| The stiffness parameter of the elastic component in electro-hydraulic servo valve directly affects the control performance of the servo valve.The elastic component,also known as armature component,consists of elastic elements spring tube and feedback rod and rigid elements baffle and armature.The existing comprehensive stiffness measurement device of the elastic component was measured under the free clamping of the ball head of the feedback rod and the pure force coupling loading of the two arms of the armature,but the existence of transmission gap and transmission friction maked the measurement accuracy low and failed to be practical.In this paper,the measurement method of the comprehensive stiffness of elastic component will be improved to enhance the accuracy and efficiency of the measurement system and to adapt to the requirements of comprehensive stiffness measurement for multi-model elastic component.Firstly,this paper proposes two definitions of the effective and measured comprehensive stiffness of the elastic component.The theoretical equation of the effective comprehensive stiffness of the component is derived based on the force state of the torque motor.Based on the analysis of armature deformation,the relationship between the measured comprehensive stiffness and the effective comprehensive stiffness of the elastic component is clarified.The effect of non--free clamping of the feedback rod ball head and non-pure force couple loading of the armature on the measurement of the comprehensive stiffness of the component is analyzed by simulation,and the comprehensive stiffness measurement method with independent symmetric loading of double arms is determined.Secondly,the structural design of the loading mechanism and positioning clamping mechanism of the elastic component is carried out;the parallel beam force transducer and differential inductive displacement transducer are selected to measure the load and displacement of the two arms of the component,and the commissioning of the secondary instrumentation circuit is completed;and the Labview software is used to collect the output signal and calculate the comprehensive stiffness.Finally,a new comprehensive stiffness measurement system is built,and the symmetry of the two arms measurement is ensured by the calibration of the transducer;the comprehensive stiffness measurement influence factor test is conducted to determine the measurement specification;and the comprehensive stiffness measurement test is conducted on two different models of the component to evaluate the performance of the measurement system;then the relationship between the measured comprehensive stiffness of the elastic component and the effective comprehensive stiffness is verified by armature deformation tests. |
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