Good news!
Got the "Payloader Max" out for a public demo at the weekend, and it worked well! This is it dropping a 2.5kg load in a Swisspost box. Unfortunately, the full ramp up to a 5kg load run was halted when...
Bad news!
The damned PM module blew! This was a supposedly a 10S unit from Hobbyking, but it blew as soon the load went up. This is now my second unit that blew, and my recommendation is DONT USE THEM! Pump anymore than 70-80A through the main circuit and it just blows. Luckily this was at low altitude, and only a single broken prop. But while I had a god SBEC to swap in, I forgot the spare props, so no more demo's...:-(
Embarrassing news!
I used a Swisspost box for the demo...and unfortunately 2x swisspost employees were in the crowd. Crashing while they were watching was not really the publicity I wanted...:-( However, they were stunned to see a reasonably substantial package getting used this way. Lets hope word gets around!
Talking to Randy right now about how to get EPM to work on CH8; at the moment the APM libraries only work on CH9, so manual drops are all I can do right now. I might have to learn programming...:-o
Comments
Euan,
Tridge seemed to indicate that it happened quite soon for him. Within a minute but he said it happened when there was a lot of force hitting the side of the cargo as the vehicle was flying forward quickly (he uses a plane) so it may be that it never affects multicopters lifting things. The REGRIP parameter is set to zero by default so it won't normally activate.
No need for the neutral state I think. When the pilot or mission initiates a grip or release, the PWM output to the gripper is held high or low for about 0.2 seconds then it drops back to the neutral position.
Wow, Randy, that's really cool. Looking forward to 3.3!
Re: magnetism "fade" - how long did Tridge find it took? I have to confess most of my test flights have been less than 10 mins - out, drop, return type of thing, so not really noticed any issues. I've even left it overnight, unpowered, and come back the next morning with the target still attached (it was an empty box though).
Re: APM/Pixhawk, It's fitted with an APM2.6 right now, but I have a pixhawk available - I have to complete my Cross-alp challenge with it first though.
Re: the states in AP Planner - won't there be 3 states? Release, steady-state, grip?
Euan,
I’ve re-worked the EPM library to make it work with the EPM gripper version #2. This is checked into master but won’t make it into AC3.2 I'm afraid. Still, hopefully AC3.3 won't take anything like the amount of time that AC3.2 has because we won't be making many code structure changes. The changes include:
Not sure if you use an APM2 or Pixhawk but if you use a Pixhawk you could give the code a try by pulling it straight from firmware.diydrones.com's Latest directory. I guess you're using an OctaQuad so if it's a pixhawk you'd want the ArduCopter-v2.px4 binary.
Small video. Just a correction - the plate is 1.5mm, not 2.0mm.
Euan, I wonder if the issue is the heat created in the current sensor during the amp loads, are actually "cooking" the voltage regulator chip?
Hugues, if the PM was simply a voltage sensor, and a regulator, we probably wouldn't have a problem. It's probably the current sensor that is at fault. So tapping off the balance connector isn't going to solve anything really.
Safest solution , assuming we only need to measure voltage (current draw constant monitoring is not needed), would be not to measure the battery voltage with a single point of failure on the main power line, but rather to use the balance connectors of the batteries with an analog voltage measurement that can then be fed into APM/PIxhawk or the receiver to be displayed as a telemetry parameter.
That should be really easy to do. Hasn't anyone done it already ?
HI Rob - yep, 'fraid so. APM completely lifeless 0.0v across the terminals of the 6 pin cable. I suspect the sensor itself is still ok, but have not had a chance to test yet.
And it did it twice...so seems to be flaw with the HK PM design - the BEC simply can't handle the input Amps.
APM itself has survived no problem - currently have it booted off a conventional SBEC as we speak.
Testing update: I ran a 3rd unit off my 6S hex doing a compassmot; max draw is 65A, and after over a minute of this, the PM is still ok. It's borderline acceptable though - the APM is only getting 4.6v! So even though it can survive 60A draws, the supply voltage to the APM is too low (to be safe). I forgot to check the APM / radio voltage before I burnt out the X8 one.
Euan, a long time ago, I picked up an AmpLoc current sensor. It should be failure-proof, as it actually just slips over the wiring. But I haven't had a chance to implement it yet.
So this was a failure of the BEC, not the current sensor? Wow, that's surprising. And total crap.
As long as it can handle 30V and a constant 100amp+ on the main rail while maintaining 5.2V and 1A to the APM/Pixhawk, I'm all ears.
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