Multilevel Evaluation of Reactive Velocity Control for Moving Targets in Conveyor-Based Construction and Demolition Waste Sorting

Construction and demolition waste (CDW) sorting on conveyors requires robots to intercept irregular targets while maintaining alignment under motion constraints. However, CDW research has emphasised perception, grasp generation, and planned trajectory execution, with limited evidence linking reactive velocity control to sorting productivity. This study formulates a control-oriented evaluation framework to characterise target tracking and examine whether conveyor motion compensation improves acquisition and recovery as conveyor speed increases. A Unity–ROS 2 digital twin using data-derived CDW objects and a UR10e manipulator compared feedback (FB) and combined feedforward and feedback (FF+FB) velocity control across three independently seeded 600 s simulation runs per operating condition. FF+FB maintained progressive tracking convergence across conveyor speeds of 0.4–0.6 m/s. At 0.5 m/s, FF+FB increased the mean pick completion rate from 40.8% to 78.1% and recovery throughput from 4.43 to 6.77 objects/min relative to FB. At 0.6 m/s, pick completion increased from 23.0% to 91.7%, while throughput increased from 2.37 to 6.63 objects/min. Despite lower Approach completion rates, FF+FB consistently achieved stronger downstream acquisition and recovery performance. Comparable cycle durations at 0.5 m/s showed that productivity gains arose from successful acquisition and transfer rather than faster cycles. Repeated seed evaluation demonstrated substantial performance differences between the controllers, although the limited number of independent runs constrains formal statistical inference. By linking motion demand and stage outcomes to throughput, the framework shows how reactive moving target control influences CDW sorting productivity across conveyor speeds.