I’m going to pick some important points in terms of tuning the arducopter. At the time of writing, the current version is AC 3.1.
My two main problems with my tricopter are these two: maintaining Alt-Hold and wobbling oscillation while quickly descending.
So, here goes:
These two terms (Rate Control P, Throttle Rate P) go a long way to making your copter perform well, and are highly dependent on the thrust to weight ratio of your copter. More thrust = lower gains.
- My copter oscillates quickly (smaller movements) when stabilized: Lower your gain in Rate Control P.
- My copter oscillates slowly (larger movements) when stabilized: Lower your gain in Stabilize Control P.
- My copter gets wobbly when descending quickly: Raise your gain in Rate Control P. You can tune most of this out, but it’s impossible to descend into your prop wash without some wobbles.
- My copter is too sluggish : Raise your Stabilize Control P gain. These gains make ask the copter to respond faster to angle errors.
- My copter yaws right or left 15° when I take off: Your Motors are not straight or your ESCs are not calibrated. Twist the motors until they are straight. Run the ESC calibration routine.
- My copter angles back in the opposite direction I’m flying after forward flight: Raise your gain in Stabilize Control P.
- After aggressive flying my copter leans to one side 10 – 30°: Do what ever you can to remove vibrations and isolate APM. You can even try and add a small weight to APM to keep it from vibrating. Also, just land for a few seconds, then continue flying, it will give APM a chance to correct without the vibration.
- My copter won’t stay perfectly still in the air: Run the level command on a flat surface. (hold disarm for 15 seconds to invoke.) You can also fly in auto-trim mode in a windless (important!) environment. Any wind will cause the changes you make to work against you when the quad rotates 180°. You can use your radio pitch and roll trims, but remember to re-center them when you set up your radio with the config tools. Using the radio trims can have a negative effect in SIMPLE mode when yawing. Never Trim Yaw, Your copter may start spinning on it’s own. (Quads are also susceptible to drafts. They will need constant corrections unless you install an optical flow sensor. One day…)
- My copter flies well, but then dips a motor arm in a fidgety manner while hovering: Your motor may be going bad or the bullets connectors between the motor and ESC may be at fault. Vibration from a bent shaft or unbalanced props can make bullet connections fail momentarily stopping the motor. A motor with bad bearings takes more power to spin. The ESC could be cutting out to protect itself. Or it maybe flying slow enough to stall the motor. Attach a current sensor between your battery and the motor and test the difference between a good motor and the bad one. If you are seeing higher draw in the bad one, replace or fix it.
- In Loiter, my copter constantly overshoots: Try and increase your Nav_P term. You can also tune down your I terms because in some cases, the Nav_I or Loiter_I can causes overshoot. Making the Iterms 0 when in still wind is the best way to tune Nav_P.
- My alt hold above 10 feet is only about 1-2m accurate: That’s actually the best you can achieve. The baro sensor is sensitive to light and wind. Use a felt cover to protect it from wind and make sure you don’t glue the hole and seal it up.
- My copter increasingly swings up and down in alt hold. It eventually get’s down to the ground: Your THROTTLE_P is too high or low. You don’t need a lot of P to do alt hold. Think of how much you move the throttle to hold alt perfectly. Not much! That’s what you need P to do. I will ramp up as your battery goes lower to make up the difference.
- I have a sonar installed but I can’t get it to work. Your sonar may be picking up electrical noise from the ESCs. Be sure to move it a few inches from any ESCs and try a shielded cable, if possible. If it’s cold outside, your sonar may stop working.
My quad loiters by rotating in a CW or CCW circle: Adjust your compass declination until it stops circling.
My First Keynote Speech at NUSYS 2014
My first keynote address!! I was very excited to share the experience gathered from the my reseach that has been mentored by Assoc. Prof. Dr. Rizal Arshad from URCG, USM. There were lots of issues that I’ve brought to the table to be think about, and some future hopes on the status of reseach in the area of sea-to-space. Particularly on widening the aspect of research, opening for new research collaborations and many more. I’ll be looking forward to come back to the seminar next year to share new findings and experience to the members.
Jim Cantrell’s answer to: Elon Musk: How did Elon Musk learn enough about rockets to run SpaceX?
I helped Elon start the company and all of these answers are spot on. He still has my book on rocket propulsion…..
What I found from working with Elon is that he starts by defining a goal and he puts a lot of effort into understanding what that goal is and why it is a good and valid goal. His goal, as I see it, has not changed form the day he first called me in August of 2001. I still hear it in his speeches. His goal was to make mankind a multi planetary species and to do that he had to first solve the transportation problem.
Once he has a goal, his next step is to learn as much about the topic at hand as possible from as many sources as possible. He is by far the single smartest person that I have ever worked with … period. I can’t estimate his IQ but he is very very intelligent. And not the typical egg head kind of smart. He has a real applied mind. He literally sucks the knowledge and experience out of people that he is around. He borrowed all of my college texts on rocket propulsion when we first started working together in 2001. We also hired as many of my colleagues in the rocket and spacecraft business that were willing to consult with him. It was like a gigantic spaceapalooza. At that point we were not talking about building a rocket ourselves, only launching a privately funded mission to Mars. I found out later that he was talking to a bunch of other people about rocket designs and collaborating on some spreadsheet level systems designs for launchers. Once our dealings with the Russians fell apart, he decided to build his own rocket and this was the genesis of SpaceX.
So I am going to suggest that he is successful not because his visions are grand, not because he is extraordinarily smart and not because he works incredibly hard. All of those things are true. The one major important distinction that sets him apart is his inability to consider failure. It simply is not even in his thought process. He cannot conceive of failure and that is truly remarkable. It doesn’t matter if its going up against the banking system (Paypal), going up against the entire aerospace industry (SpaceX) or going up against the US auto industry (Tesla). He can’t imagine NOT succeeding and that is a very critical trait that leads him ultimately to success. He and I had very similar upbringings, very similar interests and very similar early histories. He was a bit of a loner and so was I. He decided to start a software company at age 13. I decided to design and build my own stereo amplifier system at age 13. Both of us succeeded at it. We both had engineers for fathers and were extremely driven kids. What separated us, I believe, was his lack of even being able to conceive failure. I know this because this is where we parted ways at SpaceX. We got to a point where I could not see it succeeding and walked away. He didn’t and succeeded. I have 25 years experience building space hardware and he had none at the time. So much for experience.
I recently wrote an op-ed piece for Space News where I also suggest that his ruthlessly efficient way to deploy capital is another great reason for his success. He can almost smell the right way through a problem and he drives his staff and his organization hard to achieve it. The results speak for themselves. The article is here End of WWII Model Shakes Up Aerospace Industry.
In the end I think that we are seeing a very fundamental shift in the way our world takes on the big challenges facing humanity and Elon’s Way as I call it will be considered the tip of the spear. My hat’s off to the man.
Di dalam wiki Ardurover, ada diterangkan berkenaan dengan sambungan diantara Receiver (RX) dan RC Input pada APM board. Akan tetapi, di dalam gambarajahnya, ia tidak menerangkan dengan jelas, yang mana satu RX output dari segi Throttle, Rudder dan Auto mode. Bagi mereka yang memerlukan gambarajah grafik, sila rujuk gambar di bawah untuk bantuan.
Sambungan APM 2.5 dengan RX