Attitude and orbit coupled control and simulation of spacecraft formation by using intelligent adaptive control based on characteristic model
Regarding to the relative attitude and orbit of spacecraft formation flying, a nonlinear dynamic model of six degree of freedom coupled with attitude and orbits established, with the help of characteristic model, this paper mainly analyzes the factors of the spatial perturbation and multiple disturbance torques, a kind of intelligent adaptive controller is designed based on the combination of RBF neural network and the golden section adaptive control. Later, the simulation platform Jade is used to simulate and analyze the Multi-Agent system of spacecraft formation. The results show that the spacecraft formation can run along in the ideal orbit, the effect of the control system has good robustness, fault tolerance and intelligence.
A characteristic model-based anti-disturbance intelligent adaptive control law for systems with multiple disturbances
The control systems of practical engineering generally have complicated structures and high-order dynamic models, which poses great challenges to the low-order controller design. One effective way to deal with this difficulty is to establish the characteristic model (CM) of control system. However, the unmodeled dynamics may still exist in the established CM. Moreover, the other disturbances, for example, the actuator deviation, widely exist in practical control systems. As a result, the existing multiple disturbances will degrade the system control performances severely. Therefore, to deal with the multiple disturbances, this paper proposes a low-order composite hierarchical anti-disturbance control law by combing the CM-based intelligent adaptive control (CMBIAC) with disturbance observer-based control (DOBC) for the first time. The proposed controller is easy to implement due to its simple structure and enhanced anti-disturbance capability. Finally, numerical simulation of a micro flexible spacecraft is conducted to verify the effectiveness of proposed methods.
Enumeration of total coliforms, fecal coliforms, and Escherichia coli in foods by hydrophobic grid membrane filter: supplementary report.
Raw, comminuted poultry meat was used to determine the specificity of the media and incubation conditions used in the hydrophobic grid membrane filter method. Confirmation rates for target colonies were 100% for total coliforms, 98% for fecal coliforms, and 97-99% for Escherichia coli. The results of total coliform enumeration in 30 pasteurized milk samples by both the hydrophobic grid membrane filter method and AOAC method 46.013-46.016 are also reported.