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

摘要

A comprehensive mathematical model of a coaxial helicopter's swashplate mechanism is established, analyzed and verified in this paper. The mechanism widely used in helicopters to manipulate blade pitch angles is complex because of its configuration of multi closed-loop kinematic chains, especially for coaxial layout. First, geometrical method is used in determining the direct and inverse position kinematics. Based on that model, an approach of differentiation on spatial vectors is adopted to induce the relative velocity and acceleration matrices of every part of the system. The influence of rotors' rotation is also considered in the modeling of velocity and acceleration kinematics to obtain a comprehensive model. The workspace and dexterity characteristics are analyzed in detail under the constraint of actuators' inputs. After that, the complete direct kinematic model is simulated with consideration of control allocation and actuator dynamics. Finally, an integrated verification approach is designed based on experimental and simulative method to validate the established model. The work is concluded with an application prospect in future.