First takeoff in pybullet

[avikde]

• check lift magnitude and try to get it reasonable
• try to make it fly up. need to understand applyExternalForce better. Try to apply a fake force that should make it fly up
• compare fake force to aero force till it can fly up
• add gravity

Will leave controlled flight (even using old stroke deviation ideas) to the next PR.

[avikde]

Some observation of dq reveals that

• dq[0] = stroke vel ~= peak 12 rad/s
• dq[1] = hinge vel ~= peak 18 rad/s

EDIT: the problem was that timestep in the sim was still the default.

[avikde]

pybullet debugging.xlsx

[avikde]

Created an issue: bulletphysics/bullet3#2152

[avikde]

Pretty nice flapping kinematics!

[avikde]

Without fixed base it appears to spin around a lot

[avikde]

With applyExternalForce [0,0,1], a plot of zdot(t) looks like this

So zdd ~= 17 m/s^2, so force was m= 0.055kg*acc ~= 1. Oops, mass was 55g not mg.

[avikde]

Another video of flapping kinematics, after mass and hinge parameters were updated

[avikde]

Finally flying! https://youtu.be/Qm0_yIEXycU