The Structural Design And Control Analysis For Space Mechanism

There are two kinds of space mechanism included in the research of this dissertation. One is the adjustment mechanism of the imaging lens's focal length of a space solar telescope, the other is deployable space structure. Based on the particularities of the space mechanism, much meaningful work has been done in this paper.The work of the adjustment mechanism is a project which is supported by the state committee of "863". Three design mechanisms are proposed, bearing and screw style, movable bearing style mechanism and assembly style mechanism. It is difficult for the precision of the mechanism made of movable bearing to meet the requirements of the design because the bearing must be made individually. The small bearings in the assembly mechanism are mounted to the hollow cylinder. Because the thickness of the hollow cylinder is very thin, it is very difficult for the design of the assembly mechanism. A model is made according to the bearing and screw style, and the static analysis of the model has been done under launch environment. In the static analysis the couple point method is accepted for the solution of the relationship between the contact parts of the mechanism. The error of the whole mechanism is influenced by the screw, step motor, and so on. The analysis of the error is presented in the paper.The deployable space structure is a new type of space architecture bome with space science and technology development in recent years. But in our country the technique in this field is somewhat weak. The deployable parabolic antenna designed and made in our lab can make a progress in this field.This paper proposed a hexahedral deployable space antenna, which is composed of hexahedral modules. The basic hexahedral module can be deployed and stowed with the motion of the spring in the diagonal stretchy member, so is the whole structure. In fully deployed configuration the length of the surface struts, diagonal members can be calculated. But some of the surface struts will be stretched if the structure is folded into a fully stowed package. A method is presented to find these stretchy members and calculate their length in folded state. The result of the geometric analysis of the model made in my lab is presented.The impact response produced by the tension springs in the diagonal members is very serious and a stowing mechanism is designed for the control of the impact. The control system with motor is also presented.According to the static analysis and modal analysis of the mechanism, the best parameters are obtained. Compared with the results of the experiment analysis, the theory analysis is reasonable. The experiments done by our lab include modal experiment, velocity and accelerationexperiment, the deployment repetition experiment.The mechanism in space environment experiences a variety of environments that are potentially damaging to materials and to the components of the mechanism. The space environments can be divided into two kinds environment, which includes mechanical environment and outer space environment. The mechanical environment is described in the paper and then the environments in three different orbits are proposed, called LEO (Low Earth Orbits), MEO (Medium Earth Orbit) and GEO (Geosynchronous Earth Orbits). The influence produced by the atomic oxygen, micrometeorites and debris, ionizing radiation and cold welding under vacuum is presented in the paper. Some principles are proposed, which can be as the method to choose materials of the mechanism in space environment.The effects of clearances within the connections of the mechanisms and of elastic compliance of the links and members of the device are very serious. Especially to the mechanism worked in space environments, the analysis method is important. The gap element method is proposed in the paper for two kinds of problems, which include contact problem and gap joint problem. Elasticity contact problem falls into the category of unknown boundary value problems. It follows that the contact area and contact conditions or...