Hardware-in-the-loop Test Bench Research Articles

Transferability Assessment of OBD-Related Calibration and Validation Activities from the Vehicle to HiL Applications

With the Euro 7 pollutant emission legislation currently under discussion, advanced and more efficient exhaust aftertreatment systems are being developed. The technologies required for these are leading to an increase in the number of components and control systems requiring diagnoses strategies under the on-board diagnostics (OBD) legislation. With concurrent shorter development times and significant reductions in budgets allocated to conventional powertrain development, challenges in the field of OBD calibration and verification are already rising sharply. In response to these challenges, hardware-in-the-loop (HiL) approaches have been successfully introduced to support and replace conventional development methods. The use of complex simulation models significantly improves the quality of calibrations while minimizing the number of required prototype vehicles and test resources, thus reducing development costs. This paper presents a feasibility study for moving OBD-related calibration and validation tasks from the vehicle to a HiL platform. In this context, the calibration and verification process of an active diagnostic for monitoring the condition of the three-way catalyst (TWC) and the oxygen sensors in the exhaust aftertreatment system is presented. It is shown that all relevant signals are simulated with sufficient accuracy to ensure a robust transfer from the vehicle to a HiL test bench. Special attention is given to the simulation of aged components and their influence on the emission behavior of the system. Furthermore, it is discussed that transferring OBD tasks from the vehicle to the HiL test bench could result in significant savings in development time and a reduction in the number of physical prototype vehicles and test resources required.

An experimental methodology to support development of yaw damper prototypes based on a hardware-in-the-loop test bench

Research and development of innovative suspension components for rail vehicles have involved huge investments in recent years. Research efforts have focussed on designing and optimising suspension systems to deal with the new challenges introduced in railway dynamics by the continuous increase in vehicle speed. In particular, yaw dampers have been a relevant research topic due to their influence on vehicle stability. In this context, this paper aims to propose a Hardware-In-the-Loop (HIL) methodology for testing yaw dampers under experimental conditions close to real operating scenarios, comparing the influence of different prototypes on the stability of high-speed rail vehicles. A reduced vehicle model is proposed for real-time integration in HIL tests. This model provides a reference stroke to be imposed on the prototype tested, considering the actual damping force provided by the device being analysed. Two yaw damper prototypes are introduced to validate the proposed methodology by means of comparative analysis at different vehicle speeds. The experimental results provided by the HIL test bench are then compared with corresponding analysis done using Multi-Body (MB) simulations. The proposed HIL methodology has proved to be able to test physical prototypes and define guidelines to assist damper manufacturers developing and optimising yaw damper components.

Virtual Multi-Criterial Calibration of Operating Strategies for Hybrid-Electric Powertrains

In hybrid vehicle development, the operating strategy has a decisive role in meeting the development goals, such as compliance with emission standards and high energy efficiency. A considerable number of interactions and cross-influences on other topics, such as emissions, on-board diagnostics, or drivability, must be considered during the calibration process. In this context, the given time constraints pose further challenges. To overcome these, approaches for virtualization of the calibration process are an effective measure. For this purpose, in the current study, a real engine control unit is embedded into a virtual simulation environment on so-called hardware-in-the-loop (HiL) testbenches, which allow virtual calibration and validation of the complete target vehicle. In this context, the paper presents a novel method for virtual calibration of operating strategies for hybrid-electric propulsion systems. This includes an innovative multi-criterial approach that considers the requirements of several development tasks, such as emission and OBD calibration. Measurement data for this optimization is generated on a HiL testbench setup tailored for the described methodology, including both the electrical setup and the simulation environment. To validate the selection of modeling approaches and the parametrization, the simulation environment is operated in open loop. The results of the open loop validation show promising behavior regarding the proposed use case. Finally, the presented methodology is evaluated regarding time and cost savings compared to a conventional approach.

Hardware‐in‐the‐loop validation of an adaptive model predictive control on a connected and automated vehicle

SummaryConnected and automated vehicles will characterize the future of the mobility, featured by Smart Roads and Internet of Things technologies. Vehicles will behave as mobile nodes of a network enabling communication between them and with respect to the road infrastructure. In order to provide advanced driver assistance and automated driving along a Smart Road, control strategies need to take into account both parametric variations due to environmental and/or weather conditions (e.g., wind speed, presence of ice, and/or rain), and constraints related to road safety and vehicular traffic. For this reason, advanced adaptive control strategies result particularly suitable to provide a complete control of the vehicle. This article proposes an extension to a previous conference paper, concerning a Processor in the Loop testing of an Adaptive Model Predictive Control for coupled longitudinal/lateral vehicle dynamics, where the ego vehicle was simulated through a bicycle model. In the present work, a low‐cost real‐time Hardware In the Loop test bench, featured by Raspberry boards, is used to verify the control strategy in a way closer to a real application. A four‐wheel vehicle dynamic model is considered to simulate the ego vehicle, then robustness and sensitivity tests with respect to parametric variations related to road friction, wind speed and vehicle mass, and a comparison with an existing adaptive MPC are performed. The achieved results show good robustness properties, safety performances and confirm the real‐time execution of the control strategy, paving the way for future developments, where the goal will be the testing in a real road scenario by using an IoT gateway purposefully designed by the NetCom company.

