DongXu Li

Optimal Design and Control of Smart Space Structures: A Memetic Evolution Approach

To reach global optimal performance, here the authors propose a new design approach that offers concurrent design for smart space structures. In this approach, the quantity and placement of sensors/actuators and parameters of controllers are simultaneously optimized by a memetic evolution algorithm. A solar array smart structure has been used for computational experiments and the corresponding results indicate that the proposed concurrent design can obtain better performance than the sequential one.

Optimal Placement of Controls for Truss Structures in Space

The authors propose a genetic algorithm-based approach to finding the optimal placement of actuators and sensors, which is critical for controlling intelligent truss structures in space.

An online learning-based fuzzy control method for vibration control of smart solar panel

Vibration control problem of solar panel structure is an ultra-important problem which was studied by a lot of researchers. This research is devoted to design an “intelligent” control algorithm for this problem, which can learn autonomously without supervision or a priori training data. Based on this idea, an online learning-based fuzzy control method is proposed in this article. The online learning-based fuzzy control is composed of reinforce learning algorithm and fuzzy inference system. The learning algorithm learns the fuzzy rule base by interaction with the plant and changes rule base generated by policy via evaluative reward signal to realize the learning goal. In order to verify the presented control method, vibration control of a typical single-panel smart solar panel structure bonded with piezoelectric actuators is considered in this article. First, the dynamic model of the smart solar panel structure is established using finite element method. Then, the state-space equation of the control system is presented. After that, technique details of the online learning-based fuzzy control method are described. Finally, experimental validation is conducted. The experimental results show that the online learning-based fuzzy control method presented in this article can suppress the vibration of the smart solar panel effectively and faster than fuzzy control method.

A New Mechanism for the Vibration Control of Large Flexible Space Structures With Embedded Smart Devices

Large flexible space structures (LFSS), such as solar panels and synthetic aperture radar antennae, are widely employed in spacecraft. Owing to their structural peculiarities in addition with the special environment in outer space, it is easy to be aroused for the structural vibration of LFSS. This kind of vibration is very harmful to spacecraft. In this paper, we proposed a new mechanism for the vibration control of LFSS. An embedded smart device with a piezoelectric ceramic stack was built up, also. First, the nonlinear theory of structural vibration coupled with inner forces was deduced. Second, the basic principle of the new mechanism with the piezoelectric ceramic stack was expounded. Third, the smart device manufacturing and the embedded techniques were introduced. Finally, taking several solar panel structures as illustrative examples, we carried out both digital simulations and ground experiments. The research results showed us that the proposed new mechanism is quite effective to the vibration control of LFSS. This paper gives a new way to solve the vibration control problem of LFSS, especially for those with low frequencies, which is very valuable for improving the accuracy and performance of spacecraft.

Decentralized adaptive fuzzy vibration control of smart gossamer space structure

Gossamer space structures technology have gained widely applications in space missions. However, the vibration problem is a great challenge which makes the technology complicated. The overall motivation of this work is to develop a vibration control system for gossamer space structures. In this study, a space membrane structure with piezoelectric stack actuators bracketed on its support frame is considered. First, the description of the smart space membrane structure and its dynamic model are presented. Then, a decentralized adaptive fuzzy control method is developed to control the structure vibration. Finally, experimental system is built up, and two vibration control experiment cases are carried out to verify the proposed control method. Experimental results demonstrate that the proposed control method is more effective than the fuzzy control method.

The influence of orbital motion of flexible space vehicle on the dynamic traits of solar panel

This paper studies on the complex dynamics coupling phenomena between orbital motion of space vehicle and elastic vibration of solar panel. For solar panel is a typical large flexible structure and generate continuous vibration inevitably under various loads in space environment, the vibration control is necessary. To provide appropriate dynamic parameters for the design of controller, high accuracy mechanics model of flexible space vehicle must be established. The conventional method did not consider the impact of static deformation on the vibration of solar panel, and hold that solar panel vibrates under the base of zero equilibrium position, which actually not accord with the fact that static equilibrium position is varying along the time under the influence of space vehicle orbital motion. In this paper, a novel method of describing the solar panel deformation is proposed, which think the vibration is a vector superposition of static deformation and dynamic deformation. To illustrate the influence of orbital motion on the dynamic traits of solar panel, a simplified curved beam model of solar panel is adopted to simulate the vibration behavior of solar panel undergoing large overall orbital motion.