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afry-south / dragonfly-fcb

ÅF Dragonfly Quadrotor UAV Project
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Redo motor control<->thrust force mapping #39

Closed stenbergd closed 9 years ago

stenbergd commented 9 years ago

Since the HAL driver migration, modifications have been made on how to control the motor control pulse. This means the motor pulse <-> thrust mapping needs to be remade.

Plotly is an online line fitting tool useful here: https://plot.ly/plot

The motor thrust is controlled by a 16-bit int, values 0 to FFFF. Map this to generated thrust force [N](see design document on ONE project site for some data on this)

stenbergd commented 9 years ago

Linear plot https://plot.ly/~Stenis87/8

Perhaps do quadratic fit? Might be heavier to run computation-wise. Add (0,0) to table?

Future improvement: Do own measurements with experimental setup! https://wiki.bitcraze.io/misc:investigations:thrust

Do fitting with Scilab, Octave or similar

Also, estimate rotor drag function from torque using thrust and drag equations T thrust, Q rotor torque relationship (constants Ct, Cq)

stenbergd commented 9 years ago

Perhaps do a macro function for this.

stenbergd commented 9 years ago

Done.