Biologically-inspired robot spatial cognition based on rat neurophysiological studies

This paper presents a robot architecture with spatial cognition and navigation capabilities that captures some properties of the rat brain structures involved in learning and memory. This architecture relies on the integration of kinesthetic and visual information derived from artificial landmarks, as well as on Hebbian learning, to build a holistic topological-metric spatial representation during exploration, and employs reinforcement learning by means of an Actor-Critic architecture to enable learning and unlearning of goal locations. From a robotics perspective, this work can be placed in the gap between mapping and map exploitation currently existent in the SLAM literature. The exploitation of the cognitive map allows the robot to recognize places already visited and to find a target from any given departure location, thus enabling goal-directed navigation. From a biological perspective, this study aims at initiating a contribution to experimental neuroscience by providing the system as a tool to test with robots hypotheses concerned with the underlying mechanisms of rats’ spatial cognition. Results from different experiments with a mobile AIBO robot inspired on classical spatial tasks with rats are described, and a comparative analysis is provided in reference to the reversal task devised by O’Keefe in 1983.     

基于生物认知的移动机器人路径规划方法

针对移动机器人在非结构环境下的导航任务,受哺乳动物空间认知方式的启发,提出一种基于生物认知进行移动机器人路径规划的方法．结合认知地图特性,模拟海马体的情景记忆形成机理,构建封装了场景感知、状态神经元及位姿感知相关信息的情景认知地图,实现了机器人对环境的认知．基于情景认知地图,以最小事件距离为准则,提出事件序列规划算法用于实时导航过程．实验结果表明,该控制算法能使机器人根据不同任务选择最佳规划路径．     

Cognitive map formation through sequence encoding by theta phase precession

The rodent hippocampus has been thought to represent the spatial environment as a cognitive map. The associative connections in the hippocampus imply that a neural entity represents the map as a geometrical network of hippocampal cells in terms of a chart. According to recent experimental observations, the cells fire successively relative to the theta oscillation of the local field potential, called theta phase precession, when the animal is running. This observation suggests the learning of temporal sequences with asymmetric connections in the hippocampus, but it also gives rather inconsistent implications on the formation of the chart that should consist of symmetric connections for space coding. In this study, we hypothesize that the chart is generated with theta phase coding through the integration of asymmetric connections. Our computer experiments use a hippocampal network model to demonstrate that a geometrical network is formed through running experiences in a few minutes. Asymmetric connections are found to remain and distribute heterogeneously in the network. The obtained network exhibits the spatial localization of activities at each instance as the chart does and their propagation that represents behavioral motions with multidirectional properties. We conclude that theta phase precession and the Hebbian rule with a time delay can provide the neural principles for learning the cognitive map.     

Generative Modeling of Autonomous Robots and their Environments using Reservoir Computing

Autonomous mobile robots form an important research topic in the field of robotics due to their near-term applicability in the real world as domestic service robots. These robots must be designed in an efficient way using training sequences. They need to be aware of their position in the environment and also need to create models of it for deliberative planning. These tasks have to be performed using a limited number of sensors with low accuracy, as well as with a restricted amount of computational power. In this contribution we show that the recently emerged paradigm of Reservoir Computing (RC) is very well suited to solve all of the above mentioned problems, namely learning by example, robot localization, map and path generation. Reservoir Computing is a technique which enables a system to learn any time-invariant filter of the input by training a simple linear regressor that acts on the states of a high-dimensional but random dynamic system excited by the inputs. In addition, RC is a simple technique featuring ease of training, and low computational and memory demands.     

From pixels to multi-robot decision-making: A study in uncertainty

Mobile robots must cope with uncertainty from many sources along the path from interpreting raw sensor inputs to behavior selection to execution of the resulting primitive actions. This article identifies several such sources and introduces methods for (i) reducing uncertainty and (ii) making decisions in the face of uncertainty. We present a complete vision-based robotic system that includes several algorithms for learning models that are useful and necessary for planning, and then place particular emphasis on the planning and decision-making capabilities of the robot. Specifically, we present models for autonomous color calibration, autonomous sensor and actuator modeling, and an adaptation of particle filtering for improved localization on legged robots. These contributions enable effective planning under uncertainty for robots engaged in goal-oriented behavior within a dynamic, collaborative and adversarial environment. Each of our algorithms is fully implemented and tested on a commercial off-the-shelf vision-based quadruped robot.     

