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This paper aims to present a linear quadratic regulator (LQR) employed to improve performance of an electrical power steering (EPS) system.

Generally, EPS is a full electric system having an electrical motor which provides the assist torque on the steering mechanism in order to reduce the workload and to enhance the steering feel of the driver during the steering process. Since the torque sensors are considerably expensive, the authors present a control strategy that eliminates the driver torque sensor by introducing a torque estimator. Three main technical areas are described in this paper. First, the principle and structure of EPS are presented including the dynamic model. Second, LQR and Kalman filter techniques are employed to derive an optimal controller for the EPS system. Finally, the simulations and hardware results are depicted.

The combined tools of Matlab/Simulink and dSPACE provide the environment for modelling the controller in software and applying it to the actual hardware via a digital signal processing board based on the DS1401 MicroAutoBox. The controller is evaluated via simulation results, dSPACE hardware results, and verified on vehicle testing data.

This paper presents a controller design for an EPS system based on the LQR techniques. Within the controller concept shown, elimination of the driver torque sensor offers advantages in terms of both cost and mechanical performance. Simulations and measured data prove the good functionality of the controller proposed.

An electrical revolution in the automotive sector was decided on at the end of 2008, when the European Parliament passed legislation of lower CO₂ emissions of new cars. This causes and forces the development of alternative concepts of propulsion systems and alternative fuels. These new trends of propulsion technologies such as hybrid and pure electric drive will have an impact on the entire design of cars. The purpose of this paper is to present an evolution of selected fractional horsepower electrical drives used in cars. Analysis of electromechanical components can be divided into two groups: the first one contains the currently used subsystems, e.g. electric power steering system, engine cooling systems, etc.; and the second one presents the development of new components, e.g. electric air‐conditioning compressor and other by‐wire technologies. Additionally, the development and trends of new materials and technologies used in electrical drives for the automotive industry are presented.

Performed analysis based on a review of the literature and the author's own research and experience in the area of electromechanical systems for automotive applications. During motor design, computer numerical simulation method, CAD and experiment were used. The development perspectives in the area of electromechanical systems in automotive area are presented. Additionally, the evolution of fractional horse power electric motors, with the influence of new developments in the area of electric vehicles, are analysed and presented.

The presented analysis shows that a change of technology from brush type motors into brushless is inevitable. Additionally, further miniaturization will be conducted using a higher energy permanent magnet. Furthermore, an increase of efficiency will be achieved by increasing the voltage level from 12 V to 48 V or even higher, e.g. 120 V.

This is the first paper, where, in a comprehensive way, developments of fractional horse power electromechanical systems for electric and hybrid vehicles are presented. The results of this paper can be utilized during the creation of the products' road‐maps in this area.

In the last few years, the understanding of environmental problems has grown. Car producers – original equipment manufacturers – are aiming to reduce fuel consumption and pollution. In order to fulfil these aims, new technologies have been launched. Many hydraulics systems have been removed and replaced with electric ones, e.g. power steering, water and oil pump, etc. In this paper, an electromechanical subsystem used in an automotive application is analyzed. The subsystem is composed of interior permanent synchronous magnet motor and electronic control unit. The range of mechanical output power for studied system is up to 1 kW. The aim of this paper is to compare electromechanical systems working with different on‐board voltage levels in order to find the optimum balance between motors' and electronics' efficiency. This will help to decrease the total system's weight, the consequence of which will decrease fuel consumption and reduce CO₂ emissions.

During the analysis, the reduced order modelling (ROM) techniques has been applied. First, with utilization of finite‐elemente‐methode the basic motor's parameter like: synchronous inductance and flux per pole as a function of the direct‐axis current and also the quadrature‐axis current are calculated. In the second step, these parameters are used in the system simulation. During this simulation, the maximum torque per ampere control strategy together with ROM techniques was used.

As a result, the performance of the system for different voltage levels has been obtained. Additionally, the important factors for an electromechanical system, such as maximum power density, sizing and cost of the total electromechanical system, have been compared.

The performed comparison shows that the cost optimized system should work with the higher voltage, where the electric motor size is reduced ca. 25 per cent. This result is also valid for different electromechanical systems in an automotive area, e.g. automated manual transmission, engine cooling and electric compressor.

It is the first paper, where electric power steering system design for different on‐board voltage levels has been systematically analyzed and compared. Results from this paper can be also applied to different electromechanical systems mounted in hybrid or electric cars.

The purpose of this paper is to present the design procedure of an interior permanent magnet (IPM) motor used in electric power steering (EPS), and some critical issues which have considerable impacts on the machine's performance are fully discussed before detailed sizing optimization.

