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Motor Brushless gearbox
  • I'm putting together a project where the brushless motors have a gearbox, giving more power. While SIMPLEBGC controller was designed to operate with direct engines I have seen several projects where a gearbox is used

    http://www.famoushobby.com/images/l/201511/b/14486830370.jpg

    How much reduction can support without losing the system stability?

    3:1 ?
    4:1 ?
    5:1 ?

    etc...

    Thanks
  • I do not think there is any generic answer to that.

    With gearbox you loose speed, so stabilization will be slower, but if your motor is fast enough it compensates.
  • Thanks Garug,
    We wanted to try with the following engines: GB110 and GB8036, will be fast enough?
  • I can not tell, it depends also of voltage. Normally high pole count high resistance motors are slower than fewer poles and lower resistance.

    Instead a gearbox I would recommend using encoders and GB90 to GB110 type motor at 24V and full power. If that is not enough, two of them, if that is not enough waiting for Pro Board and stronger motors.

    On aerial gimbal gear box could be a good idea on Yaw, but I see no reason to use it on Pitch or Roll. GB90 with encoders + 24V is enough for any camera Pitch and Roll, taking into account that all up weight of the multicopter must be below 25 Kg. A Gearbox + GB90 + all required bearings and installation probably weight more than two GB90...
  • There is one other think to consider when thinking gearbox, it is acceleration. On direct driven motor the motor does not need to accelerate during stabilisation, it stays on place.

    With gear box the motor rotates to different direction and rotates faster than the movement, so the motor it self needs to accelerate and that takes time and causes slower response.
  • Yes Garau, I thought about all the options. Encoders seems like a great solution, but imagine this: Suppose you want to make a gimbal cameras over 25 k. As a larger and heavier gimbal, throttle response is much slower. If you use a reduction on all engines, I get more torque is the final idea, even using decoders in the final axis. If I can make a heavy equipment, camera support more weight.
    We can make it work, but before investing a lot of money, I have to have a little idea to do it.

    I'm also hoping the new controller BasecamBGC Pro, I hope it's a big step to improve the gimbal.

    I sent a private message of a video to see how it could be the gimbal I want to make.
    Thank you
  • well gear on the axis is one way to get more power the other is to use 2 motors on a single axis
  • I know that flighthead and shotover both use gears. And motors are sarcaticly small.
  • Before brushless gimbals we used servos, small motors and gears...

    Flight head and other camera heads for sure used good quality " servos": I think they are called camera heads for a reason, it is different technology, and requirements. They provide very good tongue and control, but probably not as good and fast stabilisation as brushless direct driven gimbals. The speed they provide probably is enough for the applications they are typically used. And maybe the very expensive ones also provide good speed...
  • They use tiny brushless motors with speed controllers and large gear transmission. They are superfast with payloads up to 110kg. Shotover is 6 axis stabilized (3 internal electromagnetic of cca 5cm travel and 3 outside motor driven). Latest flightgead on russianarm and latest shotover on heli use gps correction of roll under acceleration.
  • I consider BASECAM has done a very good job in their software. It can be applied to large STABILIZED HEAD, but we must work on its design, it is not easy, of course.
    If we used small brushless motors with a winding for helicopters, achieving the engine is faster than a motor gimbal. Then, joining several motors, we get closer to the system that has Shotover.

    What do you think?