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Data Efficient Behavior Cloning for Fine Manipulation via Continuity-based Corrective Labels

Deshpande, Abhay, Ke, Liyiming, Pfeifer, Quinn, Gupta, Abhishek, Srinivasa, Siddhartha S.

arXiv.org Artificial Intelligence

We consider imitation learning with access only to expert demonstrations, whose real-world application is often limited by covariate shift due to compounding errors during execution. We investigate the effectiveness of the Continuity-based Corrective Labels for Imitation Learning (CCIL) framework in mitigating this issue for real-world fine manipulation tasks. CCIL generates corrective labels by learning a locally continuous dynamics model from demonstrations to guide the agent back toward expert states. Through extensive experiments on peg insertion and fine grasping, we provide the first empirical validation that CCIL can significantly improve imitation learning performance despite discontinuities present in contact-rich manipulation. We find that: (1) real-world manipulation exhibits sufficient local smoothness to apply CCIL, (2) generated corrective labels are most beneficial in low-data regimes, and (3) label filtering based on estimated dynamics model error enables performance gains. To effectively apply CCIL to robotic domains, we offer a practical instantiation of the framework and insights into design choices and hyperparameter selection. Our work demonstrates CCIL's practicality for alleviating compounding errors in imitation learning on physical robots.


Discrete Event Simulation: It's Easy with SimPy!

Zinoviev, Dmitry

arXiv.org Artificial Intelligence

This paper introduces the practicalities and benefits of using SimPy, a discrete event simulation (DES) module written in Python, for modeling and simulating complex systems. Through a step-by-step exploration of the classical Dining Philosophers Problem, we demonstrate how SimPy enables the efficient construction of discrete event models, emphasizing system states, transitions, and event handling. We extend the scenario to introduce resources, such as chopsticks, to model contention and deadlock conditions, and showcase SimPy's capabilities in managing these scenarios. Furthermore, we explore the integration of SimPy with other Python libraries for statistical analysis, showcasing how simulation results inform system design and optimization. The versatility of SimPy is further highlighted through additional modeling scenarios, including resource constraints and customer service interactions, providing insights into the process of building, debugging, simulating, and optimizing models for a wide range of applications. This paper aims to make DES accessible to practitioners and researchers alike, emphasizing the ease with which complex simulations can be constructed, analyzed, and visualized using SimPy and the broader Python ecosystem.


HASHI: Highly Adaptable Seafood Handling Instrument for Manipulation in Industrial Settings

Allison, Austin, Hanson, Nathaniel, Wicke, Sebastian, Padır, Taşkın

arXiv.org Artificial Intelligence

The seafood processing industry provides fertile ground for robotics to impact the future-of-work from multiple perspectives including productivity, worker safety, and quality of work life. The robotics research challenge is the realization of flexible and reliable manipulation of soft, deformable, slippery, spiky and scaly objects. In this paper, we propose a novel robot end effector, called HASHI, that employs chopstick-like appendages for precise and dexterous manipulation. This gripper is capable of in-hand manipulation by rotating its two constituent sticks relative to each other and offers control of objects in all three axes of rotation by imitating human use of chopsticks. HASHI delicately positions and orients food through embedded 6-axis force-torque sensors. We derive and validate the kinematic model for HASHI, as well as demonstrate grip force and torque readings from the sensorization of each chopstick. We also evaluate the versatility of HASHI through grasping trials of a variety of real and simulated food items with varying geometry, weight, and firmness.


The weirdest studies of the year are revealed in the spoof 'Ig Nobel' awards - from research into the sex lives of ANCHOVIES to an experiment to explore whether there is an equal number of hairs in each nostril

Daily Mail - Science & tech

Keeping count of nostril hairs and investigating the promiscuity of anchovies may seem completely unrelated. But these studies are among 10 others to win this year's spoof'Ig Nobels', thanks to their ability to make scientists chuckle. Traditionally hosted at Harvard University, this ceremony is the 33rd of its kind, and sees genuine Nobel laureates handing out awards to lucky academics. The prize is ten trillion Zimbabwean dollars, which might sound like a huge amount, but is actually only the equivalent of 30p in the UK (40 cents in the US). MailOnline spoke with some of the wackiest prize winners of 2023.


Cherry-Picking with Reinforcement Learning : Robust Dynamic Grasping in Unstable Conditions

Zhang, Yunchu, Ke, Liyiming, Deshpande, Abhay, Gupta, Abhishek, Srinivasa, Siddhartha

