Congratulations to Miss HO Pui Yan and Mr. LEE Hon Lam, undergraduate students of the Energy and Environmental Engineering (EEEN) Programme and the Mechanical and Automation Engineering (MAEG) Programme, respectively, under the supervision of Dr. LI Yiyang, on receiving First Prize in the Green and Sustainable Paper Award organized by Chung Chi College, CUHK!
Paper Title: Lightweight Dual-Claw Recycling Collection Vehicle for the Last 100 Metres in Residential Estates
Project Description:
Hong Kong’s waste management system operates under mounting strain. Strategic landfills — the city’s primary disposal backbone — are approaching capacity, while community recycling infrastructure struggles to bridge the gap between policy ambition and ground-level performance. Inadequate access points, the operational constraints of the GREEN@COMMUNITY network, and chronic overflow at residential collection points converge into a single, recurring failure: intended recyclables diverted back into the mixed waste stream before they ever reach a sorting facility.
This study targets failure at its source. In high-density residential estates, the last 100 metres represents a critical juncture at which collection performance systematically deteriorates. Narrow corridors, dispersed bin locations, and fixed working hours render each service stop disproportionately time-consuming, suppressing collection frequency and leaving overflow conditions unaddressed. Upstream infrastructure investment alone cannot resolve a bottleneck that is fundamentally operational and spatial in nature.
To address this mismatch, the study adopts an iterative engineering methodology across three successive prototype generations under the constraints of no infrastructure modification, fixed manpower allocation, and limited working hours. Drawing on friction mechanics and a concise work-resistance framework: Version 1 employs an omni-wheel platform with integrated storage to validate a closed-loop collection workflow; Version 2 introduces a Mecanum-wheel platform and rotating drum for improved system integration, yet remains susceptible to slip, friction uncertainty, and control burden; Version 3 enacts a paradigm shift through a lightweight two-wheel chassis and a gear-driven dual-claw mechanism — one claw interfacing with existing community bins, the other securing an external container as mobile storage — eliminating heavy onboard compartments and establishing mass reduction as the primary design lever for high-frequency, short-haul operation.
A full-scale functional prototype validates this design rationale in practice, demonstrating reliable corridor operability and repeatable bin-and-container interfacing without requiring any modification to existing estate infrastructure.
Beyond its mechanical contributions, the proposed vehicle constitutes a meaningful intervention in support of Hong Kong’s Waste Blueprint 2035. By expanding effective collection point availability, strengthening circular material capture at the residential tier, and establishing a credible trajectory for reducing operational energy demand, the study offers not merely a technical solution to an overlooked logistical bottleneck, but a scalable and replicable model for realising the national vision of “Waste Reduction · Resources Circulation · Zero Landfill” from the ground level upward.
Final version of the team’s prototype in this competition
Note: The authors continue to refine the design beyond what is presented herein; the resulting prototype was awarded the Merit Prize at the 12th Hong Kong University Student Innovation and Entrepreneurship Competition — independently affirming its technical soundness and scalable real-world potential.