Papers by Author: H.B. Zhang

Abstract: For rigid rotor that widely applied in gyroscopes, high precision dynamic balance is very important. The paper introduces a dynamic balance method for drum-shape gyroscope rotor: the rotor is supported by gas bearing; detecting the displacement of three points on the drum-shape rotor’s end-plane, obtaining its normal direction. Then according to geometrical relation of geometric axis and polar inertia axis, the dynamic trace of the rotor can be obtained, and the rotor’s mass imbalance is calculated. Experiment result shows that the method has high balance accuracy, particularly suit for high-speed gyroscope rotor whose mass imbalance is small.

Abstract: For the measurement of ultra smooth surface topography, a surface image scanning device measurement head mechanism based on the principle of atomic force microscope (AFM) was designed. It uses coarse adjustment, semi-delicate adjustment, delicate adjustment triple-stage adjustment mechanism, and tests the atomic force between the sample and the probe by using laser generator, position sensitive detector (PSD), cantilever and probe. This mechanism has high setting accuracy and resetting accuracy, combined with two-dimension movable table, can scan the surface topography of samples.

Abstract: In order to meet the demands for high precise micro-displacement testing, a differential capacitive displacement sensor based on RC multi-oscillating circuit was designed. It has two couples of polar plates, and gets the displacement by testing frequency through the multi-oscillating circuit. This capacitive sensor has many advantages such as simple structure and testing circuit, high resolution and good stability.

Abstract: For spherical rotor of gyroscope and some other high speed rotor, static balance is important. The paper introduces a static balance method for spherical rotor: the position of the spherical rotor is fixed by the use of the special clamp apparatus, and then determines the unbalance mass using the electronic balance. This method has no strict requirement to the clamp’s symmetry and dimension and locating precision of the locating hole. The balance precision only depends on the precision of the electronic balance and shape error of the clamp’s locating surface, which makes the balance method has high precision and preferable operability.

Abstract: Because of many advantages that other kinds of bearings can not match, for example high precision and high speed, gas lubricated bearing has been used widely in areas such as ultra-precision machine tool and inertia apparatus. The paper introduced an orifice restrictor externally pressurized spherical gas bearing, which is easily shaped and has bigger stiffness in both axial and radial directions. The paper also introduced a bearing force calculation model based on finite partition of the bearing, in which the influence of the uniform pressure slot also considered.

Abstract: In order to optimize static performance of a new orifices compensated externally pressurized gas spherical bearing, the paper presents a theoretical study using finite element method (FEM). Galerkin weighted residual method is applied to reduce the order of derivatives of the transformed Reynolds equation. On the basis of theoretical analysis, the influence of supplying pressure and geometrical parameters to radial load carrying capacity and stiffness was analyzed. As a result, the reasonable range of the bearing’s parameters was proposed.