共查询到18条相似文献,搜索用时 140 毫秒
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空降空投技术是空军装备发展的基础,为使远距离投放的空降装备平稳着陆,需获取货台模块的姿态数据,以实时调整降落姿态避免着陆侧翻事故。本文设计开发了一种基于视觉的方法来解算空投货台姿态,以准确地估计空投货台在空投降落过程中的姿态。空投系统的降落距离分为远地160m和近地20m两个阶段。设计了不同尺度的标志作为不同降落阶段的视觉参考,有效地提高了空投货台的自主降落高度。当空投货台初始降落高度为160m时,利用合作目标的固有几何性质识别环境中的整体合作目标;当到达近地面20m时,利用Hu不变矩作为地面辅助特征筛选出中心合作目标,最后利用单应性对空投货台的运动进行估计。该算法有效地提高了空投货台姿态解算技术的准确性、实时性和鲁棒性,也满足了空投货台实时姿态精确计算的要求。试验结果表明了基于视觉的空投货台姿态解算技术的意义和可行性,具有较好的应用前景。 相似文献
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为了明确牵引比参数对空投货物运动状态准确性的影响,采用牵引比参数的条件下,将牵引力与实际牵引伞提供的牵引力进行对比,并建立货物牵引空投运动轨迹模型.通过实例计算出两种情况下货物运动状态,根据计算数据拟合出货物运动状态随时间的变化对比曲线,分析了牵引比参数对货物牵引空投运动状态准确性影响程度,为精确空投中确定货物运动准确状态提供了帮助. 相似文献
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空投系统出现物伞空中分离现象,而空投件离机姿态受飞机尾流影响可能是造成安全隐患的重要原因。运用计算流体动力学软件对某装备的空投过程进行了计算,模拟了装备在尾流中的动态运动过程,并对结果作了分析,得到其在气动力、降落伞拉力、重力作用下的姿态变化。分析了空投装备各个方向的受力以及俯仰力矩变化规律,以可视化的方式反映了装备在尾流中的运动过程,说明了飞机尾流对装备的运动有比较大的影响。计算结果为装备投放数字化仿真平台的开发提供了数据准备,同时对航天系统中大型投物的投放如运载火箭空中分离、大型回收物与载机分离等的研究也有一定参考意义。 相似文献
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运输机超低空重装空投纵向反步滑模控制研究 总被引:1,自引:0,他引:1
分析了超低空重装空投的空投流程,针对超低空重装空投飞行高度低、空投对象质量大的特点,把空投对象的位置和移动速度作为状态变量对货物移动时飞机运动的非线性方程进行了研究,该方程能准确描述出牵引伞的拉力、空投对象在货舱内的实时位置和移动速度对飞机姿态和高度的影响。同时,利用反馈线性化方法对模型进行输入输出线性化,并利用反步法与滑模控制相结合的方法,设计纵向滑模自适应控制器,解决了纵向不可参数化的不匹配不确定控制问题,实现了飞机在超低空重装空投时高度的稳定,保证飞机安全地完成超低空空投任务。 相似文献
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The mathematical model of a transport aircraft would be subjected to a sudden change when heavy cargo is dropped off in airdropping, which exerts serious influences upon the safety of the aircraft. A variable structure controller is specially designed for handling the airdrop process. The nonlinear system is linearized by input-output feedback linearization using differential geometry theories. On this basis, an inner loop system for velocity and attitude tracking control is designed by using the exponentially approaching rule of the variable structure theory. The whole flight control system is integrated with the outer loop flight altitude control. Digital simulation evidences the applicability of the system to potentially catastrophic course in airdropping heavy cargo and provides robustness against system parameter perturbation. 相似文献
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直升机重装空投状态下的动态特性 总被引:1,自引:1,他引:0
为了研究直升机在重装空投过程中货物的运动对直升机姿态角的影响,首先建立了直升机CH-53D的动力学模型,并通过模型仿真结果和直升机飞行实验数据的对比验证了的直升机动力学模型的合理性。然后在直升机动力学模型的基础上,采用分离法建立了直升机重装空投两个阶段的动力学模型,并进行了直升机在悬停和前飞两种空投状态下的配平仿真。结果表明:相较于悬停状态空投,前飞状态空投具有更好姿态保持能力,主要表现在前飞状态下空投只会对直升机的纵向姿态角产生影响,而在悬停状态下空投对直升机的纵横向姿态角都会产生较大的影响。 相似文献
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Heavy-equipment airdrop is a highly risky procedure that has a complicated system due to the secluded and complex nature of factors' coupling. As a result, it is difficult to study the modeling and safety simulation of this system. The dynamic model of the heavy-equipment airdrop is based on the Lagrange analytical mechanics, which has all the degrees of freedom and can accurately pinpoint the real-time coordinates and attitude of the carrier with its cargo. Unfavorable conditions accounted in the factors' models, including aircraft malfunctions and adverse environments, are established from a man-machine-environment perspective. Subsequently, a virtual simulation system for the safety research of the multi-factor coupling heavy-equipment airdrop is developed through MATLAB/Simulink, C language and Flightgear software. To verify the veracity of the theory, the verification model is built based on dynamic software ADAMS. Finally, the emulation is put to the test with the input of realistic accident variables to ascertain its feasibility and validity of this method. 相似文献
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Dynamics modeling and control of a transport aircraft for ultra-low altitude airdrop 总被引:1,自引:0,他引:1
The nonlinear aircraft model with heavy cargo moving inside is derived by using the separation body method, which can describe the influence of the moving cargo on the aircraft attitude and altitude accurately. Furthermore, the nonlinear system is decoupled and linearized through the input–output feedback linearization method. On this basis, an iterative quasi-sliding mode(SM)flight controller for speed and pitch angle control is proposed. At the first-level SM, a global dynamic switching function is introduced thus eliminating the reaching phase of the sliding motion.At the second-level SM, a nonlinear function with the property of ‘‘smaller errors correspond to bigger gains and bigger errors correspond to saturated gains' ' is designed to form an integral sliding manifold, and the overcompensation of the integral term to big errors is weakened. Lyapunovbased analysis shows that the controller with strong robustness can reject both constant and time-varying model uncertainties. The performance of the proposed control strategy is verified in a maximum load airdrop mission. 相似文献
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High-fidelity cargo airdrop simulation requires the contact dynamics between an aircraft and a cargo to be modeled accurately. This paper presents a general and efficient contact-friction model for simulation of aircraft-cargo coupling dynamics during airdrops. The proposed approach has the same essence as that of the finite element node-to-segment contact formulation, which leads to a flexible, straight forward, and efficient code implementation. The formulation is developed under an arbitrary moving frame with both the aircraft and the cargo being treated as general six-degree-of-freedom rigid bodies, and thus it eliminates the restrictions of lateral symmetric assumptions in most existing methods. Moreover, the aircraft-cargo coupling algorithm is discussed in detail, and some practical implementation details are presented. The accuracy and capability of the present method are demonstrated through three numerical examples with increasing complexity and fidelity. 相似文献
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货物在货舱内移动时飞机动态特性的研究 总被引:3,自引:0,他引:3
本文根据理论力学和飞行力学的基本原理,对货物在飞机货舱内移动时飞机和货物的运动方程作了详细推导.并对牵引伞的牵引力,约束反力的确定进行了探讨.得出了一些有益的结论.并以Y—8飞机为例,对牵引伞的牵引比、空投速度、空投高度、空机和货物重量、空投货物装置位置和操纵规律等各种田素以及空投操稳特性进行了分析研究. 相似文献