# What is the degree of freedom of the following drone?

This might be a stupid question to ask here .i am confused whether the dof of this drone is 3 or 4?

• It's not particularly hard to google the equations for degrees of freedom...To make this a learning experience, why you do think it has 3, or 4? Sep 14, 2019 at 11:02

In general i would say there is not enough information on this drawing, so we all ASSUME.

If you look at this and assume it is a multicopter with 2 counter rotating propellers (can not fly in a normal fashion without a pivoting mechanism, like a Chinook) you can only have yaw, roll and up down control which makes for 3-DoF. For the arm it give you 2 DoF (assuming no other pivot point exist that are not visible on the drawing)

From a practical point of view if the top is really a drone (multicopter) then it needs four propellers (which i can only see two of in the 2D picture)

A multicopter like i assumed moves like a ship 6-DoF (not an airplane 3-DoF)

I argue that as far as the drone is concerned it still has a 6-DoF. The attached arm has 2-DoF. wikipedia

Whether it serves any purpose to count the additional movement the arm can make as additional DoF is in my view debatable because you can not move in any more ways than before (i look at the maneuverability from the drones perspective and the arm endpoint Pe). You achieve the same result for the endpoint of the arm when you move the drone or when you move the arm.

I could of course be completely wrong being human.

Assuming that it is a planar robot (only moving in XY-plane), then from the diagram one can see it has 3-DoF (x,y,pitch) along with 2 additional DoF for the arm links.

• If it's a single drone then the number of 5-DOF is correct, but if it's a swarm of 12 drones, the total amount of Degree of freedom will become 60. It would be difficult to control all of them with a dataglove by a single human operator. Sep 16, 2019 at 17:15
• I believe we are not talking about swarm of robots here. Determining the DoF of a swarm of robots is trivial once you know the DoF of the robot. Sep 17, 2019 at 11:30