给出了两种含压电作动杆的自适应桁架抛物面天线的形状最优控制方法。分别以天线表面点相对原设计抛物面和最佳吻合抛物面(BFP)的光程差为精度指标,建立了同时考虑精度和能耗的综合控制目标。控制考虑杆件轴力与作动电压限制,以作动电压为被控量。利用桁架力学量及天线精度与作动电压的关系。将控制问题精确表达为显式数学规划问题。理论分析和仿真结果均说明基于BFP的控制方法在天线精度和能量消耗方面的优越性,最后通过仿真算例讨论了结构受载形式和电压限设定对天线形状控制能力的影响。
Original paraboloid control method and best-fit paraboloid (BFP) control method for parabolic antenna with adaptive truss structure are given and compared. The truss structure contains piezoelectric bars as active elements. Both of the two methods belong to optimum control method. The control models take precision and energy consumption as comprehensive objective functions, limitations of strengths and voltages as constrained conditions, and active voltages as controlled variables. Based on expressions of structure mechanical characters and antenna precisions in active voltage, the control models are transformed into accurate and explicit programming problems, which are easy and efficient for computation. The main difference of original paraboloid and BFP control methods is that they respectively choose optical path differences, which are relative to original designed paraboloid and BFP, as precision indexes. The superiority of BFP control method in controlled antenna precision and energy consumption is demonstrated both by analysis and emulation. Finally, effect of different load cases and voltage limitations on shape control ability of an adaptive antenna is discussed.