The design specifications are derived according to application overall requirements. Critical issues which have considerable impacts on the machine's performance, such as operation mode, rotor structure and slot/pole combination, are analyzed based on literature review. The proposed machine is optimized, and the losses and efficiency are computed, using 2‐D finite element analysis (FEA).

Before detailed sizing optimization, machine type selection is fully discussed. Aspects such as brushless ac (BLAC) operation mode, IPM rotor structure and combination of 12‐slot/10‐pole are quite suitable for EPS application. Consequently, a 12‐slot/10‐pole sinusoidally excited IPM machine with concentrated windings is selected, since it is convenient to obtain sinusoidal back electromotive force (back‐EMF), minimum cogging torque and torque ripple, short end windings and high efficiency, as well as simple rotor assembly. The estimated excellent performance confirms that the proposed machine can be an attractive solution for EPS.

The excitation current is ideal sinusoidal, while some harmonic components are neglected. Besides, in future, the experimental test should be carried out for validation.

A reasonable design procedure, where the motor type selection should be first addressed before detailed sizing design, is carried out. A 12‐slot/10‐pole sinusoidally excited IPM machine with concentrated windings is provided as a quite competitive candidate for EPS application.

Two-handed automobile steering at low vehicle speeds may lead to reduced steering ability at large steering wheel angles and shoulder injury at high steering wheel rates (SWRs). As a first step toward solving these problems, this study aims, firstly, to design a surface electromyography (sEMG) controlled steering assistance interface that enables hands-free steering wheel rotation and, secondly, to validate the effect of this rotation on path-following accuracy.

A total of 24 drivers used biceps brachii sEMG signals to control the steering assistance interface at a maximized SWR in three driving simulator scenarios: U-turn, 90º turn and 45º turn. For comparison, the scenarios were repeated with a slower SWR and a game steering wheel in place of the steering assistance interface. The path-following accuracy of the steering assistance interface would be validated if it was at least comparable to that of the game steering wheel.

Overall, the steering assistance interface with a maximized SWR was comparable to a game steering wheel. For the U-turn, 90º turn and 45º turn, the sEMG-based human–machine interface (HMI) had median lateral errors of 0.55, 0.3 and 0.2 m, respectively, whereas the game steering wheel, respectively, had median lateral errors of 0.7, 0.4 and 0.3 m. The higher accuracy of the sEMG-based HMI was statistically significant in the case of the U-turn.

Although production automobiles do not use sEMG-based HMIs, and few studies have proposed sEMG controlled steering, the results of the current study warrant further development of a sEMG-based HMI for an actual automobile.

The purpose of this paper is to investigate torque ripple and magnetic force on the teeth in interior permanent magnet (IPM) machines over a wide range of speed operation for electrical power steering (EPS) applications.

The flux-weakening capability of IPM machines has been analysed by finite element method considering the effect of cross-coupling between d- and q-axis current. The traditional method of analysing torque ripple is based on constant torque and flux-weakening region. However, the cross-coupling need to be considered when applying this technique to flux-weakening region. Meanwhile, the torque ripple with current amplitude and angle and with different speed in the flux-weakening region is also investigated. In addition, the magnetic force on the teeth due to the separated teeth with stator yoke is also investigated during the constant torque and flux-weakening region.

The torque ripple and magnetic force on teeth in IPM machine are dependent on current and current angle. Both the lowest torque ripple and magnetic force on teeth exist over the whole torque-speed region.

The purely sinusoidal currents are applied in this analysis and the effects of harmonics in the current on torque ripple and magnetic force on teeth are not considered in this application. The 12-slot/10-pole IPM machine has been employed in this analysis, but this work can be continued to investigate different slot/pole number combinations.

This paper has analysed the torque ripple and magnetic force on the teeth in IPM machines for EPS application over a wide range of operation speed, which are the main cause of vibration and acoustic noise. The variation of torque ripple with current amplitude and angle as well as speed in the flux-weakening region is also investigated. In addition, the magnetic force on the teeth is also investigated over the whole torque-speed region.

Steer-by-wire (SBW) system mainly relies on sensors, controllers and motors to replace the traditionally mechanical transmission mechanism to realize steering functions. However, the sensors in the SBW system are particularly vulnerable to external influences, which can cause systemic faults, leading to poor steering performance and even system instability. Therefore, this paper aims to adopt a fault-tolerant control method to solve the safety problem of the SBW system caused by sensors failure.

This paper proposes an active fault-tolerant control framework to deal with sensors failure in the SBW system by hierarchically introducing fault observer, fault estimator, fault reconstructor. Firstly, the fault observer is used to obtain the observation output of the SBW system and then obtain the residual between the observation output and the SBW system output. And then judge whether the SBW system fails according to the residual. Secondly, dependent on the residual obtained by the fault observer, a fault estimator is designed using bounded real lemma and regional pole configuration to estimate the amplitude and time-varying characteristics of the faulty sensor. Eventually, a fault reconstructor is designed based on the estimation value of sensors fault obtained by the fault estimator and SBW system output to tolerate the faulty sensor.

