Showing papers presented at "International Symposium on Industrial Electronics in 2005"

A three-phase step-up DC-DC converter with a three-phase high frequency transformer

Abstract: This paper presents a new 3-phase step-up DC-DC converter with a 3-phase high frequency isolation transformer. This converter was developed for industrial applications where the DC input voltage is lower than the output voltage, for instance in, installations fed by battery units, photovoltaic arrays or fuel cell systems. The converter's main characteristics are: reduced input ripple current, step-up voltage, high frequency isolating transformer, reduced output voltage ripple due to three pulsed output current and the presence of only three actives switches connected at the same reference, this being a main advantage of this converter. By means of a specific switch modulation, the converter allows two operational regions. Theoretical expressions and experimental results are presented for a 6.8 kW prototype, operating in region R2 and for a 3.4 kW prototype operating in region R3, both in continuous conduction mode.

Minimum Time vs Maximum Exit Velocity Path Optimization During Cornering

Abstract: Numerical optimization has been used as an extension of vehicle dynamics simulation in order to repro- duce trajectories and driving techniques used by expert race drivers and investigate the effects of several vehicle param- eters in the stability limit operation of the vehicle. In this work we investigate how different race-driving techniques may be reproduced by considering different optimization cost functions. We introduce a bicycle model with suspension dynamics and study the role of the longitudinal load transfer in limit vehicle operation, i.e., when the tires operate at the adhesion limit. Finally we demonstrate that for certain vehicle configurations the optimal trajectory may include large slip angles (drifting), which matches the techniques used by rally-race drivers. I. INTRODUCTION

Real-time system for monitoring driver vigilance

Abstract: In this paper we present a non-intrusive prototype computer vision system for real-time monitoring driver's vigilance. It is based on a hardware system, for real time acquisition of driver's images using an active IR illuminator, and their software implementation for monitoring some visual behaviors that characterize a driver's level of vigilance. These are the eyelid movements and the pose face. The system has been tested with different sequences recorded on night and day driving conditions in a motorway and with different users. We show some experimental results and some conclusions about the performance of the system.

Hybrid Electric Vehicle: Overview and State of the Art

Abstract: Electric traction is one of the most promising technologies that can lead to significant improvements in vehicle performance, energy utilization efficiency, and polluting emissions. Among several technologies, hybrid electric vehicle (HEV) traction is the most promising technology that has the advantages of high performance, high fuel efficiency, low emissions and long operating range. Moreover, the technologies of all the component hardware are technically and markedly available. At present, almost all the major automotive manufacturers are developing hybrid electric vehicles, and some of them have marketed their productions, such as Toyota and Honda. This paper reviews the present technologies of hybrid electric vehicle in the range of drivetrain configuration, electric motor drives and energy storages.

Indoor Robot Localization System Using WiFi Signal Measure and Minimizing Calibration Effort

Abstract: This paper presents a robot localization system for indoor environments using WiFi signal strength measure. We analyse the main causes of the WiFi signal strength variation and we experimentally demonstrate that a localization technique based on a propagation model doesn't work properly in our test-bed. We have carried out a localization system based on a priori radio-map obtained automatically from a robot navigation in the environment in a semi-autonomous way. We analyse the effect of reducing calibration effort in order to diminish practical barriers to wider adoption of this type of location measurement technique. Experimental results using a real robot moving are shown. Finally, the conclusions and future works are presented.

Controller design for direct torque controlled space vector modulated (DTC-SVM) induction motor drives

Abstract: In this paper two different methods of PI controllers for direct torque controlled-space vector modulated induction motor drives have been studied. The first one is simple method based only on symmetric optimum criterion. The second approach takes into account the full model of induction motor including rotor voltage equation and uses root locus method. Some simulated and experimental oscillograms that illustrate properties of the presented controller design methods are shown.

A review of development of hybrid excitation synchronous machine

Abstract: Hybrid excitation synchronous machine (HESM) profit the advantages of permanent machine and electric excitation machine in quality, so it has a widely used prospect. The paper introduces its operation principle, classification, characteristics and the developing situation. And, the present application situation of HESM is summarized.

