Revista elektron

Number 2, 2022

65-76
Design of a flight controller to achieve improved fault tolerance

Authors: Claudio Pose, Leonardo Garberoglio, Ezequiel Pecker-Marcosig, Ignacio Mas, Juan Giribet

Abstract

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In the last years, multirotor aerial vehicles have gained popularity both as consumer products and in professional applications. Safety is one of the main concerns during operation, and different approaches to fault tolerance have been proposed and continue to be developed. For a control system to be able to handle off-nominal situations, failures must be properly detected and identified; therefore, a fault detection and identification algorithm is required. Also, the control loop has to be accordingly modified to cope with each particular failure in the best way possible. These algorithms usually run on the vehicle’s low-level flight computer, imposing on it a large additional computational load. In this work, a fault detection and identification module is used to evaluate its impact in terms of additional processing time on a flight computer based on the Cortex-M3 microcontroller. While a highly optimized version of the algorithm is able to run, it still suggests potential hardware limitations for expanding the system capabilities. The evaluation of the same module on an improved flight computer design based on a Cortex-M7 micro-processor shows a significantly reduced footprint in the overall performance, allowing for the addition of an augmented method for faster failure detection.

75-85
Design of a rapid plug in battery charger for electric vehicles at the common connection point of the electrical power distribution network

Authors: Carlos Mauricio Orellana Uguña, Luis González Morales, Karla Verdugo

Abstract

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This article shows technical aspects related to the design of fast charging stations for light electrical vehicles under 1,5 tons, belonging at level 3 and mode 4 of DC charging according to EN 61851, within the framework of IEEE ST 2030.1.1-2022 standard, , IEEE Std 1547-2018 and IEC 61000-3-4 . In relation to the design of the charging station the article only covers the energy management “energy conversion system”, which includes energy processing devices (semiconductors, line filters and passive elements).

86-95
Coordinated control of aerial and aquatic vehicles for bathymetric survey in shallow waters

Authors: Leonardo Garberoglio, Patricio Moreno, Ignacio Mas, Juan Giribet

Abstract

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Number of views: 28

Applications with small unmanned vehicles have grown remarkably in recent years. Along with this, the interest and the need to carry out tasks using several of these vehicles has gained relevance. This paper presents the use of a formation based on the cluster space control technique between an unmanned surface vehicle and an aerial vehicle, with the aim of monitoring river basins. The different perception of the environment that each vehicle has and the ability to transport different sensors are fundamental characteristics for this type of application. Results are presented both in a simulation environment and in a real application with unmanned vehicles belonging to the research groups.

96-100
New variant of NLMS/F algorithm with low computational cost

Authors: Laura Jazmín Hidalgo Hernández, Ángel Alfonso Vázquez Piña, Xochitl Maya Rosales, Juan Gerardo Avalos Ochoa, Giovanny Sánchez Rivera

Abstract

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Number of views: 45

Adaptive filters are used in a wide variety of signal processing applications (e.g., acoustic echo cancellation, system identification, channel equalization, etc.). Adaptive algorithms are an essential part of adaptive filters since they update the filter coefficients to model the desired response. Therefore, adaptive algorithms must have low computational cost and high speed of convergence. In this paper, a new variant of the Normalized Least-Mean-Fourth (NLMF) algorithm based on set membership is presented, in addition, a method to automatically adjust the step size is presented. To evaluate its performance, the algorithm was simulated in system identification and acoustic echo cancellation applications. The results demonstrate that the proposed algorithm improves the convergence speed and exhibits low computational cost compared to the conventional NLMS/F algorithm.

101-106
Data Acquisition System using a CIAA-Safety

Authors: Juan Pablo Rumie Vittar, Dario Walter. Diaz, Gustavo Miguel Rodriguez, Juan Octavio Oviedo, Ariel Cristian Principi, Damian Hector Primo, Diego Daniel Badino, Francisco Martin Escobar

Abstract

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Number of views: 42

This paper presents the analysis, design, development and implementation of a data acquisition system from various sensors, to be installed and used in different FAA Air Vehicles, through an ARM® Cortex®-R4F CPU microcontroller that meets critical safety standards, such as IEC 61508 , ISO 26262 and DO-178 (at the Software level). The sensors are: a GNSS (Global Navigation Satellite System), an IMU (Inertial Measurement Unit) and atmospheric pressure and temperature sensors. The ARM microcontroller was mounted on a development board called CIAA-Safety and its programming was carried out under the BAREMETAL format, that is, without a Real Time Operating System.

