Event-based control system on FPGA applied to the pencil balancer robotic platform

An event-based motor controller design is presented. The system is designed to solve the classic inverted pendulum problem by using a robotic platform and a totally neuro-inspired event-based mechanism. Specifically, DVS retinas provide feedback and an FPGA implements control. The robotic platform used is the so called ’pencil balancer’. The retinas provide visual information to the FPGA that processes it and obtains the center of mass of the pencil. Once this center of mass is averaged over time, it is used joint with the cart position provided by a flat potentiometer bar to compute the angle of the pencil from the vertical. The angle is delivered to an eventbased Proportional-Derivative (PD) controller that drives the DC motor using Pulse Frequency Modulation (PFM) to accomplish the control objective. The results show an accurate, real-time and efficient controller design

On the AER Stereo-Vision Processing: A Spike Approach to Epipolar Matching

Image processing in digital computer systems usually considers visual information as a sequence of frames. These frames are from cameras that capture reality for a short period of time. They are renewed and transmitted at a rate of 25-30 fps (typical real-time scenario). Digital video processing has to process each frame in order to detect a feature on the input. In stereo vision, existing algorithms use frames from two digital cameras and process them pixel by pixel until it finds a pattern match in a section of both stereo frames. To process stereo vision information, an image matching process is essential, but it needs very high computational cost. Moreover, as more information is processed, the more time spent by the matching algorithm, the more inefficient it is. Spike-based processing is a relatively new approach that implements processing by manipulating spikes one by one at the time they are transmitted, like a human brain. The mammal nervous system is able to solve much more complex problems, such as visual recognition by manipulating neuron’s spikes. The spike-based philosophy for visual information processing based on the neuro-inspired Address-Event- Representation (AER) is achieving nowadays very high performances. The aim of this work is to study the viability of a matching mechanism in a stereo-vision system, using AER codification. This kind of mechanism has not been done before to an AER system. To do that, epipolar geometry basis applied to AER system are studied, and several tests are run, using recorded data and a computer. The results and an average error are shown (error less than 2 pixels per point); and the viability is proved

Frequency Analysis of a 64x64 Pixel Retinomorphic System with AER Output to Estimate the Limits to Apply onto Specific Mechanical Environment

The rods and cones of a human retina are constantly sensing and transmitting the light in the form of spikes to the cortex of the brain in order to reproduce an image in the brain. Delbruck’s lab has designed and manufactured several generations of spike based image sensors that mimic the human retina. In this paper we present an exhaustive timing analysis of the Address-Event- Representation (AER) output of a 64x64 pixels silicon retinomorphic system. Two different scenarios are presented in order to achieve the maximum frequency of light changes for a pixel sensor and the maximum frequency of requested directions on the output AER. Results obtained are 100 Hz and 1.66 MHz in each case respectively. We have tested the upper spin limit and found it to be approximately 6000rpm (revolutions per minute) and in some cases with high light contrast lost events do not exist.Ministerio de Ciencia e Innovación TEC2009-10639- C04-0

Neuromorphic Real-Time Objects Tracking Using Address Event Representation and Silicon Retina

This paper presents a hierarchical neuromorphic system for tracking objects. We use AER (Address Event Representation) for transmitting and processing visual information provided by an asynchronous temporal contrast silicon retina. Two AER processing layers work in cascade for firstly detecting different objects, and secondly tracking them even with crossing trajectories. The output of the system offers not only the position of the tracked object but also the speed in pixels per second. The system is fully hardware implemented on FPGA (Spartan II 200), which is part of the USB-AER platform developed in part by authors. A 97.2% of the Spartan II is used for 128x128 pixels input resolution and 6 maximum objects recognition and tracking.Ministerio de Ciencia e Innovación TEC2009-10639-C04-0

Real-time neuro-inspired sound source localization and tracking architecture applied to a robotic platform

This paper proposes a real-time sound source localization and tracking architecture based on the abilityof the mammalian auditory system using the interaural intensity difference. We used an innovative bin- aural Neuromorphic Auditory Sensor to obtain spike rates similar to those generated by the inner haircells of the human auditory system. The design of the component that obtains the interaural intensitydifference is inspired by the lateral superior olive. The spike stream that represents the IID is used toturn a robotic platform towards the sound source direction. The architecture was implemented on FPGAdevices using general purpose FPGA resources and was tested with pure tones (1-kHz, 2.5-kHz and 5-kHzsounds) with an average error of 2.32 °. Our architecture demonstrates a potential practical application of sound localization for robots, and can be used to test paradigms for sound localization in the mammalianbrain.Ministerio de Economía y Competitividad TEC2016-77785-

Bioinspired Spike-Based Hippocampus and Posterior Parietal Cortex Models for Robot Navigation and Environment Pseudomapping

The brain has great capacity for computation and efficient resolution of complex problems, far surpassing modern computers. Neuromorphic engineering seeks to mimic the basic principles of the brain to develop systems capable of achieving such capabilities. In the neuromorphic field, navigation systems are of great interest due to their potential applicability to robotics, although these systems are still a challenge to be solved. This work proposes a spike-based robotic navigation and environment pseudomapping system formed by a bioinspired hippocampal memory model connected to a posterior parietal cortex (PPC) model. The hippocampus is in charge of maintaining a representation of an environment state map, and the PPC is in charge of local decision-making. This system is implemented on the SpiNNaker hardware platform using spiking neural networks. A set of real-time experiments are applied to demonstrate the correct functioning of the system in virtual and physical environments on a robotic platform. The system is able to navigate through the environment to reach a goal position starting from an initial position, avoiding obstacles and mapping the environment. To the best of the authors’ knowledge, this is the first implementation of an environment pseudomapping system with dynamic learning based on a bioinspired hippocampal memory. © 2023 The Authors. Advanced Intelligent Systems published by Wiley-VCH GmbH.Ministerio de Educación, Cultura y Deporte (MECD). España PID2019‐105556GB‐C33Horizonte 2020 (Unión Europea) CHIST‐ERA‐18‐ACAI‐004Horizonte 2020 (Unión Europea) PCI2019‐111841‐2/AEI/10.13039/501100011033Ministerio de Ciencia e Innovación (MCIN) España AEI/10.13039/50110001103

