Planning & Scheduling
An Automatic Sound and Complete Abstraction Method for Generalized Planning with Baggable Types
Dong, Hao, Shi, Zheyuan, Zeng, Hemeng, Liu, Yongmei
Generalized planning is concerned with how to find a single plan to solve multiple similar planning instances. Abstractions are widely used for solving generalized planning, and QNP (qualitative numeric planning) is a popular abstract model. Recently, Cui et al. showed that a plan solves a sound and complete abstraction of a generalized planning problem if and only if the refined plan solves the original problem. However, existing work on automatic abstraction for generalized planning can hardly guarantee soundness let alone completeness. In this paper, we propose an automatic sound and complete abstraction method for generalized planning with baggable types. We use a variant of QNP, called bounded QNP (BQNP), where integer variables are increased or decreased by only one. Since BQNP is undecidable, we propose and implement a sound but incomplete solver for BQNP. We present an automatic method to abstract a BQNP problem from a classical planning instance with baggable types. The basic idea for abstraction is to introduce a counter for each bag of indistinguishable tuples of objects. We define a class of domains called proper baggable domains, and show that for such domains, the BQNP problem got by our automatic method is a sound and complete abstraction for a generalized planning problem whose instances share the same bags with the given instance but the sizes of the bags might be different. Thus, the refined plan of a solution to the BQNP problem is a solution to the generalized planning problem. Finally, we implement our abstraction method and experiments on a number of domains demonstrate the promise of our approach.
Inferring Implicit Goals Across Differing Task Models
Tulli, Silvia, Vasileiou, Stylianos Loukas, Chetouani, Mohamed, Sreedharan, Sarath
This should be all well and good, provided value-aligned behavior is to not only account for the human bottleneck states are also bottleneck states for the the specified user objectives but also any implicit agent. Otherwise, the agent must make an effort to figure out or unspecified user requirements. The existence what the user's underlying subgoals may be. of such implicit requirements could be particularly To see how such problems may arise, consider an agent common in settings where the user's understanding tasked with guiding a tourist to a famous art museum. The of the task model may differ from the agent's estimate tourist simply says, "Get me a plan to get to the art museum," of the model. Under this scenario, the user unaware of the city's metro system and expecting an may incorrectly expect some agent behavior to be above-ground route passing certain landmarks. The agent, inevitable or guaranteed. This paper addresses such however, might plan a route using the metro system. For the expectation mismatch in the presence of differing agent's metro route, bottlenecks migh include entering the models by capturing the possibility of unspecified metro, making transfers, and exiting at the correct station.
Front Hair Styling Robot System Using Path Planning for Root-Centric Strand Adjustment
Kim, Soonhyo, Kanazawa, Naoaki, Hasegawa, Shun, Kawaharazuka, Kento, Okada, Kei
Hair styling is a crucial aspect of personal grooming, significantly influenced by the appearance of front hair. While brushing is commonly used both to detangle hair and for styling purposes, existing research primarily focuses on robotic systems for detangling hair, with limited exploration into robotic hair styling. This research presents a novel robotic system designed to automatically adjust front hairstyles, with an emphasis on path planning for root-centric strand adjustment. The system utilizes images to compare the current hair state with the desired target state through an orientation map of hair strands. By concentrating on the differences in hair orientation and specifically targeting adjustments at the root of each strand, the system performs detailed styling tasks. The path planning approach ensures effective alignment of the hairstyle with the target, and a closed-loop mechanism refines these adjustments to accurately evolve the hairstyle towards the desired outcome. Experimental results demonstrate that the proposed system achieves a high degree of similarity and consistency in front hair styling, showing promising results for automated, precise hairstyle adjustments.
Hierarchical Trajectory (Re)Planning for a Large Scale Swarm
Pan, Lishuo, Wang, Yutong, Ayanian, Nora
We consider the trajectory replanning problem for a large-scale swarm in a cluttered environment. Our path planner replans for robots by utilizing a hierarchical approach, dividing the workspace, and computing collision-free paths for robots within each cell in parallel. Distributed trajectory optimization generates a deadlock-free trajectory for efficient execution and maintains the control feasibility even when the optimization fails. Our hierarchical approach combines the benefits of both centralized and decentralized methods, achieving a high task success rate while providing real-time replanning capability. Compared to decentralized approaches, our approach effectively avoids deadlocks and collisions, significantly increasing the task success rate. We demonstrate the real-time performance of our algorithm with up to 142 robots in simulation, and a representative 24 physical Crazyflie nano-quadrotor experiment.
Restless Multi-armed Bandits under Frequency and Window Constraints for Public Service Inspections
Municipal inspections are an important part of maintaining the quality of goods and services. In this paper, we approach the problem of intelligently scheduling service inspections to maximize their impact, using the case of food establishment inspections in Chicago as a case study. The Chicago Department of Public Health (CDPH) inspects thousands of establishments each year, with a substantial fail rate (over 3,000 failed inspection reports in 2023). To balance the objectives of ensuring adherence to guidelines, minimizing disruption to establishments, and minimizing inspection costs, CDPH assigns each establishment an inspection window every year and guarantees that they will be inspected exactly once during that window. These constraints create a challenge for a restless multi-armed bandit (RMAB) approach, for which there are no existing methods. We develop an extension to Whittle index-based systems for RMABs that can guarantee action window constraints and frequencies, and furthermore can be leveraged to optimize action window assignments themselves. Briefly, we combine MDP reformulation and integer programming-based lookahead to maximize the impact of inspections subject to constraints. A neural network-based supervised learning model is developed to model state transitions of real Chicago establishments using public CDPH inspection records, which demonstrates 10\% AUC improvements compared with directly predicting establishments' failures. Our experiments not only show up to 24\% (in simulation) or 33\% (on real data) reward improvements resulting from our approach but also give insight into the impact of scheduling constraints.
