Analysis of a Swashplate Mechanism of the Hingeless Rotor Hub with the Flybar in a Model Helicopter, Part I: Kinematics

Comprehensive kinematic modeling and analysis of a coaxial helicopter’s swashplate mechanism

“…The rotating speed of main rotors is introduced in the derivation of extended Jacobian matrix. Remember the direct transformation from x , y to ð f Þ as equation (21). Take derivative of it, one could find the influence on the declining speed of swashplate caused by rotation…”

“…By use of equation (21) and the definition in equation (22), the declining angle of any azimuth could be obtained by x and y to simplify the analysis of middle and upper module in a rotational condition. Contrarily, equations (27) and (28) are used to do a reverse transformation at any condition except for four singular places which will be shown later.…”

“…After that, the arrangement of single rotor with a flybar mechanism, widely used in small-scale helicopters, is investigated. [21][22][23] In studies done by Sabaapour and Zohoor, 21 a complete kinematic model including position, velocity and acceleration is established. The method utilizing to deduce Jacobian matrix and acceleration model is to differentiate vector equations in local coordinate systems, which is different from the screw theory used by Lange et al 19 Another method to obtain constraint equations when dealing with position kinematics is to express points in a closed loop.…”

“…Then, a velocity and acceleration model is constructed by differentiating vector equations as is adopted by Sabaapour and Zohoor. 21 The related matrices of the whole system could be obtained after combining submodules through properly defining coordinate systems. The rotation of rotors is also considered in the modeling process for reflecting the real working environment.…”

Analysis of a Swashplate Mechanism of the Hingeless Rotor Hub with the Flybar in a Model Helicopter, Part II: Dynamics

“…Here, in this second part of a two-part series of papers, the theoretical dynamics of the mentioned mechanism is derived by using the analysis methods of parallel manipulators and virtual work principle, to give a complete analytical model. The kinematics pertaining to this mechanism was discussed in detail in the part I (3) . An analytical model similar to the one developed here, can be used as a black box during design, analysis and simulation of the propeller module of model helicopter and controlling (1) .…”