Research On Flexure Hinge-based Mechanical Displacement Amplifier And 3-DOF Pose Adjusting Platform

The development of satellite technology is sharply promoted,due to the desirability of the space exploration.Currently,the satellite has involved in the field of navigation and positioning,military reconnaissance,agricultural meteorological observation,and earth observation,etc.and has made a marvelous contribution to the information society construction.The satellite may have periodically drift during the on-orbit running,as a result of the influence of the non-spherical gravitational field and other environmental factors,the angle adjustment accuracy of the thruster orientation mechanism,which is the actuator of the attitude adjusting control system,may impact the final attitude of the satellite directly.The technology of the parallel mechanism and micro-drive is the research hotspot in the field of engineering application,it makes possible to apply the high precision device in the field of aeronautics and astronautics.In this paper,for the purpose of providing theoretical basis and technical support,the research is focused on the mechanical properties of the bridge-type compliant mechanism with flexure hinge and 3-DOFs compliant parallel mechanism.The research of quasi-static mechanical property is significant because of bridge-type compliant mechanism is the core component.Considering that the common symmetry and over-constraint of the structure,this research takes 1/2 model as the object,and regards the flexure hinge as the varied cross-section beam,and builds a set of un-canonical linear homogeneous equations for calculating the mechanism performance,the ratio and input stiffness are acquired consequently.Taking the lever-type and bridge-type as the objects,and the analytical models are verified through the simulation results.Besides,the influences of the parameters are discussed in the paper.The flexure hinge is taken as the varied cross-section beam element,and the stiffness matrix is built by the element force relationship in the element coordinate,the element shape function and the mass matrix are built by means of coordinate transformation and deflection expression.Based on the Hamilton principle,the finite element dynamics equation with multipoint constraint equations is built according to the geometric characteristics.The modal analysis is carried on and the fundamental frequency is acquired.The influences of the design parameters on the first frequency are discussed.The mathematical model is testified by the simulation result.Besides,the multi-objective optimization is performed on the basis of the quasi-static mechanical model and dynamic mechanical model,the ratio,and input stiffness,the first frequency and the mass are optimization objectives,the optimal design parameters are obtained,consequently.A new 3 DOFs compliant parallel mechanism based on bridge-type compliant mechanism and flexure spherical hinge is designed,and the screw theory is employed to discuss the DOFs of the distinct parallel mechanisms.The inverse kinematics of the platform is given by using the pseudo-rigid-body model,and the full working space is simulated by the model.Besides,the static stiffness analytical model of the platform is established by the matrix superposition method issued from the structural mechanics.The influences of the design parameters on the static stiffness are derived.The experimental system of the bridge-type compliant mechanism with flexure hinge is established,the ratio and the frequency are measured under the condition of PZT is in closed loop control mode.According to the design scheme,the 3 DOFs compliant parallel orientation mechanism is produced and the experimental system is built accordingly.For the system static performance index,the range of motion and the repeat positioning accuracy of the platform are measured.The resolution and the system frequency are measured on the issue of the system dynamic performance index,and the influence of the temperature on the plat form is discussed.The experimental results show that the design scheme and theoretical analysis are reasonable.