Power converter EMI analysis including IGBT nonlinear switching transient model

Abstract: It is well known that very high dv/dt and di/dt during the switching instant is the major high frequency EMI source. This paper proposes an improved and simplified EMI modeling method considering the IGBT switching behavior model. The device turn-on and turn-off dynamics are investigated by dividing the nonlinear transition by several stages. The real device switching voltage and current are approximated by piecewise linear lines and expressed using multiple dv/dt and di/dt superposition. The derived EMI spectra suggest that the high frequency noise is modeled with an acceptable accuracy. The proposed methodology is verified by experimental results using a DC-DC buck converter.

SMC with Disturbance Observer for a Linear Belt-Drive

Abstract: Accurate position tracking control in a belt-driven servomechanism can experience vibrations and large tracking errors due to compliance and elasticity introduced by force transmission through the belt and nonlinear friction phenomenon. In this paper, a new control algorithm based on sliding mode control that is able to deal with these problems is proposed. In order to further optimize position tracking performance the control scheme has been extended by an asymptotic disturbance observer. It has been proven that robust and vibration-free operation of a linear belt-driven system can be achieved. The experiments presented in the paper show improved position tracking error response while maintaining vibration suppression.

Abstraction and Reproduction of Force Sensation from Real Environment by Bilateral Control

Abstract: In recent years, skill preservation of an expert has been a serious problem in the medical or production fields. If digital skill preservation like a bilateral database is attained, it may become an innovative solution of the above problem. In this paper, abstraction and reproduction methods of force sensation from the real environment by bilateral control, and reconstruction method of the real environment are proposed. In the abstraction mode, a master– slave system is composed and the law of action and reaction is attained by bilateral control. We succeeded in realization of a vivid sensation of touch for bilateral robot system. Force and position information of both of master and slave systems is calculated and obtained, being based on acceleration information. In the reconstruction mode, an environment model is reconstructed from the obtained data of the real environment. In the reproduction mode, only the master system is prepared. Human operates the master system and feels force sensation from the environmental model which is reconstructed in the reconstruction mode. As a result, the proposed system is able to store the real environment as a bilateral database. The experimental results show the viability of the proposed method.

Hybrid Model Predictive Control Application Towards Optimal Semi-Active Suspension

Abstract: The optimal control problem of a quarter-car semi-active suspension has been studied in the past. Considering that a quarter-car semi-active suspension can either be modelled as a linear system with state dependent constraint on control (of actuator force) input, or a bi-linear system with a control (of variable damping coefficient) saturation, the seemingly simple problem poses several interesting questions and challenges. Does the saturated version of the optimal control law derived from the corresponding un-constrained system, i.e. “clipped-optimal”, remain optimal for the constrained case as suggested in some previous publications? Or should the optimal deviate from the “clipped-optimal” as suggested in other publications? If the optimal control law of the constrained system does deviate from its unconstrained counter-part, how different are they? What is the structure of the optimal control law? Does it retain the linear state feedback form (as the unconstrained case)? In this paper, we attempt to answer some of the above questions by utilizing the recent development in model predictive control (MPC) of hybrid dynamical systems. The constrained quarter-car semi-active suspension is modelled as a switching affine system, where the switching is determined by the activation of passivity constraints, force saturation, and maximum power dissipation limits. Theoretically, over an infinite prediction horizon the MPC controller corresponds to the exact optimal controller. The performance of different finite-horizon hybrid MPC controllers is tested in simulation using mixed-integer quadratic programming. Then, for short-horizon MPC controllers, we derive the explicit optimal control law and show that the optimal control is piecewise affine in state. In the process, we show that for horizon equal to one the explicit MPC control law corresponds to clipped LQR as expected. We also compare the derived optimal control law to various semi-active control laws in the literature including the well-known “clipped-optimal”. We evaluate their corresponding performances for both a deterministic shock input case and a stochastic random disturbances case through simulations.

