Aiming at the difficulty of non-destructive testing（NDT）of the aluminum conductor composite core（ACCC）wires running in the grid

a power transmission line inspection robot based on digital radiography is designed.In order to meet the requirements of security and reliability in special NDT tasks

a redundant control system is designed

and the controller module

communication module

and power module are designed.A parallel scheduling based auto detection system is designed

to improve the efficiency of the NDT operation.A NDT system is designed for ACCC wires

and an image clarity evaluation method is used to reduce the effect of movement unsharpness and to improve imaging quality.Physical experiments prove that the proposed robot system is stable and has high efficient of detection and meets the requirements of practical application