Abstract: In order to solve the danger problem of working at height，a small self-adaptive flip climbing robot is designed and implemented，which consists of five links and four joints． The position of the key links are obtained by acceleration sensor． A control algorithm of the flip robot is proposed，and the PID ( Proportional-Integral-Derivative) closed-loop control algorithm is used to improve the climbing accuracy of the flip robot． The performance results of the robot are as follows: the average time of single step is 29 s，the maximum relative error of step distance is 4． 5%，the average relative error is 2． 1%，and the maximum load is 3． 79 kg． Therefore，the robot can realize stable and continuous climbing．

Key words: climbing robot, proportional-integral-derivative ( PID) algorithm, inverse kinematics model