| The compliant mechanism can use the deformation of its own compliant unit to realize movement and force transmission,and realize energy conversion through the storage and release of strain energy in the compliant unit.This type of mechanism can be integrated and processed without moving pairs,can significantly reduce the number of parts,reduce assembly errors and costs,clearance,friction and wear,impact vibration,etc,with high motion accuracy,and great potential for application in the field of precision engineering.The tension-compression and constant-rigidity compliant mechanism can still maintain a linear force-displacement relationship under large tension and compression loads,and can be used for precise positioning of motion platforms,etc.Based on the principle of stress stiffening,plane compliant beaums subjected to axial tensile force and compressive force are combined in series to construct a single-degree-of-freedom compliant mechanism with constant stiffness in tension and compression.Analyze the reasons for the geometric nonlinear deformation of the compliant beam under load,and introduce the common modeling methods and the application scope of each method for the large geometric deformation of the compliant mechanism.The tension and compression load conditions are discussed separately,the beam constraint model is established for each section of the compliant beam,the static balance equation is established in each part of the mechanism,and the nonlinear equation set is solved by the numerical iteration method.The linear force-displacement relationship of the compliance mechanism is deduced,and the constant stiffness of the mechanism function direction is further obtained.Using finite element tool simulation experiment to compare the theoretical model of mechanics,the error of the two is within 1%,which verifies the correctness and accuracy of the theoretical model.Design orthogonal experiments combined with finite element simulation experiments to explore the influence of the elastic modulus and structural parameters of the mechanism material on its tensile and compression characteristics and constant stiffness characteristics.The goal is to improve the maximum tension and compression load that the mechanism can withstand within the range of constant stiffness.Optimized design,after optimization,the tensile and compression performance of the mechanism is improved several times.Through the reasonable configuration of the plane compliant beams of this compliant mechanism,a combined compliant hinge with constant rotational rigidity in tensile and compression resistance is evolved.The simulation using finite element tools verifies that it is under a wide range of tension and compression loads and movement strokes.Has good constant stiffness characteristics.The proposed tensile and compressive constant stiffness single degree of freedom compliant moving mechanism can be applied to scenarios that are sensitive to gravitational factors or generate large inertial force due to high acceleration motion in one direction,etc.,which are equivalent to tensile and compressive loads.With good constant stiffness characteristics,it can be used as a basic functional unit in a compliant precision positioning,linear motion platform or other complex and multi-functional compliant platform.Established a standardized and process-oriented statics modeling and optimization design method,which has guiding significance for the selection of different beam parameters to design this type of mechanism.Obtaining a tensile and compression compliant hinge by configuring the angle of the plane compliant beam also provides a design idea of mechanism evolution.Figure 51 table 13 reference 88... |
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