Test stand design and automated sequences implementation

Chemnitz University of Technology has been involved since 2018 in an academic automotive championship gathering 1:10 fuel cell/battery-powered vehicles. The goal of the race being to travel the longest distance with a limited amount of hydrogen and electricity, it would be meaningful to predict the vehicle fuel consumption prior to the race for a given driving style. For this purpose, the present work proposes a new approach which consisted in designing a chassis dynamometer allowing to implement race driving cycles and to emulate the related road load thanks to a real time industrial automation PLC software. In particular, the chassis dynamometer was designed with PTC CREO and is composed of four trunnionmounted hub dynamometers whose power absorption is performed by hysteresis brakes. The four modules can be controlled independently to adapt the type of 1:10 vehicle powertrain and are controlled from sequences that are implemented by using TwinCAT 3. The data acquisition system from Beckho Automation based on the real time eld bus EtherCAT has enabled the system to be tested under high transient driving cycles. The work has resulted of a chassis dynamometer capable of assessing the vehicle speed from 0 to 30 km=h with an accuracy lower than 3%. The vehicle battery voltage can be measuredin the range 0 to 10 V with an uncertainty lower than 0.1 %. Moreover, the test bench allow to compute the wheel's torque with a proper stability but considering a long delay between the reference torque value and dynamometer response. Finally, a driving cycle has been implemented and the vehicle associated to the PID controller has showed a response time lower than 80 ms.Chemnitz University of Technology has been involved since 2018 in an academic automotive championship gathering 1:10 fuel cell/battery-powered vehicles. The goal of the race being to travel the longest distance with a limited amount of hydrogen and electricity, it would be meaningful to predict the vehicle fuel consumption prior to the race for a given driving style. For this purpose, the present work proposes a new approach which consisted in designing a chassis dynamometer allowing to implement race driving cycles and to emulate the related road load thanks to a real time industrial automation PLC software. In particular, the chassis dynamometer was designed with PTC CREO and is composed of four trunnionmounted hub dynamometers whose power absorption is performed by hysteresis brakes. The four modules can be controlled independently to adapt the type of 1:10 vehicle powertrain and are controlled from sequences that are implemented by using TwinCAT 3. The data acquisition system from Beckho Automation based on the real time eld bus EtherCAT has enabled the system to be tested under high transient driving cycles. The work has resulted of a chassis dynamometer capable of assessing the vehicle speed from 0 to 30 km=h with an accuracy lower than 3%. The vehicle battery voltage can be measuredin the range 0 to 10 V with an uncertainty lower than 0.1 %. Moreover, the test bench allow to compute the wheel's torque with a proper stability but considering a long delay between the reference torque value and dynamometer response. Finally, a driving cycle has been implemented and the vehicle associated to the PID controller has showed a response time lower than 80 ms

Electric-drive vehicle emulation using advanced test bench

Vehicle electrification is considered to be the most promising approach toward addressing the concerns on climate change, sustainability, and rapid depletion of fossil fuel resources. As a result electric-drive vehicle (EDV) technology is becoming the subject of many research studies, from academia and research laboratories to automotive industries and their suppliers. However, a crucial step toward the success of EDV implementation is developing test platforms that closely emulate the behavior of these vehicles. In this dissertation, a new approach for emulating an EDV system on a motor/dynamometer test bench is investigated. Two different methods of emulation are discussed which are based on predefined drive cycle and unpredictable driving behavior. MATLAB/Simulink is used to model the test bench and simulations are carried out for each case. Experimental test bench results are also presented to validate hardware-in-the-loop (HIL) real-time performance for each method. Furthermore, to provide a more realistic approach towards EDV emulation a braking system suitable for motor/dynamometer architecture is proposed. The proposed brake controller represents a very close model of an actual EDV braking system and takes into account both regenerative and friction braking limitations. Finally, the challenges and restrictions of using a full scale test bench are outlined. To overcome these limitations, the development of an educational small scale hybrid electric vehicle (HEV) learning module is discussed which provides an ideal test platform to simulate and study both electric and HEV powertrains --Abstract, page iv

Stratégies de gestion d’énergie pour véhicules électriques et hybride avec systèmes hybride de stockage d’énergie

