Intention Aware Robot Crowd Navigation with Attention-Based Interaction Graph

We study the problem of safe and intention-aware robot navigation in dense and interactive crowds. Most previous reinforcement learning (RL) based methods fail to consider different types of interactions among all agents or ignore the intentions of people, which results in performance degradation. In this paper, we propose a novel recurrent graph neural network with attention mechanisms to capture heterogeneous interactions among agents through space and time. To encourage longsighted robot behaviors, we infer the intentions of dynamic agents by predicting their future trajectories for several timesteps. The predictions are incorporated into a model-free RL framework to prevent the robot from intruding into the intended paths of other agents. We demonstrate that our method enables the robot to achieve good navigation performance and non-invasiveness in challenging crowd navigation scenarios. We successfully transfer the policy learned in simulation to a real-world TurtleBot 2i

A Data-driven Model for Interaction-aware Pedestrian Motion Prediction in Object Cluttered Environments

This paper reports on a data-driven, interaction-aware motion prediction approach for pedestrians in environments cluttered with static obstacles. When navigating in such workspaces shared with humans, robots need accurate motion predictions of the surrounding pedestrians. Human navigation behavior is mostly influenced by their surrounding pedestrians and by the static obstacles in their vicinity. In this paper we introduce a new model based on Long-Short Term Memory (LSTM) neural networks, which is able to learn human motion behavior from demonstrated data. To the best of our knowledge, this is the first approach using LSTMs, that incorporates both static obstacles and surrounding pedestrians for trajectory forecasting. As part of the model, we introduce a new way of encoding surrounding pedestrians based on a 1d-grid in polar angle space. We evaluate the benefit of interaction-aware motion prediction and the added value of incorporating static obstacles on both simulation and real-world datasets by comparing with state-of-the-art approaches. The results show, that our new approach outperforms the other approaches while being very computationally efficient and that taking into account static obstacles for motion predictions significantly improves the prediction accuracy, especially in cluttered environments.Comment: 8 pages, accepted for publication at the IEEE International Conference on Robotics and Automation (ICRA) 201

A Data-driven Model for Interaction-aware Pedestrian Motion Prediction in Object Cluttered Environments

This paper reports on a data-driven, interaction-aware motion prediction approach for pedestrians in environments cluttered with static obstacles. When navigating in such workspaces shared with humans, robots need accurate motion predictions of the surrounding pedestrians. Human navigation behavior is mostly influenced by their surrounding pedestrians and by the static obstacles in their vicinity. In this paper we introduce a new model based on Long-Short Term Memory (LSTM) neural networks, which is able to learn human motion behavior from demonstrated data. To the best of our knowledge, this is the first approach using LSTMs, that incorporates both static obstacles and surrounding pedestrians for trajectory forecasting. As part of the model, we introduce a new way of encoding surrounding pedestrians based on a 1d-grid in polar angle space. We evaluate the benefit of interaction-aware motion prediction and the added value of incorporating static obstacles on both simulation and real-world datasets by comparing with state-of-the-art approaches. The results show, that our new approach outperforms the other approaches while being very computationally efficient and that taking into account static obstacles for motion predictions significantly improves the prediction accuracy, especially in cluttered environments.Comment: 8 pages, accepted for publication at the IEEE International Conference on Robotics and Automation (ICRA) 201

