We are using ArduIMU (V3) as our Quadrotor's inertial measurement unit. (we have a separate board to control all motors, not with ArduIMU itself).
As mentioned here , the output rate of this module is only at about 8hz.
Isn't it super slow to control a quadrotor ? I'm asking because as mentioned in this answer a quadrotor needs at least 200hz of control frequency to easily stay in one spot, and our ESCs is configured to work with 450hz of refresh rate. Any working PID controller I saw before for Quadrotors used at least 200-400hz of control frequency.
I asked similar question before from Ahmad Byagowi (one of the developers of ArduIMU ) and he answered:
The arduimu calculates the dcm matrices and that makes it so slow. If you disable the dcm output, you can get up to 100 hz gyro, acc and so on.
So, what will happen if I disable DCM from the firmware ? Is it really important ? We did a simulation before and our PID controller works pretty well without DCM.