In this study, we developed a fuzzy-logic-controlled PGO (Power Gait Othosis) that controls the flexion and extension of each PGO joint using bio-signals and an FSR sensor. The PGO driving system works to couple the right and left sides of the orthosis by specially-designed hip joints and pelvic section. This driving system consists of the orthosis, sensor, and control system. An air supply system for muscle action is composed of an air compressor, 2-way solenoid valve (MAC, USA), accumulator and pressure sensor. The role of this system is to provide constant “air muscle” with compressed air at the hip joint. With the output signal of the EMG and foot sensors, air muscles assist the flexion of the hip joint during the PGO gait.