Abstract
Large-span bridge structures require rigorous and continuous structural health monitoring (SHM) to ensure operational safety and timely maintenance. Traditional inspection approaches, including manual rope-access operations and unmanned aerial vehicles, often face severe limitations regarding safety, operational duration, dynamic stability, and payload capacity. This paper presents the kinematic synthesis, dynamic modeling, and experimental evaluation of a reconfigurable 8-cable, 6-degree-of-freedom cable-driven parallel robot (CDPR) customized for automated SHM on large-span bridge trusses. Closed-form inverse kinematics are derived, incorporating sagging effects via catenary cable equations, while the system dynamics are formulated using the Lagrange-D'Alembert principle to account for end-effector inertial forces, cable elasticity, and aerodynamic cross-wind disturbances. A real-time tension distribution algorithm based on convex quadratic programming ensures continuous positive cable tensions within safe operating bounds during trajectory execution. Simulations and physical experiments on a 1:10 scaled bridge truss testbed demonstrate that the proposed system achieves a spatial workspace coverage exceeding 92% of the inspection envelope with a maximum dynamic positioning error under 7.5 mm in wind gusts up to 15 m/s. The system enables seamless deployment of non-destructive evaluation payloads, offering a robust, scalable solution for automated civil infrastructure maintenance.
