i have decided to give my Hexapod (Joe) some hover craft capabilities with a gyro and 4 brushless motors.
I will give updates as i progress.
I am now designing the mounting bracket for the motors (aluminum) to be fitted on top of the chassis like the add-on deck for the torso. i will build it so that i can add a torso later on as well.
Then all i need is an electric BB gun mounted on the arms.
Then i scale the whole thing up and fit it with a gauss rifle or 2 to terrorize a small city.
If you are planning to use the gyro to control the hover, you will need 3 of them and three motors. Align the gyros in 120 degree placements. Using 4 ducted fans wonât work. Even with thrust vectoring for leveling, smaller ducted fans have a reaction delay.
If you are using props, you will have a better chance of success. Iâve built a couple prototype VTOL aircraft as well as a large 4 foot hovercraft. If you need any help, just let me know.
I am planning on using prop based systems. As i said i am currently looking at the mounting deck. So far i have decided on 4 motors rated at 2.5 kg each this should give me about 10 kilos of lift cap.
Starting at 3 kilos for Joe as it stands now i think it can be done.
The most daunting task so far will be programming the control systems.
My reasoning is that if you establish hover thrust at say 60% increasing the rear motors thurst by 1 % should give you forward motion. Stopping is achived by changing that to 60 % and the front to 61%.
Now how would you traslate that into robot code and incorporate the suggested gyros in the middle of the whole story. Any pointers?
I am usign the BH3-R for the chassis. I orderd the CH3-R one but the distributor in the UK sent me the wrong one. i decided to keep this one after looking at the legs and after waiting for it to be shipped to South africa i was slightly impatient (they do owe me a shiping to here tho so i will use it for me next purchase 8) ) .
i can easily have a modification done on the lower part to fit a shock absorber into it. For that i am looking at a racing car syspenstion for the shocks.
Evolution, i would surely appreciate some guidance.
It sounds like you are planning to build an autopilot hovering 4 prop fixed pitch helicopter. Are an experienced R/C helicopter and airplane pilot? You will need to be in order to control such a craft. Hovering with a single head helicopter is tough enough without experience. A 4 prop hovering drone will involve precise fabricating and extensive trial and error setting the gain and sensitivity of your gyros.
For gyroâs. You actually will want to use the cheaper piezo gyros. Dual rate is good, just avoid the expensive Head-Locking gyros (AKA tail-locking, Heading Hold) Itâs a feature that wonât prove useful to you. A good place to start is with the GWS PG-03 pieze gyro. They are cheap but work good enough for prototyping. They run about $30 to $50 each.
Sounds like a similar recent thread where there seemed to some confusion between knowing the difference between a âhovercraftâ and an âaircraft that can hoverâ. The below gives a good description of a âhovercraftâ as I understand them. The description given here of the craft to be built indicates that it will be very heavy.
not really autopilot. i am looking to control it from a remote control. as a novice i can easily say that it does not look all that difficult in principle. the hover seems to be a tricky thing to archive on one engine however 4 seems rather less complicated if you use accurate modeling and the exact same motors at all 4 points. i plan to start by getting one of those X-BL Quadrocopters and expanding form there.
Trust me, having 4 heads instead of 1, is 4 times as hard to pilot. Not to mention 4 times as hard to balance, setup and trim. Not to say it canât be done, it has been many times. But it takes alot of experience in piloting helis and a decent amount of knowledge in aerodynamics and the coefficients involved.
Sonny, owner and inventor of the Dragonflyer, used a similar 4 prop system you are describing.
Sonny spend alot of time designing the Co-pilot system to stabilize the 4-rotor design. His became very popular because stabilizing a 4 rotor hovering craft, is harder than people think. He specially integrated a 3 axi 3 gyro sensor as well as using the the same horizon sensing Co-pilot technology that FMA uses in their FMA CoPilot.
You best chance of success would be starting out with a helicopter and developing some hands on experience hovering it. Then flying it. if you canât hover nose in with a normal heli, you will never be able to fly a 4-rotor craft. Iâm not trying to discourage you, just making sure you are aware of how difficult it is to pilot something like that.
