I would like to build an older version of pixhawk but for the newer pixhawk cube black. Problem is the board name is not an option when I go to configure the project with waf. Is there a way I can just update the board list specifically so I can build my project for the new list of boards??
I note the rover_diff_and_servo mixer utilises roll as opposed to yaw for the turning functionality, this seems counter intuitive but I suppose it's got something to do with a) the physical interface or b) the control loop (yaw runs a different control system correct?), Can anyone provide some background here/a suggestion as to which is the best approach for a skid steer vehicle?
Can someone direct me to who knows more about the PixHawk CubeBlacks?? We have had no issues with Pixhawk2.1 cubes using Telem1 & Telem2 ports simultaneously but there appears to be a major problem on the Cube blacks when a RC Hand controller is attatched to Telem2 and companion computer on Telem1 port, Cube wont even boot and errors out, no logs on the SD Card like some online forms say. Funny thing is when unplug the RC2 from the telem2 to allow the pixhawk to boot then replug it in, everything works fine? Any direction on who to contact or the appropriate place to post would be much appreciated.
Alfredo Bencomo
Pretty neat that you can now simulate a parachute ☂ flight termination in Gazebo: flight_termination_parachute.mp4
I need help, I downloaded the px4 Firmware, installed ros and ran the commands "make px4_sitl gazebo_iris_opt_flow" and "roslaunch mavros px4.launch fcu_url: =" udp: //: 14540@ 14557 "", however when I run "rostopic list" I don't get a topic image from the camera. Can someone point me to a tutorial on how to activate this?
I want to run px4 on crazyflie2.1.How do I need to modify.Thank you.
yalin demir
Hi Guys, Is here anybody worked with /mavros/setpoint_raw ? I want to control position, velocity and acceleration at the same time. I wonder if it is possible I think it is enough to control just acceleration but as far as i know , controlling acceleration is not possible.
hello, could someone help me with the errors below ? I was trying to build the the packages with catkin build but it did not work.
Errors << px4:make /home/zeyn/logs/px4/build.make.009.log
make[2]: [uORB/topics/uORBTopics.hpp] Error 1
make[1]: [msg/CMakeFiles/uorb_headers.dir/all] Error 2
make[1]: Waiting for unfinished jobs....
make: [all] Error 2
cd /home/zeyn/build/px4; catkin build --get-env px4 | catkin env -si /usr/bin/make --jobserver-fds=6,7 -j; cd -
Failed << px4:make [ Exited with code 2 ]
Failed <<< px4 [ 4.3 seconds ]
Abandoned <<< test_mavros [ Unrelated job failed ]
Finished <<< mavros_extras [ 3.0 seconds ]
[build] Summary: 5 of 7 packages succeeded.
[build] Ignored: None.
[build] Warnings: None.
[build] Abandoned: 1 packages were abandoned.
[build] Failed: 1 packages failed.
[build] Runtime: 13.2 seconds total.
Is anyone here using a VESC over UAVCAN with success? Everything seems to be responding to the attitude controller correctly except the idle throttle refuses to go below 4095 when armed regardless of UAVCAN_ESC_IDLT setting .
The VESC's appear to expect a range of [-8192, 8192] but I cant quite tell where the PX4 side is generating it's range. https://github.com/vedderb/bldc/blob/b6949d60dcca4dc8757ebd035889b8d214e66636/libcanard/canard_driver.c#L208
I'm running on master btw
Ram D Gadekar
Hi everyone ... i m trying to set battery voltage on v1.11.0 stable. But it seems its just taking some constant voltage and there is no change when i am changing the voltage divider value..... i checked hardware on ardupilot and everything is working fine..... seems like a bug
Ram D Gadekar
BTW: it seems to be working fine till beta2