In order to solve the precision problem of robot in productive application

a kinematic calibration based on vision measurement method is proposed to improve the precision of endposition of robots.Kinematics model is established according to structural characteristics and geometric parameters of this Tripod robot.With analyzing on geometric error sources of the mechanism

the error mapping model between the end-position of the mobile platform and the geometric error sources of the robot is obtained by analytical method

and the zero point error mapping model is further simplified.A measurement method using vision as error measurement is proposed

and the zero point error is identified with the least squares structure identification model.The calibration experiment is carried out on the robot through the proposed experimental steps with measure-point layout.And the error is compensated by the compensation model of the modified input

and the position precision before and after calibration is verified by the laser tracker.The precision of the end-position is verified to be significantly improved

that shows the feasibility and effectiveness of the visual measurement method on kinematic calibration

and the simplicity and convenience of the measurement method.