考虑控制回路变时滞的含舵面间隙非线性机翼颤振主动抑制方法研究

Active control technology can suppress the wing flutter by controlling of the control surface deflection to change the airflow distribution of the wing. The time delays are induced by the controlled loop, and have notable influences on the flutter characteristics of closed-loop aeroelastic system. As a result, it’s necessary to study on the aeroelastic system flutter active control with time delay effect. In this field, the researches have commonly concentrated on the time delay effects on two-dimensional or three-dimensional linear aeroelastic system flutter performance in subsonic or supersonic region, where the time delay is considered as a constant and only exists in one control channel. The proposal focuses on the time-varying delays in more than one channel effects on the flutter of the three-dimensional structure with free-play control surface in transonic region. In the research, the reduced-order modeling method is developed to model the low order aeroelastic model for the time-domain coupled model of CFD with the three-dimensional structure with free play. In order to compensate the time-varying delay influence, the “time stamped” marks are used in the signals transmitting in the control loop and the compensation controller is designed with receding horizon optimization. In addition, the time delay effects on the closed-loop aeroelastic system flutter boundary are analyzed while no time delay, constant time delay and time-varying delay are considered respectively, and the influences of the time-delay on active control effectiveness are analyzed. The research achievements can provide theoretical and technology support for the application of aeroelastic active control technology to the aircraft structure design.

主动控制技术通过控制机翼操纵面偏转，改变其表面气流分布，实现机翼颤振抑制。引入控制回路会带来信号时滞，对闭环气动弹性系统的颤振特性带来显著影响。因此，有必要开展考虑时滞因素的气动弹性颤振主动控制问题研究。针对当前该领域的研究主要集中在亚、超声速下，单通道存在常时滞的二维或线性三维结构颤振抑制的问题，本申请考虑闭环控制回路双通道都可能存在变时滞的情况，发展CFD与含间隙非线性CSD时域耦合模型降阶方法，建立可用于主动控制的低阶气动弹性模型，以此为被控对象，通过将“时间戳”标志附加于控制回路间传输的实时数据中，发展具有变时滞补偿功能的滚动优化预测控制算法，实现跨声速机翼颤振主动抑制；通过比较无时滞、常时滞和变时滞对闭环气动弹性系统颤振边界的影响，明晰时滞因素对主动控制技术颤振抑制效果的影响规律。研究成果为气动弹性主动控制技术更好地应用于飞行器结构设计提供理论参考和技术支撑。

主动控制技术是通过在机翼上布置多个控制面，采用控制器主动驱动其联合偏转，从而改变机翼控制气流的能力。调节结构气动弹性效应的颤振主动抑制技术成为当今国际上普通采用的颤振解决方案。控制系统的引入，会带来时滞，飞行器的飞行速度一般很高，在非常短的时间间隔里，系统的状态也会出现很大不同，即使非常小的时滞量也可能引起控制效率的降低，甚至导致被控系统失稳。现有考虑时滞的研究，通常针对低，亚声速下，假设时滞大小已知，且仅存在控制回路单通道的情况，对于飞行器通常巡航的跨声速流域，反馈通道或前向通道均可能存在不确定时滞，对在控制系统中必然存在的控制面间隙非线性的跨声速时滞气动弹性系统颤振主动抑制的研究目前尚未见有开展。对该类问题进行颤振主动控制的研究是十分必要的。.本项目开展了非线性气动力和包含舵面间隙非线性结构耦合的气动弹性低阶模型建模方法，采用基于CFD的气动力降阶模型耦合间隙非线性结构构建气动弹性模型，利用自适应时间步长以准确捕捉结构间隙切换点；研究了气动弹性系统主动控制回路中存在的变时滞参数在线辨识方法，提出了在数据传输过程中添加时间戳标志信息的方法，当控制器或者执行器接收到数据时，与当前时刻进行比较从而实现时滞的在线辨识；针对前向和反馈通道存在时变时滞，对跨声速含间隙非线性的机翼颤振主动控制方法进行了研究，提出了具有时滞补偿功能的控制器和观测器，该控制算法不受时滞大小的影响，能够有效地处理控制系统中的时滞，实现颤振的主动抑制；分析了时滞对考虑舵面间隙非线性的跨声速机翼颤振主动控制效果的影响，相比较而言，其中反馈通道时滞大小对控制系统稳定性影响更大，这主要是对于不可测的状态所构造的状态观测器，其对系统实际状态的跟踪需要一定的响应时间所致。