Hardware-in-the-loop Simulation Research Articles

Diesel engine modeling based on recurrent neural networks for a hardware-in-the-loop simulation system of diesel generator sets

Abstract The electronic speed governors are widely used in diesel generator sets (DGS). To develop and debug electronic speed governor, the best option is to build a hardware-in-the-loop (HIL) simulation system. In the HIL simulation system, the physical diesel engine is replaced with its mathematical model for reducing the cost and producing less emissions. To meet the requirement of closing to the real environment, the performance of mathematical model representatives is very important. This paper presents a diesel engine modeling method based on recurrent neural networks (RNNs). This mathematical model is identified and estimated using the real data from one physical DGS. The experimental results showed that the proposed model accurately reproduced the diesel engine output characteristics with the changes of electrical power loads. To validate the proposed model, the simulation experiment was conducted on the established HIL simulation system. In the simulation experiment, the rack displacement and rotational speed were measured from the physical part of the HIL simulation system. The simulation result has been confirmed that the proposed model could well simulate the loading and unloading processes of the DGS.

Research on discontinuous guidance and hardware-in-the-loop simulation for unmanned underwater vehicle

Based on the application of important water area blockade, a new discontinuous guidance approach of an unmanned underwater vehicle (UUV) perpendicularly towards side of surface ship is proposed, and a hardware-in-the-loop simulation (HILS) system is established to demonstrate this guidance approach. This approach can be described as follows: a near-surface straight trajectory which is perpendicular to the predicted ship trajectory is figured out by detection device of UUV which is hidden underwater after the ship target is located. When the horizontal distance between UUV and the ship target meets start-up condition, UUV climbs to a certain depth near the sea surface and then runs along the horizontal straight trajectory. During its motion, UUV periodically measures the sight line between the UUV and ship target. In order to restrain the horizontal rotation of the sight line, a discontinuous guidance approach is proposed by using the deviation of the two adjacent sight lines and the distance between the UUV and the ship target to adjust the UUV’s velocity. After certain times of adjustment of the UUV’s velocity, UUV impacts the side of ship target perpendicularly with required accuracy. This near-surface discontinuous guidance approach makes it possible for UUV to be guided through optical or radar detection. Further discussions are made including miss distance caused by this proposed guidance approach, cycle of sight line detection, UUV’s non-attack zone and UUV start-up condition. Finally, a set of HILS is carried out to demonstrate the performance of the discontinuous guidance approach on an experimentally validated UUV model.

Robust Autopilot Design and Hardware-in-the-Loop Simulation for Air to Air Guided Missile

This paper proposed a robust autopilot design for air to air guided missile and a Hardware-in-the-Loop (HIL) simulation which is based on the derived missile-control transfer functions and the 6DOF simulation model. The introduced autopilot is implemented within the 6DOF simulation to check its robustness against non-modeled dynamics and nonlinearities. The nonlinear 6DOF equations of motions are solved together to obtain the pitch and yaw transfer functions. The missile equations are described in the form of modules programmed within the C++ environments to form the baseline for subsequent design and analysis. Furthermore, a comparison between both our previous work, i.e. classical and robust autopilot, are justified via HIL simulation. The simulation results demonstrated the robustness capability in presence disturbance and noise.

Development of an educational interactive hardware‐in‐the‐loop missile guidance system simulator

AbstractThis paper presents a hardware‐in‐the‐loop (HIL) simulator, named HIL‐GSS, which aims to help the students of aerospace engineering learn control and missile guidance theories effectively by using interactive instrumentation. Electromechanical components and interactive panels are illustrated. Two case‐based studies are presented to show the advantages that HIL‐GSS offers to engineering education. Steady‐state tracking errors of the PID controller based on the HIL‐GSS are around zero. The final miss distance in the real‐time HIL TV guidance engagement simulation is 0.2376 m. Those results show the reliability of the proposed HIL simulator. In addition, the students' average response to survey questions is 4.22 (1–5 grade scale), which indicates that students strongly agree or agree that HIL‐GSS is an effective educational tool.