Experimental validation of disturbance observer-based adaptive terminal sliding mode control subject to control input limitations for SISO and MIMO systems

Nowadays, advances in different fields of technology have increased demands for reliable controllers. Uncertainty, disturbances, and limitations in control inputs are inevitable with most systems. Hence, considering them in designing a practical controller seems indispensable to any system. We propose an adaptive, robust, and finite time control technique for both multi-input multi-output (MIMO) and single-input single-output (SISO) systems. In the design of the proposed control technique, due to the undeniable existence of disturbances and control input limitations, their effects are fully taken to account. On the basis of a finite time sliding mode strategy, controllers and disturbance observers are designed. Then, the stability and finite time convergence of the proposed control scheme and disturbance observer are proven via the Lyapunov stability theory. Eventually, to investigate the performance of the proposed method in real-world applications, a hardware-in-the-loop (HIL) test is carried out for the proposed control scheme. Through numerical simulation and the results of the HIL test, the high-effective performance of the proposed controller for uncertain chaotic systems was demonstrated. Moreover, the results of the HIL test showed that by implementing continuous functions in the design of the controller, chattering, which has detrimental effects on systems, will be reduced in practical applications. Numerical simulations and the results of the HIL test bench for the modified controller clearly confirmed the effective performance of the offered control technique for practical systems. Thereby applying the proposed control technique for complex nonlinear systems subject to control input limitations, disturbances, and time-varying uncertainties will be useful.

Real Driving Emissions—Conception of a Data-Driven Calibration Methodology for Hybrid Powertrains Combining Statistical Analysis and Virtual Calibration Platforms

The combination of different propulsion and energy storage systems for hybrid vehicles is changing the focus in the field of powertrain calibration. Shorter time-to-market as well as stricter legal requirements regarding the validation of Real Driving Emissions (RDE) require the adaptation of current procedures and the implementation of new technologies in the powertrain development process. In order to achieve highest efficiencies and lowest pollutant emissions at the same time, the layout and calibration of the control strategies for the powertrain and the exhaust gas aftertreatment system must be precisely matched. An optimal operating strategy must take into account possible trade-offs in fuel consumption and emission levels, both under highly dynamic engine operation and under extended environmental operating conditions. To achieve this with a high degree of statistical certainty, the combination of advanced methods and the use of virtual test benches offers significant potential. An approach for such a combination is presented in this paper. Together with a Hardware-in-the-Loop (HiL) test bench, the novel methodology enables a targeted calibration process, specifically designed to address calibration challenges of hybridized powertrains. Virtual tests executed on a HiL test bench are used to efficiently generate data characterizing the behavior of the system under various conditions with a statistically based evaluation identifying white spots in measurement data, used for calibration and emission validation. In addition, critical sequences are identified in terms of emission intensity, fuel consumption or component conditions. Dedicated test scenarios are generated and applied on the HiL test bench, which take into account the state of the system and are adjusted depending on it. The example of one emission calibration use case is used to illustrate the benefits of using a HiL platform, which achieves approximately 20% reduction in calibration time by only showing differences of less than 2% for fuel consumption and emission levels compared to real vehicle tests.

Experimental Implementation of Power-Split Control Strategies in a Versatile Hardware-in-the-Loop Laboratory Test Bench for Hybrid Electric Vehicles Equipped with Electrical Variable Transmission

The energy management strategy (EMS) or power management strategy (PMS) unit is the core of power sharing control in the hybridization of automotive drivetrains in hybrid electric vehicles (HEVs). Once a new topology and its corresponding EMS are virtually designed, they require undertaking different stages of experimental verifications toward guaranteeing their real-world applicability. The present paper focuses on a new and less-extensively studied topology of such vehicles, HEVs equipped with an electrical variable transmission (EVT) and assessed the controllability validation through hardware-in-the-loop (HiL) implementations versus model-in-the-loop (MiL) simulations. To this end, first, the corresponding modeling of the vehicle components in the presence of optimized control strategies were performed to obtain the MiL simulation results. Subsequently, an innovative versatile HiL test bench including real prototyped components of the topology was introduced and the corresponding experimental implementations were performed. The results obtained from the MiL and HiL examinations were analyzed and statistically compared for a full input driving cycle. The verification results indicate robust and accurate actuation of the components using the applied EMSs under real-time test conditions.

