CPP-DIP: Multi-objective Coverage Path Planning for MAVs in Dispersed and Irregular Plantations

TL;DR

This paper introduces CPP-DIP, a multi-objective coverage path planning framework for MAVs in irregular plantations, optimizing flight paths using aerial imagery, density-aware strategies, and multiple TSP solvers to enhance efficiency and reduce redundancy.

Contribution

The paper presents a novel multi-objective CPP framework that does not rely on GPS, integrating aerial imagery, density-aware waypoint selection, and multiple TSP solutions for improved MAV navigation in complex terrains.

Findings

MCRL reduces travel distance by 16.9% compared to ACO.

Path smoothness improved by reducing turning angles by up to 59.9%.

The framework effectively eliminates path intersections.

Abstract

Coverage Path Planning (CPP) is vital in precision agriculture to improve efficiency and resource utilization. In irregular and dispersed plantations, traditional grid-based CPP often causes redundant coverage over non-vegetated areas, leading to waste and pollution. To overcome these limitations, we propose CPP-DIP, a multi-objective CPP framework designed for Micro Air Vehicles (MAVs). The framework transforms the CPP task into a Traveling Salesman Problem (TSP) and optimizes flight paths by minimizing travel distance, turning angles, and intersection counts. Unlike conventional approaches, our method does not rely on GPS-based environmental modeling. Instead, it uses aerial imagery and a Histogram of Oriented Gradients (HOG)-based approach to detect trees and extract image coordinates. A density-aware waypoint strategy is applied: Kernel Density Estimation (KDE) is used to reduce redundant waypoints in dense regions, while a greedy algorithm ensures complete coverage in sparse areas. To verify the generality of the framework, we solve the resulting TSP using three different methods: Greedy Heuristic Insertion (GHI), Ant Colony Optimization (ACO), and Monte Carlo Reinforcement Learning (MCRL). Then an object-based optimization is applied to further refine the resulting path. Additionally, CPP-DIP integrates ForaNav, our insect-inspired navigation method, for accurate tree localization and tracking. The experimental results show that MCRL offers a balanced solution, reducing the travel distance by 16.9 % compared to ACO while maintaining a similar performance to GHI. It also improves path smoothness by reducing turning angles by 28.3 % and 59.9 % relative to ACO and GHI, respectively, and effectively eliminates intersections. These results confirm the robustness and effectiveness of CPP-DIP in different TSP solvers.