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 Planning & Scheduling


Learning off-road maneuver plans for autonomous vehicles

arXiv.org Artificial Intelligence

This thesis explores the benefits machine learning algorithms can bring to online planning and scheduling for autonomous vehicles in off-road situations. Mainly, we focus on typical problems of interest which include computing itineraries that meet certain objectives, as well as computing scheduling strategies to execute synchronized maneuvers with other vehicles. We present a range of learning-based heuristics to assist different itinerary planners. We show that these heuristics allow a significant increase in performance for optimal planners. Furthermore, in the case of approximate planning, we show that not only does the running time decrease, the quality of the itinerary found also becomes almost always better. Finally, in order to synthesize strategies to execute synchronized maneuvers, we propose a novel type of scheduling controllability and a learning-assisted algorithm. The proposed framework achieves significant improvement on known benchmarks in this controllability type over the performance of state-of-the-art works in a related controllability type. Moreover, it is able to find strategies on complex scheduling problems for which previous works fail to do so.


Multi-objective Conflict-based Search Using Safe-interval Path Planning

arXiv.org Artificial Intelligence

This paper addresses a generalization of the well known multi-agent path finding (MAPF) problem that optimizes multiple conflicting objectives simultaneously such as travel time and path risk. This generalization, referred to as multi-objective MAPF (MOMAPF), arises in several applications ranging from hazardous material transportation to construction site planning. In this paper, we present a new multi-objective conflict-based search (MO-CBS) approach that relies on a novel multi-objective safe interval path planning (MO-SIPP) algorithm for its low-level search. We first develop the MO-SIPP algorithm, show its properties and then embed it in MO-CBS. We present extensive numerical results to show that (1) there is an order of magnitude improvement in the average low level search time, and (2) a significant improvement in the success rates of finding the Pareto-optimal front can be obtained using the proposed approach in comparison with the state of the art. Finally, we also provide a case study to demonstrate the potential application of the proposed algorithms for construction site planning.


Orientation-Aware Planning for Parallel Task Execution of Omni-Directional Mobile Robot

arXiv.org Artificial Intelligence

Omni-directional mobile robot (OMR) systems have been very popular in academia and industry for their superb maneuverability and flexibility. Yet their potential has not been fully exploited, where the extra degree of freedom in OMR can potentially enable the robot to carry out extra tasks. For instance, gimbals or sensors on robots may suffer from a limited field of view or be constrained by the inherent mechanical design, which will require the chassis to be orientation-aware and respond in time. To solve this problem and further develop the OMR systems, in this paper, we categorize the tasks related to OMR chassis into orientation transition tasks and position transition tasks, where the two tasks can be carried out at the same time. By integrating the parallel task goals in a single planning problem, we proposed an orientation-aware planning architecture for OMR systems to execute the orientation transition and position transition in a unified and efficient way. A modified trajectory optimization method called orientation-aware timed-elastic-band (OATEB) is introduced to generate the trajectory that satisfies the requirements of both tasks. Experiments in both 2D simulated environments and real scenes are carried out. A four-wheeled OMR is deployed to conduct the real scene experiment and the results demonstrate that the proposed method is capable of simultaneously executing parallel tasks and is applicable to real-life scenarios.


Multi-Objective Path-Based D* Lite

arXiv.org Artificial Intelligence

Incremental graph search algorithms, such as D* Lite, reuse previous search efforts to speed up subsequent similar path planning tasks. These algorithms have demonstrated their efficiency in comparison with search from scratch, and have been leveraged in many applications such as navigation in unknown terrain. On the other hand, path planning typically involves optimizing multiple conflicting objectives simultaneously, such as travel risk, arrival time, etc. Multi-objective path planning is challenging as the number of "Pareto-optimal" solutions can grow exponentially with respect to the size of the graph, which makes it computationally burdensome to plan from scratch each time when similar planning tasks needs to be solved. This article presents a new multi-objective incremental search algorithm called Multi-Objective Path-Based D* Lite (MOPBD*) which reuses previous search efforts to speed up subsequent planning tasks while optimizing multiple objectives. Numerical results show that MOPBD* is more efficient than search from scratch and runs an order of magnitude faster than existing incremental method for multi-objective path planning.