Observer-based nonlinear control strategies for Hardware-in-the-Loop simulations of multiaxial suspension test rigs

The Hardware-in-the-Loop (HiL) simulation is a powerful and well-established approach for the development and testing of mechatronic systems. The specimen is coupled appropriately with mathematical models of the remainder of a larger system that run in parallel on a real-time computer. For test rigs with multiaxial excitation of the specimen, the realization of HiL simulations is a challenging task. The excitation units are serial or parallel kinematic manipulators and the dynamic properties of the specimen vary in different spatial directions. In particular, the interaction forces and torques at the interface between manipulator and specimen have to be considered. Thus, appropriate control strategies are necessary to drive the manipulators enabling realistic and safe HiL simulations. This article deals with the design of motion and force control strategies for a vehicle axle test rig with a highly dynamic hydraulic hexapod used as the excitation unit. The realization of motion and force control for a hexapod requires the knowledge of its current system state. Therefore, sliding mode state observation techniques using super-twisting algorithms (STA) are presented. The developed controllers, observers and HiL configurations are validated with simulation and experimental results.

Simulation and experimental investigation of vehicle braking system employing a fixed caliper based electronic wedge brake

This paper presents an investigation into the performance of a fixed caliper based electronic wedge brake (FIXEWB) in a vehicle braking system. Two techniques were used as assessment methods, which are simulation via MATLAB Simulink software and experimental study through hardware-in-the-loop-simulation (HILS). In the simulation study, the vehicle braking system was simulated by using a validated quarter vehicle traction model with a validated FIXEWB model as the brake actuator. A proportional–integral–derivative controller was utilized as the brake torque control, whereas proportional–integral and proportional controllers were used as the position and speed control of the actuator, respectively. To study the effectiveness of the FIXEWB, the response of the vehicle using the FIXEWB is compared with the responses of a vehicle using a conventional hydraulic brake. A dynamic test, namely braking in the sudden braking at constant speeds of 40 and 60 km/h was then used as the testing method. The simulation results show that the usage of the FIXEWB with an appropriate control strategy produces similar behavior to that of a hydraulic brake in terms of the produced desired braking torque but with faster time response. To study the performance of the FIXEWB when implemented on a real vehicle, an experimental rig using HILS was designed and the results are analyzed using the same dynamic tests. The performance areas evaluated are vehicle body speed, wheel speed, tire longitudinal slip, and the stopping distance experienced by the vehicle. The outcomes from this study can be considered in the design optimization of an antilock braking system control in a real car in the future.

Comparison of performance between Virtual Controller Interface Device and Controller Interface Device

A Controller Interface Device (CID) is a hardware that connects a signal controller to simulation software. Running traffic simulation with an actual controller is called hardware-in-the-loop simulation (HILS) and is an important tool for simulating the operations of traffic signals. In practice, it has been found that the existing traditional CIDs have some limitations, particularly when simulating multiple signals. In this regard, a Virtual CID (VCID) is proposed in this study. VCID can connect traffic signal controllers to a micro-simulation software through the National Transportation Communications for ITS Protocol (NTCIP). A case study is conducted that uses the same traffic networks to compare the performance of VCID to CID. Queue length, travel time and simulation stability are considered in the evaluation. Results show that VCID could provide accurate and reliable simulation results. In comparison to traditional CIDs, VCID has more advantages as it does not depend on any hardware device and is easy to operate. In addition, since the communications are transformed through Ethernet, thus providing a convenient learning and testing environment for those who do not own a physical signal control laboratory. Therefore, VCID will have a broader prospect for development than CID.