의미론적 환경 이해 기반 인간 로봇 협업

학위논문(박사)--서울대학교 대학원 :공과대학 전기·정보공학부,2020. 2. 이범희.Human-robot cooperation is unavoidable in various applications ranging from manufacturing to field robotics owing to the advantages of adaptability and high flexibility. Especially, complex task planning in large, unconstructed, and uncertain environments can employ the complementary capabilities of human and diverse robots. For a team to be effectives, knowledge regarding team goals and current situation needs to be effectively shared as they affect decision making. In this respect, semantic scene understanding in natural language is one of the most fundamental components for information sharing between humans and heterogeneous robots, as robots can perceive the surrounding environment in a form that both humans and other robots can understand. Moreover, natural-language-based scene understanding can reduce network congestion and improve the reliability of acquired data. Especially, in field robotics, transmission of raw sensor data increases network bandwidth and decreases quality of service. We can resolve this problem by transmitting information in the form of natural language that has encoded semantic representations of environments. In this dissertation, I introduce a human and heterogeneous robot cooperation scheme based on semantic scene understanding. I generate sentences and scene graphs, which is a natural language grounded graph over the detected objects and their relationships, with the graph map generated using a robot mapping algorithm. Subsequently, a framework that can utilize the results for cooperative mission planning of humans and robots is proposed. Experiments were performed to verify the effectiveness of the proposed methods. This dissertation comprises two parts: graph-based scene understanding and scene understanding based on the cooperation between human and heterogeneous robots. For the former, I introduce a novel natural language processing method using a semantic graph map. Although semantic graph maps have been widely applied to study the perceptual aspects of the environment, such maps do not find extensive application in natural language processing tasks. Several studies have been conducted on the understanding of workspace images in the field of computer vision; in these studies, the sentences were automatically generated, and therefore, multiple scenes have not yet been utilized for sentence generation. A graph-based convolutional neural network, which comprises spectral graph convolution and graph coarsening, and a recurrent neural network are employed to generate sentences attention over graphs. The proposed method outperforms the conventional methods on a publicly available dataset for single scenes and can be utilized for sequential scenes. Recently, deep learning has demonstrated impressive developments in scene understanding using natural language. However, it has not been extensively applied to high-level processes such as causal reasoning, analogical reasoning, or planning. The symbolic approach that calculates the sequence of appropriate actions by combining the available skills of agents outperforms in reasoning and planning; however, it does not entirely consider semantic knowledge acquisition for human-robot information sharing. An architecture that combines deep learning techniques and symbolic planner for human and heterogeneous robots to achieve a shared goal based on semantic scene understanding is proposed for scene understanding based on human-robot cooperation. In this study, graph-based perception is used for scene understanding. A planning domain definition language (PDDL) planner and JENA-TDB are utilized for mission planning and data acquisition storage, respectively. The effectiveness of the proposed method is verified in two situations: a mission failure, in which the dynamic environment changes, and object detection in a large and unseen environment.