【摘要】：大型空間索網(wǎng)結(jié)構(gòu)由于折疊體積小、質(zhì)量輕、展開(kāi)后口徑大等特點(diǎn),廣泛應(yīng)用于信號(hào)傳輸、對(duì)地觀測(cè)、深空探測(cè)等領(lǐng)域,是世界各國(guó)爭(zhēng)相研究的熱點(diǎn)。由于柔性大,剛度低、阻尼小,一旦受到空間擾動(dòng)將會(huì)長(zhǎng)時(shí)振蕩影響在軌運(yùn)行精度,因此進(jìn)行有效的振動(dòng)主動(dòng)控制至關(guān)重要。首先,采用力密度法對(duì)給定幾何形態(tài)的三向拋物面索網(wǎng)進(jìn)行了找形分析,并基于復(fù)位平衡法確定了均勻分布的索網(wǎng)預(yù)拉力。利用有限元法建立了基于預(yù)拉力索應(yīng)力剛化效應(yīng)及壓電作動(dòng)器等效“壓電疊堆-彈簧”力學(xué)模型的壓電智能索耦合動(dòng)力學(xué)方程。然后,研究了含作動(dòng)器/傳感器的壓電智能索的優(yōu)化配置。在降階的模態(tài)坐標(biāo)下建立狀態(tài)空間形式的結(jié)構(gòu)動(dòng)力學(xué)方程,得到模態(tài)控制力能量自相關(guān)矩陣,并根據(jù)該矩陣的秩來(lái)優(yōu)化同位配置的作動(dòng)器/傳感器數(shù)目。根據(jù)系統(tǒng)總儲(chǔ)能積分最小、傳感器接收信號(hào)能量最大的復(fù)合優(yōu)化準(zhǔn)則,利用基于字典序排列組合編碼的遺傳算法獲得作動(dòng)器/傳感器全局最優(yōu)配置的位置。隨后,基于索網(wǎng)動(dòng)力學(xué)方程狀態(tài)空間描述設(shè)計(jì)了LQG控制器;建立了含剛度不確定性的索網(wǎng)結(jié)構(gòu)廣義受控對(duì)象,并通過(guò)浮點(diǎn)數(shù)編碼遺傳算法優(yōu)化得到閉環(huán)系統(tǒng)加權(quán)函數(shù)參數(shù),分析了H?混合靈敏度控制器的魯棒穩(wěn)定性;進(jìn)一步設(shè)計(jì)了?綜合控制器,發(fā)現(xiàn)在相同的結(jié)構(gòu)不確定下,?綜合控制器有效的降低了控制器保守性,確保了系統(tǒng)的魯棒穩(wěn)定性及魯棒性能;最后就三種控制器的控制效果進(jìn)行了對(duì)比分析,綜合考慮選取?綜合控制器;針對(duì)控制器階數(shù)過(guò)高,用Hankle范數(shù)近似法對(duì)控制器進(jìn)行了降階。本文實(shí)現(xiàn)了大型空間索網(wǎng)結(jié)構(gòu)的預(yù)拉力確定及有限元?jiǎng)恿W(xué)建模,優(yōu)化了作動(dòng)器/傳感器數(shù)目/配置位置,基于此得到參數(shù)優(yōu)化的加權(quán)函數(shù),進(jìn)一步設(shè)計(jì)了確保閉環(huán)系統(tǒng)魯棒穩(wěn)定性及魯棒性能的主動(dòng)控制器。
[Abstract]:Large space cable-net structures are widely used in the fields of signal transmission, earth observation and deep space exploration because of their small folding volume, light mass and large caliber. Because of the large flexibility, low stiffness and low damping, once the spatial disturbance will affect the accuracy of orbit operation, it is very important to carry out effective active vibration control. Firstly, the force density method is used to find the shape of the triaxial paraboloid cable network with given geometric shape, and the pretension force of the cable net with uniform distribution is determined based on the reset balance method. Based on the stress hardening effect of the pretension cable and the equivalent "piezoelectric stacked spring" mechanical model of the piezoelectric actuator, the coupled dynamic equations of the piezoelectric intelligent cable are established by using the finite element method. Then, the optimal configuration of piezoelectric intelligent cables with actuators / sensors is studied. The structural dynamics equation in the form of state space is established in the reduced order modal coordinates, and the energy autocorrelation matrix of modal control force is obtained, and the number of actuators / sensors in the same position configuration is optimized according to the rank of the matrix. According to the composite optimization criterion of minimum total energy storage integral and maximum energy of sensor received signal, the position of actuator / sensor global optimal configuration is obtained by genetic algorithm based on dictionary-ordered array and combination coding. Then, the LQG controller is designed based on the state space description of cable network dynamics equation. The generalized controlled object of cable net structure with stiffness uncertainty is established, and the weighted function parameters of closed loop system are obtained by genetic algorithm of floating point coding, and the parameters of the weighted function of the closed-loop system are analyzed. Robust Stability of mixed sensitivity Controller; further designed? Integrated controller, found under the same structure uncertainty,? The integrated controller effectively reduces the conservatism of the controller and ensures the robust stability and robustness of the system. Finally, the control effects of the three controllers are compared and analyzed, and the selection of the controller is considered synthetically. For the controller order is too high, the Hankle norm approximation method is used to reduce the order of the controller. In this paper, the pretension force determination and finite element dynamic modeling of large space cable-net structures are realized, and the actuator / sensor number / configuration position is optimized. Based on this, the weighting function of parameter optimization is obtained. Furthermore, an active controller is designed to ensure the robust stability and robustness of the closed loop system.
【學(xué)位授予單位】：南京航空航天大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類(lèi)號(hào)】：V414;TB535
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本文編號(hào)：2309170