Towards a Theoretical Framework of Autonomous Systems Underpinned by Intelligence and Systems Sciences

Autonomous systems are an emerging AI technology functioning without human intervention underpinned by the latest advances in intelligence,cognition,computer,and systems sciences.This paper explores the intelligent and mathematical foundations of autonomous systems.It focuses on structural and behavioral properties that constitute the intelligent power of autonomous systems.It explains how system intelligence aggregates from reflexive,imperative,adaptive intelligence to autonomous and cognitive intelligence.A hierarchical intelligence model(HIM)is introduced to elaborate the evolution of human and system intelligence as an inductive process.The properties of system autonomy are formally analyzed towards a wide range of applications in computational intelligence and systems engineering.Emerging paradigms of autonomous systems including brain-inspired systems,cognitive robots,and autonomous knowledge learning systems are described.Advances in autonomous systems will pave a way towards highly intelligent machines for augmenting human capabilities.     

Embodied spatial cognition: Biological and artificial systems

In this paper, we sketch out a computational theory of spatial cognition motivated by navigational behaviours, ecological requirements, and neural mechanisms as identified in animals and man. Spatial cognition is considered in the context of a cognitive agent built around the action–perception cycle. Besides sensors and effectors, the agent comprises multiple memory structures including a working memory and a longterm memory stage. Spatial longterm memory is modelled along the graph approach, treating recognizable places or poses as nodes and navigational actions as links. Models of working memory and its interaction with reference memory are discussed. The model provides an overall framework of spatial cognition which can be adapted to model different levels of behavioural complexity as well as interactions between working and longterm memory. A number of design questions for building cognitive robots are derived from comparison with biological systems and discussed in the paper.     

Axiomatic approach to computational attention

Here we describe, in terms of a decision problem, any situation in which a computational system will be forced to allocate attention at any time to one spatial location to improve the reconstruction fidelity on a neighborhood of the chosen point. The result is a rational model of computational attention in which a multi-bitrate attention map will provide us with the attention score for each spatial location at high and low quality versions of the image reconstruction. At any time a rational system should choose, even though without any outside knowledge, among alternative spatial locations in such a way as to avoid certain forms of behavioral inconsistency. We compare the performance between a rational approach of computational attention and various models for predicting visual target distinctness, using scenes that represent military vehicles in complex rural backgrounds.     

A hierarchy of associations in hippocampo-cortical systems: cognitive maps and navigation strategies

In this letter we describe a hippocampo-cortical model of spatial processing and navigation based on a cascade of increasingly complex associative processes that are also relevant for other hippocampal functions such as episodic memory. Associative learning of different types and the related pattern encoding-recognition take place at three successive levels: (1) an object location level, which computes the landmarks from merged multimodal sensory inputs in the parahippocampal cortices; (2) a subject location level, which computes place fields by combination of local views and movement-related information in the entorhinal cortex; and (3) a spatiotemporal level, which computes place transitions from contiguous place fields in the CA3-CA1 region, which form building blocks for learning temporospatial sequences.At the cell population level, superficial entorhinal place cells encode spatial, context-independent maps as landscapes of activity; populations of transition cells in the CA3-CA1 region encode context-dependent maps as sequences of transitions, which form graphs in prefrontal-parietal cortices. The model was tested on a robot moving in a real environment; these tests produced results that could help to interpret biological data. Two different goal-oriented navigation strategies were displayed depending on the type of map used by the system.Thanks to its multilevel, multimodal integration and behavioral implementation, the model suggests functional interpretations for largely unaccounted structural differences between hippocampo-cortical systems. Further, spatiotemporal information, a common denominator shared by several brain structures, could serve as a cognitive processing frame and a functional link, for example, during spatial navigation and episodic memory, as suggested by the applications of the model to other domains, temporal sequence learning and imitation in particular.     