Les véhicules électriques et hybrides font partie des éléments clés pour résoudre les problèmes de réchauffement de la planète et d'épuisement des ressources en combustibles fossiles dans le domaine du transporte. En raison des limites des différents systèmes de stockage et de conversion d’énergie en termes de puissance et d'énergie, les hybridations sont intéressantes pour les véhicules électriques (VE). Dans cette thèse, deux hybridations typiques sont étudiées • un sous-système de stockage d'énergie hybride combinant des batteries et des supercondensateurs (SC) ; • et un sous-système de traction hybride parallèle combinant moteur à combustion interne et entraînement électrique. Ces sources d'énergie et ces conversions combinées doivent être gérées dans le cadre de stratégies de gestion de l'énergie (SGE). Parmi celles-ci, les méthodes basées sur l'optimisation présentent un intérêt en raison de leur approche systématique et de leurs performances élevées. Néanmoins, ces méthodes sont souvent compliquées et demandent beaucoup de temps de calcul, ce qui peut être difficile à réaliser dans des applications réelles. L'objectif de cette thèse est de développer des SGE simples mais efficaces basées sur l'optimisation en temps réel pour un VE et un camion à traction hybride parallèle alimentés par des batteries et des SC (système de stockage hybride). Les complexités du système étudié sont réduites en utilisant la représentation macroscopique énergétique (REM). La REM permet de réaliser des modèles réduits pour la gestion de l'énergie au niveau de la supervision. La théorie du contrôle optimal est ensuite appliquée à ces modèles réduits pour réaliser des SGE en temps réel. Ces stratégies sont basées sur des réductions de modèle appropriées, mais elles sont systématiques et performantes. Les performances des SGE proposées sont vérifiées en simulation par comparaison avec l’optimum théorique (programmation dynamique). De plus, les capacités en temps réel des SGE développées sont validées via des expériences en « hardware-in-the-loop » à puissances réduites. Les résultats confirment les avantages des stratégies proposées développées par l'approche unifiée de la thèse.Abstract: Electric and hybrid vehicles are among the keys to solve the problems of global warming and exhausted fossil fuel resources in transportation sector. Due to the limits of energy sources and energy converters in terms of power and energy, hybridizations are of interest for future electrified vehicles. Two typical hybridizations are studied in this thesis: • hybrid energy storage subsystem combining batteries and supercapacitors (SCs); and • hybrid traction subsystem combining internal combustion engine and electric drive. Such combined energy sources and converters must be handled by energy management strategies (EMSs). In which, optimization-based methods are of interest due to their high performance. Nonetheless, these methods are often complicated and computation consuming which can be difficult to be realized in real-world applications. The objective of this thesis is to develop simple but effective real-time optimization-based EMSs for an electric car and a parallel hybrid truck supplied by batteries and SCs. The complexities of the studied system are tackled by using Energetic Macroscopic Representation (EMR) which helps to conduct reduced models for energy management at the supervisory level. Optimal control theory is then applied to these reduced models to accomplish real-time EMSs. These strategies are simple due to the suitable model reductions but systematic and high-performance due to the optimization-based methods. The performances of the proposed strategies are verified via simulations by comparing with off-line optimal benchmark deduced by dynamic programming. Moreover, real-time capabilities of these novel EMSs are validated via experiments by using reduced-scale power hardware-in-the-loop simulation. The results confirm the advantages of the proposed strategies developed by the unified approach in the thesis

Evaluation of a CIDI Pre-Transmission Parallel Hybrid Drivetrain with CVT

ABSTRACT Argonne National Laboratory (ANL) is the lead laboratory for hardware-in-the-loop (HIL) testing and technology validation for the U.S. Department of Energy's Office of Advanced Automotive Technologies (DOE OAAT). In this role, ANL contributes to DOE OAAT goals by setting technical targets and evaluating new technologies in a vehicle systems context, with a focus on hybrid electric vehicle (HEV) technology. ANL employs a unique integrated process based on powerful simulation tools and experimental facilities to perform system-level tests quickly and costeffectively. This approach allows ANL researchers to simulate a vehicle system, design an optimal control strategy, and then apply it to the real components and subsystems being evaluated. The objective is to better understand 1) component/subsystem performance and control requirements in a simulated vehicle environment and 2) the effect of control on emissions and efficiency. This process has been applied to the evaluation of a hybrid powertrain consisting of a Compression-Ignition DirectInjection (CIDI) engine, an electric traction motor, and a Continuously Variable Transmission (CVT). This paper describes the testing methodology, the building of the powertrain, the control strategy used, and the analysis of results

