To fulfill ever increasingly stringent emission regulations, a great many studies on engine contr... more To fulfill ever increasingly stringent emission regulations, a great many studies on engine control and catalytic converter performance have been made. Topics of great interest in this area, to name a few, include: the relationship between catalyst light-off time and air-fuel (A/F) ratio; the relationship between forced A/F ratio modulation and catalyst efficiency; the effects of phaseshifted A/F ratio modulation between banks of a dual bank engine, or among cylinders of a single manifold engine on catalyst efficiency; and methods of modeling and measuring the oxygen storage capacity of a catalytic converter by rich-lean transition, A/F ratio sweeping, or other on-line estimation methods. To undertake this type of research, an engine control system with necessary functions, especially with very flexible A/F ratio control capabilities, is needed. Mass production ECU does not provide the flexibility desired and it is also hard to develop and integrate the control algorithms needed for catalyst testing into the existing ECU software. An engine rapid control prototyping system is set up in an engine dynamometer test cell environment to overcome the limitations of mass production ECU and fulfill the requirements for catalyst research and testing. Model-based development methodology is adopted for the design and implementation of necessary software. Control algorithms, including individual bank control of a dual bank engine, A/F ratio modulation of different frequencies and amplitudes, with and without phase shift between banks, A/F ratio rich-lean transition and sweeping etc, are designed using graphical language, automatically converted into executables to run on the real-time target. UDP communication for real-time command and variable exchange between the engine controller and the test cell controller is developed to facilitate testing. The system provides the flexibility and good control performance desired for catalyst research and evaluation testing. Application and results of the system on a 4.6L V8 gasoline engine is given.
To meet the ever increasing requirements for engines and vehicles in the areas of performance, fu... more To meet the ever increasing requirements for engines and vehicles in the areas of performance, fuel economy and emission, and reduce product development time, we see the need for an integrated development environment which combines engine rapid control prototyping (RCP) capability with real-time vehicle simulation capability using an engine dynamometer in the test cell. Design and implementation of such a system with the ADX universal high-speed system controllers are described. An application example of simulating an FTP-75 cycle in the test cell while the engine is under ADX control is presented. This system moves a lot of work from the whole vehicle environment to the engine test cell environment, and is a powerful tool for quick development and testing of control algorithms as well as calibration.
Due to the ever increasing requirements for engine performance, variable compression ratio and di... more Due to the ever increasing requirements for engine performance, variable compression ratio and displacement are drawing great interest, since these features provide further degrees of freedom to optimize engine performance for various operating conditions. Different types of mechanisms are used to realize variable compression ratio and displacement. These mechanisms usually involve relatively complicated mechanical design compared with conventional engines. While the flexibility in these mechanisms introduces additional engine design and control possibilities, it also increases the challenges for the development and optimization, since how the geometry of the mechanisms affects the engine performance is not straightforward, and building prototype engines of various mechanical design parameters takes a long time with high cost. This paper presents a study of a multiple-link mechanism that realizes variable compression ratio and displacement by varying the piston motion, specifically ...
To meet the ever increasing requirements for engine and vehicle performance, and at the same time... more To meet the ever increasing requirements for engine and vehicle performance, and at the same time shorten product development time, model-based development methodologies have been quickly adopted by OEMs and suppliers in recent years. With model-based development, new algorithms are specified in a highlevel graphical language and directly compiled into executables to be implemented and tested on rapid control prototyping hardware. This seamless transition from design to implementation and testing greatly improves the efficiency of the development process for modern automotive control strategies, especially in engine control system development. A model-based development environment and its application in engine control functions development are presented. The environment consists of the ADX rapid prototyping controller, various functional boards, necessary signal conditioning and power electronics modules, and graphical user interface (GUI) software VirtualConsole. Control algorithms...
Good battery modeling is critical for energy management of electric vehicles and hybrid electric ... more Good battery modeling is critical for energy management of electric vehicles and hybrid electric vehicles. Because of its simplicity and satisfactory performance, equivalent circuit models are widely used in this area. A frequently adopted equivalent circuit model is one that consists of an open-circuit voltage and a resistor in series with two sets of parallel resistorcapacitor combinations. This model performs well in describing battery transient behavior due to the dynamics of such physical phenomena as mass transport effects and double layer effects. Generic methods for obtaining the parameters of this model involve analyzing the battery voltage behavior under step changes of load current. The fact that the model has two time constants places a challenge on parameter identification. Some most often used method makes use of the property that each of the two time constants plays a dominant role at different stages of the battery voltage response, and calculates the model parameters accordingly. For such method, the results are greatly influenced by the partition of faster and slower dynamics of the battery, and selection of the data points used for the calculation. Moreover, because majority of the testing data is not used towards calculating the parameters, the obtained model might not reflect the overall battery characteristics well and consequently might not give highfidelity predictions. For other methods that use nonlinear curve fitting or genetic algorithm for parameter searching, the successful implementation greatly depends on the proper setting of initial values and searching space. A novel method of parameter identification for the equivalent circuit model is presented in this paper. It makes use of a regression equation which is linear in variables that can be measured or calculated from the test. With this approach, all testing data during the relaxation period of a constant current pulse discharge or charge test is used towards obtaining the model parameters and the calculation is in the sense of least squared error. Application of the method to real battery testing data is presented. The example indicates that the method gives very good results with modeling error of less than 0.5%.
