A Cloud based Reinforcement Learning Framework for humanoid grasping

This work presents an innovative approach to a common task on robotics: grasping a set of objects. Autonomously grasping a previously unknown object still remains a challenging problem. This Thesis presents a new framework, inspired by the classical sense-model-act architecture and the knowledge processing of Cognitive Robotics. The framework tries to generalize the grasping task toope

Benchmarking Deep Reinforcement Learning for Continuous Control

Recently, researchers have made significant progress combining the advances in deep learning for learning feature representations with reinforcement learning. Some notable examples include training agents to play Atari games based on raw pixel data and to acquire advanced manipulation skills using raw sensory inputs. However, it has been difficult to quantify progress in the domain of continuous control due to the lack of a commonly adopted benchmark. In this work, we present a benchmark suite of continuous control tasks, including classic tasks like cart-pole swing-up, tasks with very high state and action dimensionality such as 3D humanoid locomotion, tasks with partial observations, and tasks with hierarchical structure. We report novel findings based on the systematic evaluation of a range of implemented reinforcement learning algorithms. Both the benchmark and reference implementations are released at https://github.com/rllab/rllab in order to facilitate experimental reproducibility and to encourage adoption by other researchers.Comment: 14 pages, ICML 201

Multilayered skill learning and movement coordination for autonomous robotic agents

With advances in technology expanding the capabilities of robots, while at the same time making robots cheaper to manufacture, robots are rapidly becoming more prevalent in both industrial and domestic settings. An increase in the number of robots, and the likely subsequent decrease in the ratio of people currently trained to directly control the robots, engenders a need for robots to be able to act autonomously. Larger numbers of robots present together provide new challenges and opportunities for developing complex autonomous robot behaviors capable of multirobot collaboration and coordination. The focus of this thesis is twofold. The first part explores applying machine learning techniques to teach simulated humanoid robots skills such as how to move or walk and manipulate objects in their environment. Learning is performed using reinforcement learning policy search methods, and layered learning methodologies are employed during the learning process in which multiple lower level skills are incrementally learned and combined with each other to develop richer higher level skills. By incrementally learning skills in layers such that new skills are learned in the presence of previously learned skills, as opposed to individually in isolation, we ensure that the learned skills will work well together and can be combined to perform complex behaviors (e.g. playing soccer). The second part of the thesis centers on developing algorithms to coordinate the movement and efforts of multiple robots working together to quickly complete tasks. These algorithms prioritize minimizing the makespan, or time for all robots to complete a task, while also attempting to avoid interference and collisions among the robots. An underlying objective of this research is to develop techniques and methodologies that allow autonomous robots to robustly interact with their environment (through skill learning) and with each other (through movement coordination) in order to perform tasks and accomplish goals asked of them. The work in this thesis is implemented and evaluated in the RoboCup 3D simulation soccer domain, and has been a key component of the UT Austin Villa team winning the RoboCup 3D simulation league world championship six out of the past seven years.Computer Science

Making friends on the fly : advances in ad hoc teamwork

textGiven the continuing improvements in design and manufacturing processes in addition to improvements in artificial intelligence, robots are being deployed in an increasing variety of environments for longer periods of time. As the number of robots grows, it is expected that they will encounter and interact with other robots. Additionally, the number of companies and research laboratories producing these robots is increasing, leading to the situation where these robots may not share a common communication or coordination protocol. While standards for coordination and communication may be created, we expect that any standards will lag behind the state-of-the-art protocols and robots will need to additionally reason intelligently about their teammates with limited information. This problem motivates the area of ad hoc teamwork in which an agent may potentially cooperate with a variety of teammates in order to achieve a shared goal. We argue that agents that effectively reason about ad hoc teamwork need to exhibit three capabilities: 1) robustness to teammate variety, 2) robustness to diverse tasks, and 3) fast adaptation. This thesis focuses on addressing all three of these challenges. In particular, this thesis introduces algorithms for quickly adapting to unknown teammates that enable agents to react to new teammates without extensive observations. The majority of existing multiagent algorithms focus on scenarios where all agents share coordination and communication protocols. While previous research on ad hoc teamwork considers some of these three challenges, this thesis introduces a new algorithm, PLASTIC, that is the first to address all three challenges in a single algorithm. PLASTIC adapts quickly to unknown teammates by reusing knowledge it learns about previous teammates and exploiting any expert knowledge available. Given this knowledge, PLASTIC selects which previous teammates are most similar to the current ones online and uses this information to adapt to their behaviors. This thesis introduces two instantiations of PLASTIC. The first is a model-based approach, PLASTIC-Model, that builds models of previous teammates' behaviors and plans online to determine the best course of action. The second uses a policy-based approach, PLASTIC-Policy, in which it learns policies for cooperating with past teammates and selects from among these policies online. Furthermore, we introduce a new transfer learning algorithm, TwoStageTransfer, that allows transferring knowledge from many past teammates while considering how similar each teammate is to the current ones. We theoretically analyze the computational tractability of PLASTIC-Model in a number of scenarios with unknown teammates. Additionally, we empirically evaluate PLASTIC in three domains that cover a spread of possible settings. Our evaluations show that PLASTIC can learn to communicate with unknown teammates using a limited set of messages, coordinate with externally-created teammates that do not reason about ad hoc teams, and act intelligently in domains with continuous states and actions. Furthermore, these evaluations show that TwoStageTransfer outperforms existing transfer learning algorithms and enables PLASTIC to adapt even better to new teammates. We also identify three dimensions that we argue best describe ad hoc teamwork scenarios. We hypothesize that these dimensions are useful for analyzing similarities among domains and determining which can be tackled by similar algorithms in addition to identifying avenues for future research. The work presented in this thesis represents an important step towards enabling agents to adapt to unknown teammates in the real world. PLASTIC significantly broadens the robustness of robots to their teammates and allows them to quickly adapt to new teammates by reusing previously learned knowledge.Computer Science