The Application of Hardware-in-the-Loop (HIL) Simulation for Evaluation of Active Safety of Vehicles Equipped with Electronic Stability Control (ESC) Systems

Automated vehicles are one of the most popular trends of modern R&D in the automotive industry. However autonomous driving is impossible without such electronic systems as Anti-Lock Braking System (ABS) and Electronic Stability Control (ESC). Development, adaptation, setup and debugging of mentioned systems require a large amount of field tests. The application of modern real-time simulation technologies based on Hardware-in-the-Loop (HIL) simulation allows to decrease the number of field tests. The paper is dedicated to the development and validation of a HIL test bench for virtual real-time testing of the GAZ Group light commercial vehicles equipped with ESC systems.

A testing framework for predictive driving features with an electronic Horizon

This paper proposes a novel approach for automated functional testing of map-based fusion algorithms in complex vehicle networks. The hybrid data representation of detailed digital maps and physical automotive sensors provides an extended view of the ego-vehicle environment and thereby facilitates improved inferences and more competent decision-making. It has therefore been instrumental in the ongoing development of predictive driving features, e.g. fuel-efficient driving, traffic sign recognition and highway-pilot. The presented approach utilises a closed-loop Hardware-in-the-Loop (HiL) co-simulation framework to evaluate the performance of the decision level fusion algorithms. The method contains both the structural design and resource-efficient integration into the HiL test bench in the example of traffic sign recognition. In reality, discrepancy between visual and map data is omnipresent due to map errors, old map data or optical detection failure. Through fault injection, defined inconsistencies can be produced within the HiL simulation environment. Amongst others, the fault injection covers the placement and value of traffic signs. These failures can be used for robustness testing of the fusion algorithms. Subsequently, a method for correlation analysis between field observations and synthetic simulation is realised to extend the requirements-based test coverage adaptively and systematically by modular and parameterised scenario specifications. In summary, the results show that the extended HiL environment is capable of generating electronic Horizon data which can easily be adapted or extended.

Pressure Following Strategy for Conventional Braking Control Applied to a HIL Test Bench

Brake systems represent important components for passenger cars since they are strictly related to vehicle safety: Anti-lock Braking Systems (ABS) and Electronic Stability Control (ESC) are the most well-known examples. The paper is focused on the characterization of the braking hydraulic plant and on the design of a pressure following control strategy. This strategy is aimed at pursuing performances and/or comfort objectives beyond the typical safety task. The low-level logic (focus of the paper) consists of a Feedforward and Proportional Integral controller. A Hardware In the Loop (HIL) braking test bench is adopted for pressure controller validation by providing some realistic reference pressure histories evaluated by a high-level controller. Results prove that innovative control strategies can be applied to conventional braking systems for achieving targets not limited to braking issues, i.e., comfort or NVH tasks.

Model of a Hybrid Electrical System for Software and System V & V on Hardware In the Loop Test Bench

Abstract Pressure to reduce CO 2 emissions is driving the automotive industry toward the electrification of powertrains. To support this trend Continental Automotive continues to develop components and advanced system control functionalities. To validate these new control functionalities, the existing Hardware In the Loop vehicle model was extended to include a model of the hybrid system. This paper describes the model requirements, the modelling methodology and the model validation process. Finally an insight is given into some typical use cases for this model during the verification & validation (V & V) phase.

Influence of Tire Parameters on ABS Performance

ABSTRACT The antilock braking system (ABS) is an active control system, which prevents the wheels from locking-up during severe braking. The ABS control cycle rapidly modulates braking pressure at each wheel mainly based on tire peripheral acceleration. Significant wheel speed oscillations and consequent fast variations of tire longitudinal slip are a consequence, which, in turn, produce a corresponding variation of tire longitudinal force according to the ABS control cycle. Clearly, tire characteristics, namely, tire peak friction (regulating maximum vehicle deceleration), longitudinal stiffness, optimal slip ratio, curvature factor (regulating the position of the peak of μ-slip curve and the subsequent drop), and relaxation length (accounting for tire dynamic response) may significantly influence ABS performance. The aim of the present paper is to evaluate the effect of the main tire parameters on ABS performance. This task is, however, very challenging, since tire characteristics are intrinsically related, and the analysis involves interaction between tires, vehicle, and ABS control logic. A methodology based on the hardware-in-the-loop (HiL) technique is used. This approach was selected to overcome limitations of numerical simulations or difficulties related to the execution of on-road experimental tests (repeatability, costs, etc.). The developed HiL test bench includes all the physical elements of the braking system of a vehicle (comprising the ABS control unit) and a 14 degrees of freedom (dofs) vehicle model, which are synchronized by a real-time board. With the developed HiL test bench, a sensitivity analysis was carried out to assess the influence of tire peak friction, longitudinal stiffness, and relaxation length on ABS performance, evaluated in terms of braking distance, mean longitudinal acceleration, and energy distribution.

