# Can not commander takeoff in multi vehicle simulation

**URL:** <https://discuss.px4.io/t/can-not-commander-takeoff-in-multi-vehicle-simulation/5892>\
**Category:** Uncategorized\
**Created:** [March 2, 2018, 5:45am UTC](https://discuss.px4.io/t/can-not-commander-takeoff-in-multi-vehicle-simulation/5892 "2018-03-02T05:45:31Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![angelasnail](https://discuss.px4.io/letter_avatar_proxy/v4/letter/a/dec6dc/32.png) [@angelasnail](https://discuss.px4.io/u/angelasnail)\
**Post date:** [March 2, 2018, 5:45am UTC](https://discuss.px4.io/t/can-not-commander-takeoff-in-multi-vehicle-simulation/5892/1 "2018-03-02T05:45:31Z")

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Hello,

I did as the multi\_vehicle simulation:

 ![](https://discuss.px4.io/uploads/default/original/2X/7/7713d3c69cec7c8933d952aeeb6c25227d18d8c5.png)  
and I can launch the gazebo with 2 uav like this:  
 ![](https://discuss.px4.io/uploads/default/original/2X/9/9d86b25ea180bf11492cd1b028ac70463e082ec3.jpg)  
But I cannot communicate with them. And these are errors I found in console:

node name: sitl\_2  
data path: /home/shk/src/Firmware  
commands file: /home/shk/src/Firmware/posix-configs/SITL/init/ekf2/iris\_2  
**ERROR [Unknown] Error creating symlink /home/shk/src/Firmware/ROMFS → /home/shk/.ros/ROMFS**  
Restoring terminal  
**failed to start local process: /home/shk/src/Firmware/build/posix\_sitl\_default/px4 /home/shk/src/Firmware /home/shk/src/Firmware/posix-configs/SITL/init/ekf2/iris\_2 \_\_name:=sitl\_2 \_\_log:=/home/shk/.ros/log/06f35bf8-1ddc-11e8-b355-0016eb5a019a/uav2-sitl\_2-7.log**  
**local launch of px4/px4 failed**  
process[uav2/iris\_2\_spawn-8]: started with pid [9417]  
[INFO] [1519969149.795848471]: Plugin fake\_gps initialized  
[INFO] [1519969149.796313894]: Plugin ftp loaded  
process[uav2/mavros-9]: started with pid [9426]

Please help me if you know how to solve this issue. Thanks!!

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**Author:** ![Yograj\_Singh\_Mandloi](https://discuss.px4.io/letter_avatar_proxy/v4/letter/y/d78d45/32.png) [@Yograj\_Singh\_Mandloi](https://discuss.px4.io/u/Yograj_Singh_Mandloi)\
**Post date:** [March 3, 2018, 12:24am UTC](https://discuss.px4.io/t/can-not-commander-takeoff-in-multi-vehicle-simulation/5892/2 "2018-03-03T00:24:32Z")

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are you able to connect with Qgroundcontrol?

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**Author:** ![angelasnail](https://discuss.px4.io/letter_avatar_proxy/v4/letter/a/dec6dc/32.png) [@angelasnail](https://discuss.px4.io/u/angelasnail)\
**Post date:** [March 4, 2018, 1:53am UTC](https://discuss.px4.io/t/can-not-commander-takeoff-in-multi-vehicle-simulation/5892/3 "2018-03-04T01:53:04Z")

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I have not tried that.

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**Author:** ![angelasnail](https://discuss.px4.io/letter_avatar_proxy/v4/letter/a/dec6dc/32.png) [@angelasnail](https://discuss.px4.io/u/angelasnail)\
**Post date:** [March 4, 2018, 2:04am UTC](https://discuss.px4.io/t/can-not-commander-takeoff-in-multi-vehicle-simulation/5892/4 "2018-03-04T02:04:02Z")

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I think the problem is from my error but maybe I could try your advice first. I have saw your demo on youtube, it’s very nice. Thanks for your advice.