Coverage Path Planning and Room Segmentation in Indoor Environments using the Constriction Decomposition Method

The task of complete coverage path planning in complex 2D environments is a classic NP- Hard problem that has been an active research topic for well over 30 years. A common approach to solving coverage problem in such environments is to partition, or segment, the target environment into a set of cells that have some property that allows any given cell to be covered in an optimal or near optimal manner. If each cell of an environment is visited and covered by some agent, then the entire environment is said to be covered. This work proposes a novel segmentation method, called the Constriction Decomposition Method (CDM), that works by locating constriction points in indoor, 2D environment and then partitioning the environment based on the constriction points. When the CDM is applied to 2D maps of office or laboratory environments, the CDM produces a segmentation that closely resembles a room based decomposition. Once the environment has been decomposed into regions, this work demonstrates that each room can be covered using a simple coverage path planning algorithm that exploits the fact that the resulting cells do not contain any constriction points. The lack of constriction points in each region means that each region, or room, can be completely covered using a series of contour following paths followed by a series of back and forth motions. Once a set of coverage paths are pro- duced for each cell, a tour between all path is found using a heuristic Traveling Salesman Problem (TSP) solver. The proposed segmentation and coverage path planning methods are tested on a set of 15 indoor environments that are derived from a set of floor plans corresponding to five office and seven laboratory environments. The quality of the segmentation produced by the CDM is directly compared to existing methods on a qualitative and quantitative basis using a series of metrics proposed by other authors. The set of coverage paths for each environment are compared to existing work based on the ratio between the total path length and the ratio between the inter-sector path and the total coverage path length. Based on these metrics it is demonstrated that the CDM and the CDM coverage path planner produces both superior segmentations and coverage plans in 2D indoor environments

The BG News September 20, 2006

The BGSU campus student newspaper September 20, 2006. Volume 97 - Issue 23https://scholarworks.bgsu.edu/bg-news/8640/thumbnail.jp

Near-Optimal Coverage Path Planning with Turn Costs

Coverage path planning is a fundamental challenge in robotics, with diverse applications in aerial surveillance, manufacturing, cleaning, inspection, agriculture, and more. The main objective is to devise a trajectory for an agent that efficiently covers a given area, while minimizing time or energy consumption. Existing practical approaches often lack a solid theoretical foundation, relying on purely heuristic methods, or overly abstracting the problem to a simple Traveling Salesman Problem in Grid Graphs. Moreover, the considered cost functions only rarely consider turn cost, prize-collecting variants for uneven cover demand, or arbitrary geometric regions. In this paper, we describe an array of systematic methods for handling arbitrary meshes derived from intricate, polygonal environments. This adaptation paves the way to compute efficient coverage paths with a robust theoretical foundation for real-world robotic applications. Through comprehensive evaluations, we demonstrate that the algorithm also exhibits low optimality gaps, while efficiently handling complex environments. Furthermore, we showcase its versatility in handling partial coverage and accommodating heterogeneous passage costs, offering the flexibility to trade off coverage quality and time efficiency

Vision-Based Autonomous Robotic Floor Cleaning in Domestic Environments

Fleer DR. Vision-Based Autonomous Robotic Floor Cleaning in Domestic Environments. Bielefeld: Universität Bielefeld; 2018

Vulnerability of Electric Power Systems to Volcanic Ashfall Hazards

Volcanic eruptions are powerful natural events which impact strongly on society. As human populations grow and expand into volcanically active areas, their exposure and vulnerability to volcanic hazards is also increasing. Of all volcanic hazards, ashfall is the most likely to impact lifelines because of the large areas affected. The widespread dispersal of ash can cause large-scale disruption of vital infrastructure services, aviation, and primary production. Electric power supply is arguably the most crucial of modern infrastructure systems, especially considering the dependence of other sectors on electricity to maintain functionality. During and immediately after ashfalls, electric power systems are vulnerable to a number of impacts, but disruption from volcanic ash-induced insulator flashover (unintended, disruptive electrical discharge) is most common. This thesis investigates the vulnerability of electric power systems to volcanic ashfall by examining impacts to the different sectors of the modern power system and exploring appropriate mitigation strategies. Analogue laboratory trials using a pseudo (synthetic) ash are undertaken to verify the environmental, volcanological and electrical parameters that most affect electrical conductivity and therefore the flashover mechanism in these experiments. While dry ash is highly resistant to the flow of electric current, increasing moisture content, soluble salt load, and compaction (bulk density) will reduce this resistance and, in turn, increase the potential for flashover. Volcanic ash is an acute form of airborne pollution for areas downwind of active volcanoes. Results from laboratory experiments in this thesis suggest that insulator pollution (volcanic ash) performance (dielectric strength) is primarily dictated by (1) the conductivity of the ash, and (2) insulator material, profile (shape) and dimensioning. Composite polymer insulators tested herein effectively minimise sinusoidal leakage current and partial discharge activity and also exhibit higher pollution performance when compared to ceramic equivalents. Irrespective of insulator material, however, the likelihood of flashover increases significantly once the bottom surface of suspension insulator watersheds become contaminated in wet ash. The thesis investigates the vulnerability (hazard intensity/damage ratio) of electric power systems to volcanic ashfall hazards. Identification, analysis, and reduction of the risk of ashfall impacts to power networks is explored as a part of holistic volcanic risk assessment. The findings of the thesis contribute to the readiness, response and recovery protocols for large electric power systems in volcanic disasters; which directly affects the functional operation and economics of industrial and commercial society