Variable compression ratio and variable displacement technologies are adopted in internal combust... more Variable compression ratio and variable displacement technologies are adopted in internal combustion engines because these features provide further degrees of freedom to optimize engine performance for various operating conditions. This paper focuses on a multiple-link mechanism that realizes variable compression ratio and displacement by varying the piston motion, specifically the Top Dead Center (TDC) and Bottom Dead Center (BDC) positions relative to the crankshaft. It is determined that a major requirement for the design of this mechanism is when the control action changes monotonically over its whole range, the compression ratio and the displacement should change in opposite directions monotonically. This paper presents an approach on how to achieve multiple-link mechanism geometric designs that fulfill this requirement. First, a necessary and sufficient condition, and a stronger sufficient condition are obtained on how the TDC and BDC positions should change with respect to the control action to fulfill the design requirement. Then Design of Experiments (DoE) methodology is used for creating sets of geometric designs of the mechanism, for which kinematics are calculated and checked against the conditions. A feasible design that satisfies the conditions is selected and detailed study on such characteristics as piston motion, stroke length, displacement, combustion chamber volume, and compression ratio etc. is performed. The design approach and obtained results serve as a basis for further analysis and optimization of the multiple-link mechanism.
To fulfill ever increasingly stringent emission regulations, a great many studies on engine contr... more To fulfill ever increasingly stringent emission regulations, a great many studies on engine control and catalytic converter performance have been made. Topics of great interest in this area, to name a few, include: the relationship between catalyst light-off time and air-fuel (A/F) ratio; the relationship between forced A/F ratio modulation and catalyst efficiency; the effects of phaseshifted A/F ratio modulation between banks of a dual bank engine, or among cylinders of a single manifold engine on catalyst efficiency; and methods of modeling and measuring the oxygen storage capacity of a catalytic converter by rich-lean transition, A/F ratio sweeping, or other on-line estimation methods. To undertake this type of research, an engine control system with necessary functions, especially with very flexible A/F ratio control capabilities, is needed. Mass production ECU does not provide the flexibility desired and it is also hard to develop and integrate the control algorithms needed for catalyst testing into the existing ECU software. An engine rapid control prototyping system is set up in an engine dynamometer test cell environment to overcome the limitations of mass production ECU and fulfill the requirements for catalyst research and testing. Model-based development methodology is adopted for the design and implementation of necessary software. Control algorithms, including individual bank control of a dual bank engine, A/F ratio modulation of different frequencies and amplitudes, with and without phase shift between banks, A/F ratio rich-lean transition and sweeping etc, are designed using graphical language, automatically converted into executables to run on the real-time target. UDP communication for real-time command and variable exchange between the engine controller and the test cell controller is developed to facilitate testing. The system provides the flexibility and good control performance desired for catalyst research and evaluation testing. Application and results of the system on a 4.6L V8 gasoline engine is given.
The Electronic Throttle Control (ETC) system is more and more used and increasingly becoming a st... more The Electronic Throttle Control (ETC) system is more and more used and increasingly becoming a standard part of the engine. It controls the amount of air intake into the cylinders by precisely positioning the throttle plate at the desired opening. An ETC system provides the possibility of improving the overall engine and vehicle performance because with such a mechanism, the engine controller can decide and set the throttle position not only based on driver intention, but also taking into consideration the specific engine operation mode information, such as safety factors, emission constraints, etc. After the throttle position target is determined, the requirement for the ETC system is that the throttle plate should achieve the commanded position as accurately and as quickly as possible. In many cases the controller is designed by first establishing a model of the electronic throttle system using experimental identification. However, due to such nonlinear effects as static friction, dynamic friction, and nonlinear return springs etc., identification of a model for the electronic throttle system sometimes does not give good results. This makes a controller design based on the model far from optimal. Iterative Feedback Tuning (IFT) is a method for directly tuning the controller parameters based on the data of closed loop experiments without the need for an explicit model of the system. This property makes IFT an attractive method for ETC design. In this paper a Two-Degree-of-Freedom (2-DOF) Proportional-Integral-Derivative (PID) controller for an engine electronic throttle system is designed and the PID control gains are optimized using IFT. The application shows that the IFT method gives very good performance for controller tuning.
