捕获轨迹系统并联机构地面标定方法

捕获轨迹系统（CTS）是一种先进的预测外挂物投放轨迹的试验系统，普遍采用六自由度（6-DoF）串联机构作为其运动机构，串联机构因惯性力大和关节累积误差大使其定位精准度不足。相比串联机构，并联机构具有惯性力小和关节误差不累积等优点。采用6-PTRT并联机构作为CTS试验系统的六自由度运动机构，在空间受限的风洞环境中对CTS并联机构进行地面标定：提出动平台位姿的测量和计算方法，建立包含直线驱动平台安装夹角修正的标定模型，并基于非线性最小二乘法辨识结构参数。辨识后CTS并联机构的位移定位准度优于0.1 mm，姿态定位准度优于0.05°，最后以CTS并联机构和常规攻角机构进行8#标模的对比风洞试验。风洞试验结果表明，CTS并联机构的风载定位准度满足测力试验精准度要求。

Ground calibration method of captive trajectory system parallel mechanism

Captive Trajectory System (CTS) is an advanced test system for predicting the release trajectory of the external storages, which commonly uses the six-degree-of-freedom (6-DOF) series mechanism as the motion mechanism. As the large inertia force and the accumulated joint error, the positioning precision of the series mechanism is not enough. Compared with the series mechanism, the parallel mechanism has the advantages of small inertia force and non-accumulation of joint errors. In this paper, 6-PTRT parallel mechanism is employed as the 6-DOF motion mechanism for the CTS. The ground calibration method of the CTS parallel mechanism is studied in the space-constrained wind tunnel environment:the method of measuring and calculating the position and posture of the moving platform is presented, the calibration model which included the clamped angel repairman of the linear drive platform is established, the structural parameters are identified base on the method of nonlinear least squares. After identification, the position accuracy of the CTS parallel mechanism is better than 0.1 mm and the posture accuracy is better than 0.05°. Finally the CTS parallel mechanism and the regular attack angle mechanism are compared in the wind tunnel test. The wind tunnel test results show that the position and posture accuracy of the CTS mechanism under wind-load meets the requirements of the force wind tunnel test.