Research And Development On A Pneumatic Gyroscope With A Spherical Gas-Bearing

Gyroscope, which has the ability of measuring the attitude information of carrier without limiting to anything outside, is widely used in the aerospace and navigation field since it has come into the world. With the advancement of the society and the development of the inertia technology, the measurement system which is based on gyroscopes is going from the traditional military market to the widely civilian market. It is always an important mission for every country to develop gyroscopes and the technology, and that is an essential index for weighting the science level and military strength of a country. Besides exploiting new type gyroscopes continuously, it is very significant to modify the existing gyroscopes, improve their precision and inducing the cost. ESG and fluid floated gyroscope have high accuracy, but they are not widely used because of complicated structures and high price. The technique of solid gyroscopes being studied is needed to be proved, and there are many difficulties and problems to be solved. It will need a great deal of manpower and finance to improve the accuracy and make it further widely used. The viscosity of gas is lower than the liquid. The gas bearings have such advantage as low friction, less power consumption, high speed and less pollution, and the gas bearings with high speed can provide reliability, life and accuracy for the instrument. All these advantages of gas bearings make them not only being used in inertial device, but also has the possibility of improving accuracy, inducing cost, simplifying structure and deducing volume. So it has an important significance to development a new type gas gyroscope with low cost, high accuracy and simple structure.Combining gas bearing technique with pneumatic technology, a new type gas floated pneumatic gyroscope is proposed in this paper. The motion equation of the gyroscope is erected, the influence of the parameters such as pneumatic nozzles mounting around the gyro-rotor, supply pressure etc on the driving performance of the gyroscopes is studied, at the same time the influence of the rotor's unbalance on the gyroscope's drift error is analyzed. All the above study provides the theoretical preparation for designing and manufacturing the gyroscope.In order to improve the start-stop performance, prolong the life and deduce the disturbance, a scheme which adopt a motor with solid rotor to driving and braking the gyroscope auxiliary is put forward. According to the dynamic equation of the gyroscope with electromagnetic torque, the author study the influence of the structure parameters of the gyroscope and the motor parameters on the driving and braking performance, and this paper establish a foundation for having good start-stop performance by choosing and design motor.To guarantee the gas floated pneumatic gyroscope rotor running steadily, the first job is to make dynamic design and determine the dynamic coefficients of the gas gyro-bearing. In viewing of the new type gas floated pneumatic gyroscope, this paper put forward a method which can solve the dynamic characteristics of the similar structure: the slot film and spherical film are united by compatibility condition, and the united film is meshed by triangular finite elements. Based on small perturbation theory, the pressure of the united film in the gas gyro-bearing is decomposed into two parts: static pressure and dynamic pressure; the Reynolds equation can be deduced from two order to one order by Galerkin residual method, and it can decrease the requirement to the interpolation function. Based on the flow conservation function and the static pressure function, the static pressure in the film can be obtained, the dynamic pressure and dynamic coefficients of gas film can also be achieved, and the influence of different structure parameters on the dynamic coefficient is also analyzed.Based on the dynamic coefficients and the motional function of the gas gyro-rotor, the critical stability equation of the gyro-rotor running steadily is obtained, and the critical mass, which is used as the stability criterion to determine whether the gas gyro-rotor is stable or not, is also obtained. Based on the stability criterion, the influence of different structure parameters on the stability is studied in the paper. In order to get both higher static load capacity and dynamic stability, optimal designing the gas gyroscope is taken in the paper considering the static load capacity.In order to guarantee the gas gyroscope running steadily and decrease the drifting error arising from the unbalance mass, the gas gyroscope must be balanced. Because the spherical cavity's position of the new type gyro-rotor is difficult to ascertain, and the centroid of the gyro-rotor doesn't lie in the rotor, so the idea and method of balance, which is static balance using auxiliary workpiece firstly, then adopting the static balance method called gas floating simple pendulum, lastly dynamic balance, is adopted in the paper aiming at the above questions. Based on the mentioned method, the unbalance of the new type gas gyro-rotor is solved.Lastly, on the above work, the preliminary test about the maching error of the gas gyroscope and various performance of the gas gyro-bearing is made, the gas gyroscope is verified to be correct preliminary.