Mirela Dobra

Rapid prototyping of control systems using embedded target for TI C2000 DSP

The paper presents a digital control application, in which a tuning method is proposed for DC motors, using DSP from Texas Instruments (TI). Experimental application for the DC motor illustrates the effectiveness and the simplicity of the proposed method for controller design. The control algorithm for the drive application runs on a TMS320F2812 DSP. Once the desired functionality has been captured and simulated, using MATLAB/Simulink/Embedded Target for TI C2000 DSP environment can be generated code for the DSP. All task assignments to processor are automatically made by the software. The DC Motor is driven by pulse width modulated (PWM) signals generated by the DSP.

Reliability indicators analysis for the cam box module of industrial knitting machines

This paper studies the reliability of an industrial knitting machine, emphasizing the reliability value and the reliability indicators: failure rate and MTBF (Mean Time Between Failures). This study has been conducted on an industrial knitting machine and has duration of 4500 hours (approximately 6 months), after which preventive maintenance operations are planned. This study analyses the behavior of the reliability, failure rate and of the MTBF depending on the functioning environment and of the temperature to which the knitting machine was subjected. The last part presents an analysis of the top ten components that are most likely to malfunction.

Efficient implementation of sliding mode control for BLDC PM motor using TMS320F28335 microcontroller

The sliding mode control (SMC) approach is reconsidered for the three phase brushless direct current motor with permanent magnets (BLDC PM). For mathematically matching the SMC to BLDC PM, brief discussion is also made on the mathematical modelling of the BLDC PM motor. The speed control loop for electric drive with BLDC PM is tested especially for load torque variation that will be assumed as additive uncertainty. The loop control implementation uses the TMS320F28335 microcontroller with special processing facilities for electric drive signals. The final target is to validate a fast procedure of setting up the speed/position control loop with a simple starting SMC algorithm. Test results using different valued parameters of the proposed SMC support the rapid prototyping procedure.

Hydropower Structures Monitoring System with Hierarchically Distributed Smart Sensor Network

Traditionally, a remote monitoring system for the geotechnical instruments intended for surveillance of a hydropower structure is made using large concentrated data acquisition stations with a capacity of up to 256 measurement channels, connected to a local data acquisition server. This paper proposes a new hydropower structure monitoring system, based on a distributed architecture of smart sensor, organized as hierarchical sensor networks. Several developments are required in order to implement such a new system: development of a new family of network interfacing modules, implementation of a group of new smart wired and wireless sensors, implementation of a software application for configuring the sensor network, acquiring, visualizing and archiving data from sensors.

Two stage scheduling method of touristic transport in multimodal networks

The presented paper proposes a method suitable to support scheduling activities in multimodal transport networks, whose adapted structures correspond to specific requirements of actual tourism services. Considering characteristic aspects of the application type, a two-stage approach was chosen to find an appropriate solution. First, a Delay Time Petri Nets (DTPN) model was developed to describe all touristic routes and their associated activities in the considered area. Then, using the elaborated model and following a visit planning, Genetic Algorithms were utilized to find convenient schedules for transport activities. For simulation purposes, scenarios inspired from real situations were chosen. The obtained results lead to the elimination of critical values of time that could generate unwanted behaviors.

Control Loops Comparative Study Based on IR Thermal Imaging for Electrical Drives with BLDC PM Motors

The effects of choosing among different control strategy when electric drives with BLDC PM motors are involved, lead inevitably to different heat losses even if the error performances are accepted as similar. A comparative study based on unconventional infrared thermal imaging is proposed to evaluate heat losses. Two cases are considered for medium power BLDC PM speed control. First control structure revises the classic P control loop and its practical implementation advantages. The second control algorithm present a modified PID control derived from state space approach. Thermal infrared captures are externally made, at the housing level of the BLDC PM motor. When using current and speed feedback, the captured external temperature results higher, in comparison to the case when using only speed as correction signal. A trade off must be established between torque requirements, heat losses and tracking reference signal.

Model based fault detection for electrical drives with BLDC motor

Continuous improvements in microelectronic circuitry make possible the implementation of process diagnostics to a variety of systems in order to increase performances and reliability. The monitoring stage in the area of failure detection and isolation aims to classify and arrange the failure sources. In case of BLDC machines, one of the most important methods for failure detection and diagnosis starts with the analysis of the variations of the machine estimated parameters. The paper focuses on the implementation details of failure detection and diagnosis based on continuous time parameters estimation of BLDC motor mathematical model. Continuous time parameters are directly related to the physical characterizations of BLDC Motor. The parameters are estimated by the well-known prediction error methods devised for dynamic system identification. By changing the process coefficients and by applying statistical decision methods, failure detection occurs. The case of frequency domain identification in fail detection is also covered on a real CNC machine. Discrete Fourier Transform (DFT) with the particular case of Goertzel algorithms is implemented for fault detection purposes. Unlike existing work and results in the fault detection area, the failure can be detected among time-varying process parameters.

Household Water Tank Temperature Control

This paper presents an identification solution of the thermal process corresponding to a heating installation of domestic water in a tank and the temperature control. For experimental identification the tangent and Coon Cohen methods were applied, and for control Cohen Coon criterion, Oppelt criterion, respectively modulus criterion. We performed a comparison of the overall performance of each controller.

Low cost environment for teaching and experimenting current based testing

This paper presents a low cost environment for teaching and experimenting current based testing techniques. An original hardware platform built around and USB communication capable microcontroller together with a set of software applications were developed. This environment allows construction of IDDQ signature collections and experimenting of testing methods based on analysis of IDDQ signature. It also permits to study the setups appropriate for built-in current sensor based techniques for analog or digital circuits. Real-time data exchange with MATLAB is provided for experimenting methods of fault detection and diagnosis based on the analysis of IDDT waveform (wavelet based analysis, spectrum, etc.).

Adaptive system identification of automotive power generation

Abstract The paper presents an adaptive system identification application using a Digital Signal Processor from Texas Instruments. The system to be identified is an automotive alternator. Experimental application illustrates the effectiveness and the simplicity of the proposed method. The application runs on a TMS320F2812 DSP. Once the desired functionality has been captured and simulated, using MATLAB/Simulink/Embedded Target for TI C2000 DSP environment can be generated code for the DSP. All task assignments to processor are automatically made by the software. Once the coefficients of a digital filter are calculated the mathematical model of the unknown system is determined.