Pixhawk: how to ensure waypoint alt is reached?

ArduCopter Copter 3.3
1

Hi guys…

I fly in mountainous terrain in New Mexico.

I’d like to ensure that my F550 reaches a waypoint altitude before moving on to the next waypoint (more important of course flying UP along rising terrain than the other way around).

Couple questions:

  1. Does the Pixhawk do this by default? Perhaps adjusting horizontal speed between waypoints so as to reach the next waypoint’s altitude at the same time the next waypoint is reached horizontally? (Seems to be a reasonable safety precaution.)

  2. If not, how can I program a flight plan so as to guarantee reaching the next waypoint altitude before moving on?

Thanks…

–

Bill

2

Hi wsalopek,

My experience is primarily with Arduplane, so the parameters I’m pointing out are for that build. I’ll take a look later (or a copter person can pop in) and see if I can find the counterparts for Copter.

These parameters (for plane) enable terrain following, which will mean your waypoint altitude will be AGL, or as close as can be estimated by your map data.

I spent awhile looking for a parameter that I thought existed, which dealt with requiring a certain altitude before a waypoint could be marked as completed. Couldn’t find it, maybe I’m mistaken and was thinking of loiter to alt. I hope this helps a bit.

[quote]Use terrain following (ArduPlane:TERRAIN_FOLLOW)

This enables terrain following for CRUISE mode, FBWB mode, RTL and for rally points. To use this option you also need to set TERRAIN_ENABLE to 1, which enables terrain data fetching from the GCS, and you need to have a GCS that supports sending terrain data to the aircraft. When terrain following is enabled then CRUISE and FBWB mode will hold height above terrain rather than height above home. In RTL the return to launch altitude will be considered to be a height above the terrain. Rally point altitudes will be taken as height above the terrain. This option does not affect mission items, which have a per-waypoint flag for whether they are height above home or height above the terrain. To use terrain following missions you need a ground station which can set the waypoint type to be a terrain height waypoint when creating the mission.

VALUE MEANING
0 Disabled
1 Enabled[/quote]

[quote]Terrain data enable (TERRAIN_ENABLE)

enable terrain data. This enables the vehicle storing a database of terrain data on the SD card. The terrain data is requested from the ground station as needed, and stored for later use on the SD card. To be useful the ground station must support TERRAIN_REQUEST messages and have access to a terrain database, such as the SRTM database.

VALUE MEANING
0 Disable
1 Enable[/quote]

[quote]Terrain lookahead (ArduPlane:TERRAIN_LOOKAHD)

This controls how far ahead the terrain following code looks to ensure it stays above upcoming terrain. A value of zero means no lookahead, so the controller will track only the terrain directly below the aircraft. The lookahead will never extend beyond the next waypoint when in AUTO mode.

Range: 0 10000
Units: meters[/quote]

3

Mario,

Thanks for that.

I too saw those parameters in plane…but can’t find anything like them in copter…some are supposed to be implemented in the next version or two.

I have also been looking for a document that might be called “complete feature list” of arducopter (to figure out if “ensure waypoint alt is reached” is already part of the code)…and can’t really find anything…I find things like “complete parameter list”, and “release notes”, but never a full description of what features the code already has.

Seems weird not to be able to find that document.

–

Bill