Modelling and simulation of conducted emissions in the powertrain of electric vehicles

In the general framework of intelligent transportation, the increasing use of information communication technology in full or hybrid electric vehicles requires careful assessment of electromagnetic compatibility, with specific reference to the conducted emissions (CE) generated by the inverter in a broad frequency range (10 kHz-100 MHz). To this aim, this work reports a modelling approach for the prediction of CE in electric powertrains, which is based on circuit representation of each single subsystem, that is, the battery, the inverter, the three-phase synchronous motor, and the power buses composed of shielded cables. The proposed models are able to represent both low-frequency functional aspects and high-frequency parasitic effects of paramount importance for CE analysis, and can be implemented into a Simulation-Programme-with-Integrated-Circuit-Emphasis (SPICE) solver. The proposed modelling approach is exploited to simulate virtual CE measurements according to international standard CISPR 25, and to investigate the impact of setup features, including grounding connections of shields, the propagation of CE in electrically long power buses, the operating point (power, torque, speed) of the motor-drive system

Platform-based design, test and fast verification flow for mixed-signal systems on chip

This research is providing methodologies to enhance the design phase from architectural space exploration and system study to verification of the whole mixed-signal system. At the beginning of the work, some innovative digital IPs have been designed to develop efficient signal conditioning for sensor systems on-chip that has been included in commercial products. After this phase, the main focus has been addressed to the creation of a re-usable and versatile test of the device after the tape-out which is close to become one of the major cost factor for ICs companies, strongly linking it to model’s test-benches to avoid re-design phases and multi-environment scenarios, producing a very effective approach to a single, fast and reliable multi-level verification environment. All these works generated different publications in scientific literature. The compound scenario concerning the development of sensor systems is presented in Chapter 1, together with an overview of the related market with a particular focus on the latest MEMS and MOEMS technology devices, and their applications in various segments. Chapter 2 introduces the state of the art for sensor interfaces: the generic sensor interface concept (based on sharing the same electronics among similar applications achieving cost saving at the expense of area and performance loss) versus the Platform Based Design methodology, which overcomes the drawbacks of the classic solution by keeping the generality at the highest design layers and customizing the platform for a target sensor achieving optimized performances. An evolution of Platform Based Design achieved by implementation into silicon of the ISIF (Intelligent Sensor InterFace) platform is therefore presented. ISIF is a highly configurable mixed-signal chip which allows designers to perform an effective design space exploration and to evaluate directly on silicon the system performances avoiding the critical and time consuming analysis required by standard platform based approach. In chapter 3 we describe the design of a smart sensor interface for conditioning next generation MOEMS. The adoption of a new, high performance and high integrated technology allow us to integrate not only a versatile platform but also a powerful ARM processor and various IPs providing the possibility to use the platform not only as a conditioning platform but also as a processing unit for the application. In this chapter a description of the various blocks is given, with a particular emphasis on the IP developed in order to grant the highest grade of flexibility with the minimum area occupation. The architectural space evaluation and the application prototyping with ISIF has enabled an effective, rapid and low risk development of a new high performance platform achieving a flexible sensor system for MEMS and MOEMS monitoring and conditioning. The platform has been design to cover very challenging test-benches, like a laser-based projector device. In this way the platform will not only be able to effectively handle the sensor but also all the system that can be built around it, reducing the needed for further electronics and resulting in an efficient test bench for the algorithm developed to drive the system. The high costs in ASIC development are mainly related to re-design phases because of missing complete top-level tests. Analog and digital parts design flows are separately verified. Starting from these considerations, in the last chapter a complete test environment for complex mixed-signal chips is presented. A semi-automatic VHDL-AMS flow to provide totally matching top-level is described and then, an evolution for fast self-checking test development for both model and real chip verification is proposed. By the introduction of a Python interface, the designer can easily perform interactive tests to cover all the features verification (e.g. calibration and trimming) into the design phase and check them all with the same environment on the real chip after the tape-out. This strategy has been tested on a consumer 3D-gyro for consumer application, in collaboration with SensorDynamics AG

