Passive attitude stabilization of ionic-wind-powered micro air vehicles

The ionic-wind-powered Micro Air Vehicles (MAVs) can achieve a higher thrust-to-weight ratio than other MAVs. However, this kind of MAV has not yet achieved controlled flight because of the unstable thrust produced by the ionic wind and the dynamic instability related to the small size. In this paper, a passive attitude stabilization method of the ionic-wind-powered MAV using air dampers is introduced. The key factors that influence the performance of the air dampers, including the layout, position, and area of the air dampers, are theoretically studied. The appropriate optimal position of the air dampers is also obtained by Monte Carlo stochastic simulations. Then the proposed passive attitude stabilization method is applied to the ionic-wind-powered MAVs of different wingspan (2 cm and 6.3 cm). Finally, the experimental results show that using the proposed method, attitude stabilization is achieved for the first time for the ionic-wind-powered MAV. Moreover, the altitude control of an ionic-wind-powered MAV with a wingspan of 6.3 cm is also demonstrated.     

Collaborative force and shape control for large composite fuselage panels assembly

This study proposed a force and shape collaborative control method that combined method of influence coefficients(MIC) and the elitist nondominated sorting genetic algorithm(NSGA-II) to reduce the shape deviation caused by manufacturing errors, gravity deformation,and fixturing errors and improve the shape accuracy of the assembled large composite fuselage panel. This study used a multi-point flexible assembly system driven by hexapod parallel robots. The proposed method simultaneously considers...     

临近空间高超声速稀薄流中梯形缝隙绕流分析

针对高超声速飞行器表面不规则缝隙的构型特征，将其简化为梯形缝隙模型；采用直接模拟蒙特卡洛(DSMC)方法对高超声速稀薄流中的缝隙绕流问题进行数值模拟；研究了不同的缝隙壁面倾角对流场结构以及壁面参数的影响，为航天器结构设计以及热防护设计提供了数值支持。结果表明：改变倾角会改变流场结构，当倾角减小时，外部流场会更深入缝隙内部，使得缝隙内流场和表面的气动参数增强，且倾角越小，影响的程度越深。同时，倾角减小也会减小缝隙内的旋涡强度，当倾角小于30°时，缝隙内的旋涡区域完全消失。     

多空间机器人协同工作空间的数值求解方法

针对未来在轨服务过程中，可能遇到单个空间机器人难以独立胜任的应用场景，需要多个空间机器人协同操作，但目前针对多空间机器人协同工作空间的研究很少。考虑到解析法计算工作空间难度很大，提出了一种基于蒙特卡洛法的一般协同工作空间数值求解方法。再进一步针对空间机器人协同的特殊性，提出了广义协同工作空间的概念，并给出了数值求解方法。仿真结果表明，基座姿态约束会引起协同工作空间的缩小，同时广义协同工作空间的范围明显大于一般协同工作空间。所得结论可以为空间机器人任务设计与规划提供参考。     

火箭发动机涡轮泵转速遥测数据实时处理方法

火箭飞行试验过程中,一般通过连续处理测量设备输出的脉冲周期计算发动机涡轮泵转速.受测控站接力跟踪及接收条件限制,遥测数据存在不连续、短时中断等现象,极易造成数据处理错误.通过研究脉冲参数在传输时的状态及状态转移,并对实时跟踪时出现的数据中断、异常值处理等情况进行分析,提出一种基于有穷自动机理论的处理模型,有效解决了测量...     

GPS接收机的自主完善性监测算法研究

完善性监测是 GPS接收机研制过程中的重要技术问题之一 ,其功能是在接收机不能用于导航服务时向用户提供告警信息。文中对基于最小二乘残差法的 GPS接收机自主完善性监测 (RAIM)算法进行分析与研究 ,并给出了检测门限的求解方法 ,最后对将该算法应用于 GPS/GL ONASS组合接收机时存在的问题进行了探讨。这一算法在某型号接收机的相关实验中取得了较好的效果。