Low-cost Control Unit Research Articles

Development of a Flexible, Extendable, and Low-Cost Control Unit for Surface Drifters

AbstractAn extensible, low-cost drifter control unit (VELELLA) design is presented, developed for use in drifters that are deployed in inland water bodies or near-coast regions. The control unit is custom built from basic components built around a small footprint microcontroller, making use of a GPS receiver for position tracking, a Global System for Mobile Communications [Groupe SpécialMobile (GSM)] radio for data transmission, and two sensor buses to handle analog and digital data generated by an arbitrary array of external sensors. A cloud-based data collection platform has been implemented to receive and store data transmitted over general packet radio service (GPRS) from the drifter. The control unit was found to perform satisfactorily in operational testing, providing data at subhertz frequency for position and temperature during extended time. However, some issues related to temporary data loss and power consumption spikes were identified, indicating that some further development of the control unit is required to achieve a production-ready platform for extensive and prolonged field operations.

Real-Time Model-Based Estimation of SOC and SOH for Energy Storage Systems

To obtain a full exploitation of battery potential in energy storage applications, an accurate modeling of electrochemical batteries is needed. In real terms, an accurate knowledge of state of charge (SOC) and state of health (SOH) of the battery pack is needed to allow a precise design of the control algorithms for energy storage systems (ESSs). Initially, a review of effective methods for SOC and SOH assessment has been performed with the aim to analyze pros and cons of standard methods. Then, as the tradeoff between accuracy and complexity of the model is the major concern, a novel technique for SOC and SOH estimation has been proposed. It is based on the development of a battery circuit model and on a procedure for setting the model parameters. Such a procedure performs a real-time comparison between measured and calculated values of the battery voltage while a PI-based observer is used to provide the SOC and SOH actual values. This ensures a good accuracy in a wide range of operating conditions. Moreover, a simple start-up identification process is required based on battery data-sheet exploitation. Because of the low computational burden of the whole algorithm, it can be easily implemented in low-cost control units. An experimental comparison between SOC and SOH estimation performed by suggested and standard methods is able to confirm the consistency of the proposed approach.

INCREASING ION SELECTIVE ELECTRODES PERFORMANCE USING NEURAL NETWORKS

This paper reports the implementation of a neural processing structure as a component of an intelligent measuring system that uses ion selective electrodes (ISEs) as sensing elements of heavy metal ions (Pb+2, Cd+2) concentration. The neural network (NN), designed and implemented to reduce errors due to ion interference and to pH and temperature variations, is of the multiple-input multiple-output Multilayer Percepton (MLP-NN) type. The NN is a component of a virtual instrument that includes a PC laptop, a PCMCI data acquisition board with associated conditioning circuits and the specific ISE sensors. A practical approach concerning the optimal neural processing solution (number of NN structures, number of neurons, neuron transfer functions) to increase the performance of low cost ISEs is presented. Results are presented to evaluate the performance of the NN intelligent ISE system and to discuss the possibility of transferring the acquisition and processing task to a low cost acquisition and control unit such as a microcontroller.

An Experimental Vehicular Wireless System and Link Performance Analysis

Reliable wireless communication is a key component for intelligent transportation systems (ITS). This paper develops a wireless module for ITS using an AR7100 series embedding platform. The module consists of a low-cost multi-interface wireless mesh and control unit to provide high quality of services for different applications. It acts as a node in a vehicular wireless network with a pure software extension without costly hardware modifications. The developed system was tested in the urban area of the Wuhan city, China. It is observed that the fast fading effect plays a significant role in the performance of vehicular communications. To characterize these effects, a physical-level model of the radio link between two moving vehicles is proposed. This model takes the impacts of Rician K-factor, vehicle speed ratio, and Doppler spectrum into consideration. Compared with the existing physical models, the proposed physical-level model is shown to be more accurate in describing the packet-level characteristics of vehicle communications. Furthermore, the analysis of the proposed physical-level model indicates the necessity of cross-layer design of vehicular wireless networks.

