Design And Analysis Of The Reset Mechanism For The Wind Tunnel Balance Calibration System

The wind tunnel balance calibration system is the wind tunnel balance measuring device.We can get the balance formula(the relationship matrix between output signal and load)accurately by applying static load(force and torque)to balance according to the known coordinate axes,so as to evaluate the performance of wind tunnel balance.In the calibration of wind tunnel balance in the loading system due to the load effect of deformation,rigid shaft alignment of shafting and the wind tunnel balance model constituted no longer coincide,in order to make the recovery of the initial position,accurate pose adjustment of the reset mechanism,a reset mechanism is an important part of wind tunnel balance calibration system,the reset precision directly affects the accuracy of the final balance.With the development of aircraft upgrades,the calibration system of wind tunnel balance low load has been difficult to meet the needs of national defense,put forward new requirements for the calibration system of wind tunnel balance,so the design of the calibration system of wind tunnel balance has important strategic significance and project value.In this paper,the reset mechanism in the calibration system of wind tunnel is taken as the research object,and the topic is the design and analysis of the reset mechanism of the wind tunnel balance calibration system,aiming to improve the reset accuracy of the reset mechanism.The main contents and conclusions of this paper are as follows:(1)Introduces the working principle of the reset mechanism,and then put forwar d on the basis of the technical requirements,including traditional tandem configuration,a novel series hybrid configuration,configuration of traditional and new hybrid config uration four reset mechanism configuration,through a comprehensive analysis of the configuration of new type of hybrid selection mechanism as the reset mechanism.then the mixed model combined with mechanism for the overall design,laying the ground work for the static analysis and modal analysis.(2)Using a static analysis of the reset mechanism of ANSYSWorkbench software,the static analysis gets reset mechanism of maximum deformation is 0.8033mm less than the overall reset mechanism of technology requirements allowed maximum deform ation is 1.5mm,which meets the stiffness requirements of the reset mechanism.the maximum equivalent in the six load cases reset mechanism of stress is smaller than the material for 73.12Mpa the allowable safety stress 157Mpa,meet the strength requi rements of the reset mechanism.The modal analysis has been reset mechanism of the first six order natural frequency and vibration mode,resetting mechanism of the firstorder natural frequency is 11.893Hz and frequency control system and the reset mecha nism is about 3Hz,when resonance does not occur,meet the vibration resistance of the reset mechanism,verify the rationality of mechanism design and configuration.(3)Using the method of coordinate transformation,establish the kinematic model,obtained the inverse position equation,inverse position analysis for pose error equation lays a foundation;gradient descent method based on the idea of using sample positive solutions of BP neural network algorithm training,training,testing and validation of the network are at variance the network model trained,ideal,and random samples to verify the error in the acceptable range,can be used for positive solutions,positive so lutions laid the foundation for the motion control mechanism for position;in order to direct and inverse kinematics analysis to verify the correctness and validity of the deri ved formula of velocity and acceleration that has separately carried on the simulation software and simulation analysis of kinematics theory,using Matlab and Adams softwa re,the Matlab inverse solution of velocity and acceleration theory Adams simulation a nd inverse kinematic solution curve comparison simulation,verified the correctness of the inverse solution model,velocity and acceleration are derived,by Adams inverse so lution and positive solution for simulation of motion curve comparison,verify the corr ectness of the simulation process and results;compared three verified the mechanism has good performance,meet technical requirements.(4)The main error sources of the orthogonal parallel mechanism were analyzed and identified.Based on the inverse kinematics model,the integral error model and the single error model of the mechanism were established by differential method.Analysis of the individual errors affect the structure of the end pose error and online,that the influence of length,Hooke joint and ball joint error on the mechanism of the end pose error is less than the maximum error of the technical requirements of the value;Monte Carlo method of parallel mechanism and the end pose error was simulated and the effect of comprehensive error error the source of the end pose error to a maximum of 0.0361mm and 7.6e-04rad is less than the technical requirements of the 0.1mm and 0.001 rad;the sensitivity of the position error of end effector was analyzed,found little difference between the influence degree of Hooke and spherical joints position error and the length error of position error of end effector,provide the basis for the design and manufacture of electric cylinder and the hinge selection.