Voice operated intelligent wheelchair - VOIC

Abstract: A development of the intelligent wheelchair lab prototype is shown in the paper. VOIC is designed for physically disabled person, who can not control their movements and control the wheelchair with the joystick. The article describes basic components of voice recognition and wheelchair control system. Voice recognition begins with input signal sampling, word isolation, LPC cepstral analysis, coefficient dimension reduction and trajectory recognition using fixed point approach with neural networks. Wheelchair control system is divided into system for sensors data acquisition and system for wheelchair steering. The complexity of the voice recognition is reduced using LPC cepstral analysis and coefficient dimension reduction with minimum loss of vital information. A proper decision for the speech recognition using neural networks is supported with experimental results.

Vehicle velocity, side slip angles and yaw rate estimation

Abstract: This paper presents a nonlinear body side slip angle and yaw rate observer based on an estimation of the vehicle velocity. The design of this observer uses a linearisa- tion which is modelled on the Luenberger observer and the output used for this observer is the lateral acceleration. The rotational equivalent wheel speeds are used to estimate the vehicle velocity. The observation error dynamic is stabilized using a Lyapunov function. It is shown that the required specifications are met by the designed observer. Simulation results are given. I. Introduction The lateral dynamic motion is a major component of a vehicle's dynamics. For this reason a number of works have been devoted to the control of the lateral velocity and the yaw rate: the increase of the two variables is a major cause of vehicle instability. Most of the algorithms which have been proposed in the literature assume the avail- ability of the lateral velocity or the body side slip angle. In practice this variable is never measured, the yaw rate is measured but the sensor is expensive, and the vehicle velocity is in general estimated. In the literature one may find works related to this lateral velocity estimation issue, see for instance (1), (2), (3), (4). Some problems resulting from lateral forces modelling errors such as the cornering stiffness coefficients Cf and Cr have been addressed in some works, see for instance (5), (3). In the latter works enough arguments have been brought for the relevance of the estimation of the latter coefficients. In the present work we propose a nonlinear observer of the two components of the lateral motion, namely the body side slip angle and the yaw rate, and an estimation of the vehicle velocity. When the wheel ground contact point velocities are approximated by the rotational equivalent wheel speeds, we can write a simple expression of the vehicle velocity. But the presence of the body side slip and the yaw rate in this expression prevent us to use it as an estimation. To solve this problem we take an observer derived from a linear bicycle model, and immediately another problem appears which is the vehicle velocity- dependence of the matrices of the linear model. The proposed solution in this paper is to replace the velocity in the linear model by its approximation, the resulting model are non-linear. In practice the available measure- ments in the lateral motion are the lateral acceleration and the yaw rate. In this work The used output is the lateral acceleration, and the yaw rate is observed even if we can get it with a sensor (to reduce the cost (6)), another advantage of the lateral acceleration is that we have an information about the body side slip angle and the yaw rate at each instant, which implies that the components of the Jacobian vector are different to zero and the determination of the gain vector is possible in the proposed observer. After a suitable choice of this gain vector which ensure the convergence we can estimate the vehicle velocity. The paper is organized as follows. In the first section, a simplified linear model (bicycle model) is presented to provide the basic understanding of the vehicle dynamics. In the next section we show how to compute the expression of the vehicle velocity and the equations of the nonlinear observer. In this section we propose a method to compute the gain vector of the nonlinear observer which ensure the convergence of the error observation to zero using a Lyapunov function. Finally, numerical simulations with a complete non-linear vehicle model are proposed and discussed to show the effectiveness of the proposed observer.

Optimal Velocity Profile Generation for Given Acceleration Limits; The Half-Car Model Case

Abstract: A method to generate on-line optimal acceler- ation/deceleration and attitude profiles for a half-car model in high-speed cornering is presented. The methodology is an extension of (1) where a point-mass model of the vehicle was used. The acceleration envelope of the vehicle (GG- diagram) from the locus of the front and rear tire forces is used for selecting the optimal control inputs. A stable implementation of the algorithm for a path of increasing radius is also presented.

