模块化六自由度机器人运动学标定与实验研究

Kinematic calibration and experimental study of a modular six-DOF robot

针对自主研发的模块化六自由度轻载搬运机器人,使用激光跟踪仪并采用直接标定法进行了运动学标定与实验研究。采用D-H法构建了机器人连杆坐标系和机器人运动学模型,并运用微分变换的方法建立误差模型。通过激光跟踪仪测量机器人末端位置,将其与运动学模型求解得到的机器人末端位置进行比较,验证了误差模型的正确性。然后将误差模型计算得到的机器人连杆参数误差在机器人控制系统软件中进行修正。最后利用激光跟踪仪测量机器人的关节转角间隙误差,将误差值转换成脉冲数并在软件中进行补偿。机器人运动学标定实验表明,使用激光跟踪仪进行连杆参数误差补偿和关节转角间隙误差补偿可以明显的减小绝对定位误差,绝对定位误差降低了69.6%,定位精度有了明显的提高。

A laser tracker and a direct calibration method were applied to the kinematic calibration and experimental study of an indepently developed light load robot with six DOF （ degree of freedom） .The D-H method was used to construct the robot’ s coordinate system of connecting rod and kinematic model, and its error model was established by using the method of differential transformation.The end position of the robot was measured by the laser tracker, and the measured value was compared to that obtained through the kinematic model to verify the correctness of the error model.Then, the error of the robot’ s connecting rod parameter error calculated by the error model was modi-fied in the robot’ s control system software.Finally, the robot’ s joint angle gap error was measured by the laser tracker, and the error value was transformed into the pulse number for compensation by software.The experiment on robot kinematic calibration shows that the absolute positioning error can be significantly reduced through the compensation of connecting rod parameter and the error compensation of the rotation angle of joint clearance with the laser tracker.The absolute positioning error was reduced by 69.6%and the location accuracy was significantly improved.