Law and Ethics of Morally Significant Machines: The case for pre-emptive prevention

Interest in the ethics of Artificial Intelligence systems is dominated by the question of how these sorts of technologies will benefit or harm human individuals and societies. Much less attention is given to the ethics of our interaction with AI systems from the perspective of what may harm or benefit the systems themselves. Despite this, there is potential for future AI systems to be designed in a way that makes them either morally significant entities, or gives them the tools with which to develop degrees of moral significance, perhaps even personhood in the moral sense. This thesis proposes how certain contemporary paradigms in AI might in the future create a morally significant machine, perhaps even a machine person; one which can be harmed to a degree similar to ourselves. This type of system would be the first technology towards which the design of law and policy would be obliged to consider not just human best interests, but the best interests of the technology itself: how it is designed, what we can use it for, what can be done to it, and what we are duty-bound to provide it with. The thesis proposes a wide range of legal and social problems that the invention of such a system would engender, particularly in relation to paradigms like property, legal personality, and rights of both positive and negative nature. It also explores the fraught line-drawing problem of establishing which systems matter and which do not, and what the legal implications of this would be. It establishes that the net demands such a machine would place upon humans informs an argument that there should be a pre-emptive policy to prevent their creation, so as to mitigate harms to both human society and the machines themselves. When closely examined, the reality of a social partnership between persons – both human and machine – is too problematic and too profoundly challenging to the conception of anthropocentric hegemony to be justifiable

Incorporating and Learning Behavior Constraints for Sequential Decision Making

Writing a program that performs well in a complex environment is a challenging task. In such problems, a method of deterministic programming combined with reinforcement learning (RL) can be helpful. However, current systems either force developers to encode knowledge in very specific forms (e.g., state-action features), or assume advanced RL knowledge (e.g., ALISP). This thesis explores techniques that make it easier for developers, who may not be RL experts, to encode their knowledge in the form of behavior constraints. We begin with the framework of adaptation-based programming (ABP) for writing self-optimizing programs. Next, we show how a certain type of conditional independency called "influence information" arises naturally in ABP programs. We propose two algorithms for learning reactive policies that are capable of leveraging this knowledge. Using influence information to simplify the credit assignment problem produces significant performance improvements. Next, we turn our attention to problems in which a simulator allows us to replace reactive decision-making with time-bounded search, which often outperforms purely reactive decision-making at significant computational cost. We propose a new type of behavior constraint in the form of partial policies, which restricts behavior to a subset of good actions. Using a partial policy to prune sub-optimal actions reduces the action branching factor, thereby speeding up search. We propose three algorithms for learning partial policies offline, based on reducing the learning problem to i.i.d. supervised learning and we give a reduction-style analysis for each one. We give concrete implementations using the popular framework of Monte-Carlo tree search. Experiments on challenging problems demonstrates large performance improvements in search-based decision-making generated by the learned partial policies. Taken together, this thesis outlines a programming framework for injecting different forms of developer knowledge into reactive policy learning algorithms and search-based online planning algorithms. It represents a few small steps towards a programming paradigm that makes it easy to write programs that learn to perform well

Data efficient reinforcement learning with off-policy and simulated data

Learning from interaction with the environment -- trying untested actions, observing successes and failures, and tying effects back to causes -- is one of the first capabilities we think of when considering autonomous agents. Reinforcement learning (RL) is the area of artificial intelligence research that has the goal of allowing autonomous agents to learn in this way. Despite much recent success, many modern reinforcement learning algorithms are still limited by the requirement of large amounts of experience before useful skills are learned. Two possible approaches to improving data efficiency are to allow algorithms to make better use of past experience collected with past behaviors (known as off-policy data) and to allow algorithms to make better use of simulated data sources. This dissertation investigates the use of such auxiliary data by answering the question, "How can a reinforcement learning agent leverage off-policy and simulated data to evaluate and improve upon the expected performance of a policy?" This dissertation first considers how to directly use off-policy data in reinforcement learning through importance sampling. When used in reinforcement learning, importance sampling is limited by high variance that leads to inaccurate estimates. This dissertation addresses this limitation in two ways. First, this dissertation introduces the behavior policy gradient algorithm that adapts the data collection policy towards a policy that generates data that leads to low variance importance sampling evaluation of a fixed policy. Second, this dissertation introduces the family of regression importance sampling estimators which improve the weighting of already collected off-policy data so as to lower the variance of importance sampling evaluation of a fixed policy. In addition to evaluation of a fixed policy, we apply the behavior policy gradient algorithm and regression importance sampling to batch policy gradient policy improvement. In the case of regression importance sampling, this application leads to the introduction of the sampling error corrected policy gradient estimator that improves the data efficiency of batch policy gradient algorithms. Towards the goal of learning from simulated experience, this dissertation introduces an algorithm -- the grounded action transformation algorithm -- that takes small amounts of real world data and modifies the simulator such that skills learned in simulation are more likely to carry over to the real world. Key to this approach is the idea of local simulator modification -- the simulator is automatically altered to better model the real world for actions the data collection policy would take in states the data collection policy would visit. Local modification necessitates an iterative approach: the simulator is modified, the policy improved, and then more data is collected for further modification. Finally, in addition to examining them each independently, this dissertation also considers the possibility of combining the use of simulated data with importance sampled off-policy data. We combine these sources of auxiliary data by control variate techniques that use simulated data to lower the variance of off-policy policy value estimation. Combining these sources of auxiliary data allows us to introduce two algorithms -- weighted doubly robust bootstrap and model-based bootstrap -- for the problem of lower-bounding the performance of an untested policy.Computer Science