| Servo mechanism is the core of the seeker,and its dynamic performance directly determines the performance of precision guided weapons.In order to solve the problem of controling the dynamic characteristics of the servos during the assembly process,the on-line testing technology of the resonant frequency,friction torque and its inhomogeneity of the servomechanism is studied.In this paper,the key factors affecting the dynamic characteristics of two types of servo mechanisms are studied,including the preload force of the bearing and the eccentricity of the pinch roller.The effects of these two key factors on the resonant frequency and friction torque of the servo are established.Based on the test principle of the resonant frequency,the starting torque and the motoring torque of the electrical performance test,a set of on-line testing system of dynamic characteristic of universal servo is developed,and the effectiveness of the system is verified by the test.The main contents of this paper include:(1)The factors of dynamic characteristics of servos are researched.Firstly,the structure of servo mechanism is summarized and two kinds of typical structures are analyzed.Then the model of preload-rigidity and eccentricity-friction of bearing are established based on Hertz elastic contact theory.The influence of preload force and roller's eccentricity on resonant frequency and friction torque of servos are analyzed.(2)The on-line testing technology of dynamic characteristics of servo system is researched.Firstly,the test principle and test method of resonant frequency and frictional torque are studied.Then,based on the requirement of on-line test and the common characteristics of servomechanism,the integrated testing principle based on electrical performance is proposed.The measurement methods of resonant frequency,starting torque and motorng torque of servos are analyzed.Finally,based on MATLAB / Simulink,the test method of resonant frequency is simulated and verified.(3)A set of universal on-line testing systerm for the dynamic characteristics of seeker servo is developed.Based on LabVIEW,the control software of testing device is developed,and the dynamic characteristic testing device of servo mechanism is set up.(4)The validity of servos dynamic characteristic test system is verified by the experiment.The test of resonant frequency,starting torque and motoring torque of three types of servos are carried out.The running test of arch-shaped framewok servo mechanism is carried out.The above test proves that the test method and test system proposed in this paper are effective,which can support the assembly-adjustments of servo mechanism. |
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