As a key infrastructure in national industry, the inspection requirements for oil and gas pipelines are becoming increasingly complex and sophisticated. Aiming at the limitations of existing pipeline robots in complex pipe networks—such as poor adaptability to variable diameters, low pass rates in non-coplanar continuous bends, and overly complex control systems—this article proposes and develops an adaptive V-shaped pipeline robot based on active wall-pressure regulation. First, the system adopts a novel architecture featuring a symmetrical dual-support cabin layout driven by a central joint. An active tension adjustment method based on the locked-rotor characteristics of the joint motor is proposed, ensuring reliable wall adhesion and adaptive stable walking within 110~160 mm variable-diameter pipes. Second, to address the trafficability in spatial non-coplanar continuous bends, a passive bending mechanism based on joint admittance control is proposed innovatively. This mechanism discards the traditional closed-loop control mode that relies on multi-dimensional force sensors and complex trajectory planning. By establishing an admittance dynamics model based on joint physical interaction, the robot independently achieves smooth bending through a "collision-deflection-pathfinding-recovery" sequence, effectively overcoming the impact of self-weight during vertical climbing and turning. Finally, a physical pipe network scenario—including horizontal, vertical, 90° continuous bends, variable-diameter sections, and multi-obstacle environments—was constructed for experimental verification. The results demonstrate that the robot can smoothly navigate non-coplanar bends under various initial attitudes, maintaining sufficient traction and obstacle-surmounting capability. This verifies the effectiveness of the proposed mechanism and the robust environmental adaptability of the system.