Hebbian imprinting and retrieval in oscillatory neural networks

We introduce a model of generalized Hebbian learning and retrieval in oscillatory neural networks modeling cortical areas such as hippocampus and olfactory cortex. Recent experiments have shown that synaptic plasticity depends on spike timing, especially on synapses from excitatory pyramidal cells, in hippocampus, and in sensory and cerebellar cortex. Here we study how such plasticity can be used to form memories and input representations when the neural dynamics are oscillatory, as is common in the brain (particularly in the hippocampus and olfactory cortex). Learning is assumed to occur in a phase of neural plasticity, in which the network is clamped to external teaching signals. By suitable manipulation of the nonlinearity of the neurons or the oscillation frequencies during learning, the model can be made, in a retrieval phase, either to categorize new inputs or to map them, in a continuous fashion, onto the space spanned by the imprinted patterns. We identify the first of these possibilities with the function of olfactory cortex and the second with the observed response characteristics of place cells in hippocampus. We investigate both kinds of networks analytically and by computer simulations, and we link the models with experimental findings, exploring, in particular, how the spike timing dependence of the synaptic plasticity constrains the computational function of the network and vice versa.     

基于扩散原理的冗余机器人逆运动学的学习方法

本文介绍一种基于扩散原理的机器人逆运动学学习方法．首先运用偏微分扩散方程, 只需少量的试验运动即可求解在有限作业空间上拥有同样拓扑关系的机器人逆运动学变换． 然后应用反馈误差学习法修正学习误差．在此基础上,提出一种并行分布结构用于冗余机器 人逆运动学计算．分析与仿真结果表明,该方法不仅算法简单、精度高,而且可获得连续的 逆运动学映射．     

The Psikharpax project: towards building an artificial rat

Drawing inspiration from biology, the Psikharpax project aims at endowing a robot with a sensory-motor equipment and a neural control architecture that will afford some of the capacities of autonomy and adaptation that are exhibited by real rats. The paper summarizes the current state of achievement of the project. It successively describes the robot's future sensors and actuators, and several biomimetic models of the anatomy and physiology of structures in the rat's brain, like the hippocampus and the basal ganglia, which have already been at work on various robots, and that make navigation and action selection possible. Preliminary results on the implementation of learning mechanisms in these structures are also presented. Finally, the article discusses the potential benefits that a biologically inspired approach affords to traditional autonomous robotics.     

A Spatial Cognitive Model that Integrates the Effects of Endogenous and Exogenous Information on the Hippocampus and Striatum

Machine Intelligence Research - Reproducing the spatial cognition of animals using computational models that make agents navigate autonomously has attracted much attention. Many biologically...     

一种创新的独立学院软件专业人才培养模式

本文从独立院校的特殊性出发,依据建构主义认知学说,提出一种以专业实训融合专业课程教学的创新人才培养模式。模式体现了建构主义的学习观和教学观。文章对推行该模式可能存在的困难进行分析,并给出建议的线路图。     

Morris水迷宫视频中目标识别与轨迹跟踪的研究与实现①

对Morris水迷宫视频中大鼠的运动轨迹进行跟踪是研究实验室大鼠空间学习和记忆能力的必要环节。为了有效且准确地对Morris水迷宫视频中大鼠的运动轨迹进行跟踪,设计了一个基于模板匹配和轨迹预测的Morris水迷宫视频分析系统,该系统能自动配置到任何大小的Morris水迷宫。通过简单的鼠标操作来快速准确地定位水迷宫和逃逸平台的位置;采用基于最大类间方差算法来把大鼠从水迷宫中分割出来;设计了基于模板匹配和轨迹预测的小区域搜索算法来跟踪迷宫中的大鼠。实验结果表明,该系统性能可靠,能有效地对水迷宫中的大鼠进行识别和跟踪并计算出各种水迷宫运动参数。     