Take-off and landing control for a coaxial ducted fan unmanned helicopter

PurposeThis paper aims to present a control strategy that eliminates the longitudinal and lateral drifting movements of the coaxial ducted fan unmanned helicopter (UH) during autonomous take-off and landing and reduce the coupling characteristics between channels of the coaxial UH for its special model structure.Design/methodology/approachUnidirectional auxiliary surfaces (UAS) for terminal sliding mode controller (TSMC) are designed for the flight control system of the coaxial UH, and a hierarchical flight control strategy is proposed to improve the decoupling ability of the coaxial UH.FindingsIt is demonstrated that the proposed height control strategy can solve the longitudinal and lateral movements during autonomous take-off and landing phase. The proposed hierarchical controller can decouple vertical and heading coupling problem which exists in coaxial UH. Furthermore, the confronted UAS-TSMC method can guarantee finite-time convergence and meet the quick flight trim requirements during take-off and landing.Research limitations/implicationsThe designed flight control strategy has not implemented in real flight test yet, as all the tests are conducted in the numerical simulation and simulation with a hardware-in-the-loop (HIL) platform.Social implicationsThe designed flight control strategy can solve the common problem of coupling characteristics between channels for coaxial UH, and it has important theoretical basis and reference value for engineering application; the control strategy can meet the demands of engineering practice.Originality/valueIn consideration of the TSMC approach, which can increase the convergence speed of the system state effectively, and the high level of response speed requirements to UH flight trim, the UAS-TSMC method is first applied to the coaxial ducted fan UH flight control. The proposed control strategy is implemented on the UH flight control system, and the HIL simulation clearly demonstrates that a much better performance could be achieved.

A Novel Emulation Model of the Cardiac Conduction System

Models of the cardiac conduction system are usually at two extremes: (1) high fidelity models with excellent precision but lacking a real-time response for emulation (hardware in the loop simulation); or (2) models amenable for emulation, but that do not exhibit appropriate dynamic response, which is necessary for arrhythmia susceptibility. We introduce two abstractions to remedy the situation. The first abstraction is a new cell model, which is a semi-linear hybrid automata. The proposed model is as computationally efficient as current state-of-the-art cell models amenable for emulation. Yet, unlike these models, it is also able to capture the dynamic response of the cardiac cell like the higher-fidelity models. The second abstraction is the use of smooth-tokens to develop a new path model, connecting cells, which is efficient in terms of memory consumption. Moreover, the memory requirements of the path model can be statically bounded and are invariant to the emulation step size. Results show that the proposed semi-linear abstraction for the cell reduces the execution time by up to 44%. Furthermore, the smooth-tokens based path model reduces the memory consumption by 40 times when compared to existing path models. This paves the way for the emulation of complex cardiac conduction systems, using hardware code-generators.

Real-Time Testing Approaches for Microgrids

Microgrids (MGs) are seen today as the solution to the challenge of meeting the ever-increasing demand of energy which is clean. A variety of challenges need to be overcome for these MGs to be successful varying from stability, power quality to protection, and management. Since the various control strategies are actively being researched and emerging challenges still being addressed, there has been a lot of interest related to the aspect of testing. The ever-increasing complexity of control mechanisms invokes the need for safer, faster yet reliable testing methods, which do not compromise on the degree of detail and at the same time are economical and require the minimum testing time. Off-line simulation, real-time (RT) simulation, hardware in the loop simulation, RT emulation, hardware test beds, pilot plants, and other integrated approaches are the major methods for testing in MGs. This paper gives an overview of the testing techniques and discusses the trends in the various technologies employed for testing MGs. First, the various methods are briefly discussed and a comparison is provided. Next, the various research efforts carried out on the aspect of MG testing are categorized and presented one-by-one. Furthermore, new methodologies and emerging approaches for the testing have also been highlighted, and the challenges and future research avenues have been presented.

On-line Optimal Control of the Gearshift Command for Multispeed Electric Vehicles

A design method for the gearshift strategy in powertrain systems is proposed to explore the energy saving potential of an electric vehicle (EV) equipped with a multispeed automated manual transmission (AMT). The optimal gearshift schedule is obtained by solving a nonlinear time-varying optimal problem in the framework of model predictive control, wherein, the vehicle driveability, represented by the driver's power demand satisfaction, and battery efficiency are considered. The solution approach is developed basing on the combination of Pontryagin's minimum principle and numerical methods, in addition to the real-time applications. Simulation results for a passenger EV with four-speed AMT on different drive cycles show that compared with the case of a standard gearshift strategy, an additional fuel saving can reach 3–5% and even more when considering road characteristic such as road slope. Furthermore, hardware in the Loop simulation for experimental validation is also given in this paper. Results indicate that both energy efficiency and computational speed are improved.

