Maybe I was lucky and got the Altitude Hold (AH) worked the very first time. After I have the V2.5.5 firmware installed and fixed my latest crash, my AH no longer work. Once I switch to AH mode, the heli immediately slammed onto the ground with negative collective pitch. It happened once way before V2.5.4 and I thought it was an isolated incident. Luckily I already have a very strong 500 landing skid mod on this 450 and a set of plastic golf balls as landing cushion, there was no damage.
Anyway, so I played around with the PIDs and noticed that it had no effect at all. Finally it dawned on me that it could be the trim. So I went to the Heli Setup, Swash Travel, and changed the Collective Zero to a higher number! Voilà! It hovered and AH!
So, in case your heli jump to way high or slam onto the ground when switching to AH, change your collective pitch zero setting in the Heli Setup page.
Thanks for the report. The collective zero should really only affect the angle boost (i.e. how much additional collective pitch is applied when you lean over more). Still, maybe you've stumbled onto a bug so I'll try and have a look and see if there's really a bug there. thanks again.
Thanks Wes, I'll have a look since I've got your params loaded in my 450 now. I did a test hop yesterday and it went OK, except I find the rudder isn't working well.
Did you set yours up with mechanical trim on the rudder thrust? I found that with your rudder settings, I had to hold right stick to stop it rotating. The Yaw I term should fix this, so you must not have enough. However if you set it up with mechanical trim, then it might work out.
I prefer to set it up with zero mechanical trim, and then let COLYAW and Yaw I term sort it out.
Yea, the COLYAW would help a lot. The Skookum has it, and it's not linear as well. When I was doing bench testing the Skookum, it's quite interesting to see the rudder move around while I increase the throttle.
For my 450, i used the Heli Setup page to put in some rudder trim. I also apply a little rudder correction before it liftoff and it works well.
COLYAW should be back if you have updated your MP. Michael O fixed it. I know it works on mine.
Oh, and I also have APM controlling my ESC directly in my clone. It works.
Cool!! Good to know.
I haven't updated my MP, since my heli crashed again from joy "flying" over the weekend. lol. I had a great time flying the APM2 on my 450 now FINALLY! I found some settings that make it fly like a normal heli. But there are still some collective mix issue that make it doesn't work too well, so I crashed.
Just watched Align's to-be-release APS system video. Amazing postion hold! Quite funny with some Asian humor.
What is the problem with the collective mix?
I don't put a lot of weight the APS video performance. Most of the shots of position hold are really quick 1-3 seconds, and of course it's the manufacturer putting together a marketing video. My 600 can hover that well with no GPS at all as long as there's no wind. I'll await customer videos, we'll see.
Over that weekend, I was really enjoying flying the APM2 on the 450. So I gave it a big workout. :D That Collective Mix thing is something that I sometimes have to tune in the SK720 for aggressive flying. When you are flying the heli and apply a lot of collective, the tail would goes left or right and the HH parameter itself sometimes is not enough. The Collective Mix field in the SK720 tuning would fix that.
I agree with the manufacturer video could be just a promo video with certain wind condition. Even my 450 FBL on SK720 can hover steadily with no wind. So do my 700e with flybar without any flight controllers. Just my 450 FBL on APM2 cannot. lol
This is one of the SK720's advanced tuning screens. Usually you don't need to tune that unless you do 3D or very aggressive flying.
Ok, so that's just like the Colyaw. You know Colyaw is working now right?
But the problem you mention is something I have noticed, and wondering about. It seems like if something causes a large yaw error, it's like it takes the yaw error as the new setpoint, and then just holds it, instead of trying to go back to the original heading. I've been meaning to look into it.
They have a build in Colyaw as well. That one is not tunable and it's not linear. When I have the heli sit on the bench and just increase the throttle, you can see the tail servo starts moving out, and then in a little according to the position of the throttle. I'll shoot a video when I have a chance. Apparently, it works extremely work. Out of the 3 SK720 heli that I've worked on, only 1 of them needed the Collect Mix adjustment slightly.