移动机器人动态避障的调节发育学习

在环境认知的动态避障过程中,除了预期不确定性事件,移动机器人还可能会遇到非预期不确定性事件.如何高效、灵活地应对非预期不确定性事件是移动机器人动态避障中面临的一个重要挑战.目前关于这方面的研究相对较少,且基于这些研究的移动机器人普遍缺乏自主学习能力,难以快速、灵活地应对突变的外部环境.鉴于此,首先,设计一个新的碰撞危险度指标,该指标不仅考虑障碍物的距离,同时也考虑障碍物速度对移动机器人运动的影响.模拟人脑中乙酰胆碱和去甲肾上腺素在应对环境不确定性时的反应机理,通过碰撞危险度指标引导移动机器人的注意力网络在关注预期刺激的背侧注意力网络和关注新刺激的腹侧注意网络之间切换,使得机器人灵活应对环境中的不确定性事件;然后,设计新的神经元学习率,以增强调节发育网络隐含层神经元的学习能力,提高机器人应对突变环境的快速响应能力;接着,修改突触权值更新规则,以提高移动机器人行为决策的准确性;最后,通过在两种不同场景下的仿真实验以及物理环境中的实验,验证所提出的应对环境中非预期不确定性事件的移动机器人调节发育学习方法的可行性.     

Computational Aspects of Cognition and Consciousness in Intelligent Devices

We review computational intelligence methods of sensory perception and cognitive functions in animals, humans, and artificial devices. Top-down symbolic methods and bottom-up sub-symbolic approaches are described. In recent years, computational intelligence, cognitive science and neuroscience have achieved a level of maturity that allows integration of top-down and bottom-up approaches in modeling the brain. Continuous adaptation and teaming is a key component of computationally intelligent devices, which is achieved using dynamic models of cognition and consciousness. Human cognition performs a granulation of the seemingly homogeneous temporal sequences of perceptual experiences into meaningful and comprehensible chunks of concepts and complex behavioral sehemas. They are accessed during action selection and conscious decision making as part of the intentional cognitive cycle. Implementations in computational and robotic environments are demonstrated.     

视觉选择性注意计算模型

提出一种用于智能机器人的视觉注意计算模型．受生物学启发,该模型模仿人类自下而上和自上而下 两种视觉选择性注意过程．通过提取输入图像的多尺度下的多个底层特征,在频域分析各特征图的幅度谱,在空域 构造相应的特征显著图．根据显著图,计算出注意焦点的位置和注意区域的大小,结合给定的任务在各注意焦点之 间进行视觉转移．在多幅自然图像上进行实验,并给出相应的实验结果、定性和定量分析．实验结果与人类视觉注 意结果一致,表明该计算模型在注意效果、运算速度等方面有效．     

Hierarchical refinement of skills and skill application for autonomous robots

One of the major goals in designing learning robots is to let these robots develop useful skills over time. These skills are not only related to physical actions of the robot, but also to the coordination of activities, communication with humans, and active sensing. Throughout this paper, the interdependency between these different kinds of skills is analyzed. For the case of elementary action skills and coordination skills, methods for inegration of skill application and refinement are developed. It is shown that this integration has the potential to support long-term learning and autonomous experimentation.     

Statistical Learning for Humanoid Robots

The complexity of the kinematic and dynamic structure of humanoid robots make conventional analytical approaches to control increasingly unsuitable for such systems. Learning techniques offer a possible way to aid controller design if insufficient analytical knowledge is available, and learning approaches seem mandatory when humanoid systems are supposed to become completely autonomous. While recent research in neural networks and statistical learning has focused mostly on learning from finite data sets without stringent constraints on computational efficiency, learning for humanoid robots requires a different setting, characterized by the need for real-time learning performance from an essentially infinite stream of incrementally arriving data. This paper demonstrates how even high-dimensional learning problems of this kind can successfully be dealt with by techniques from nonparametric regression and locally weighted learning. As an example, we describe the application of one of the most advanced of such algorithms, Locally Weighted Projection Regression (LWPR), to the on-line learning of three problems in humanoid motor control: the learning of inverse dynamics models for model-based control, the learning of inverse kinematics of redundant manipulators, and the learning of oculomotor reflexes. All these examples demonstrate fast, i.e., within seconds or minutes, learning convergence with highly accurate final peformance. We conclude that real-time learning for complex motor system like humanoid robots is possible with appropriately tailored algorithms, such that increasingly autonomous robots with massive learning abilities should be achievable in the near future.