A Simplified Power Factor Correction Using Low-Cost Micro Control Unit for White Goods

A Simplified Power Factor Correction Using Low-Cost Micro Control Unit for White Goods

Experimental Study of Coupling Fiber-Optic Vibration Sensor Based on Variational Theory

According to the character of fiber-optic coupler, its coupling output is sensitive to the variation of coupling region’s length. A new kind of coupling fiber-optic vibration sensor is presented base on this principle. The theory of coupling single-mode fiber-optic sensor is analyzed. A prototype of fiber optic vibration detection system has been successfully built, including a sensor head, a low-cost control unit and a software package for signal processing with high resolution. The response of fiber-optic sensor and piezoelectric sensor to periodic vibration and shock is measured and the results of the coupling fiber-optic vibration sensor are closely in accordance with high precision piezoelectric sensor. The cross-axis anti-disturbance ability of the fiber-optic sensor is discussed in addition. Experimental results indicate that the coupling fiber-optic vibration sensor has favorable vibration detection capability; it can meet the requirement of vibration measurement.

Feedback control laws for proof-mass electrodynamic actuators

This paper presents a simulation study about the stability and performance of a controlsystem with five decentralized feedback control units mounted on a flat panel in order toreduce its vibration and sound radiation. Each control unit consists of a proof-masselectrodynamic actuator with a velocity sensor at its base. The aim is to design light,simple, robust and low cost control units which can be attached in large numbers to flexiblestructures in order to control their spatially averaged response and sound radiation at lowaudio-frequencies. Thus four basic feedback control functions have been studied:(a) proportional, (b) integral (c) derivative and (d) PID. Two types of controllers havebeen considered which drive the actuators either with current or voltage signals.This paper shows that proportional control loops generate active damping which effectivelyreduces the frequency averaged response of the plate except at the fundamental resonancefrequency of the actuator and at higher frequencies where control spillover effects takeplace. The PID control loops can mitigate these control spillover problems with no loss ofcontrol performance. Finally, integral and derivative control loops are characterized byimportant stability issues and also produce little control effects since they generateactive stiffness and active mass effects which just shift the resonances of the platestructure.

A SIMPLE APPROACH TO IMPLEMENTING AN ENVIRONMENTAL CONTROL UNIT FOR THE DISABLED

Environmental control units play a role in enabling disabled people to carry out routine and repetitive tasks (e.g. watching TV, making a phone call, etc.) in their home environments. Unfortunately, most commercially available environmental control units are either too expensive or they require the disabled persons' home environments to be remodelled. In this paper we report the development of a low-cost environmental control unit which enables disabled people to control mostly existing consumer electronics with an infrared remote control functionality. Finally, we use a simple scenario to evaluate the performance of the proposed environmental control unit.

Novel fiber optic accelerometer system using geometric moiré fringe

This paper presents an innovative fiber optic accelerometer system for monitoring vibration of large-size structures. The system is composed of one (or multiple) sensor head and a control unit for driving the sensor and processing sensor data. The sensing mechanism is based on a novel integration of the moiré fringe phenomenon with fiber optics, resulting in accurate and reliable measurement. A prototype fiber optic accelerometer system has been successfully developed, including a sensor head, a low-cost control unit and a software package with a unique algorithm for processing the moiré fringe signals into accelerations with a high resolution. Finally, free vibration and shaking table tests were performed to identify the dynamic characteristics and demonstrate the high performance of the sensor system developed in this study.

A system for inverter protection and real-time monitoring

A real-time system for protecting and monitoring a DC/AC converter has been designed and constructed. The proposed system consists of (a) a hardware protection unit for fast reaction, load protection and inverter fail-safe operation and (b) a microcontroller unit for calculating critical parameters of the inverter operation. The control unit malfunctions have not been investigated in this study. The proposed hardware architecture and sensors form a low-cost and reliable control unit. The experimental results show that the proposed system ensures the inverter protection and fail-safe features. The proposed unit can be used to increase the reliability of any power inverter in AC motor drives, renewable energy systems, etc. or can be incorporated in any UPS system.

A COMPARATIVE EXAMINATION OF AUTOMATIC SEQUENTIAL DIRECT SYSTEMS FOR STRAIN-GAGE DATA READINGS RASED ON A LOW-COST SWITCH-CONTROL UNIT

Small zero drift values can be reached with a low-cost switch control unit when the devices are utilized in field test situations. The evaluation of the zero drift values allow proper utilization of the systems examined for long-term strain measurements.