Reinforcement Learning
gym-gazebo2, a toolkit for reinforcement learning using ROS 2 and Gazebo
Lopez, Nestor Gonzalez, Nuin, Yue Leire Erro, Moral, Elias Barba, Juan, Lander Usategui San, Rueda, Alejandro Solano, Vilches, Vรญctor Mayoral, Kojcev, Risto
This paper presents an upgraded, real world application oriented version of gym-gazebo, the Robot Operating System (ROS) and Gazebo based Reinforcement Learning (RL) toolkit, which complies with OpenAI Gym. The content discusses the new ROS 2 based software architecture and summarizes the results obtained using Proximal Policy Optimization (PPO). Ultimately, the output of this work presents a benchmarking system for robotics that allows different techniques and algorithms to be compared using the same virtual conditions. We have evaluated environments with different levels of complexity of the Modular Articulated Robotic Arm (MARA), reaching accuracies in the millimeter scale. The converged results show the feasibility and usefulness of the gym-gazebo 2 toolkit, its potential and applicability in industrial use cases, using modular robots.
Deep Reinforcement Learning with Decorrelation
Mavrin, Borislav, Yao, Hengshuai, Kong, Linglong
Learning an effective representation for high-dimensional data is a challenging problem in reinforcement learning (RL). Deep reinforcement learning (DRL) such as Deep Q networks (DQN) achieves remarkable success in computer games by learning deeply encoded representation from convolution networks. In this paper, we propose a simple yet very effective method for representation learning with DRL algorithms. Our key insight is that features learned by DRL algorithms are highly correlated, which interferes with learning. By adding a regularized loss that penalizes correlation in latent features (with only slight computation), we decorrelate features represented by deep neural networks incrementally. On 49 Atari games, with the same regularization factor, our decorrelation algorithms perform $70\%$ in terms of human-normalized scores, which is $40\%$ better than DQN. In particular, ours performs better than DQN on 39 games with 4 close ties and lost only slightly on $6$ games. Empirical results also show that the decorrelation method applies to Quantile Regression DQN (QR-DQN) and significantly boosts performance. Further experiments on the losing games show that our decorelation algorithms can win over DQN and QR-DQN with a fined tuned regularization factor.
ROS2Learn: a reinforcement learning framework for ROS 2
Nuin, Yue Leire Erro, Lopez, Nestor Gonzalez, Moral, Elias Barba, Juan, Lander Usategui San, Rueda, Alejandro Solano, Vilches, Vรญctor Mayoral, Kojcev, Risto
We propose a novel framework for Deep Reinforcement Learning (DRL) in modular robotics to train a robot directly from joint states, using traditional robotic tools. We use an state-of-the-art implementation of the Proximal Policy Optimization, Trust Region Policy Optimization and Actor-Critic Kronecker-Factored Trust Region algorithms to learn policies in four different Modular Articulated Robotic Arm (MARA) environments. We support this process using a framework that communicates with typical tools used in robotics, such as Gazebo and Robot Operating System 2 (ROS 2). We evaluate several algorithms in modular robots with an empirical study in simulation.
Q Learning - Ashwin Vaidya
Before I explain what Q Learning is, I will quickly explain the basic principle of reinforcement learning. Reinforcement learning is a category of machine learning algorithms where the systems learn on their own by interacting with the environment. The idea is that a reward is provided to the agent if the action it takes is correct. Otherwise, some penalty is assigned to discourage the action. It is similar to how we train dogs to perform tricks, give it a snack for successfully doing a roll and rebuke it for dirtying your carpet.
Pricing algorithms can learn to collude with each other to raise prices
If you shop on Amazon, an algorithm rather than a human probably set the price of the service or item you bought. Pricing algorithms have become ubiquitous in online retail as automated systems have grown increasingly affordable and easy to implement. But while companies like airlines and hotels have long used machines to set their prices, pricing systems have evolved. They have moved from rule-based programs to reinforcement-learning ones, where the logic of deciding a product's price is no longer within a human's control. If you recall, reinforcement learning is a subset of machine learning that uses penalties and rewards to incentivize an AI agent toward a specific goal.
A Multi-Agent Off-Policy Actor-Critic Algorithm for Distributed Reinforcement Learning
Suttle, Wesley, Yang, Zhuoran, Zhang, Kaiqing, Wang, Zhaoran, Basar, Tamer, Liu, Ji
In this work we develop a new off-policy actor-critic algorithm that performs policy improvement with convergence guarantees in the multi-agent setting using function approximation. To achieve this, we extend the method of emphatic temporal differences (ETD(ฮป)) to the multi-agent setting with provable convergence under linear function approximation, and we also derive a novel off-policy policy gradient theorem for the multi-agent setting. Using these new results, we develop our two-timescale algorithm, which uses ETD(ฮป) to perform policy evaluation for the critic step at a faster timescale and policy gradient ascent using emphatic weightings for the actor step at a slower timescale. We also provide convergence guarantees for the actor step. Our work builds on recent advances in three main areas: multi-agent on-policy actor-critic methods, emphatic temporal difference learning for off-policy policy evaluation, and the use of emphatic weightings in off-policy policy gradient methods.
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RL for Real Life ICML 2019 Workshop
Reinforcement learning (RL) is a general learning, predicting, and decision making paradigm. RL provides solution methods for sequential decision making problems as well as those can be transformed into sequential ones. RL connects deeply with optimization, statistics, game theory, causal inference, sequential experimentation, etc., overlaps largely with approximate dynamic programming and optimal control, and applies broadly in science, engineering and arts. RL has been making steady progress in academia recently, e.g., Atari games, AlphaGo, visuomotor policies for robots. RL has also been applied to real world scenarios like recommender systems and neural architecture search. See a recent collection about RL applications.
Learning Dynamics Model in Reinforcement Learning by Incorporating the Long Term Future
Ke, Nan Rosemary, Singh, Amanpreet, Touati, Ahmed, Goyal, Anirudh, Bengio, Yoshua, Parikh, Devi, Batra, Dhruv
In model-based reinforcement learning, the agent interleaves between model learning and planning. These two components are inextricably intertwined. If the model is not able to provide sensible long-term prediction, the executed planner would exploit model flaws, which can yield catastrophic failures. This paper focuses on building a model that reasons about the long-term future and demonstrates how to use this for efficient planning and exploration. To this end, we build a latent-variable autoregressive model by leveraging recent ideas in variational inference. We argue that forcing latent variables to carry future information through an auxiliary task substantially improves long-term predictions. Moreover, by planning in the latent space, the planner's solution is ensured to be within regions where the model is valid. An exploration strategy can be devised by searching for unlikely trajectories under the model. Our method achieves higher reward faster compared to baselines on a variety of tasks and environments in both the imitation learning and model-based reinforcement learning settings.
Leveling the Playing Field - Fairness in AI Versus Human Game Benchmarks
Canaan, Rodrigo, Salge, Christoph, Togelius, Julian, Nealen, Andy
From the beginning if the history of AI, there has been interest in games as a platform of research. As the field developed, human-level competence in complex games became a target researchers worked to reach. Only relatively recently has this target been finally met for traditional tabletop games such as Backgammon, Chess and Go. Current research focus has shifted to electronic games, which provide unique challenges. As is often the case with AI research, these results are liable to be exaggerated or misrepresented by either authors or third parties. The extent to which these games benchmark consist of fair competition between human and AI is also a matter of debate. In this work, we review the statements made by authors and third parties in the general media and academic circle about these game benchmark results and discuss factors that can impact the perception of fairness in the contest between humans and machines