Mobile Robotic Coordinate Measuring System for In Situ Geometric Inspection of Large Cast Valves

Large cast industrial valves pose challenges for dimensional and geometric inspection due to their size, weight, and complex shapes. Conventional coordinate measuring machines (CMMs) are restricted by fixed work volumes, while manual tools are labor-intensive and unable to evaluate certain form tolerances. This paper presents the development and experimental validation of a Mobile Robotic Coordinate Measuring System (MRCMS) for in situ inspection of industrial valves. The system integrates a two-degree-of-freedom touch probe mounted on an omnidirectional mobile platform, with a unified kinematic model to transform local measurements into a global coordinate frame. Dedicated algorithms were implemented to extract critical geometric features, including circularity, concentricity, and flatness. Experimental evaluation was performed on 10 different cast industrial valves, and measurements were compared with conventional inspection methods. Bland–Altman plots were analyzed to evaluate agreement, demonstrating that the MRCMS provides reliable geometric insights while reducing inspection effort. The results highlight the potential of the system for efficient, in situ inspection of large and complex components.