Mechanical Mechanism Of Oblate Spheroid Shell Actuator And Its Application In Truss Shape Control

The shape control and optimization of trusses are research directions of mechanics and modern design and manufacture. In most cases, the deformation process of the truss must not be continuous but achieve the predetermined deformation. Therefore in this paper a new oblate spheroid shell actuator is made up to apply to the shape control of the static truss, and the applied driving force is calculated from the perspective of mechanical mechanism, that is, flat spherical shell jump load when large deformation buckling. On this basis, the optimization of the shape control model and solution methods are provided. Main works are composed of three parts:1. Mechanical mechanism is researched when the large deformation bending of the shell cause the jumping phenomenon. For the bending jumping phenomenon of the oblate spheroid shell, the jumping curve of the oblate spheroid shell is simulated by the energy method. The approximate analytical solution of the jumping load of the oblate spheroid shell is calculated by the program of the free parameter perturbation method and compared with the simulation solution by the ANSYS. Thus, the jumping load of the shell with certain size parameters is obtained.2. A new oblate spheroid shell actuator applied to the static truss shape control is proposed. The spheroid shells and bars which occur the jumping phenomenon are composed to make actuators. When the spheroid shells reverse, the length of the bar can elongate or shorten to change the shape of the truss. Analysis of actuators with different types and states is got to carry the shape control and optimization's point.3. The optimization model and the solving algorithms of the truss shape control are introduced. To realize the specify shape of the truss structure, the oblate spheroid shell actuator must lie to the reasonable position. Therefore the optimization model (0,1,2) of the oblate spheroid shell actuator shape control is made up. According to actual needs, the optimizing model takes into account the following two design variables:First, for the known highness f of the actuator, this is only the actuator position information with discrete variables to control and shape optimization of truss. Second, for the unknown highness f of the actuator, this is both the continuous variable of the height actuator and the discrete variables of the location information. In this paper, the jumping curves of shells are simulated with energy method and the jump loads of shells are solved with the free parameter perturbation method by MATLAB language. Also in MATLAB software, the genetic algorithm optimization design module is realized and the control and optimization of truss shape are completed.