"Time out" or " Mode changed" when use offboard mode

[wangsen1312]

I send a stream of setpoints and tried offboard mode using command ''rosrun mavros mavsys mode -c OFFBOARD".
It shows "Time out" or "Mode changed".
The UAV move unstablized and cannot takeoff.
Can someone give me suggestion, Thank you very much!

[vooon]

/diagnostics please!

[wangsen1312]

@vooon @TSC21 Thank for your help.
My main purpose is control the UAV fly to the position which offered by mocap.
I use new stable PX4 firmware installed yesterday, 3DRradio connect to UAV directly without any onboard computer.

1. The first stage seems OK now. I use Vicon_bridge get the mocap data and publish the data to vision_pose/pose, and I change the INAV's parameters, only left the CBRK_no_vision = 0, vision weight max value 10, others are zero.
   Now I can get the /mavros/local_position/local data as Vicon system offers.

2. Now I want to set local postition for my UAV. I do following steps:
   a. arm the UAV first (it works well) rosrun mavros mavsafety arm
   b. sending a stream of setpoints (I use the the demo set point https://raw.githubusercontent.com/kuri-kustar/indoor_uav_control/master/scripts/setpoint_demo_2.py), which seems OK.

c. request offboard rosrun mavros mavsys mode -c OFFBOARD
This is the problem I meet, the quad is not taking off as I wish and not stablized and sometimes show "Time out". I only use demo to set positions, should I change some other parameters to stablize the UAV?

The /diagnostics file is below:

header:
seq: 78
stamp:
secs: 1434983924
nsecs: 567774546
frame_id: ''
status:

level: 0
name: mavros: FCU connection
message: connected
hardware_id: /dev/ttyUSB0:57600
values:

key: Received packets:
value: 1781

• key: Dropped packets:
  value: 0
• key: Buffer overruns:
  value: 0
• key: Parse errors:
  value: 0
• key: Rx sequence number:
  value: 25
• key: Tx sequence number:
  value: 91
• key: Rx total bytes:
  value: 65234
• key: Tx total bytes:
  value: 1814
• key: Rx speed:
  value: 607.000000
• key: Tx speed:
  value: 20.000000

• level: 2
  name: mavros: GPS
  message: No satellites
  hardware_id: /dev/ttyUSB0:57600
  values:

  key: Satellites visible
  value: 0

  key: Fix type
  value: 0

  key: EPH (m)
  value: Unknown

  key: EPV (m)
  value: Unknown

• level: 0
  name: mavros: Heartbeat
  message: Normal
  hardware_id: /dev/ttyUSB0:57600
  values:

  key: Heartbeats since startup
  value: 72

  key: Frequency (Hz)
  value: 1.099231

  key: Vehicle type
  value: Quadrotor

  key: Autopilot type
  value: PX4

  key: Mode
  value: ALTCTL

  key: System status
  value: Standby

• level: 0
  name: mavros: System
  message: Normal
  hardware_id: /dev/ttyUSB0:57600
  values:

  key: Sensor present
  value: 0x00000000

  key: Sensor enabled
  value: 0x00000000

  key: Sensor helth
  value: 0x00000000

  key: CPU Load (%)
  value: 32.8

  key: Drop rate (%)
  value: 0.0

  key: Errors comm
  value: 0

  key: Errors count mavconn library. #1
  value: 0

  key: Errors count Pub/sub for Mavlink.msg #2
  value: 0

  key: Errors count Plugin loading functionality. #3
  value: 0

  key: Errors count Diagnostic mesages. #4
  value: 0

• level: 0
  name: mavros: Battery
  message: Normal
  hardware_id: /dev/ttyUSB0:57600
  values:

  key: Voltage
  value: 11.76

  key: Current
  value: 0.3

  key: Remaining
  value: 65.0

• level: 0
  name: mavros: 3DR Radio
  message: Normal
  hardware_id: /dev/ttyUSB0:57600
  values:

  key: RSSI
  value: 165

  key: RSSI (dBm)
  value: -40.2

  key: Remote RSSI
  value: 168

  key: Remote RSSI (dBm)
  value: -38.6

  key: Tx buffer (%)
  value: 100

  key: Noice level
  value: 22

  key: Remote noice level
  value: 25

  key: Rx errors
  value: 0

  key: Fixed
  value: 1

By the way, after radio connect to UAV, some error information occurs, such as
[ERROR] [1434915513.490270708]: FCU: REJ. WP CMD: partner id mismatch
I don't know it will cause something wrong or not?

Can you give me some suggestion? Thank you very much.

[mhkabir]

Check if your local position estimates (LOCAL_POSITION_NED message) match your mocap data.
I have a strong suspicion that setting weights to zero in INAV is causing a bad estimate.

And the timeouts are likely because the 3DR radio doesn't have nearly enough bandwidth to be used for streaming vicon + setpoints. You need better radios like LairdTech ones.

[Royalcheese]

Or use ODROID onboard + WIFI + ROS network :)

[wangsen1312]

@mhkabir @Royalcheese @vooon Thank you for your suggestion.
I have check the local position, which is matched with my mocap data.
I have reduce the frequency to 20HZ and the timeout cannot be seen, but the UAV cannot take off either. The propeller changed their speed but cannot take off!
Have you ever tried use mavros to take off? or I should do something else before take off?
How can you try the offboard Mode?
Thank you very much!

[Royalcheese]

I think, it is because PID parameters have to be set following the weight of your drone , as i told you by mail. If you have a look on equations which are the basis of mc_pos_control, you'll see that there is the weight taken in count. but in the controller, you only control the Thrust, without taking care of the inertial characteristics of your uav.
I guess you have to set proportional parameters the proper way in order to compensate weight, and this is that why I've tried to make a scilab simulation of the controller , to find the good parameters including the inertial characteristics.
But you can also do it step by step, increasing proportional part of controller incrementally until it takes off. but it can be "dangerous" cause of unstability induced by proportional controller ( I think.. ).

[vooon]

Updates?

[wangsen1312]

@vooon I don't know why TImeout see again. The UAV cannot takeoff with mavros? Have you ever try to use the mavros to make the UAV takeoff first without GPS?

[vooon]

FCU armed?

[wangsen1312]

@vooon arm works well. Now it cannot follow the set local position command.

[vooon]

Hmm, strange. Please don't use master now. Seems that transform are broken...

[Royalcheese]

@vooon You mean the tf of ROS ?

[TSC21]

You have to limit the tf publishing rate or it will result in timeouts

[wangsen1312]

@vooon @mhkabir @TSC21
I find it's hard to takeoff from floor so have tested another method:

1. use MANUAL mode to take off and stabilize.
2. Send local position stream
3. change to the OFFBOARD mode using RC
   I find something dangerous happen, UAV fly to some position far away from setting position.
   Do you think the set_local_position function works well when I use VICON replace INAV vision parameters?

[vooon]

Bug #273 still opened, but there workaround in mavros.

[LorenzMeier]

It was fixed on the Firmware side and I consequently closed it.

[LorenzMeier]

@Royalcheese That comment should be removed consequently.

[TSC21]

@LorenzMeier @Royalcheese we will remove comment soon then.