一种基于指数积的移动机械臂联合标定方法

提出一种基于指数积的移动机械臂联合标定方法,以实现移动平台和机械臂两者间位姿标定与机械臂运动学参数标定模型的统一.机械臂运动学参数标定使用最多的是基于D-H参数法,但D-H参数法无法克服相邻关节平行或接近平行时的奇异性问题,以及建模过程复杂、建模后的模型通用性差等问题.基于指数积的移动机械臂联合标定方法建模时不会因为关节轴平行而出现奇异性问题,建模过程简单.通过对整个系统的运动学方程进行微分运算,获得末端位姿误差和移动机械臂零位状态旋量误差及关节旋量误差的线性化模型.利用伴随矩阵方式建立关节旋量理论值与关节旋量实际值的关系,并通过改变伴随矩阵实现基于最小二乘法的参数辨识计算过程中参数更新.使用高精度激光跟踪仪作为测量工具,通过实验验证所提出方法的有效性.

A joint calibration method of mobile manipulator based on product of exponential

This paper proposes a joint calibration method for a mobile manipulator based on product of exponential, to realize the unification of the pose calibration and the kinematic parameter calibration model of the manipulator between the mobile platform and the manipulator. The most used kinematic parameter calibration of robotic arms is based on the D-H parameter method, but the D-H parameter method cannot overcome the singularity problem when the adjacent joints are parallel or nearly parallel, and the modeling process is complicated and the model after modeling is poorly generalized. Therefore, this paper proposes a product of exponential based joint calibration method for the mobile manipulator, which does not cause singularity problems due to the parallelism of joint axes and has a simple modeling process. The method obtains the linearized models of the end position error, the zero position state rotational error and joint rotational error of the mobile arm by differentiating the kinematic equations of the whole system. The method establishes the relationship between the theoretical and actual values of joint spins by means of the concomitant matrix, and realizes the parameter update during the calculation of parameter identification based on the least squares method by changing the concomitant matrix. Using a high-precision laser tracker as the measurement tool, the effectiveness of the proposed method is demonstrated through experiments.