arXiv.org Artificial Intelligence

Abstract--Grasping small objects surrounded by unstable or non-rigid material plays a crucial role in applications such as surgery, harvesting, construction, disaster recovery, and assisted feeding. This task is especially difficult when fine manipulation is required in the presence of sensor noise and perception errors; errors inevitably trigger dynamic motion, which is challenging to model precisely. Circumventing the difficulty to build accurate models for contacts and dynamics, data-driven methods like reinforcement learning (RL) can optimize task performance via trial and error, reducing the need for accurate models of contacts and dynamics. Applying RL methods to real robots, however, has been hindered by factors such as prohibitively high sample complexity or the high training infrastructure cost for providing resets on hardware. This work presents CherryBot, an RL system that uses chopsticks for fine manipulation that surpasses human reactiveness for some dynamic grasping tasks. By integrating imprecise simulators, suboptimal demonstrations and external state estimation, we study how to make a realworld robot learning system sample efficient and general while reducing the human effort required for supervision. Our system shows continual improvement through 30 minutes of real-world interaction: through reactive retry, it achieves an almost 100% success rate on the demanding task of using chopsticks to grasp small objects swinging in the air. We demonstrate the reactiveness, robustness and generalizability of CherryBot to varying object shapes and dynamics (e.g., external disturbances However, this research investigates a more universal solution: assuming that fine manipulation is required, inaccuracy is How can we automate the task of picking cherries from a unavoidable and real-time reaction is necessary, can we enable tree branch that is blowing in the wind, causing the branch dynamic fine grasping without stable support? An ideal agent to shake and the cherries to tremble? This scenario is an should be: example of fine grasping without rigid-surface support, and its challenges are two-fold.


Edge Coverage Path Planning for Robot Mowing

Tian, Zhaofeng, Shi, Weisong

arXiv.org Artificial Intelligence

Thanks to the rapid evolvement of robotic technologies, robot mowing is emerging to liberate humans from the tedious and time-consuming landscape work. Traditionally, robot mowing is perceived as a "Coverage Path Planning" problem, with a simplification that converts non-convex obstacles into convex obstacles. Besides, the converted obstacles are commonly dilated by the robot's circumcircle for collision avoidance. However when applied to robot mowing, an obstacle in a lawn is usually non-convex, imagine a garden on the lawn, such that the mentioned obstacle processing methods would fill in some concave areas so that they are not accessible to the robot anymore and hence produce inescapable uncut areas along the lawn edge, which dulls the landscape's elegance and provokes rework. To shrink the uncut area around the lawn edge we hereby reframe the problem into a brand new problem, named the "Edge Coverage Path Planning" problem that is dedicated to path planning with the objective to cover the edge. Correspondingly, we propose two planning methods, the "big and small disk" and the "sliding chopstick" planning method to tackle the problem by leveraging image morphological processing and computational geometry skills. By validation, our proposed methods can outperform the traditional "dilation-by-circumcircle" method.


Learning to Use Chopsticks in Diverse Gripping Styles

Yang, Zeshi, Yin, KangKang, Liu, Libin

arXiv.org Artificial Intelligence

Learning dexterous manipulation skills is a long-standing challenge in computer graphics and robotics, especially when the task involves complex and delicate interactions between the hands, tools and objects. In this paper, we focus on chopsticks-based object relocation tasks, which are common yet demanding. The key to successful chopsticks skills is steady gripping of the sticks that also supports delicate maneuvers. We automatically discover physically valid chopsticks holding poses by Bayesian Optimization (BO) and Deep Reinforcement Learning (DRL), which works for multiple gripping styles and hand morphologies without the need of example data. Given as input the discovered gripping poses and desired objects to be moved, we build physics-based hand controllers to accomplish relocation tasks in two stages. First, kinematic trajectories are synthesized for the chopsticks and hand in a motion planning stage. The key components of our motion planner include a grasping model to select suitable chopsticks configurations for grasping the object, and a trajectory optimization module to generate collision-free chopsticks trajectories. Then we train physics-based hand controllers through DRL again to track the desired kinematic trajectories produced by the motion planner. We demonstrate the capabilities of our framework by relocating objects of various shapes and sizes, in diverse gripping styles and holding positions for multiple hand morphologies. Our system achieves faster learning speed and better control robustness, when compared to vanilla systems that attempt to learn chopstick-based skills without a gripping pose optimization module and/or without a kinematic motion planner.


Benchmarks, Algorithms, and Metrics for Hierarchical Disentanglement

Ross, Andrew Slavin, Doshi-Velez, Finale

arXiv.org Artificial Intelligence

In representation learning, there has been recent interest in developing algorithms to disentangle the ground-truth generative factors behind data, and metrics to quantify how fully this occurs. However, these algorithms and metrics often assume that both representations and ground-truth factors are flat, continuous, and factorized, whereas many real-world generative processes involve rich hierarchical structure, mixtures of discrete and continuous variables with dependence between them, and even varying intrinsic dimensionality. In this work, we develop benchmarks, algorithms, and metrics for learning such hierarchical representations.


How Modern Game Theory is Influencing Multi-Agent Reinforcement Learning Systems Part II

#artificialintelligence

This is the second part of an article discussing new areas of game theory that are influencing deep reinforcement learning systems. The first part focused on types of games that we are actively seeing in multi-agent reinforcement learning systems. Today, I would like to cover three new areas of deep learning theory that can influence new generations of reinforcement learning systems. Game theory plays a fundamental factor in modern artificial intelligence(AI) solutions. Specifically, deep reinforcement learning(DRL) is an area of AI that embraced game theory as a first-class citize.


A Crash Course in Game Theory for Machine Learning: Classic and New Ideas - KDnuggets

#artificialintelligence

Game theory is one of the most fascinating areas of mathematics that have influenced diverse fields such as economics, social sciences, biology and, obviously, computer science. Games are playing a key role in the evolution of artificial intelligence(AI). For starters, game environments are becoming a popular training mechanism in areas such as reinforcement learning or imitation learning. In theory, any multi-agent AI system can be subjected to gamified interactions between its participants. The branch of mathematics that formulates the principles of games is known as game theory.