ADVANCED BRAKING SYSTEM CONTROL PROTOTYPING USING NETWORKED HARDWARE-IN-THE-LOOP TECHNIQUE

Control functions for the base-braking and emergency braking situations are important element of the vehicle active safety and have high requirements to robustness. The corresponding control algorithms should be reliable, provide sufficient level of system adaptiveness and be able to reject external disturbances. This demands not only the well-organized controller from the theoretical point of view, but also its systematic experimental validation. Moreover, effects and factors, which can potentially produce deterioration of braking system control functions, should be properly taken into account in the simulation and during the experiments. Another important factor is that brake control systems have a closed-loop operation with the tyre-road interaction, and its operation is accompanied by such complex effects like (i) variation of disc/pad friction coefficient and (ii) brake hysteresis. This produces strong demand on extension of the conventional testing facilities for the braking system control evaluation. Therefore, besides the part of the control system design, this paper represents possible advancement of hardware-in-the-loop testing procedure for development and validation of braking system control functions

Modelling and simulations of a narrow track tilting vehicle

Narrow track tilting vehicle is a new category of vehicle that combines the dynamical abilities of a passenger car with a motorcycle. In the presence of overturning moments during cornering, an accurate assessment of the lateral dynamics plays an important role to improve their stability and handling. In order to stabilise or control the narrow tilting vehicle, the demand tilt angle can be calculated from the vehicle’s lateral acceleration and controlled by either steering input of the vehicle or using additional titling actuator to reach this desired angle. The aim of this article is to present a new approach for developing the lateral dynamics model of a narrow track tilting vehicle. First, this approach utilises the well-known geometry ‘bicycle model’ and parameter estimation methods. Second, by using a tuning method, the unknown and uncertainties are taken into account and regulated through an optimisation procedure to minimise the model biases in order to improve the modelling accuracy. Therefore, the optimised model can be used as a platform to develop the vehicle control strategy. Numerical simulations have been performed in a comparison with the experimental data to validate the model accuracy

Modelling and simulations of a narrow track tilting vehicle

Narrow track tilting vehicle is a new category of vehicle that combines the dynamical abilities of a passenger car with a motorcycle. In the presence of overturning moments during cornering, an accurate assessment of the lateral dynamics plays an important role to improve their stability and handling. In order to stabilise or control the narrow tilting vehicle, the demand tilt angle can be calculated from the vehicle’s lateral acceleration and controlled by either steering input of the vehicle or using additional titling actuator to reach this desired angle. The aim of this article is to present a new approach for developing the lateral dynamics model of a narrow track tilting vehicle. First, this approach utilises the well-known geometry ‘bicycle model’ and parameter estimation methods. Second, by using a tuning method, the unknown and uncertainties are taken into account and regulated through an optimisation procedure to minimise the model biases in order to improve the modelling accuracy. Therefore, the optimised model can be used as a platform to develop the vehicle control strategy. Numerical simulations have been performed in a comparison with the experimental data to validate the model accuracy

Enhanced active front steering control using sliding mode control under varying road surface condition

In vehicle lateral dynamic control, the handling quality or steering ability of the vehicle is determined by the yaw rate response performances. The uncertainty of tire cornering stiffness due to varying tire-road adhesion coefficient, u caused by road surfaces perturbation during cornering manoeuvre may influence the transient performances of yaw rate response. Therefore, in this research, the enhanced control law of robust yaw rate tracking controller using the Sliding Mode Control (SMC) algorithm is proposed for active front steering (AFS) control strategy to improve the yaw rate response as desired. The vehicle lateral dynamics behaviors are described using the linear and nonlinear vehicle models. The linear 2 degree-of-freedom (DOF) single track model is used for controller design while the nonlinear 7 DOF two-track model is used for simulation and controller evaluations. The sliding surface of SMC is design based on yaw rate tracking error information. The control law equation is enhanced by integrating the uncertainty of cornering stiffness at the front wheels and to ensure the controller stability, the Lyapunov stability theory is applied. The transient performances and performance indices of AFS control responses are evaluated using the step steer and single lane change cornering manoeuvres test for varying values of u at dry, wet and snow or icy road surfaces. The simulations results demonstrated that the proposed enhanced control law using SMC is able to track the reference yaw rate with similar transient response performances. The proposed enhanced control law also provided low performance indices of ITAE and IAE compared to the conventional control law using SMC and robust CNF control for lower value of u at wet and snow or icy road surface. In terms of percentage of differential performance indices, the proposed control law has a better tracking ability of up to 58.45% compared to two other control laws. Therefore, this research concluded that the proposed enhanced control law using SMC has overcome the cornering stiffness uncertainty in AFS control strategy for different road surfaces during cornering manoeuvre and this enhancement is expected as a knowledge contribution to vehicle lateral dynamic study