利用正交位移测量系统进行六自由度并联机构参数标定

为了简化六自由度并联机构的参数标定过程,提高标定效率,降低标定成本,提出了基于正交位移测量系统的位姿测量装置及方法。首先,研究了该装置的位姿解算方法,利用空间解析几何的方法,求解其运动学正解与逆解。其次,利用微小位移合成法,建立了并联机构及正交位移测量系统组合体的误差模型。然后,基于误差模型,构建了组合体参数误差辨识的最优化问题数学模型,其中,传感器示值的平方和最小为目标函数,组合体的结构参数误差为设计变量。最后,利用正交位移测量系统对六自由度并联机构位姿进行测量,利用OASIS奥希思软件直接搜索出参数误差最优解,将其补偿到并联机构控制系统中,完成并联机构的参数标定。标定前后位姿误差对比表明:最大位置误差降低了58%~96%,最大姿态误差降低了92%~97%。利用正交位移测量系统进行并联机构参数标定,不仅可有效提升并联机构的定位精度,还可有效简化标定工作,提升标定效率,降低标定成本。

Parameter calibration of 6-dof parallel mechanism using orthogonal displacement measurement system

In order to simplify the parameter calibration process of 6-DOF parallel mechanism,improve the calibration efficiency and reduce the calibration,a novel device and method of pose measurement based on orthogonal displacement measurement system is described.First,the pose calculation method of the device is studied,and the forward and reverse kinematic solution is solved by using the method of spatial analytic geometry.Secondary,the error model of the combination of parallel mechanism and orthogonal displacement measurement system is established by using the method of micro displacement synthesis.Then,based on the error model,the model of optimal problem of parameter identification is constructed.The minimum square sum of the sensor indication error is the objective function,and the parameter error of the combination is the variables.Finally,the pose of the parallel mechanism are measured by orthogonal displacement measurement system,and the optimal solution of the parameter error is found by OASIS,and model parameter in the control system is compensated.the calibration of parallel mechanism is completed.The comparison of the pose error before and after calibration show that:the maximum position error is reduced by 58%-96%,the maximum attitude error is reduced by 92%-97%.Using the orthogonal displacement measurement system to calibration the parameters of the parallel mechanism can not only improve the position accuracy of the parallel mechanism,but also simplify the calibration work,improve the calibration efficiency and reduce the cost.