To meet the ever increasing requirements for engines and vehicles in the areas of performance, fu... more To meet the ever increasing requirements for engines and vehicles in the areas of performance, fuel economy, emission, and meanwhile reduce product development time, Hardware-in-the-loop (HIL) simulation is increasingly used in automotive control system development. Engine-in-the-loop (EIL) vehicle simulation, which is a specific form of HIL simulation, is an approach in which a physical engine (together with its control unit) is coupled to virtual vehicle and driver models through a high power, low inertia engine dynamometer in the engine test cell environment. EIL can be used to perform powertrain control development, as well as engine and vehicle performance evaluation. Because of its advantages in repeatability and flexibility etc., especially for transient operating mode study, EIL has become a powerful tool and will be more widely used in the near future. Design and implementation of an EIL vehicle simulation system is described. Driver and vehicle simulation models are developed and executed in real time on a high-speed system controller. A highly responsive permanent magnet AC engine dynamometer and a vehicle acceleration pedal are controlled such that the dynamometer loads the connected engine as a real vehicle would and the simulated vehicle speed trace follows the targeted driving cycle. With this system, developers can perform transient engine control development before whole vehicle integration is available. Vehicle parameters, including driveline configurations can be easily modified and the effect on engine and vehicle performance can be studied. An application example of simulating a 10-15 mode emission test cycle is given. The result verifies the effective performance of the system in simulating vehicle dynamics and shows its great potential in engine and vehicle system development.
Due to growing interest in hybrid and electric vehicles, the battery, being one of the critical c... more Due to growing interest in hybrid and electric vehicles, the battery, being one of the critical components, is receiving a lot of attention from designers and researchers. Two batterymodeling approaches, though seemingly different, share the same mathematical challenge of robust non-linear curvefitting. The two methods are battery equivalent circuit model and battery system level thermal modeling using the linear time-invariant (LTI) method. Both modeling approaches involve curve-fitting testing data or data from advanced models to identify four parameters in a circuit model consisting of two pairs of RC elements. Such curve-fitting is mathematically a non-linear least-squares (LS) problem. Standard methods like the Levenberg-Marquardt (LM) method can be used for non-linear curve-fitting, but the LM method is known to be sensitive to initial conditions. Due to the unique features of the two pairs of RC values in the model, the curve-fitting problem can be reformulated into a linear LS problem. Solution from the linear LS problem can then be used as an initial condition for the LM method for greater accuracy. Since the initial conditions from the linear LS problem are already close to the minimum, the sensitivity issue associated with the LM method is mitigated.
To meet the ever increasing requirements in the areas of performance, fuel economy and emission, ... more To meet the ever increasing requirements in the areas of performance, fuel economy and emission, more and more subsystems and control functions are being added to modern engines. This leads to a quick increase in the number of control parameters and consequently dramatic time and cost increase for engine calibration. To deal with this problem, the automotive industry has turned to model-based calibration for a solution. Model-based calibration is a method that uses modern Design of Experiments (DoE), statistical modeling and optimization techniques to efficiently produce high quality calibrations for engines. There are two major enablers for carrying out this method-fully automated engine control and measurement system, and advanced mathematical tools for DoE, modeling and optimization. This paper presents a case study of adopting this methodology for the determination of optimum steady state calibrations of ignition timing, air-fuel ratio and intake cam phasing for a gasoline engine. ORION automated engine control and measurement system is used for testing data collection. EasyDoE Toolsuite is used for DoE, engine response modeling and control parameter optimization. Major features of these tools are described. Each step in performing this process, including definition of factors and responses, DoE, automatic measurement on engine test bench, creation of engine models of sufficient accuracy, and generation of control maps using optimization techniques, is covered. The results demonstrate that the model-based approach is a well suited method for engine calibration, and the integrated system provides an effective solution for implementing model-based calibration.
2010 IEEE/ASME International Conference on Advanced Intelligent Mechatronics, 2010
... Dr. Shugang Jiang, Dharshan Medonza, James Kitchen and Dr. Michael Smith are with A&D... more ... Dr. Shugang Jiang, Dharshan Medonza, James Kitchen and Dr. Michael Smith are with A&D Technology Inc., Ann Arbor, MI. Rahul Ahlawat is a PhD candidate at the University of Michigan, Ann Arbor and was with A&D during this work. ... 689 Page 3. MSe Tm 1 ωe I : Je − Jim ...
