Design and dynamics of a novel parallel coaxial twin rotor of helicopter

In order to simplify a conventional coaxial rotor of the helicopter, to improve the dynamic performances of the coaxial rotor, to reduce the weight of the helicopter and to increase its safety, a novel parallel coaxial twin rotor (PCTR) of the helicopter is designed by combining a 2PSS + PSR + SP parallel mechanism with a coaxial twin rotor. Its kinematics and dynamics models are established. Firstly, the structure principle and the performances of the PCTR are explained, and the degree of freedom of the 2PSS + PSR + SP parallel mechanism is calculated. Secondly, the kinematics formulas are derived for solving the displacement, Jacobian matrix, general velocity, Hessian matrix, and acceleration of the PCTR and its moving limbs. Thirdly, a dynamics model of the PCTR is established for solving the dynamic actuation forces and the dynamic constrained forces. Finally, the theoretical solutions of the kinematics and dynamics of the PCTR of the helicopter are verified to be correct by its simulation mechanism.