Reverse Design Of The Space Deployable Antenna And Study On Stowing Of The Space Structure

The deployable truss antenna on the satellite and the space optical tilt mirror belong to the space structure, which require the light quality and small volume, and also meet the technology requirements of the task. This dissertation covers the following six fields based on the studies of surface precision of the antenna and the tilt mirror influenced by their structures, which affect their physical performance. These six fields include: the configuration of the tension reflector on the deployable element truss antenna; the far-field radiation of the antenna; the influence on the far-field by the partly spring invalidation and the space thermal environment; the shape design of the truss antenna; the stowing distortion of the space optical tilt mirror; and the dynamic analysis of the tilt mirror system.The reflector configuration of the deployable truss antenna greatly influences its far-field radiation. The dissertation analyzes the configuration with the membrane configuration analytical method: nonlinear finite element method and force density method. The obtained conclusion is that: when the upper joints are all on the designing paraboloid, the RMS of the curved surface and the standard paraboloid is the least, which is composed by the triangular planes of the upper truss. In addition, the computing formula of the fitting paraboloid of the curved surface which is composed by the triangular plains is deduced. And the corresponding program is made. And the Agrawal error is analyzed.The precise Electro Magnetic Field synthetical method is especially important because all the antenna studies aim to obtain the best electro magnetic field performance. According to the features of the deployable reflector configuration and the geometry optical theory, the computing formula of the electro-field intensity of the truss antenna is inferred. Then, the integral of the far-field is conducted with the analytical method, and the corresponding program is designed when the paraboloid is separated to form rectangular grid on the aperture plane. Because this program also applies to the computation of the reflector radiation field of the standard paraboloid or any paraboloid whose distortion is already described, the method is proved to be correct by comparing with the result of Rahmat-Samii. This method directly related the structure with the electro magnetic field, which improves the design by leaving out the RMS value.When the deployable antenna deploys after orbiting, the configuration of the whole structure will be influenced by the outer space heat current and the spring. This dissertation provides the instant temperature field when the antenna runs on the Summer Solstice and the midwinter, as well as the thermal flexibility and the structure distortion caused by the partly spring invalidation. Furthermore, the best installing position of the feed is obtained based on the internal relationship between the reflector and the radiation features.The shape designing of the antenna can focus the limited energy on the sensitive area, so much attention has been paid to it. Because the topology structure of the deployable truss antenna is very special, the shape designing method can not copy that of the solid reflector. This dissertation applies the penalty function to construct the target function when the parameters in the normal equation of the reflector are used as the optimized variables. The direct searching method is used to optimize the computation considering the complicated target function with multi variables. The corresponding shape designing program is made and an example is given to illustrate that the total power in the target area improves and the distribution of the power is more smooth. If the moving range of the joints is enlarged, such direction becomes more evident.The space tilt mirror requires the least surface error and the high system resonance frequency, so the structure and the stowing of the mirror become more crucial. The dissertation designs the structure of the 150mm mirror. The Zernike polynomial is used in the elastic plane equation. The equation of the out loop is presented based on the elasticity groundsill. Two equivalent Bessel equations are deduced. And the general solution is obtained by use of the special function. An equation group of Zernike polynomial coefficients is obtained based on the harmony between the deformations of the outer and the inside loops. A group of null space vectors which indicate all the possible distortions of the mirror is gained by means of inverse matrix. The energy functional is established and a group of composed coefficients of the null space function is obtained by gaining the least energy when the load on the mirror's arms is specified. So the actual displacement under each model is obtained. And each coefficient corresponds to each Seidel aberration coefficient. And the mirror surface error is gained by adding all the displacements.As to the complicated tilt mirror structure, the effective way is to apply the finite element method to solve the problem. The dissertation analyzes the 80mm tilt mirror system stowed with pressing board by means of contact nonlinear model in ANSYS. The experiment proves the validity of the model. And 150mm system is designed. In addition, the static and dynamic analysis is conducted. As a result, a series of systematic frequency is obtained by changing the joint stiffness and the optimized load can be found. At last, the theoretical result of the 150mm tilt mirror is checked.