Development and performance evaluation of a photovoltaic-powered robotic system for cleaning multi-span greenhouse roofs

Greenhouse roof surfaces accumulate dust and residues that reduce light transmittance and can compromise crop performance, while routine manual cleaning is labor-intensive, water-intensive, and exposes workers to safety risks during work at height. To address these challenges, a PV-powered mobile robot was designed, fabricated, and experimentally validated as a sustainable roof-cleaning solution for multi-span greenhouse structures. The robot integrates a PV power supply with a lightweight drive system and a mechanical cleaning module optimized for smooth greenhouse roof materials. Experimental evaluation was conducted using robot speed 0.26 m s⁻¹, and four soiling levels defined by light transmittance: clean (≥86%), slight (80–85%), moderate (75–79%), and intense (<74%). The system was experimentally evaluated for cleaning performance, light transmittance before and after cleaning, and resource use, including water and energy consumption. In all cases, the cleaning robot improved light transmittance to 88-90%. Cleaning performance tests showed rapid optical recovery with low resource demand: at 0.26 m s⁻¹, light transmittance increased from 77.7% to 88.6% (ΔT = 10.9 percentage points), while the robot achieved a cleaning capacity of 1.04 m² s⁻¹, solution consumption of 0.20 L.m⁻², and an energy consumption of 0.23 Wh.m⁻². The proposed system provides a practical pathway to safer, sustainable, and more resource-efficient cleaning of greenhouse roofs.