102-128
A measurement system with dual Modbus connections linked through MQTT/TLS to a remote server: internal details and first operation results

Authors: Marcelo Castello, Rafael Beltran Oliva

Abstract

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Number of views: 27

This work presents a renewable energy measurement system with two Modbus protocol connections (RTU/Serial to internal modules, TCP to external units) and achieves a TLS-encrypted link between the datalogger module and a centralized remote dashboard application. Recent installation and commissioning of high quality instruments allow for reliable information to be collected, and the system offers remote monitoring and data persistence. The logger acquires wind data using Thies sensors installed on the wind turbine tower, and current and voltage from both the wind turbine and an array of photovoltaic panels. Energy is stored in a battery bank and is used to supply electric power to a greenhouse. In this nearby building, an additional module to measure temperature and humidity of the plant-growing environment was developed and programmed. The module communicates via RS485 using Modbus RTU with the main datalogger, which also uses an internal network connection through Modbus TCP to a Raspberry Pi4B board. The Pi board converts the readings to MQTT/TLS, an added security feature before sending data to the remote server which runs the dashboard application. A continuous performance analysis of the renewable energy unit is possible due to the availability and persistence of real-time data on the server and also on the CF card of the datalogger.

107-114
B-VGG16: Binary Quantized Convolutional Neuronal Network for image classification

Authors: Nicolás Urbano Pintos, Héctor Lacomi, Mario Lavorato

Abstract

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Number of views: 38

In this work, a Binary Quantized Convolution neural network for image classification is trained and evaluated. Binarized neural networks reduce the amount of memory, and it is possible to implement them with less hardware than those that use real value variables (Floating Point 32 bits). This type of network can be implemented in embedded systems, such as FPGA. A quantization-aware training was performed, to compensate for the errors caused by the loss of precision of the parameters. The model obtained an evaluation accuracy of 88% with the CIFAR-10 evaluation set.

115-119
PGA implementation of a BPSK modulator with adjustable parameters

Authors: Mariao Morel, Lucas Rabioglio, Raúl Lopresti, Maximiliano Antonelli, Luciana De Micco

Abstract

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Number of views: 30

This work presents the design and implementation of a phase-modulated signal generator, which allows a widerange of variation in its transmission parameters. The implemented circuit uses a minimum amount of FPGA resources. This was possible since the developed design stores a quarter cycle of the carrier, then the control logic decides which samples to take to obtain the established frequency and number of cycles per data, allowing a great variation. The output power of the signal is also configurable. In addition, the developed system allows data to be received through an external input or generated internally through a pseudo-random number generator (PRNG). The circuit was implemented using an FPGA (Field Programmable Gate Array) and a digital-analogue converter (DAC).

129-134
Spectrograms of baleen whale records synthesized from Autoenconder architectures: CAE, VAE and CAE-LSTM

Authors: María Celeste Cabedio, Marco Carnaghi

Abstract

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Number of views: 35

In this paper, different architectures of simple convolutional networks are analyzed to generate synthetic spectrograms corresponding to baleen whales. Simplicity in these models plays an important role in the implementations of these type of networks on embedded systems. In addition, the scarcity of available data requires the generation of efficient models. With this aim in mind, simple Autoencoder architectures with a low number of as- sociated parameters are presented and trained in this paper. Then, adequate metrics are obtained and the corresponding comparison among the architecture alternatives is made. The obtained results show that the more straightforward architecture is, in turn, the most convenient. Finally, from these models, synthetic spectrograms are generated from few data samples are generated, employing a low complexity architecture and assuming a normal distribution of the latent space vectors from the training data.

135-139
Alternative and emergency cellular system based on OpenBTS and SDR

Authors: Alian Ernesto Matos Rodríguez, Marcelino Sánchez Posada

Abstract

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Number of views: 35

The Global System for Mobile Communications (GSM) has been widely accepted around the world. The implementation of this system for a comunity are expensive because to use high-cost equipment, but thanks to the development of software-defined radio systems, it is possible to develop this type of network at a reduced cost. Access to telecommunications services in rural communities in Cuba is today a great challenge, mainly caused by the geographical location and the small number of habitants that make the deployment of infrastructure not economically feasible. The main contributions of the present work focus in an alternative cellular system and GSM network management software. It was shown that it is possible to build a mobile telephone network using free software components and low-cost hardware, which can be used in sparsely populated rural communities, as well as in emergency situations.