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A new scheme of adaptive control is proposed for a class of linear time-invariant( LTI) dynamical systems,especially in aerospace,with matched parametric uncertainties and input constraints. Based on a typical and conventional direct model reference adaptive control scheme,various modifications have been employed to achieve the goal. "C omposite model reference adaptive control"of higher performance is seam-lessly combined with "positive μ-mod",which consequently results in a smooth tracking trajectory despite of the input constraints. In addition,bounded-gain forgetting is utilized to facilitate faster convergence of parameter estimates. The stability of the closed-loop systemcan be guaranteed by using Lyapunov theory.The merits and effectiveness of the proposed method are illustrated by a numerical example of the longitudinal dynamical systems of a fixed-wing airplane. 相似文献
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基于自抗扰控制技术的实时飞行仿真研究(英文) 总被引:1,自引:0,他引:1
针对四旋翼无人机欠驱动、强耦合的非线性动力学特性,文中研究设计了基于自抗扰控制技术的闭环飞行控制系统。自抗扰控制技术中,扩张观测器与基于误差的非线性反馈控制是其重要的两个部分。扩张状态观测器估计外部干扰和模型不确定性,以实现干扰和模型不确定性的动态补偿;此外,采用基于误差的非线性反馈可以改善控制效果。为保证飞行任务中精确的航迹跟踪,文中分析设计了一种实用的制导策略,并构建实时可视化飞行仿真系统以实现对所设计的制导策略和自抗扰飞行控制系统更为严格有效的验证。仿真结果表明所研究设计的制导策略和闭环飞行控制系统具有良好的制导和控制性能。 相似文献
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Research on the attitude regulation of 3-DOF hover system 总被引:1,自引:0,他引:1
Quadrotor helicopter is emerging as a popular platform for unmanned aerial vehicle re- search, due to its simplicity of structure and maintenance as well as the capability of hovering and vertical take-off and landing. The attitude controller is an important feature of quadrotor helicopter since it allows the vehicle to keep balance and perform the desired maneuver. In this paper, nonlin- ear control strategies including active disturbance rejection control (ADRC), sliding mode control (SMC) and backstepping method are studied and implemented to stabilize the attitude of a 3-DOF hover system. ADRC is an error-driven control law, with extended state observer (ESO) estimating the unmodeled inner dynamics and external disturbance to dynamically compensate their impacts. Meanwhile; both backstepping technique and SMC are developed based on the mathematical model, whose stability is ensured by Lyapunov global stability theorem. Furthermore, the performance of each control algorithm is evaluated by experiments. The results validate effectiveness of the strate- gies for attitude regulation. Finally, the respective characteristics of the three controllers are high- lighted by-comparison, and conclusions are drawn on the basis of the theoretical and experimental a- nalysis. 相似文献
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以典型缝合式复合材料夹芯板为研究对象,建立其动力学方程,开展该夹芯板的动态特性研究,探讨了缝合密度和缝合线角度对夹芯板模态特性、频响特性以及随机动响应的影响。研究结果表明:缝合线的存在增强了面板与夹芯层间的整体性,提高了夹芯板的固有频率,并约束了夹芯板的局部模态,降低了结构的模态密度,整体上降低了夹芯板在噪声载荷作用下的加速度及响应能量,但对结构应力响应影响较小;缝合线主要降低了上面板的动响应,对主承力板的动响应影响相对较小;随着缝合密度的增大,缝合式夹芯板的整体性逐渐提高,加速度及响应能量逐渐降低并收敛;缝合线角度则对结构总体动态特性影响不明显。 相似文献