PWM Control of a Buck Converter with an Amorphous Core Coil

Pulse-width modulation is widely used to control electronic converters. One of the most topologies used for high DC voltage/low DC voltage conversion is the Buck converter. It is obtained as a second order system with a LC filter between the switching subsystem and the load. The use of a coil with an amorphous magnetic material core instead of air core lets design converters with smaller size. If high switching frequencies are used for obtaining high quality voltage output, the value of the auto inductance L is reduced throughout the time. Then, robust controllers are needed if the accuracy of the converter response must not be affected by auto inductance and load variations. This paper presents a robust controller for a Buck converter based on a state space feedback control system combined with an additional virtual space variable which minimizes the effects of the inductance and load variations when a not-toohigh switching frequency is applied. The system exhibits a null steady-state average error response for the entire range of parameter variations. Simulation results are presented

Using the Own Flexibility of a Climbing Robot as a Double Force Sensor

Force sensors are used when interaction tasks are carried out by robots in general, and by climbing robots in particular. If the mechanics and electronics systems are contained inside the own robot, the robot becomes portable without external control. Commercial force sensors cannot be used due to limited space and weight. By selecting the links material with appropriate stiffness and placing strain gauges on the structure, the own robot flexibility can be used such as force sensor. Thus, forces applied on the robot tip can be measured without additional external devices. Only gauges and small internal electronic converters are necessary. This paper illustrates the proposed algorithm to achieve these measurements. Additionally, experimental results are presented

Sound Recognition System Using Spiking and MLP Neural Networks

In this paper, we explore the capabilities of a sound classification system that combines a Neuromorphic Auditory System for feature extraction and an artificial neural network for classification. Two models of neural network have been used: Multilayer Perceptron Neural Network and Spiking Neural Network. To compare their accuracies, both networks have been developed and trained to recognize pure tones in presence of white noise. The spiking neural network has been implemented in a FPGA device. The neuromorphic auditory system that is used in this work produces a form of representation that is analogous to the spike outputs of the biological cochlea. Both systems are able to distinguish the different sounds even in the presence of white noise. The recognition system based in a spiking neural networks has better accuracy, above 91 %, even when the sound has white noise with the same power.Ministerio de Economía y Competitividad TEC2012-37868-C04-02Junta de Andalucía P12-TIC-130

Biomimetic organisations: a management model that learns from nature

Since the end of the last century, different approaches for corporate management have been appearing that try to incorporate the social advances that are being produced and disseminated thanks to the greater capacity of communication available through social networks and other traditional avenues. Among the best known are Corporate Social Responsibility, Sustainability, the Circular Economy, and Collaborative Economics. All of them add value to organisations, and all of them have a common characteristic: they are anthropocentric approaches. Our proposal goes a step further: we need a worldview that is capable of placing organisations in a position of continuous learning looking at nature, because it is the best way to integrate into it as a more ecosystem and thus achieve its flowering respecting the once to all the other subsystems that make up the planet: Organizational Biomimicry. This work compares the anthropocentric vision with the worldview at the same time that it offers a guide of the essential steps so that Organizational Biomimicry is the new model of corporate management.Peer ReviewedPostprint (published version

Live Demonstration: On the distance estimation of moving targets with a Stereo-Vision AER system

Distance calculation is always one of the most important goals in a digital stereoscopic vision system. In an AER system this goal is very important too, but it cannot be calculated as accurately as we would like. This demonstration shows a first approximation in this field, using a disparity algorithm between both retinas. The system can make a distance approach about a moving object, more specifically, a qualitative estimation. Taking into account the stereo vision system features, the previous retina positioning and the very important Hold&Fire building block, we are able to make a correlation between the spike rate of the disparity and the distance.Ministerio de Ciencia e Innovación TEC2009-10639-C04-0

Effective Power Signal Filtering using LC Filters with Air Core Coils

Computer controlled power supplies are usually expensive when high performance (power, wide voltage range, low ripple factor and low response time) are required. This paper presents a simple and effective computer controlled DC system based on a commercial V/f inverter combined with a three-phase bridge rectifier and a LC power filter. Because of the widely variable frequency range of the V/f inverter when a wide range of voltage is required, amorphous or ferromagnetic core coils are avoided, and air core coils become an excellent solution to implement the filter and increase the efficiency of the power system. The proposed method for designing the LC filter is based on the full dynamic model of the filter-load set and the selection of the desired poles of the system according to the load to be coupled. The proposed topology lets obtain good time responses (setting time less than 100 ms) and good ripple factor (less than 1%) without any overshooting, even when low voltage output is required

Some eigenvalue problems with non-local boundary conditions and applications

In this paper we study an elliptic eigenvalue problem with non-local boundary condition. We prove the existence of the principal eigenvalue and its main properties. As consequence, we show the existence and uniqueness of positive solution of a nonlinear problem arising from population dynamics.Ministerio de Economía y CompetitividadFondo Europeo de Desarrollo Regiona

On the Designing of Spikes Band-Pass Filters for FPGA

In this paper we present two implementations of spike-based bandpass filters, which are able to reject out-of-band frequency components in the spike domain. First one is based on the use of previously designed spike-based low-pass filters. With this architecture the quality factor, Q, is lower than 0.5. The second implementation is inspired in the analog multi-feedback filters (MFB) topology, it provides a higher than 1 Q factor, and ideally tends to infinite. These filters have been written in VHLD, and synthesized for FPGA. Two spike-based band-pass filters presented take advantages of the spike rate coded representation to perform a massively parallel processing without complex hardware units, like floating point arithmetic units, or a large memory. These low requirements of hardware allow the integration of a high number of filters inside a FPGA, allowing to process several spike coded signals fully in parallel.Ministerio de Ciencia e Innovación TEC2009-10639-C04-0

Nonlinear Cascade-Based Control for a Twin Rotor MIMO System

This research is focused on the development of a nonlinear cascade-based control algorithm for a laboratory helicopter-denominated Twin Rotor MIMO System (TRMS). The TRMS is an underactuated nonlinear multivariable system, characterised by a coupling effect between the dynamics of the propellers and the body structure, which is caused by the action-reaction principle originated in the acceleration and deceleration of the propeller groups. Firstly, this work introduces an extensive description of the platform’s dynamics, which was carried out by splitting the system into its electrical and mechanical parts. Secondly, we present a design of a nonlinear cascade-based control algorithm that locally guarantees an asymptotically and exponentially stable behaviour of the controlled generalised coordinates of the TRMS. Lastly, a demonstration of the effectiveness of the proposed approach is provided by means of numerical simulations performed under the MATLAB®/Simulink® environment

Spikes Monitors for FPGAs, an Experimental Comparative Study

In this paper we present and analyze two VHDL components for monitoring internal activity of spikes fired by silicon neurons inside FPGAs. These spikes monitors encode each spike according to the Address-Event Representation, sending them through a time multiplexed digital bus as discrete events, using different strategies. In order to study and analyze their behavior we have designed an experimental scenario, where diverse AER systems have been used to stimulate the spikes monitors and collect the output AER events, for later analysis. We have applied a battery of tests on both monitors in order to measure diverse features such as maximum spike load and AER event loss due to collisions.Ministerio de Ciencia e Innovación TEC2009-10639-C04-02Ministerio de Economía y Competitividad TEC2012-37868-C04-0