Planning with Learned Binarized Neural Networks Benchmarks for MaxSAT Evaluation 2021

arXiv.org Artificial Intelligence

This document provides a brief introduction to learned automated planning problem where the state transition function is in the form of a binarized neural network (BNN), presents a general MaxSAT encoding for this problem, and describes the four domains, namely: Navigation, Inventory Control, System Administrator and Cellda, that are submitted as benchmarks for MaxSAT Evaluation 2021.


Task and Situation Structures for Service Agent Planning

arXiv.org Artificial Intelligence

Everyday tasks are characterized by their varieties and variations, and frequently are not clearly specified to service agents. This paper presents a comprehensive approach to enable a service agent to deal with everyday tasks in open, uncontrolled environments. We introduce a generic structure for representing tasks, and another structure for representing situations. Based on the two newly introduced structures, we present a methodology of situation handling that avoids hard-coding domain rules while improving the scalability of real-world task planning systems.


Coal country cleanup: U.S. plan sketches out possible future for former miners

The Japan Times

Now, with mining jobs hard to find, he's cleaning up the mess the industry left behind. The 68-year-old operates a bucket loader scraping away red, rocky waste dumped years ago by failed coal mine operators in a valley in the town of Clinchco, Virginia. The $17.50 an hour before overtime he makes cleaning up massive "gob piles," as the locals call them, is less than what he earned in decades as a miner. "If this work goes away, I don't know what I would do," Mullins said. Appalachia, long the heart of the U.S. coal-mining industry, may be set for a surge in jobs like Mullins' if President Joe Biden is successful in his ambitions to transition the United States to a cleaner energy economy to fight climate change.


Abstracting & Indexing – Artificial Intelligence – Journal – Elsevier

#artificialintelligence

The journal of Artificial Intelligence (AIJ) welcomes papers on broad aspects of AI that constitute advances in the overall field including, but not limited …


Monte Carlo Tree Search for high precision manufacturing

arXiv.org Artificial Intelligence

They can be treated as deterministic, as the noise of the manufacturing Monte Carlo Tree Search (MCTS) has shown its outcomes influence the processing result only to a minor strength for a lot of deterministic and stochastic extent. In this paper, we deal with the less common case examples, but literature lacks reports of applications of high precision manufacturing: here, the manufacturing to real world industrial processes. Common tolerances of the different processing steps are in the range reasons for this are that there is no efficient simulator of the product tolerance. As the manufacturing outcomes of the process available or there exist problems vary, the chain of manufacturing steps has to be adapted.


A strawberry harvest-aiding system with crop-transport co-robots: Design, development, and field evaluation

arXiv.org Artificial Intelligence

Mechanizing the manual harvesting of fresh market fruits constitutes one of the biggest challenges to the sustainability of the fruit industry. During manual harvesting of some fresh-market crops like strawberries and table grapes, pickers spend significant amounts of time walking to carry full trays to a collection station at the edge of the field. A step toward increasing harvest automation for such crops is to deploy harvest-aid collaborative robots (co-bots) that transport the empty and full trays, thus increasing harvest efficiency by reducing pickers' non-productive walking times. This work presents the development of a co-robotic harvest-aid system and its evaluation during commercial strawberry harvesting. At the heart of the system lies a predictive stochastic scheduling algorithm that minimizes the expected non-picking time, thus maximizing the harvest efficiency. During the evaluation experiments, the co-robots improved the mean harvesting efficiency by around 10% and reduced the mean non-productive time by 60%, when the robot-to-picker ratio was 1:3. The concepts developed in this work can be applied to robotic harvest-aids for other manually harvested crops that involve walking for crop transportation.