Low Latency Event-Based Filtering and Feature Extraction for Dynamic Vision Sensors in Real-Time FPGA Applications

Dynamic Vision Sensor (DVS) pixels produce an asynchronous variable-rate address-event output that represents brightness changes at the pixel. Since these sensors produce frame-free output, they are ideal for real-time dynamic vision applications with real-time latency and power system constraints. Event-based ltering algorithms have been proposed to post-process the asynchronous event output to reduce sensor noise, extract low level features, and track objects, among others. These postprocessing algorithms help to increase the performance and accuracy of further processing for tasks such as classi cation using spike-based learning (ie. ConvNets), stereo vision, and visually-servoed robots, etc. This paper presents an FPGA-based library of these postprocessing event-based algorithms with implementation details; speci cally background activity (noise) ltering, pixel masking, object motion detection and object tracking. The latencies of these lters on the Field Programmable Gate Array (FPGA) platform are below 300ns with an average latency reduction of 188% (maximum of 570%) over the software versions running on a desktop PC CPU. This open-source event-based lter IP library for FPGA has been tested on two different platforms and scenarios using different synthesis and implementation tools for Lattice and Xilinx vendors

Mapas nacionales de calidad de estación para Pinus sylvestris, Pinus nigra, Pinus pinaster, Fagus sylvatica y Quercus pyrenaica

La determinación de la calidad de estación de un rodal es fundamental para poder establecer una gestión sostenible de los recursos. La mayor parte de los trabajos que estudian las variables que explican la calidad de estación se ha llevado a cabo a escala local o regional y fundamentalmente utilizando índices, como el índice de sitio (relación altura dominante-edad), aplicables únicamente a masas regulares. Los objetivos de este trabajo son: i) ajustar modelos de calidad de estación a escala nacional para algunas de las principales especies arbóreas forestales de la Península Ibérica (Pinus sylvestris, P. nigra, P. pinaster, Fagus sylvatica y Quercus pyrenaica) válidos para masas con distinta forma principal; y ii) elaborar mapas de calidad de estación a escala nacional. Los modelos de calidad de estación se ajustaron usando modelos no lineales a partir de los pares de datos altura dominante-diámetro dominante de las parcelas del Tercer Inventario Forestal Nacional. Los mapas de calidad de estación se desarrollaron usando las predicciones de modelos aditivos espaciales que incluían variables fisiográficas como predictores. La precisión de nuestros modelos aditivos espaciales se encuentra entre 38,2 % y 47,9 %. La altitud y la orientación son variables fundamentales para determinar la calidad de estación. Los mapas mostrados pueden ser útiles tanto para la gestión forestal a escala regional como para el desarrollo de políticas forestales a nivel nacionalEste trabajo se ha financiado por los siguientes proyectos de investigación: AGL2016-76769-C2-1-R y AGL2016-76769-C2-2-R. Daniel Moreno Fernández es beneficiario de un contrato predoctoral de Formación del Profesorado Universitario (FPU13/02113) del Ministerio de Educación, Cultura y Deporte. César Pérez Cruzado es beneficiario de un contrato Juan de la Cierva financiado por la Secretaria de Estado de Investigación, Desarrollo e Innovación, y MSCA-EF de la Comisión EuropeaS

Recensiones [Revista de Historia Económica Año VII Invierno 1989 n. 1 pp. 219-253]

Linda Newson. The Cost Of Conquest. Indian decline in Honduras under the Spanish rule e Indian survival in colonial Nicaragua (Por Pedro Pérez Herrero).-- Pedro Rodríguez Campomanes. Reflexiones sobre el comercio español a Indias. (Por Luis Perdices Blas).-- Josep Fontana y otros. El comercio libre entre España y América Latina, 1765- 1824 (Por Andrés José Moreno Mengíbar).-- David-Sven Reher. Familia, población y sociedad en la provincia de Cuenca, 1700- 1970 (Por Concepción De Castro).-- Harvey J. Graff. The labyrinths of literacy. Reflections on literacy past and present (Por Clara E. Núñez).-- Bernard Elbaum y William Lazonick (Eds.) The decline of the Brittish Economy (Por Antonio F. Cubel Montesinos).-- Antonio Gómez Mendoza. Ferrocarril y mercado interior, Vol. 1: cereales, harinas y vinos, y Vol. 2: Manufacturas textiles, materias textiles, minerales, combustibles y metales (Por James Simpson).-- Carmen Sanchís Deusa. El transporte en el País Valenciano. Carreteras y ferrocarriles (Por Javier Vidal Olivares).-- José Manuel Naredo. La economía en evolución. Historia y perspectivas de las categorías básicas del pensamiento Eeconómico (Por Manuel Santos Redondo).-- Roger Backhouse. Historia del análisis económico moderno (Por Fernando Méndez Ibisate).-- William N. Parker (Ed.). Economic History and the modern economist (Por Gabriel Tortella)Publicad