Abstract: A single joint error model of service robot has been set up independently,which is based on MDH (Modified Denavit-Hartenberg) model,the distance between two points in space to measure the error absolute positioning accuracy of the robot,and combined with the establishment of a single joint error model,the kinematic calibration model based on distance error was deduced.The kinematics calibration model not only can simplify the measurement process,but also avoids coordinate conversion between measurement system and robot system,and improves measurement accuracy.Finally,combined with the decoupling of the service robot structure characteristics to select the scheme of the experimental measurement points,and use three coordinates measuring instrument measuring the terminal position.Experimental results show that the precision of the robot has been increased by more than 60%.

Key words: service robot, Modified Denavit-Hartenberg (MDH) model, distance error, kinematic calibration