To meet the requirements of automatic weld detection for large boiler drums

a wall-climbing robot that can flexibly adjust the direction is proposed. Firstly

a rotating chassis structure and a multi-joint torsionally compressed probe coupling structure are designed

which realizes the scanning action of transverse and longitudinal welds. The key parameters of Halbach permanent magnet wheel via Ansys EM are simulated and analyzed

and the appropriate parameter values is selected which can produce sufficient magnetic adsorption force. Then

the dynamic performance of the robot in the scanning process is analyzed

and the PID algorithm is designed to compensate the fluctuations in velocity and attitude angles. Finally

the wall-climbing robot is manufactured according to the designed model

and the plane scanning and the cross-weld scanning experiments of Q235 steel plane are carried out. The results show that the present wall-climbing robot can realize TOFD scanning action

and can stably cross the weld after introducing the PID algorithm

which meets the requirements of large boiler drum weld detection.