ABSTRACT This paper presents the development of real-time (RT) engine and vehicle models for emul... more ABSTRACT This paper presents the development of real-time (RT) engine and vehicle models for emulating transient loads during transmission-in-the-loop (TIL) experiments. The models emulating these vehicle-components are required to possess sufficient fidelity to simulate engine torque pulse (ETP) and wheel-slip dynamics while being computationally efficient to run in RT. The emulation of ETP is accomplished by decomposing the waveform into inertia and combustion based components, and implemented using the high switching frequency of AC-dynamometer drive. The task of emulating wheel slip is achieved by using a RT physics based hybrid tire model developed to avoid the singularly perturbed dynamics at high velocities. Parameters of the engine model are identified using experimental data, and both models are validated in pure simulation. Finally, closed loop TIL test results are presented to demonstrate successful emulation during experimentation.
The Electronic Throttle Control (ETC) system is more and more used and increasingly becoming a st... more The Electronic Throttle Control (ETC) system is more and more used and increasingly becoming a standard part of the engine. It controls the amount of air intake into the cylinders by precisely positioning the throttle plate at the desired opening. An ETC system provides the possibility of improving the overall engine and vehicle performance because with such a mechanism, the engine controller can decide and set the throttle position not only based on driver intention, but also taking into consideration the specific engine operation mode information, such as safety factors, emission constraints, etc. After the throttle position target is determined, the requirement for the ETC system is that the throttle plate should achieve the commanded position as accurately and as quickly as possible. In many cases the controller is designed by first establishing a model of the electronic throttle system using experimental identification. However, due to such nonlinear effects as static friction, dynamic friction, and nonlinear return springs etc., identification of a model for the electronic throttle system sometimes does not give good results. This makes a controller design based on the model far from optimal. Iterative Feedback Tuning (IFT) is a method for directly tuning the controller parameters based on the data of closed loop experiments without the need for an explicit model of the system. This property makes IFT an attractive method for ETC design. In this paper a Two-Degree-of-Freedom (2-DOF) Proportional-Integral-Derivative (PID) controller for an engine electronic throttle system is designed and the PID control gains are optimized using IFT. The application shows that the IFT method gives very good performance for controller tuning.
ABSTRACT This paper presents the development of real-time (RT) engine and vehicle models for emul... more ABSTRACT This paper presents the development of real-time (RT) engine and vehicle models for emulating transient loads during transmission-in-the-loop (TIL) experiments. The models emulating these vehicle-components are required to possess sufficient fidelity to simulate engine torque pulse (ETP) and wheel-slip dynamics while being computationally efficient to run in RT. The emulation of ETP is accomplished by decomposing the waveform into inertia and combustion based components, and implemented using the high switching frequency of AC-dynamometer drive. The task of emulating wheel slip is achieved by using a RT physics based hybrid tire model developed to avoid the singularly perturbed dynamics at high velocities. Parameters of the engine model are identified using experimental data, and both models are validated in pure simulation. Finally, closed loop TIL test results are presented to demonstrate successful emulation during experimentation.
... Dr. Shugang Jiang, Dharshan Medonza, James Kitchen and Dr. Michael Smith are with A&D... more ... Dr. Shugang Jiang, Dharshan Medonza, James Kitchen and Dr. Michael Smith are with A&D Technology Inc., Ann Arbor, MI. Rahul Ahlawat is a PhD candidate at the University of Michigan, Ann Arbor and was with A&D during this work. ... 689 Page 3. MSe Tm 1 ωe I : Je − Jim ...
To meet the ever increasing requirements for engines and vehicles in the areas of performance, fu... more To meet the ever increasing requirements for engines and vehicles in the areas of performance, fuel economy and emission, and reduce product development time, we see the need for an integrated development environment which combines engine rapid control prototyping (RCP) capability with real-time vehicle simulation capability using an engine dynamometer in the test cell. Design and implementation of such a system with the ADX universal high-speed system controllers are described. An application example of simulating an FTP-75 cycle in the test cell while the engine is under ADX control is presented. This system moves a lot of work from the whole vehicle environment to the engine test cell environment, and is a powerful tool for quick development and testing of control algorithms as well as calibration.
