Papers by Author: Dong Li Qin

Abstract: In order to solve the automatic localization problem of the surface or curve detection, this paper presents a method for obtaining a global optimal solution, the method uses particle swarm algorithm to solve the position and orientation. To solve the problem of premature convergence and slow convergence in particle swarm algorithm, a chaotic mapping logistic model is presented to improve the performance of particle swarm algorithm and the shrinking chaotic mutation operator is applied into the method to increase the diversity and ergodicity of particle populations. In this paper, the objective matrix is separately described by quaternion and Euler angles, and the accuracy and convergence of the algorithm are analyzed taken into account these matrices. Simulation results demonstrate that two mentioned expressions can comply with the requirements of adaptive localization, and while Euler angles as optimization variables, chaotic particle swarm optimization have higher accuracy results. Finally, compared to Hong-Tan algorithms, the method is effective and reliable.

Abstract: Balance precision of gyroscope rotor influences its performance directly. Aiming at the special gyroscope with a spherical cavity mentioned in this paper, a static balance method is proposed. This method can determine not only radial direction but also axial direction relative position between the mass center of rotor and the centroid of rotor’s outer outline. Combined with outer outline location, which can determine the relative position and direction between the mass center of rotor and the centroid of rotor’s outer outline, the relative position and direction between the centroid of spherical cavity and the centroid of outer outline can be determined, and we will know the position of removal amount.

Abstract: It is an important performance for gyroscopes to read out the angle information of the gyroscope rotor accurately. There are few methods for measuring the deflection angle of gyroscopes, and they are only fit for the special rotors. A new method based on laser triangulation with position sensitive device (PSD), and the calculation theory of measuring the deflection angle are presented in this paper, which is designed for measuring the deflection angle of a new type gyroscope rotor, and can improve the precision of measuring by several reflections. It indicates by calculation that the method presented in this paper is feasible, and the precision can be improved several times by many reflections, furthermore, the more the number of reflection is, the higher the precision of measurement is improved.

Abstract: The influence of parameters to load performances of a high-speed externally pressurized spherical gas bearing compensated by two-rows of orifices has been studied numerically based on finite element method (FEM). Reynolds equation governing the flow field in the clearance space in spherical coordinates system is transformed into a analogous style in Descartesian coordinates by parameter substitution, and Galerkin weighted residual method is applied to reduce the order of derivatives of the transformed equation. Pressure distribution on the gas-film is obtained by solving of the equation. On the basis of theories, influences of rotating speed, nominal gas-film thickness and supplying pressure to load carrying capacity and stiffness are analyzed. Comparison of performances between hydrostatic and hybrid state of the bearing has also presented.

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.