| In the theory and application process of research institutions,people have found that the parallel mechanism has advantages such as greater stiffness,stronger load capacity,and less inertia of the end parts compared with the series mechanism,and therefore it is valued by the medical,civil,and military industries.With the rapid development of science and technology,the research on parallel institutions is changing with each passing day.People are pursuing lower economic costs and more flexible work while also demanding the work space,while less-degree-of-freedom parallel agencies have been able to meet these needs.It is the concern of the world.The application of helicopters in the military and civilian industries is also increasingly important,and the rotors are the most critical components of helicopters.Therefore,the application of a less-degree-of-freedom parallel mechanism to helicopter rotors is increasingly drawing attention from experts from various countries.The 3-DOF 2SPS+UPU/SP type parallel mechanism with intermediate restraint branches was studied.The main research content has the following aspects.The degree of freedom of the mechanism was calculated and analyzed.A three-dimensional model was created in the advanced CAD.The position vector of the model was analyzed based on the vector method.Based on this analysis,the placement of each pair of motion pairs was analyzed,and each motion pair was analyzed.The relationship between the constraints to determine the direction of the binding force/torque in the mechanism,and then use the impact coefficient method to analyze its kinematic model.When analysing the working space of the institution,a three-dimensional space model was drawn using advanced CAD variable geometry.The mechanical properties of the parallel mechanism were analyzed,and the static mechanics and dynamics mathematical model was established using the principle of virtual work.A detailed analysis was carried out.The model and programming simulation were performed by combining three-dimensional先进CAD and Matlab software to establish a mathematical model.Correctness is verified.After a detailed explanation of the basic parameters and aerodynamic knowledge of helicopter rotor blades,the blade hinge torque of the rotor system was obtained,a nd the force and moment balance was used according to the dynamic study results of the parallel mechanism 2SPS+UPU/SP.The relationship between the ball joint of the parallel mechanism passed by the rotor hub was analyzed,and the practicality of the combination of this mechanism and the rotor system was proved.It also provided a reliable theoretical proof for the application of the mechanism to other fields. |
