Specifications

2.1.3 Propellers (Components #1 and #7)
The pitch and yaw propeller assemblies are composed of the actual propeller, which is directly mounted to the
motor shaft, and the aluminum propeller shield. The propellers used for both the pitch and yaw motors are
Graupner 20/15 cm or 8/6”. The pitch motor/propeller has an identified thrust-force constant of 0.104 N/V and the
yaw motor/propeller has a thrust-force constant of 0.43 N/V.
2.1.4 Encoders (Components #4 and #15)
The 2DOF Helicopter experiment has two encoders: the encoder measuring the pitch angle, component #4, and the
encoder measuring the yaw angle, component #15. In quadrature mode, the pitch encoder has a resolution of 4096
counts per revolution and the yaw encoder has a resolution of 8192 counter per revolution. Thus the effective
position resolution is 0.0879 degrees about the pitch axis and 0.0439 degrees about the yaw axis
2.2 System Specifications
The main parameters of the 2DOF Helicopter is summarized in Table 2. The motor and encoder specifications are
listed in Table 3 below. Finally, Table 4 lists various dimensions, masses, and inertias of the 2DOF Helicopter system.
Table 2: 2DOF Helicopter model parameters
Symbol
Description
Value
Unit
Kpp
Thrust force constant of yaw motor/propeller
0.204
N.m/
Kyy
Thrust torque constant of yaw axis from yaw
motor/propeller
0.072
N.m/
Kpy
Thrust torque constant acting on pitch axis from
yaw motor/propeller
0.0068
N.m/
Kyp
Thrust torque constant acting on yaw axis from
pitch motor/propeller
0.0219
N.m/
Beq,
Equivalent viscous damping about pitch axis
0.800
N/
Beq,
Equivalent viscous damping about yaw axis
0.318
N/
mheli
Total moving mass of the helicopter (body, two
propeller assemblies, etc.)
1.3872
kg
lcm
Center of mass length along helicopter body
from pitch axis
0.186
Jeq,
Total moment of inertia about pitch axis
0.0384
kg.m2
Jeq,
Total moment of inertia about yaw axis.
0.0432
kg.m2
Table 3: 2DOF Helicopter motor and encoder specifications
Symbol
Description
Value
Unit
Rm,
Armature resistance of pitch motor
0.83
Rm,
Armature resistance of yaw motor
1.60
Kt,
Current-torque constant of pitch motor
0.0182
N.m/
Kt,
Current-torque constant of yaw motor
0.0109
N.m/
Jm,
Rotor moment of inertia of pitch motor
1.91 10−
kg.m2
Jm,
Rotor moment of inertia of yaw motor
1.37 10−
kg.m2
Kf,
Pitch propeller force-thrust constant (found
experimentally)
0.1037
N/
Kf,
Yaw propeller force-thrust constant (found
experimentally)
0.428
N/
mm,
Mass of pitch motor
0.292
kg
mm,
Mass of yaw motor
0.128
kg
KEC,LN,
Yaw encoder resolution (in quadrature
8192
counts/rev