Midterm review 2E1242 – Automatic Control Helicopter Project

Introduction The Helicopter team: David Höök Pontus Olsson Henric Jöngren Vivek Sharma Ksenija Orlovskaya

Resources Helicopter with two degrees of freedom (Humusoft) Input voltage to two DC motors driving the main and tail propellers (MIMO- system) Output horisontal and vertical angles Labview (communicating with process) Matlab (simulation, model validation)

Main objective The helicopter is supposed to:  Follow a prespecified trajectory that illustrates its performance limitations.  Attenuate external disturbances

Modelling Subsystems Main motor and vertical movement Tail motor and horisontal movement Two systems corresponding to the cross coupling between the movements

Mathematical modelling of the helicopter Subsystem #1 Main motor and vertical movement Order of transfer function Matlab identification toolbox ==> g11 and g12 T gyro Vertical angle TfTf T upp Tmg T tail

Mathematical modelling of the helicopter Subsystem #2 Tail motor and horisontal movement Order of transfer function Matlab identification toolbox ==> g22 and g21 T horizontal T main TfTf T gyro Horisontal angle

Step response, real and simulated system

Transfer function matrix Decoupling: minimizing effect of g12 and g21 in system

Step response, model

Decoupling, approach 1 A simpler method to reduce the cross coupling, Neglect influence from tail motor in elevation. Find required u to tail motor to compensate torque from main propeller at different main rotor velocities. Efficient in the static case, has to be enhanced to also reduce cross coupling when accelerating/decelerating main propeller because of the extra torque from rotational intertia.

U2(u1)

Decoupling matrix, approach 2

Decoupling, new system - decoupled The cross coupling has been eliminated Strange behaviour of outsignals

Future work Enhance model  Model corresponding to actual process  Use model for control deriving Design optimal controllers for different regions  transfer functions for different angle segments  Find smooth transition between the segments