Multirate Sampling Method for Acceleration Control System

Abstract: This paper focuses on realization of high per- formance motion control based on acceleration control. A high sampling frequency is known to be effective for improving the performance. Characteristics of acceleration control are investigated and the relationship between the performance and the sampling frequency of the system is discussed. Based on these considerations, a new multirate sampling method for the acceleration control system is proposed. Disturbance observer is redesigned for application in the multirate system. Stability analysis is performed to verify the validity of the proposal. Feasibility of the proposal and influence on the performance are also verified by experimental results. frequency of acceleration control. The needs of a higher sampling frequency for output than for input are de- scribed. From this point of view, this paper proposes a new multirate sampling method with a shorter output sampling period for improvement of acceleration control performance. Disturbance observer is redesigned to fit to the multirate system with a new definition of dis- turbance torque. Stability analysis is performed to make a comparison with single-rate control and to verify the validity of the proposal. Experimental results support the feasibility of the proposed method and improvement of the performance. This study considers the system in the 1st dimension for simplicity.

Wireless-control strategy for parallel operation of distributed generation inverters

Abstract: In this paper, a method for the parallel operation of inverters in an ac-distributed system is proposed. The paper explores the control of active and reactive power flow through the analysis of the output impedance of the inverters and its impact on the power sharing. As a result, adaptive virtual output impedance is proposed in order to achieve a proper reactive power sharing regardless of the line impedance unbalances. A soft-start operation is also included, avoiding the initial current peak, which results in a seamless hot-swap operation. Active power sharing is achieved by adjusting the frequency in load transient situations only, thanks to which the proposed method obtains constant steady-state frequency and amplitude. As opposed to the conventional droop method, the transient response can be modified by acting on the main control parameters. Linear and nonlinear loads can be properly shared due to the addition of a current harmonic loop in the control strategy. Experimental results are presented from a two 6-kVA parallel-connected inverters system, showing the feasibility of the proposed approach.

Boost-buck inverter variable structure control for grid-connected photovoltaic systems with sensorless MPPT

Abstract: The present work describes the analysis, modeling and control of a transformerless boost-buck power inverter used as a DC-AC power conditioning stage for grid-connected photovoltaic (PV) systems. The power conditioning system's control scheme includes a variable structure controller to assure output unity power factor and a sensorless maximum power point tracking (MPPT) algorithm to optimize the PV energy extraction. To maximize the steady-state input-output energy transfer ratio a discrete linear controller is designed from a large-signal sampled data model of the system. The achievement of the DC-AC conversion at unity power factor and the efficient PVs energy extraction are validated with simulation results.

Sensor Free Power Assisting Control Based on Velocity Control and Disturbance Observer

Abstract: In this paper, we design a controller that makes a plant sensitive to disturbance, which can be adopted for power assisting systems. Conventional power assisting controllers need force sensing, and only focus on the amplifi- cation of the force. But our proposed controller does not need force sensing. We just focus on the physical dynamics of the assisted plant considering sensitivity function of feedbacked system. Recently, various electric motor systems are used near people including power assisting system. Controllers for those motor systems need other control specifications than precise tracking or strict disturbance rejections. Proposed method can be a good solution for these specifications and can be called frequency weighted assistance control.

Ultracapacitor Plus Battery Energy Storage System Sizing Methodology for HEV Power Split Electronic CVT's

Abstract: The power split architecture has become the "gold standard" of hybrid propulsion systems because the global OEM's have converged to the electronic-continuously variable transmission, or e-CVT in two different configurations. For Toyota and Ford the single epicyclic gear set, THS and FHS respectively e-CVT. For GM-DCX and others to the dual epicyclic gear set, AHS designs possessing 2- modes of operation. Regardless of architecture, power split transmissions require a pair of electric motor-generators in order to deliver their intended function. This paper explores several techniques of incorporating ultracapacitors into the power split system and proposes a novel configuration in which the battery is downsized and power constrained by its interface dc-dc converter whereas the ultracapacitor is directly tied to the power split electric path floating bus. Different signal processing techniques are introduced for the decomposition of driveline power into command signals to control engine power and battery power levels while the ultracapacitor responds autonomously to the residue of propulsion power demand. Relative battery and ultracapacitor sizes are presented for the proposed configuration.