Design and implementation of hardware in the loop simulation for electric ducted fan rocket control system using 8-bit microcontroller and real-time open source middleware

Hardware in the Loop Simulation (HILS) is intended to reduce time and development cost of control system design. HILS systems are mostly built by integrating both controller hardware and simulator software where the software is not an open source. Moreover, implementing HILS by using manufactured system is costly. This paper describes the design and implementation of HILS for Electric Ducted Fan (EDF) rocket by using open-source platform for development with middleware. This middleware system is used to bridge the data flow between controller hardware and simulator software. A low-cost ATMEGA 2560 8-bit microcontroller is used to calculate rocket’s attitude with Direction Cosine Matrix (DCM) algorithm and PID controller is employed to regulate rocket’s dynamics based on desired specifications. X-Plane 10 simulator software is used for generating simulated sensory data. The test results validate that HILS design meets the defined specifications, i.e. angle difference of 0.3 degrees and rise time of 0.149 seconds on pitch angle.

SwarmSim: a framework for modeling swarming unmanned aerial vehicles using Hardware-in-the-Loop

Unmanned Aerial Vehicle (UAV) swarm applications, algorithms, and control strategies have experienced steady growth and development over the past 15 years. Yet, to date, most swarm development efforts have gone untested and unimplemented. The major inhibitors to successful swarm implementation seem to include the cost of aircraft systems, government imposed airspace restrictions, and the lack of adequate modeling and simulation tools. This paper examines how the open-source OpenEaagles simulation framework was leveraged to bridge this gap to create Hardware-in-the-Loop (HIL) simulations. Leveraging OpenEaagles through software extension to create HIL simulations provides developers with a functional capability with which to develop and test the behaviors of scalable and modular swarms of autonomous UAVs. Using HIL-based simulations in this capacity provides assurance that defined behaviors will propagate to live flight tests in the real world. The demonstrations in the work show how the framework enhances and simplifies swarm development through encapsulation, possesses high modularity, provides realistic aircraft modeling, and is capable of simultaneously accommodating multiple hardware-piloted and purely simulated swarming UAVs during simulation.

HIL simulation of the DTC for a three-level inverter fed a PMSM with neutral-point balancing control based on FPGA

This paper presents a hardware description methodology for the direct torque control (DTC) of a three-level voltage source inverter (VSI) fed a permanent magnet synchronous motor drive with neutral-point balancing control algorithm based on field programmable gate array (FPGA). The main drawback of the conventional DTC during its digital implementation is the high torque ripple, and to overcome this problem, the use of a three-level VSI and a simple hardware description methodology for DTC based on FPGA is proposed. However, the circuit limitations of the three-level inverter, such as neutral-point balance, should be taken into account in the selection of the future space vector applied to the machine; for this reason, a simple and effective procedure to maintain the neutral-point balance is presented. The proposed methodology has been validated using hardware in the loop simulation, and results under different operating points are presented.

Power Balancing Control for Grid Energy Storage System in Photovoltaic Applications—Real Time Digital Simulation Implementation

A grid energy storage system for photo voltaic (PV) applications contains three different power sources i.e., PV array, battery storage system and the grid. It is advisable to isolate these three different sources to ensure the equipment safety. The configuration proposed in this paper provides complete isolation between the three sources. A Power Balancing Control (PBC) method for this configuration is proposed to operate the system in three different modes of operation. Control of a dual active bridge (DAB)-based battery charger which provides a galvanic isolation between batteries and other sources is explained briefly. Various modes of operation of a grid energy storage system are also presented in this paper. Hardware-In-the-Loop (HIL) simulation is carried out to check the performance of the system and the PBC algorithm. A power circuit (comprised of the inverter, dual active bridge based battery charger, grid, PV cell, batteries, contactors, and switches) is simulated and the controller hardware and user interface panel are connected as HIL with the simulated power circuit through Real Time Digital Simulator (RTDS). HIL simulation results are presented to explain the control operation, steady-state performance in different modes of operation and the dynamic response of the system.

Hardware-In-the-Loop Simulation of Traction Power Supply for Power Flows Analysis of Multitrain Subway Lines

Multitrain systems are difficult to study due to the size of the system and its specificities. To tackle these difficulties, this paper develops a reduced-scale power Hardware-In-the-Loop (HIL) simulation dedicated to subway line emulations. Energetic macroscopic representation (EMR) is used to organize the HIL simulation. A first mono-train HIL simulation is developed and validated by experimental results. The HIL simulation is then extended to a two-train study to analyze the different power flows between subsystems.

