Design For The Vibration Damping And Mounting Structure Of IMU In Missile

A kind of design for the vibration damping mounting structure of the lasergyroscope IMU is introduced in this article. Fix IMU by four groups of vibrationdampers on the mounting plate that is connected with the missile body rigidly. Themovement of the missile body causes that of IMU. This model can be simplified assingle-degree-of-freedom linear vibration. Design the rigidity and inherentcharacteristics of the mounting plate and vibration dampers reasonably to keep themaway from the inherent and harmful frequencies of IMU, so that the vibration couplingis not to occur. Firstly, carry out sine scan for the prototype of IMU to define itsinherent and harmful frequencies. Secondly, in order to find the dynamic ambientcondition for IMU to work normally, carry out random vibrations for its prototype.Through loading different spectral types and vibration magnitudes and carrying outnavigation computation in power-on state, determine the vibration magnitude andfrequency distribution spectral shapes that can meet the requirements of navigationaccuracy. This is taken as the design target for the dampers. Then, design the frequencyand rigidity of the dampers according to the vibration-damping principle; analyze andcalculate the structural parameters of the dampers in the light of the materials selectedand the structure of the dampers; manufacture the dampers according to the preliminarydesign and carry out vibration screening test to select one or two groups that meet therequirements. It is required that the mounting plate is designed with low mass and goodrigidity. Moreover, its front two order inherent frequency should avoid the inherent andharmful frequencies of IMU. In this article, the method of topology optimization isadopted. The software of OPTISHAPE-TS is utilized to set up and optimize the mode ofmounting plate that is designed preliminarily according to the functional requirements.By confining the area that can’t be designed and adopting the homogenization theory,through loop iteration operation, the optimal configuration of structural material isdetermined. In the precondition that ensure the maximum rigidity and modal value,slash materials according to the design requirements to make the mounting plate withthe lowest mass have good rigidity and modality that meets the requirements. Lastly,combine the respectively designed mounting plate with the dampers and verify thedesign of the damping supporter for this combination by testing. Combine the twogroups of dampers that have different eigenvalues with the mounting plate respectively.Take the section body instead of the missile (Limited by conditions) to carry out randomvibration test. The measurements of vibration response on IMU are pretty close to thedesign target that the test indicates. Moreover, all the navigation accuracy of IMU inpower-on state is up to the expected requirements.