인간과 이종 로봇 간의 협업은 높은 유연성과 적응력을 보일 수 있다는 점에서 제조업에서 필드 로보틱스까지 다양한 분야에서 필연적이다. 특히, 서로 다른 능력을 지닌 로봇들과 인간으로 구성된 하나의 팀은 넓고 정형화되지 않은 공간에서 서로의 능력을 보완하며 복잡한 임무 수행을 가능하게 한다는 점에서 큰 장점을 갖는다. 효율적인 한 팀이 되기 위해서는, 팀의 공통된 목표 및 각 팀원의 현재 상황에 관한 정보를 실시간으로 공유할 수 있어야 하며 함께 의사 결정을 할 수 있어야 한다. 이러한 관점에서, 자연어를 통한 의미론적 환경 이해는 인간과 서로 다른 로봇들이 모두 이해할 수 있는 형태로 환경을 인지한다는 점에서 가장 필수적인 요소이다. 또한, 우리는 자연어 기반 환경 이해를 통해 네트워크 혼잡을 피함으로써 획득한 정보의 신뢰성을 높일 수 있다. 특히, 대량의 센서 데이터 전송에 의해 네트워크 대역폭이 증가하고 통신 QoS (Quality of Service) 신뢰도가 감소하는 문제가 빈번히 발생하는 필드 로보틱스 영역에서는 의미론적 환경 정보인 자연어를 전송함으로써 통신 대역폭을 감소시키고 통신 QoS 신뢰도를 증가시킬 수 있다. 본 학위 논문에서는 환경의 의미론적 이해 기반 인간 로봇 협동 방법에 대해 소개한다. 먼저, 로봇의 지도 작성 알고리즘을 통해 획득한 그래프 지도를 이용하여 자연어 문장과 검출한 객체 및 각 객체 간의 관계를 자연어 단어로 표현하는 그래프를 생성한다. 그리고 자연어 처리 결과를 이용하여 인간과 다양한 로봇들이 함께 협업하여 임무를 수행할 수 있도록 하는 프레임워크를 제안한다. 본 학위 논문은 크게 그래프를 이용한 의미론적 환경 이해와 의미론적 환경 이해를 통한 인간과 이종 로봇 간의 협업 방법으로 구성된다. 먼저, 그래프를 이용한 의미론적 환경 이해 부분에서는 의미론적 그래프 지도를 이용한 새로운 자연어 처리 방법에 대해 소개한다. 의미론적 그래프 지도 작성 방법은 로봇의 환경 인지 측면에서 많이 연구되었지만 이를 이용한 자연어 처리 방법은 거의 연구되지 않았다. 반면 컴퓨터 비전 분야에서는 이미지를 이용한 환경 이해 연구가 많이 이루어졌지만, 연속적인 장면들은 다루는데는 한계점이 있다. 따라서 우리는 그래프 스펙트럼 이론에 기반한 그래프 컨볼루션과 그래프 축소 레이어로 구성된 그래프 컨볼루션 신경망 및 순환 신경망을 이용하여 그래프를 설명하는 문장을 생성한다. 제안한 방법은 기존의 방법들보다 한 장면에 대해 향상된 성능을 보였으며 연속된 장면들에 대해서도 성공적으로 자연어 문장을 생성한다. 최근 딥러닝은 자연어 기반 환경 인지에 있어 급속도로 큰 발전을 이루었다. 하지만 인과 추론, 유추적 추론, 임무 계획과 같은 높은 수준의 프로세스에는 적용이 힘들다. 반면 임무를 수행하는 데 있어 각 에이전트의 능력에 맞게 행위들의 순서를 계산해주는 상징적 접근법(symbolic approach)은 추론과 임무 계획에 있어 뛰어난 성능을 보이지만 인간과 로봇들 사이의 의미론적 정보 공유 방법에 대해서는 거의 다루지 않는다. 따라서, 인간과 이종 로봇 간의 협업 방법 부분에서는 딥러닝 기법들과 상징적 플래너(symbolic planner)를 연결하는 프레임워크를 제안하여 의미론적 이해를 통한 인간 및 이종 로봇 간의 협업을 가능하게 한다. 우리는 의미론적 주변 환경 이해를 위해 이전 부분에서 제안한 그래프 기반 자연어 문장 생성을 수행한다. PDDL 플래너와 JENA-TDB는 각각 임무 계획 및 정보 획득 저장소로 사용한다. 제안한 방법의 효용성은 시뮬레이션을 통해 두 가지 상황에 대해서 검증한다. 하나는 동적 환경에서 임무 실패 상황이며 다른 하나는 넓은 공간에서 객체를 찾는 상황이다.1 Introduction 1 1.1 Background and Motivation 1 1.2 Literature Review 5 1.2.1 Natural Language-Based Human-Robot Cooperation 5 1.2.2 Artificial Intelligence Planning 5 1.3 The Problem Statement 10 1.4 Contributions 11 1.5 Dissertation Outline 12 2 Natural Language-Based Scene Graph Generation 14 2.1 Introduction 14 2.2 Related Work 16 2.3 Scene Graph Generation 18 2.3.1 Graph Construction 19 2.3.2 Graph Inference 19 2.4 Experiments 22 2.5 Summary 25 3 Language Description with 3D Semantic Graph 26 3.1 Introduction 26 3.2 Related Work 26 3.3 Natural Language Description 29 3.3.1 Preprocess 29 3.3.2 Graph Feature Extraction 33 3.3.3 Natural Language Description with Graph Features 34 3.4 Experiments 35 3.5 Summary 42 4 Natural Question with Semantic Graph 43 4.1 Introduction 43 4.2 Related Work 45 4.3 Natural Question Generation 47 4.3.1 Preprocess 49 4.3.2 Graph Feature Extraction 50 4.3.3 Natural Question with Graph Features 51 4.4 Experiments 52 4.5 Summary 58 5 PDDL Planning with Natural Language 59 5.1 Introduction 59 5.2 Related Work 60 5.3 PDDL Planning with Incomplete World Knowledge 61 5.3.1 Natural Language Process for PDDL Planning 63 5.3.2 PDDL Planning System 64 5.4 Experiments 65 5.5 Summary 69 6 PDDL Planning with Natural Language-Based Scene Understanding 70 6.1 Introduction 70 6.2 Related Work 74 6.3 A Framework for Heterogeneous Multi-Agent Cooperation 77 6.3.1 Natural Language-Based Cognition 78 6.3.2 Knowledge Engine 80 6.3.3 PDDL Planning Agent 81 6.4 Experiments 82 6.4.1 Experiment Setting 82 6.4.2 Scenario 84 6.4.3 Results 87 6.5 Summary 91 7 Conclusion 92Docto

