So happy to find you folks! I've been working on this
project for 6 months, after a successful "regular" balloon launch.
Any comments much appreciated...
My half-ideas are as follows:
In the parameter file, set "Throt_Max" to 0. The RC has
to glide home due to power constraints, until it is visible
to the pilot, who will then switch it to manual and land it.
I don't know how the condition commands work yet, but
I think there is one related to altitude.
I think you always need a waypoint command to start.
(I'll have another system onboard which will trigger a release
mechanism upon reaching altitude, to free the RC glider
from the balloon).
So, given wind calculations, and ascent rate of balloon,
my first few commands would look like:
1. Condition altitude = 35,000 ft --> Do skip to 3
2. Waypoint (lat/long at projected release location, altitude 40k ft)
(so on the way up Ardu is adjusting flight surfaces wildly,
trying to orient itself towards this point -- not good!)
3. Waypoint (lat / long at first point along optimal return trajectory),
(altitude 30,000 ft -- so it begins its descent)
Is this the best I can do, without getting into Arduino programming,
or other hardware?
And please advise how the condition commands work.
--Lt Prahas David Nafissian,
Aerospace Education Officer,
Civil Air Patrol
I'm glad I came across this Discussion. I'm also working on a balloon launch system:
Objective: Build experience with Balloon launched ArduPlane for future high altitude flights. The purpose of the flights is for amateur photography and video. I should add that I am all for promoting responsible use of UAV’s and adhering to FAA regulations.
Background: This will be the second launch. The first launch was in February 2013 and was accomplished using the same plane but without a motor. The entire flight from release to landing was a “controlled” glide done in Joystick manual from 2,200 feet. Using Joystick without a motor was not ideal because it was difficult to control the plane’s speed by manually adjusting the pitch. Given the circumstances (I burnt up my only ESC), the method to release a small foam plane from a balloon by way of 3DR telemetry worked well and has led me to try a second launch.
-Plane: Bixler 1400
-Motor & Prop: 2822-17 1100KV Turnigy & 7x5EP Prop
-ESC: HK 30A w/ 3A BEC
-Battery: LiPo 2200 mAh Turnigy
-TX: Spectrum DX7 2.4 GHz, RX: Orange DSM 610
-Joystick: Interlink Elite Controller by Futaba (RealFlight6 simulator controller)
-Mechanical release hook operated by 9g servo on APM 2.5 output CH5 (1-Manual)
-Telemetry: Stock 3DR 900 Mhz run on default parameters.
-Camera: GoPro Hero-3 Black edition
-200 gram balloon. Filled with weather balloon grade helium to lift 1500 gram weight. (Estimated weight of payload: 950 g)
-Fill balloon until it will lift the test weight.
-APM 2.5 booted, MP in Joystick Mode. (Motor Failsafe disabled)
-Connect plane release hook to balloon tether.
-During ascent, monitor altitude and Telemetry in MP.
-While still in joystick mode just prior to release, select ‘Stabilize’ release when Telemetry signal strength degrades to 70% or plane reaches an altitude of 2,500 feet. –Height limited to keep the plane in sight and maintain adequate Telemetry signal.
-Watch for release on OSD, when released apply 50% throttle while in Joystick ‘Stabilize’.
-Mission Modes: Follow me, Loiter, right-click Fly Here, etc..., while conserving battery by gliding from altitude.
-Estimated flight time: 7-8 minute Ascent, 25 minute glide and powered flight.
- Last few minutes of flight: Regain lock with TX and land.
I’m still working through the APM’s Parameters to make sure I haven’t missed anything critical. I may try to use an inline Altimeter timer I bought from HK as a Failsafe for the release servo but it seems finicky and the manual is difficult to understand. I would like to up the release altitude but I don’t have the hardware to increase my Telemetry’s range. I would consider adjusting the Telemetry’s settings to increase the release altitude if someone had solid and tried input. Unfortunately I don’t have the ability to test the range. We’ll see how the rest of the prep goes for the 2nd launch, which I hope to be mid-April.
adam, you can set the failsafe on the telemetry link (so, when it stops hearing heartbeats from the groundstation, it activates failsafe), this way it'll release from the baloon as soon as telemetry goes off. in RTL mode, it'll probably come back quickly.
for improved telemetry range, you can reduce the data rate for the telemetry and work a bit with directional antenas and maybe an antenna tracker, with maestro servo controler from polulu it's very simple to be done with mission planner. also, trying one mod. at a time may save some time for you and get you going over small milestones instead of a "win or wall" flight.
i know helium is not cheap, but loosing a plane with a gopro and full eletronics is much more expensive than filling 5 baloons before going for a full trip. you can also fill it with the flamable, dangerous and cheap nytrogen, as long as you take care on the release, and be sure it'll explode high on the air.
Thank you for the response.
As for the Failsafe options, I would like CH-5 to operate the release and then have the plane RTL. It would seem that I can only enable or disable the throttle channel for Failsafe, which I don't want to do. If I were to use the Failsafe, the plane would try to RTL but the release hook would remain set. Am I missing something in the settings?
I attempted the launch yesterday. The setup was done as per my previous description in my April 3rd Reply. Unfortunately, our single balloon (we only had one) was not filled with enough helium to provide the required lift to pick up the total weight of 3 lbs of payload: Small Camera Pod and chute (1.3 lbs) and the ArduPlane (1.7lbs). Anyway, the sequence of events:
1) Balloon filled and tethered.
2) Camera Pod release set (Mechanical kitchen timer) and attached to tether.
3) Pay out Pod and connect plane’s release to fuselage bridle. The plane was in “manual” Joystick connected though 900MGz 3DR telemetry.
Given the options and that the Camera Pod’s release was ticking away, I just disconnected the plane and let the Pod go. I then hand launched the plane and enjoyed a solid 25 minutes of flight. The Pod started its descent 18:45 minutes later after releasing at approximately 18,000 feet. Another 20 minutes later, the fun was over and all the equipment was recovered.
1) Condensation will fog the camera lenses if sealed in hot humid sent to cold (Altitude) and then returned to hot (descent). - Maybe I’m off on this but the GoPro lenses had slight condensation on them when they landed. The condensation formed toward the end of the mission.
2) Situational Awareness; Not filling the balloon with enough helium was a major oversight and pretty embarrassing!
3) Do your best to K.I.S.S.
I plan on launching from a balloon again. In the meantime, I will be working on increasing my TX/RX and Telemetry range. Also, I am investigating how to build an Arduino Altimeter Release system for the Camera Pod. It would be nice to have an Altimeter Release system incorporated into the ArduPilot MP program since the hardware is all there. I would have to look back at some of Graham’s post on his quadcopter parachute system. That may be the route to go.