Design of Pneumatic Control System for Pipeline Inner Wall Adsorbing Soft Robot

Complex pipelines exist in a variety of industrial equipment, such as aircraft engine. The traditional examining and repairing method using borescope possibly brings additional damage of inner wall, even has the limitation in length and turns. In order to solve the problems above, a soft robot which can absorb and move freely on the inner wall of pipeline is designed, and its key technology ‘pneumatic control system’ is introduced in this paper. Firstly, according to the real-time attitude sensor information of the robot, the algorithm for estimating the required negative pressure value (NPV) is studied; Secondly, by adjusting the flow of the air pump and using the flow difference between the air pump and the vacuum pump, the realization method of negative pressure (NP) is studied; Thirdly, the real-time NPV is measured by the air pressure sensor and compared with the estimated NPV to form a closed loop control; Finally, the feasibility of the pneumatic control system is verified through simulation experiments, the result shows that this control system can successfully support the robot's absorbing and moving functions. Overall, this paper provides an accurate pneumatic control strategy for the inner wall detecting robot and also has a wide application of other air pressure control situations.