Research on the mechanism of walking error in large-span sludge scraper

To address walking errors such as rail-biting and derailment in large-span sludge scrapers, this study establishes a kinematic theoretical model to describe the geometric motion relationship between the scraper's wheels and rails. Based on this model, the constraint conditions for rail-biting and derailment are derived, including the critical deviation angle and the permissible wheel-rail clearance. To better match real engineering conditions, a Δ correction factor is introduced to account for chamfers, transition arcs, and structural deviations of the wheel-rail system.An experimental platform was built to validate the model, using high-precision laser ranging sensors and rainfall sensors to monitor wheel-rail distance variations under both normal and critical states. The results show that the Δ correction reduces the prediction error of the critical deviation angle by about 91%, confirming the model's reliability. This study clarifies the geometric mechanism of scraper walking errors and provides a theoretical basis for the synchronous control and safety optimization of large-span sludge scrapers.