The numerical analysis shows that the fault observer can be rapidly activated to detect the fault while the sensors fault occurs. Moreover, the estimation accuracy of the fault estimator can reach to 98%, and the fault reconstructor can make the faulty SBW system to retain the steering characteristics, comparing to those of the fault-free SBW system. In addition, it was verified for the feasibility and effectiveness of the proposed control framework.

As the SBW fault diagnosis and fault-tolerant control in this paper only carry out numerical simulation research on sensors faults in matrix and laboratory/Simulink, the subsequent hardware in the loop test is needed for further verification.

Aiming at the SBW system with parameter perturbation and sensors failure, this paper proposes an active fault-tolerant control framework, which integrates fault observer, fault estimator and fault reconstructor so that the steering performance of SBW system with sensors faults is basically consistent with that of the fault-free SBW system.

In order to reduce CO₂ emissions of new cars many hydraulic and mechanical systems like e.g.: water pump, oil pump, power steering, clime compressor have been exchanged with pure electromechanical systems, which are driven only on request. This helps to reduce fuel consumption. This trend requires of utilization of modern brushless electric motors, which are controlled from power electronic control unit – ECU. In today's car can be found between 30 to 150 electric motors. Many of them are still simple brush type with ferrite magnets. Also in this area, drift in the direction of brushless motors can bee seen, because of higher efficiency, longer lifetime, lower noise, better EMC and more controllable torque vs speed characteristic. There are different technological solutions, which can been used in the area of brushless motors in order to reduce size and cost of single component. One major factor of BLDC/AC motor is rear earth permanent magnet material used during production. A magnet material cost could be in the range from 30 percent (basis price 2010) up to 90 percent (basis price 2011) of total material motor cost, depends on actual rear earth material price level. In order to reduce magnet cost, the aim of this paper is to find the most robust motor design, which can be resistant against maximum temperature and phase current amplitude for the same magnet material properties, coercive force – Hcj. This behaviour is called demagnetization property.

Analysis was performed based on review of literature, own theoretical and practical research and experience in the area of electromechanical systems for automotive application. During motor analysis computer numerical simulation method, CAD and experiment were used.

As a result, comparison of different motors' topologies with different properties of magnet materials is presented. The worked out methodology shows very good correlation between simulations and measurements. This work can be used in order to reduce test effort and reduce cost of design.

The presented methodology reduces for new designs test effort and development cost and gives an implication of robust motor topology for demagnetization effects.

It is the first paper where demagnetization effects have been studied theoretically and in laboratory in order to find the most robust design, reduce magnet cost by reduction of dysprosium content and develop simulation procedure for analysis of demagnetizations behaviours of interior and surface permanent magnet.

The purpose of this paper is to give an overview of the design issues of permanent magnet machines for the hybrid electric and plug‐in electric vehicles, including railway traction and naval propulsion.

Focus is given on both synchronous permanent magnet and reluctance machines. An overview of the design rules are provided, covering the topics of: fractional‐slot windings, fault‐tolerant configurations, flux‐weakening capability, and torque quality.

The peculiarities of these machines and the advanced design considerations to fit the automotive requirements are analyzed.

The paper includes a wide description of innovative electrical machines for electric vehicles, including not only the traction capability, but also analysis of features as weight reduction, torque ripple reduction, increase of fault tolerance, and so on.

This paper studies the lateral stability regulation of intelligent electric vehicle (EV) based on model predictive control (MPC) algorithm.

Firstly, the bicycle model is adopted in the system modelling process. To improve the accuracy, the lateral stiffness of front and rear tire is estimated using the real-time yaw rate acceleration and lateral acceleration of the vehicle based on the vehicle dynamics. Then the constraint of input and output in the model predictive controller is designed. Soft constraints on the lateral speed of the vehicle are designed to guarantee the solved persistent feasibility and enforce the vehicle’s sideslip angle within a safety range.

The simulation results show that the proposed lateral stability controller based on the MPC algorithm can improve the handling and stability performance of the vehicle under complex working conditions.

The MPC schema and the objective function are established. The integrated active front steering/direct yaw moments control strategy is simultaneously adopted in the model. The vehicle’s sideslip angle is chosen as the constraint and is controlled in stable range. The online estimation of tire stiffness is performed. The vehicle’s lateral acceleration and the yaw rate acceleration are modelled into the two-degree-of-freedom equation to solve the tire cornering stiffness in real time. This can ensure the accuracy of model.