一种少自由度飞行模拟运动平台误差分析

Error Analysis of a Flight Simulator Platform with Less DOF

将一种少自由度并联机构3-PRS用作飞行模拟运动平台,为使该平台运动精度满足系统要求,对其进行误差分离与灵敏度分析。通过研究平台运动学逆解模型获得驱动雅克比矩阵与约束雅克比矩阵,采用空间闭环误差矢量链的误差建模方法,对运动平台进行误差建模,获得各个几何误差源与终端输出位姿误差之间的映射函数,在所建立的全误差源模型的基础上,利用解析法去除冗余误差源后,借助驱动雅克比矩阵与约束雅克比矩阵将影响该平台末端可补偿位姿误差的误差源和不可补偿位姿误差的误差源分离。最后,在整个运动空间内,借助灵敏度分析,获得影响末端不可补偿位姿误差源的全局灵敏度影响系数。根据灵敏度影响系数可指导前期设计阶段各零部件公差等级的选择以及装配阶段装配公差的确定,研究结果对同类少自由度并联机构具有指导意义。

It introduces the 3-PRS parallel mechanism as a flight simulator platform.In order to increase the accuracy of simulation,error separation and sensitivity analysis are discussed.By deducing the inverse kinematics model,the actuated and constrainted Jacobian matrix are derived.Geometric error model that includes all parameters of geometric errors of the platform is established by closed-loop vector method.After that,the mapping function between the pose error for terminal output and the geometric error sources was obtained.On the basis of the error model,redundant error sources are removed by analytical method.According to error separation,geometric error sources that influence the uncompensable pose accuracy are isolated.Lastly,in the entire work space,the influence about the geometric error sources on the platform’s pose accuracy is revealed by making use of sensitivity analysis method.According to the influence coefficient of sensitivity,it can guide the choice of the tolerance level of the parts in the early design stage and the determination of the assembly tolerances in the assembly stage.The results of this research is of universal significance to the design of parallel mechanism with less DOF.