Hardware-in-the-loop simulation for verification of the drive motor management software in a series hybrid electric bus

Hardware-in-the-loop (HiL) simulation is known as a reliable approach for testing and verification of the control system of hybrid vehicles. In this paper, a low-cost functional HiL test bench is utilised to test and verify the drive motor management software (DMMS) in a series hybrid electric bus. The HiL simulator in the current research is a laptop computer where the real-time simulation model of the virtual parts runs on it and the communication with the real hardware is made through high speed CAN. The simulation model is comprised of three subsystems: energy storage system (ESS), traction system (TS) and vehicle which are designed in LabVIEW environment. The simulation results demonstrate the ability of the designed HiL platform to test and verify the DMMS. Using the designed test bench, all control logics of the DMMS can be evaluated and this will reduce the development costs and time immensely.

Hardware in the loop test bench using Modelica: A platform to test and improve the control of heating systems

HVAC manufacturers make important investments to develop more efficient technologies for space heating (SH) and domestic hot water generation (DHW). Among these technologies, this article focuses on Double service air-to-water-heat-pumps (AWHP). The control of AWHP strongly impacts their performances, so that manufacturers of AWHP need to optimize the control of their systems to increase their performances. This paper presents the implementation of a Hardware-In-the-Loop – HIL – real time simulation test bench for AWHP. The new test bench proposed uses real weather conditions and simulates building’s and occupants’ response thanks to a virtual model. This test bench allows R&D departments and manufacturers to test several heating systems in parallel as well as different control options. It may also limit the need for field testing. It thus has the potential to reduce the cost and time required for AWHP development-to-market process. The test bench presented in this paper is used for a specific AWHP and a typical building in France. The analysis of the impact of the heat pump’s control on the system dynamics and on the indoor thermal comfort enables to highlight control issues related to the heating curve, the DHW management and the defrost process of AWHP. Optimized control parameters throughout time are proposed in view of reaching lower consumption and better performances. This case study shows the potential of the HIL test benches for manufacturers to optimize the development of their products controls.

An Equivalent Circuit Method for Modelling and Simulation of Modular Multilevel Converters in Real-Time HIL Test Bench

In China, two modular multilevel converter (MMC) projects were recently commissioned, and another two are currently under construction. The real-time hardware-in-the-loop (HIL) test bench played an important role in validating the manufacturer's controllers. The full detail MMC model does not fit with the HIL test bench, which has to solve the circuit containing numerous switches and handles a large amount of inputs and outputs at a small time step for real-time simulation. The main challenge is to find a method to model and simulate the MMC systems with sufficient detail, accuracy, and speed. This paper presents an equivalent circuit method for the HIL test bench. The circuit inside the submodule is represented by mathematical equations, implemented in CPU or a field-programmable gate array, and solved in parallel to achieve real-time performance. This method-based test bench is used in those MMC projects in China and connected to the manufacturer's controllers for HIL tests. The model accuracy and simulation speed achieved by this method met the requirements of the HIL tests. In this paper, various scenarios are tested in an MMC HVDC study system. The results achieved by the proposed method have high agreement with those of a reference model in EMTP-RV.

Development and validation of double and single Wiebe function for multi-injection mode Diesel engine combustion modelling for hardware-in-the-loop applications

The improvement of Diesel engine performances in terms of fuel consumption and pollutant emissions has a huge impact on management system and diagnostic procedure. Validation and testing of engine performances can benefit from the use of theoretical models, for the reduction of development time and costs. Hardware in the Loop (HiL) test bench is a suitable way to achieve these objectives. However, the increasing complexity of management systems rises challenges for the development of very reduced physical models able to run in real time applications. This paper presents an extension of a previously developed phenomenological Diesel combustion model suitable for real time applications on a HiL test bench. In the earlier study, the modelling efforts have been targeted at high engine speeds with a very short computational time window, and where the engine operates with single injection. In the present work, a modelling of in-cylinder processes at low and medium engine speeds with multi-injection is performed. In order to reach an adequate computational time, the combustion progress during the pilot and main injection periods has been treated through a double Wiebe function, while the post combustion period has required a single Wiebe function. This paper describes the basic system models and their calibration and validation against experimental data. The use of the developed correlations of Wiebe coefficients and ignition delay times for each combustion phase, included in the in-cylinder crank angle global model, is applied for the prediction of ignition delay time and in-cylinder pressure profiles at varying engine operations. As discussed in this paper, the behaviour of the simulated in-cylinder pressure confirms the good accuracy of the developed sub-models for ignition delay and of the combustion process description with double Wiebe approach. A lower but acceptable accuracy with single Wiebe function has been observed for post-injection combustion process.

