一种基于指数积公式的空间机械臂自标定方法

To overcome the influence of launching process and on-orbit extreme temperature environment on the tool pose accuracy of a space manipulator, a space manipulator kinematics on-orbit self-calibration method based on product of exponentials (POE) formula was presented. Using the binocular space camera fixed on the end-effector and a checkerboard calibration plate, the actual tool pose of the space manipulator was measured. According to the adjoint transformation between the theoretical value and actual value of joint twists, the actual kinematics model of the space manipulator was established. The linearized kinematics error model of the space manipulator was obtained by differentiating the kinematics model. A least-squares kinematics calibration model for the space manipulator was given. Kinematics self-calibration simulation of a seven-degree-of-freedom space manipulator was carried out. The simulation results show that the kinematics calibration process can converge to a stable value quickly and there is a significant improvement on the tool pose accuracy of the space manipulator after kinematics calibration.