Quadrotor model accepts negative control input affecting output moment

[a6a3uh]

RobotZoo.jl/src/quadrotor.jl

Line 96 in 6ceea23

M1 = km*w1;

Force calculation explicitly uses max(0, u[i]) to account only for positive control command.
Meanwhile moment calculation does not rejects negative control inputs.

Indeed optimal control calculated in https://github.com/RoboticExplorationLab/TrajectoryOptimization.jl/blob/master/examples/Quadrotor.ipynb calculates control with negative inputs found in each of 4 control channels which in turn affect dynamics. Either Quadrotor example should explicitly apply bounds on control or Quadrotor model should reject negative control inputs.

[a6a3uh]

Sorry. Bound on control is defined in TrajectoryOptimization Quadrotor example. And Altro solver obeys these bounds, meanwhile iLQRSolver solver doesn't and produces solution with negative controls and error message MethodError: no method matching max_violation(::Altro.iLQRSolver... But this might be a subject for another issue.