Hybrid analytical model of switched reluctance machine for real‐time hardware‐in‐the‐loop simulation

Applications of switched reluctance machine (SRM) are increasing in the industry due to their many desirable features. This study proposes a hybrid analytical model (HAM) of the SRM for the hardware-in-the-loop (HIL) simulation. To obtain satisfactory accuracy, the phase flux linkage is solved by the magnetic equivalent circuit (MEC) method when the stator and rotor poles overlap, and by the space harmonic method (SHM) when the poles do not overlap. The backward Euler and Newton–Raphson methods are used to calculate the exciting current, while the Gaussian quadrature is used to compute the electromagnetic torque in the HIL simulation. The digital hardware implementation of computation components are developed on the field-programmable gate array by exploiting the parallel hardware architecture and fully pipelined arithmetic processing. To highlight the performance of the HAM, the captured real-time results are compared with the off-line transient solution obtained through the co-simulation of Ansys Maxwell®, Ansys Simplorer®, and Simulink®, which model the SRM, drive circuit, and control system, respectively.

A Hardware-In-The-Loop Simulator for the Development of Medical Therapy Devices

Medical therapy devices need to interact with the patient to achieve a desired clinical result. Therefore, the patient is part of the final therapy system. But during the development and validation phase of medical devices the patient can not be involved in the design process. A replacement for the patient, or rather the body part which interacts with the therapy device, is needed. Simulators can be used to solve this problem. This contribution introduces the concept of a Hardware-In-The-Loop (HIL) simulator which is designed to be usable in a wide range of applications in the field of medical technology. HIL simulators consist of a software model of the simulated process and a physical interface to the therapy device. Actuators are used to influence the states of the physical interface and sensors measure the interaction between the HIL simulator and the therapy device. As a first application, the process of a minimally invasive surgery (MIS) was chosen. Insight to the process of the MIS was elaborated at the example of an arthroscopy. A software model of the knee, representing the operation area, was developed. A prototype was designed and different types of actuators were implemented. An over-actuated design was chosen to ensure a high flexibility. Control oriented models of the used actuators were derived. Finally, different actuator control strategies were developed, implemented and validated successfully.

Real‐time hardware‐in‐the‐loop simulation for islanding detection schemes in hybrid distributed generation systems

The increasing penetration level of renewable energy brings new challenges to the field of islanding detection. In this study, a decision-tree (DT)-learning method with hardware-in-the-loop (HIL) simulations is proposed to address the non-detection zone (NDZ) issue of islanding detection in hybrid distributed generation systems including both inverter- and synchronous-machine-based distributed energy resources. This method can effectively reduce the NDZ through advanced relay training strategy and utilise the advantage of real-time simulators on simulation efficiency. In addition, the generated DT can be programmed into a real relay and then get validated through HIL simulations. The HIL implementation adds a practical dimension to the proposed method. With the proposed method, the laboratory testing results indicate promising islanding detection performance in terms of dependability, security, reduced NDZ area and detection time.

Evaluation of Red Clearance Extension designs with Hardware-in-the-Loop simulation

Advances in signal controller software and hardware are introducing new safety-enhancing functions to the signal engineer’s toolbox. Hardware-in-the-Loop (HITL) simulation can evaluate alternative timing parameters, detection strategies, and intersection geometries in a safe and cost-effective manner. Red Clearance Extension (RCE) is one design alternative that can be evaluated by HITL simulation. RCE operates by predicting Red Light Running vehicles and dynamically increasing red clearance interval duration to reduce crash probability. In this study, HITL simulation was used to evaluate four alternative RCE detection strategies. Novel code was developed in R to visualize output in Enhanced Time-Space Diagrams (ETSDs). RLR vehicles triggered the highest rate of correct RCE events when the downstream detection alternative was used. However, the ETSDs showed that RCE events triggered by smart upstream speed-conditional detection alternatives at 125, 215, and 475 ft provided greater safety for vehicles with no significant increase to intersection delay incurred.