Construction And Experiment Of A Compliant Constant-force Mechanism Based On The Double-slider Four-bar Mechanism With Springs

The compliant mechanism actively considers the good benefits brought by the deformed members in the mechanism,and uses deformation to improve and improve the performance of the mechanical system.The mechanism uses elastic deformation of the material to transfer or convert motion,force or energy,mainly through the flexible unit in the mechanism,including deformation stores strain energy,restores the released strain energy to achieve energy transfer and target function.The compliant mechanism has no motion pair or less motion pair,frictionless and no wear,high mechanism motion accuracy,and can realize the miniaturization and miniaturization design of the mechanism system.The field of electromechanical systems and precision instruments has a wide range of applications.The compliant constant-force mechanism,as an important branch ofthe compliant mechanism,has zero stiffness and can be used to grasp fragile objects.This dissertation constructs a compliant constant-force gripping mechanism based on double-slider four-bar mechanism with springs.Different from avoiding the singularity of closed-loop linkages,this paper uses motion singularity to construct a compliant mechanism with expected nonlinear stiffness characteristics to enrich the comprehensive method of compliant mechanism.A theory was proposed to generate the nonlinear static stiffness characteristics of kinematics through the motion singularity of a double-slider four-bar mechanism Based on the principle of virtual work,a motion static model of a four-bar mechanism with spring was established The influence of spring stiffness on the force-displacement relationship is analyzed.The analysis results show that when the mechanism works near the position of the singular point of motion,the corresponding spring stiffness may produce one of four nonlinear stiffness characteristics,including bistable state,local negative stiffness,zero stiffness or positive stiffness.Therefore,a compliant mechanism having a desired stiffness characteristic can be constructed by using a pseudo-rigid body model of a mechanism in which a joint or a link is replaced by a corresponding compliant unit.The finite element analysis software is used to verify the feasibility of the mechanism's theoretical model to establish a compliant constant-force mechanism.Through simulation analysis and testing of experimental prototypes,the designed compliant mechanism has zero stiffness characteristics(constant-force)within a certain displacement range.Theoretical analysis The error between simulation and analysis is within 8%.The experimental test results agree well with the simulation analysis results,which further verifies the accuracy and feasibility of the theoretical model.Then a new type of compliant constant-force holder with symmetrical structure was connstructed based on the designed compliant constant-force mechanism.The design method of the compliant constant force gripper can also be applied to the design of compliant mechanisms with nonlinear stiffness characteristics of other types of additional spring mechanisms.Figure[41]table[4]reference[93]...