Combined mean value engine model and crank angle resolved in-cylinder modeling with NOx emissions model for real-time Diesel engine simulations at high engine speed

This study is an extension of a previous MVEM (Mean Value Engine Models) and in-cylinder single zone model dedicated for HIL (Hardware In the Loop) applications. The in-cylinder single zone model has been modified into a two zone model for the combustion phase. Thus a Zeldovich extended mechanism has been used to simulate engine out NOx level. The entire model works as a combination of an MVEM approach for the engine periphery, of a single zone in-cylinder model for the intake-compression-exhaust strokes and of a two zone model for the combustion process. The combustion process is modeled through a double Wiebe equations developed previously. The proposed two zone and NOx models have been first coded using Matlab/Simulink software before its implementation on a HIL test bench. The in-cylinder extended model has required a quad Core RTPC to reach the step time of real time simulations where one core has been dedicated to the combustion process. The comparison of measured and calculated in-cylinder pressure and NOx emissions has shown a good accuracy. The mean relative error between the calculated and the measured indicated mean effective pressure is for example lower than 2%.

A Hardware-in-the-Loop Simulation Test Bench for Subway Train Brake Systems

A hardware-in-the-loop (HIL) simulation test bench for subway train brake systems is built in this paper to avoid the high costs of brake system field tests and maintain the reliability of test results. The HIL simulation test bench consists of a simulation part a hardware part. The simulation part includes a train model and a GUI. The hardware part mainly consists of six pneumatic brakes and a driver controller, which is used to generate brake commands. Signal transmissions between the simulation and hardware parts are realized using DAQ and signal transformation boards, as well as an MVB network. Test results suggest that the HIL test bench proposed is able to reproduce the braking behaviours of a train rather well, thus it can be used to carry out train braking tests in place of the costly field tests in some occasions.

Testing nacelles of wind turbines with a hardware in the loop test bench

Testing of wind energy converters (WEC) at ground level in contrast to an in-field setup has increased in the last years. As it is an approach which is fundamentally different to in field-testing, it requires significant modifications of the measurement environment and the layout of the sensor system. To increase the reliability of WECs, a detailed investigation of the status of various electrical and mechanical values is necessary because good condition monitoring guarantees a well-controlled state of the turbine in the desired point of operation. This leads to an appropriate maintenance strategy that enhances the lifetime of the WEC. Crucial physical values can be identified easier at ground level testing than with an in-field setup. This article addresses the realization of Hardware in the Loop (HIL) concepts on signal and power level for the use in WEC nacelle testing. Moreover, the functionality of the 1 MW demonstrator test bench operating in HIL mode with a DUT controlled by the original nacelle controller is shown.

A Novel Mechanical Hardware in the Loop Platform for Distributed Generation Systems

The growing number of distributed generation (DG) plants has emphasized the need to perform tests before the plants begin to operate. DG systems are complex enough that setting up of an experimental phase requires high costs and efforts. Moreover, renewable energy sources are intrinsically intermittent as they vary randomly with the time of day, the season and the weather. Consequently, the possibility of emulating the behavior of the whole renewable generation system in a real time environment, where a part of the real system, the natural energy source, is replaced by a real time computer simulation allows one to test the actual system in all the operating conditions, optimizing the control strategy before its service entrance, overcoming the randomness of renewable energy sources. This article proposes a mechanical hardware in the loop approach applied to a renewable energy generating system, where the whole drive (control, power electronics and electric machine) is tested and the mechanical part is simulated in real time environment. The problem of emulating the inertial torque, which can have a significant high value, is solved through an approach that relaxes the high dynamic requirements of the electrical drive that emulates the mechanical part. The hardware in the loop test bench emulates two energy sources (hydro and wind). In addition, a control strategy that emulates the inertial torque is implemented. An experimental phase in which different energy sources are modeled and emulated in a real time environment is presented as well. The underlying hardware-in-the-loop energy source emulation and experimentation scheme is shown to accurately represent real systems performance, under various control strategies and varying operating conditions.