Full order dynamic model of SEPIC converter

Abstract: In this paper a full order dynamic model of the non-isolated and isolated DC-DC SEPIC (single ended primary inductance converter) is presented The switches (transistor and diode) are substituted by PWM averaged switch model equivalent circuit The SEPIC converter is used in the cases when the wide range of input voltages has been required There are two inductors and two capacitors inside the converter circuit Due to this, its mathematical model is of the fourth order differential equations system Duty-cycle and transformer turn ratio have impact on the converter dynamics The derived dynamic model was verified by simulation toolbox Sim PowerSystems

On-chip integrated CMOS optical detection microsystem for spectrophotometric analyses in biological microfluidic systems

Abstract: An integrated optical detection microsystem, which includes photodetectors and a light-to-frequency converter for readout, is designed and fabricated in a standard CMOS process without extra masks. This detection microsystem is designed for use in biological microsystems for fluids analysis. The application is in the low-cost concentration measurement of biomolecules in biological fluids, by the optical absorption in a part of the visible spectrum defined by the specific molecule. Signals proportional to the intensity of the light transmitted through the biological fluid are available at the output in the form of bit streams, which allows simple computer interfacing. The quantitative measurement of uric acid in urine is successfully demonstrated. The photodiode responsivity is 224 mA/W at /spl lambda/= 495 nm (the wavelength at which the uric acid has its absorption maximum). The optical system sensitivity is 1 kHz/Wm/sup -2/ at /spl lambda/ =670 nm (using the TLS230 from Texas Instruments as reference).

Development of Sensorless PMSM Drives: Application of Extended Kalman Filter

Abstract: This paper describes in detail guidelines for the development of fixed-point control systems with the main emphasis on the sensorless drives, presents the approaches used in the stage of fixed-point simulation as well as approach for the verification of the microprocessor code. The presented development method significantly speed-ups control system prototyping and increases the reliability of microprocessor code. The described design process is documented on the sensorless control system based on the extended Kalman filter (EKF), which is very difficult for the fixed-point implementation. This paper presents and compares different structures of EKF that can be employed in PMSM drives without either speed or position sensor. I. INTRODUCTION The most of the industrial control systems employ the fixed-point microcontrollers. The development, imple- mentation and debugging of the fixed-point control systems and especially development of sensorless techniques, which often introduce complex computational problems, requires special skills from the researcher. The specific problems of the fixed-point implementation together with the trend to reduce time-to-market have to be respected already in the stage of control system simulation. Therefore, the aim of this paper is to present development method, which can significantly speed-up control system prototyping and increases the reliability of the microprocessor code. The described design process is in this paper illustrated on the development of the sensorless control system of PMSM machine with surface magnets based on the extended Kalman filter (EKF) that represents very complicated problem for fixed-point implementation. II. ROTOR SPEED AND POSITION ESTIMATION USING

State-of-charge indication in portable applications

Abstract: The known methods of state-of-charge (SoC) indication in portable applications are not accurate enough under all practical conditions The method presented in this paper aims at designing and testing an SoC indication system capable of predicting the remaining capacity of the battery and the remaining run-time with an accuracy of 1 minute or better under all realistic user conditions, including a wide variety of load currents and a wide temperature range The basis of the proposed algorithm is current measurement and integration during charge and discharge state and voltage measurement during equilibrium state One of the main problems in designing an accurate SoC indication system is aging of the battery A simple method of adapting the maximum battery capacity used in the system with the aging effects is presented in this paper A first set of experimental results shows the effectiveness of our novel approach for improving the accuracy of the SoC indication

New control methods for rectifier-less PFC-stages

Abstract: The paper describes a new PFC topology with a reduced number of rectifier stages. The proposed converter is capable to deliver an output power of 2 kW. Simplified voltage and current measurement circuits are implemented. The static and dynamic behaviour of the converter using a new Infineon control IC is shown.