Body gestures recognition for human robot interaction

In this project, a solution for human gesture classification is proposed. The solution uses a Deep Learning model and is meant to be useful for non-verbal communication between humans and robots. The State-of-the-Art is researched in an effort to achieve a model ready to work with natural gestures without restrictions. The research will focus on the creation of a temPoral bOdy geSTUre REcognition model (POSTURE) that can recognise continuous gestures performed in real-life situations. The suggested model takes into account spatial and temporal components so as to achieve the recognition of more natural and intuitive gestures. In a first step, a framework extracts from all the images the corresponding landmarks for each of the body joints. Next, some data filtering techniques are applied with the aim of avoiding problems related with the data. Afterwards, the filtered data is input into an State-of-the-Art Neural Network. And finally, different neural network configurations and approaches are tested to find the optimal performance. The obtained outcome shows the research has been done in the right track and how, despite of the dataset problems found, even better results can be achievedObjectius de Desenvolupament Sostenible::9 - Indústria, Innovació i Infraestructur

Ornithopter Trajectory Optimization with Neural Networks and Random Forest

Trajectory optimization has recently been addressed to compute energy-efficient routes for ornithopter navigation, but its online application remains a challenge. To overcome the high computation time of traditional approaches, this paper proposes algorithms that recursively generate trajectories based on the output of neural networks and random forest. To this end, we create a large data set composed by energy-efficient trajectories obtained by running a competitive planner. To the best of our knowledge our proposed data set is the first one with a high number of pseudo-optimal paths for ornithopter trajectory optimization. We compare the performance of three methods to compute low-cost trajectories: two classification approaches to learn maneuvers and an alternative regression method that predicts new states. The algorithms are tested in several scenarios, including the landing case. The effectiveness and efficiency of the proposed algorithms are demonstrated through simulation, which show that the machine learning techniques can be used to compute the flight path of the ornithopter in real time, even under uncertainties such as wrong sensor readings or re-positioning of the target. Random Forest obtains the higher performance with more than 99% and 97% of accuracy in a landing and a mid-range scenario, respectively.Ministerio de Economía y Competitividad MTM2016-76272- R AEI/FEDER,UEMinisterio de Ciencia e Innovación PID2020-114154RB-I00Unión Europea, Horizon 2020, Marie Sklodowska-Curie grant agreement #73492

Neural network based country wise risk prediction of COVID-19

The recent worldwide outbreak of the novel coronavirus (COVID-19) has opened up new challenges to the research community. Artificial intelligence (AI) driven methods can be useful to predict the parameters, risks, and effects of such an epidemic. Such predictions can be helpful to control and prevent the spread of such diseases. The main challenges of applying AI is the small volume of data and the uncertain nature. Here, we propose a shallow long short-term memory (LSTM) based neural network to predict the risk category of a country. We have used a Bayesian optimization framework to optimize and automatically design country-specific networks. The results show that the proposed pipeline outperforms state-of-the-art methods for data of 180 countries and can be a useful tool for such risk categorization. We have also experimented with the trend data and weather data combined for the prediction. The outcome shows that the weather does not have a significant role. The tool can be used to predict long-duration outbreak of such an epidemic such that we can take preventive steps earlie