Servos instead of brushless motors.

[Techdesk]

Hi All
I am designing a special quadcopter drone with CC3d Revolution flight controller. I used ESCs and brushless motors. Everything works fine.
Now I have 4 x 360 servos which I am attempting to use instead of the ESCs and brushless motors. So I replaced each motor and ESC with the servos. The Esc has three wires, similar to the ESC. When I did the connections, all 4 servos just continue to rotate. I cannot control with the transmitter sticks. Yet when I chose Vehicle Setup in LibrePilot, I had to choose some ESC as there is no direct choice for servo.
Strangely enough, I am able to control the speed in this menu. But after saving, the servos just jump to max speed and turns continuously. There is just no way to stop or control them. Has anyone ever tried this configuration before? Please don't ask me why I am substituting slow servos for high speed brushless motors. Like I said it is for a special project. I need the slow rotation.
If I fail in this project, I will just have to add in a small 100:1 miniature gearbox onto these brushless motors. That could work, But servos would be so much cheaper and easier.

 

[Merv]

...Now I have 4 x 360 servos ...I am able to control the speed in this menu. But after saving, the servos just jump to max speed and turns continuously....

I have never worked with a 360 degree servo, I suspect they will act differently than the ones we are used to working with.
With any problem, it is best to take it one step at a time. Try hooking the servo directly to the Rx or a servo tester to see if you can control the speed & direction. If you can, then you know the problem is with the flight controller. If you can't, then you know the problem is with the servo. It's not designed to do what you want.

 

[Bricks]

You will need some type of speed controller not sure if variable voltage regulator would work or not, amount of voltage is the only control you have with a servo.

 

[Tench745]

Please tell me if I am understanding this correctly: You had a flight controller hooked up to four ESCs and brushless motors, and it worked like a normal quad copter. Now you have unplugged the ESCs and plugged 360 degree servos into the same channels?

Remember that ESCs and servos look at PWM signals differently. For servos a PWM signal of 1000 is full speed one direction, 1500 is stationary, and 2000 is full speed the other direction.
For a non-reversing ESC, a PWM signal of 1000 means 0 throttle and 2000 is full throttle.
(This assumes you are using the PWM ports of the CC3D board.)

As far as how to set up your flight controller to make it do what you want, I'm not entirely clear what it is you want it to be doing.

 

[Techdesk]

Please tell me if I am understanding this correctly: You had a flight controller hooked up to four ESCs and brushless motors, and it worked like a normal quad copter. Now you have unplugged the ESCs and plugged 360 degree servos into the same channels?

Remember that ESCs and servos look at PWM signals differently. For servos a PWM signal of 1000 is full speed one direction, 1500 is stationary, and 2000 is full speed the other direction.
For a non-reversing ESC, a PWM signal of 1000 means 0 throttle and 2000 is full throttle.
(This assumes you are using the PWM ports of the CC3D board.)

As far as how to set up your flight controller to make it do what you want, I'm not entirely clear what it is you want it to be doing.

Actually my purpose for this whole project is to save costs on ESCs, brushless motors and gearboxes. We have about 30 quads. The quads will use this slow motion rotation for some special purpose. I have decided to rather use brushless motors with ESC's coupled to miniature gearboxes. It works well. Only downside is the cost.

 

[Piotrsko]

Might need to do a helicopter style mixing for cyclic as all those functions are set up for what you need.

If you decouple the feedback mechanism it would work somewhat like an esc controlled motor however it would be a big experiment to set it up correctly and IIRC reverse thrust gets expensive during a flight unless one is inverted.