Research On Dynamic Characteristics Of Electric Steering Gear Based On Space 4R Mechanism

With the rapid development of modern warfare,high requirements were made on the rocket projectile,mortar projectile and other conventional ammunition against precision,sensitivity and reliability.Electromechanical actuator is one of the important parts of two-dimensional correction projectile,has important scientific significance to improve the precision of ammunition.In this paper,the spatial 4R mechanism is used as the working mechanism of the actuator system,considering the influence of clearance and the deformation of the structure on the dynamic characteristics of the mechanism,the virtual prototype technology is used to simulation analysis of mechanism.Firstly,the spatial 4R mechanism is used as the working mechanism,the motion and dynamic equations are established by using the cosine matrix method,the kinematics and dynamics of the mechanism are calculated by introducing the supplemental equation,then the angular displacement,angular velocity,angular acceleration,joint force and joint counter-torque of the mechanism are also determined.Then,in consideration of the mechanism of the rotary hinge clearance,the L-N contact force collision model and the modified Coulomb friction model are established.Through the simulation example,it is verified that the L-N contact force collision model is suitable for the case where the recovery coefficient is close to 1 and the collision speed is low.Next,the multi-rigid body model is established for the spatial 4R mechanics,studying the effect of clearance on the dynamic characteristics of mechanism,it is determined that the optimal clearance is 0.04mm-0.1mm when the mechanism is single clearance.It is determined that the optimal clearance is 0.06mm-0.1mm when the mechanism is in the two clearance.Finally,rigid-flexible coupling model is established for the spatial 4R mechanism,for analyzing the law of dynamic characteristics of mechanism,spatial 4R mechanism contains one or two clearance,with or without flexible body.Research results show that the flexible body can reduce the impact of the clearance collision.Through theoretical and simulation analysis the research shows that,the spatial 4R mechanism to meet the requirements of the working mechanism of electric actuator,the results of this paper can provide reference for the design of the spatial 4R mechanism,which is beneficial to the practical application of the project.