Robust Mobile Robot Path Planning via LLM-Based Dynamic Waypoint Generation
Tariq, Muhammad Taha, Wang, Congqing, Hussain, Yasir
Mobile robot path planning in complex environments remains a significant challenge, especially in achieving efficient, safe and robust paths. The traditional path planning techniques like DRL models typically trained for a given configuration of the starting point and target positions, these models only perform well when these conditions are satisfied. In this paper, we proposed a novel path planning framework that embeds Large Language Models to empower mobile robots with the capability of dynamically interpreting natural language commands and autonomously generating efficient, collision-free navigation paths. The proposed framework uses LLMs to translate high-level user inputs into actionable waypoints while dynamically adjusting paths in response to obstacles. We experimentally evaluated our proposed LLM-based approach across three different environments of progressive complexity, showing the robustness of our approach with llama3.1 model that outperformed other LLM models in path planning time, waypoint generation success rate, and collision avoidance. This underlines the promising contribution of LLMs for enhancing the capability of mobile robots, especially when their operation involves complex decisions in large and complex environments. Our framework has provided safer, more reliable navigation systems and opened a new direction for the future research. The source code of this work is publicly available on GitHub.
QuIP: Experimental design for expensive simulators with many Qualitative factors via Integer Programming
The need to explore and/or optimize expensive simulators with many qualitative factors arises in broad scientific and engineering problems. Our motivating application lies in path planning - the exploration of feasible paths for navigation, which plays an important role in robotics, surgical planning and assembly planning. Here, the feasibility of a path is evaluated via expensive virtual experiments, and its parameter space is typically discrete and high-dimensional. A carefully selected experimental design is thus essential for timely decision-making. We propose here a novel framework, called QuIP, for experimental design of Qualitative factors via Integer Programming under a Gaussian process surrogate model with an exchangeable covariance function. For initial design, we show that its asymptotic D-optimal design can be formulated as a variant of the well-known assignment problem in operations research, which can be efficiently solved to global optimality using state-of-the-art integer programming solvers. For sequential design (specifically, for active learning or black-box optimization), we show that its design criterion can similarly be formulated as an assignment problem, thus enabling efficient and reliable optimization with existing solvers. We then demonstrate the effectiveness of QuIP over existing methods in a suite of path planning experiments and an application to rover trajectory optimization.
Reviews: Maximum Entropy Monte-Carlo Planning
This paper proposes a new MCTS algorithm, Maximum Entropy for Tree Search (MENTS), which combines the maximum entropy policy optimization framework with MCTS for more efficient online planning in sequential decision problems. The main idea is to replace the Monte Carlo value estimate with the softmax value estimate as in the maximum entropy policy optimization framework, such that the state value can be estimated and back-propagated more efficiently in the search tree. Another main novelty is that it proposes an optimal algorithm, Empirical Exponential Weight (E2W), to be the tree policy to do more exploration. It shows that MENTS can achieve an exponential convergence rate towards finding the optimal action at the root of the tree, which is much faster than the polynomial convergence rate of the UCT method. The experimental results also demonstrate that MENTS performs significantly better than UCT in terms of sample efficiency, in both synthetic problems and Atari games.
Reviews: Maximum Entropy Monte-Carlo Planning
This paper presents an appealing idea to combine current max-entropy methods in RL with Monte-Carlo Tree Search. A theoretical result shows improved rate of convergence, while empirical results show improved sample efficiency. The initial reviews were quite positive; I only noted a small number of issues mentioned in the reviews of R1 and R3. In our discussions after reading the author feedback, R3 noted that some of his concerns have not been addressed. R2 replied, saying that these concerns are relatively minor and can be addressed in the final version.
Interpretable and Personalized Apprenticeship Scheduling: Learning Interpretable Scheduling Policies from Heterogeneous User Demonstrations
Resource scheduling and coordination is an NP-hard optimization requiring an efficient allocation of agents to a set of tasks with upper- and lower bound temporal and resource constraints. Due to the large-scale and dynamic nature of resource coordination in hospitals and factories, human domain experts manually plan and adjust schedules on the fly. To perform this job, domain experts leverage heterogeneous strategies and rules-of-thumb honed over years of apprenticeship. What is critically needed is the ability to extract this domain knowledge in a heterogeneous and interpretable apprenticeship learning framework to scale beyond the power of a single human expert, a necessity in safety-critical domains. We propose a personalized and interpretable apprenticeship scheduling algorithm that infers an interpretable representation of all human task demonstrators by extracting decision-making criteria via an inferred, personalized embedding non-parametric in the number of demonstrator types.