Haptic Telepresent Control Technology Applied to Disposal of Explosive Ordnances: Principles and Experimental Results

Abstract: This paper presents a novel approach for performing disposal of explosive ordnances by application of bimanual haptic telepresent control technology. For improved task execution the proposed system enables an operator to perceive multimodal feedback, especially de- tailed kinesthetic feedback, from a remote task environment. Details of a developed experimental setup, comprising a two-handed human system interface and a corresponding two-arm teleoperator, are reported. In particular a novel structure adapting architecture for control of the display and manipulator is introduced. Human-system performance is enhanced by means of stereo visualization of the remote task environment with overlayed Augmented Reality assis- tance. In addition, an algorithm for avoidance of dangerous manipulator configurations is supported by augmented force feedback. The usability and effectiveness of the developed bimanual telepresence system are demonstrated by focusing execution of demining operations in a remote environment

Sensorless sliding mode direct torque control (DTC) of induction motor

Abstract: A new approach to sensorless field oriented induction motor (IM) drive with a single loop control, which may correspond to DTC without a switching table, is presented. The proposed algorithm, presented in previous work by the author, is based on discrete-time sliding mode (SM) control theory and obtained by using two identical sliding surfaces with defining some part of the motor model as its control input. Benefits of this approach are that it reduces the control loops, generally in two cascaded structures, to a single loop and so that it reduces the computing time and it is also easy to design. On the other hand the performance of a SM current controller, employed to extract the proposed single control loop, is discussed for the direct and indirect type vector control drives of IM. Validity of proposed control schemes are confirmed by computer simulation, which showed both the high performance of the drive systems and their robustness against to some parameter variation.

Sensorless operation of active damping methods for three-phase PWM converters

Abstract: The three-phase PWM (active) rectifiers with bi-directional power flow and regulation of power factor to unity become to be more popular. These converters are connected to the supply network through inductance or LCL filter, what ensures attenuation of switching harmonics. LCL filter is more effective and reduce harmonic distortion at lower switching frequency, however such solution brings stability problems. In order to assure stable operation either a damping resistor or active damping algorithm has to be used. However, extra resistor causes additional losses and active damping algorithm usually needs extra sensors. This paper shows possibility to eliminate AC voltage sensors in two active damping methods making them more reliable and inexpensive.

Vector control of single-phase induction machine with maximum torque operation

Abstract: By the advent of power electronic and microelectronic devices, together with their steadily cost reduction, single phase induction motors (SPIMs) are increasingly considered as variable speed drives in recent years. Vector control proved to be practical and effective in these drives. However, winding asymmetry in SPIMs causes extra coupling between two stator windings and time varying terms, and resulting in an unbalanced machine operation. In this paper a symmetric model of SPIM with no extra coupling and time varying terms is obtained. An indirect vector control system based on maximum torque per ampere strategy is then proposed. It is shown that the proposed scheme substantially improves the motor torque.

Robot Workspace Optimization Based on a Novel Local and Global Performance Indices

Abstract: In this paper, a novel performance index is introduced for the kinematics optimization of serial robot manipulators. The serial robot manipulators used in order to compare optimization results were classified as in (1). The new performance index is a combination of a manipulability measure and condition number used by previous authors. To find the optimum link lengths and volumes of these robot manipulators, two design objectives are used: maximize the workspace area covered by the robot manipulator and maximize the new local index. As examples, two spherical three-link robot manipulators are examined based on above design objectives. Finally, optimization results of these robot manipulators are obtained and compared to each other. Generally speaking, a robot manipulator structure can be subdivided into a regional structure and orientation structure. The regional structure consists of the arm (first three links), which moves the end-effector to a desired position in the workspace of the robot manipulator. The orientation structure, comprised of the last three links, rotates the end- effector to the desired orientation in the workspace. In this study, the regional structure of the robot manipulators is examined rather then the orientation structure.

Optimum Vehicle Trajectory Control for Obstacle Avoidance Problem

Abstract: This paper discusses an obstacle avoidance problem. A new control algorithm for obstacle avoidance within the shortest possible distance is proposed. The algorithm is composed of two steps. In the first step, optimal trajectory and a corresponding force and moment are determined based on a second-order cone pro- gramming. In the second step, the computed force and moment are realized through the controlling brake and steering systems while using a sequential quadratic programming with pseudo-inverse matrix for the derivation. Index Terms—Optimum control, tire force, vehicle dynamics.