超空泡航行器稳定性分析及其非线性切换控制

Stability analysis and nonlinear switching controller design for supercavitating vehicles

中文关键词  超空化航行器  滑行力  极点约束  切换控制

英文关键词  supercavitating vehicles  planing force  poles restriction  switching control

中文摘要

      超空泡航行器在航行过程中绝大部分被超空泡包裹, 必然面临着航行器与空泡剧烈非线性作用力带来的稳定控制困难. 针对超空泡航行器的控制问题, 本文以Dzielski提出的航行器模型为研究对象, 首先通过一系列系统变换使其成为线性系统环节和非线性环节反馈连接的形式, 运用圆判据定理利用系统Nyquist曲线给出了系统绝对稳定的充分条件；而后结合工程实际, 分析了极点约束对系统性能的影响, 为进一步改善系统性能, 提出了加入非 线性激励来削弱系统固有非线性特性的切换控制策略. 仿真结果表明, 超空化航行器在极点约束情况下完全可以通过非线性切换控制达到系统对所有非线性特性的绝对稳定, 且对于滑行力存在不确定性的情况切换控制依然有效.

英文摘要

      In the cruise phase, the supercavitating vehicle is enveloped almost completely by a cavity; it is confronted by the stable control problems caused by the nonlinear planing forces produced by reactions between the vehicle and cavity. To deal with the problems, a supercavitating vehicle model proposed by Dzielski is employed as our research object. This model is converted into the Lure’s form by a series of system transforms. The sufficient condition for the global stability of the system is obtained by using the Nyquist diagram based on the circle criterion. The influence on the system performance produced by the pole-placement is analyzed. To improve the system performance, a switching control strategy is proposed, in which a nonlinear excitation is introduced to weaken the inherent nonlinearity. The simulation results show that the supercavitating vehicle system with pole-placement can be stabilized globally by our nonlinear switching control strategy; and these results hold even when uncertainties in the modeling of planing force are existing.