Fast waypoints help. unable to reach wpnav_speed in auto

ArduCopter Copter 4.4
1

Hi, thanks everyone in this community.

we have some issue in auto mode with many waypoints missions.

we have setup the wpnav_speed at 800 (8m/s), but…

now we use a missions with wp each few meters (about 40m), large missions to power lines inspection.

the problem its that with these wp distances, the drone is unable to reach the target speed. always keeps below 8m/s.

time before, we use less wp points in missions, and the target speed goes OK

at the moment, we need to use more wp points closer to get better terrain clearance.

even in MP simulation with latest firmware, the behaviour its similar.

if the distance bettween WP points are closer (about 30-40m) the drone dont mantain the target speed.

any solution? how to activate “fast waypoints” mode?

or what its the minimum distance between waypoints to consider “fast waypoints” ?

2

What is the altitude difference between waypoints ?

3

very flat mission, vertical speeds tends to 0-0,2m/s. the altitude target in wp is not the cause of these behaviour.

even in MP sitl simulation, at constant altitude wp, if the wp are very close, the target speed its unable to get

4

its like there are some hidden feature that enables/disables the “fast waypoints” behaviour in function of the waypoints distance each one

5

As long as a waypoint does not have the delay set, it is a fast waypoint.

  • You can increase the waypoint radius, allow the vehicle to cut corners.
  • Increase the yaw rate of the vehicle.

Waypoints with high-angle breaks in the route need slowing down since the vehicle cannot turn on a dime.

6

yes, i understand that in corners, the vehicle have to slow down to can make the turns. there is no problem

but… i talk about waypoints in large straigh lines. if the waypoints are closer each one a distance less than 60m… the vehicle not mantain the wpnav_speed.

with waypoints separated more than 60m each other in straigh line, the fast waypoints behaviour works ok.

i have tested on sitl simulation with latest firmare.

7

Quick fix, on the straight segments use spline_waypoints. On turns when you need precision path use normal waypoints

8

thanks for the suggestion. we will try it, there could be the solution for these large straight segments on missions

therefore, in the online docs, would be appear that feature, the fast waypoints need some distance between waypoints to consider real “fast waypoints”

9

The problem is about the acceleration/deceleration capabilities of the vehicle and look ahead of the wpnav code.
I agree that the docs need update

10

I don’t know what “fast waypoints” is. I have flown missions to 38 m/s with considerations for accel, deccel, max angle, thrust/weight…

11

the issue is

in a large straight segment of a mission, if the distance bettween waypoints are below 60m, the drone dont reach the wpnav_speed.

if the distance are bigger than 60m, all works ok

12

Sure, that seems obvious. Not really an “issue”.