To fulfill ever increasingly stringent emission regulations, a great many studies on engine contr... more To fulfill ever increasingly stringent emission regulations, a great many studies on engine control and catalytic converter performance have been made. Topics of great interest in this area, to name a few, include: the relationship between catalyst light-off time and air-fuel (A/F) ratio; the relationship between forced A/F ratio modulation and catalyst efficiency; the effects of phaseshifted A/F ratio modulation between banks of a dual bank engine, or among cylinders of a single manifold engine on catalyst efficiency; and methods of modeling and measuring the oxygen storage capacity of a catalytic converter by rich-lean transition, A/F ratio sweeping, or other on-line estimation methods. To undertake this type of research, an engine control system with necessary functions, especially with very flexible A/F ratio control capabilities, is needed. Mass production ECU does not provide the flexibility desired and it is also hard to develop and integrate the control algorithms needed for catalyst testing into the existing ECU software. An engine rapid control prototyping system is set up in an engine dynamometer test cell environment to overcome the limitations of mass production ECU and fulfill the requirements for catalyst research and testing. Model-based development methodology is adopted for the design and implementation of necessary software. Control algorithms, including individual bank control of a dual bank engine, A/F ratio modulation of different frequencies and amplitudes, with and without phase shift between banks, A/F ratio rich-lean transition and sweeping etc, are designed using graphical language, automatically converted into executables to run on the real-time target. UDP communication for real-time command and variable exchange between the engine controller and the test cell controller is developed to facilitate testing. The system provides the flexibility and good control performance desired for catalyst research and evaluation testing. Application and results of the system on a 4.6L V8 gasoline engine is given.
To meet the ever increasing requirements for engines and vehicles in the areas of performance, fu... more To meet the ever increasing requirements for engines and vehicles in the areas of performance, fuel economy and emission, and reduce product development time, we see the need for an integrated development environment which combines engine rapid control prototyping (RCP) capability with real-time vehicle simulation capability using an engine dynamometer in the test cell. Design and implementation of such a system with the ADX universal high-speed system controllers are described. An application example of simulating an FTP-75 cycle in the test cell while the engine is under ADX control is presented. This system moves a lot of work from the whole vehicle environment to the engine test cell environment, and is a powerful tool for quick development and testing of control algorithms as well as calibration.
Due to the ever increasing requirements for engine performance, variable compression ratio and di... more Due to the ever increasing requirements for engine performance, variable compression ratio and displacement are drawing great interest, since these features provide further degrees of freedom to optimize engine performance for various operating conditions. Different types of mechanisms are used to realize variable compression ratio and displacement. These mechanisms usually involve relatively complicated mechanical design compared with conventional engines. While the flexibility in these mechanisms introduces additional engine design and control possibilities, it also increases the challenges for the development and optimization, since how the geometry of the mechanisms affects the engine performance is not straightforward, and building prototype engines of various mechanical design parameters takes a long time with high cost. This paper presents a study of a multiple-link mechanism that realizes variable compression ratio and displacement by varying the piston motion, specifically ...
To meet the ever increasing requirements for engine and vehicle performance, and at the same time... more To meet the ever increasing requirements for engine and vehicle performance, and at the same time shorten product development time, model-based development methodologies have been quickly adopted by OEMs and suppliers in recent years. With model-based development, new algorithms are specified in a highlevel graphical language and directly compiled into executables to be implemented and tested on rapid control prototyping hardware. This seamless transition from design to implementation and testing greatly improves the efficiency of the development process for modern automotive control strategies, especially in engine control system development. A model-based development environment and its application in engine control functions development are presented. The environment consists of the ADX rapid prototyping controller, various functional boards, necessary signal conditioning and power electronics modules, and graphical user interface (GUI) software VirtualConsole. Control algorithms...
Good battery modeling is critical for energy management of electric vehicles and hybrid electric ... more Good battery modeling is critical for energy management of electric vehicles and hybrid electric vehicles. Because of its simplicity and satisfactory performance, equivalent circuit models are widely used in this area. A frequently adopted equivalent circuit model is one that consists of an open-circuit voltage and a resistor in series with two sets of parallel resistorcapacitor combinations. This model performs well in describing battery transient behavior due to the dynamics of such physical phenomena as mass transport effects and double layer effects. Generic methods for obtaining the parameters of this model involve analyzing the battery voltage behavior under step changes of load current. The fact that the model has two time constants places a challenge on parameter identification. Some most often used method makes use of the property that each of the two time constants plays a dominant role at different stages of the battery voltage response, and calculates the model parameters accordingly. For such method, the results are greatly influenced by the partition of faster and slower dynamics of the battery, and selection of the data points used for the calculation. Moreover, because majority of the testing data is not used towards calculating the parameters, the obtained model might not reflect the overall battery characteristics well and consequently might not give highfidelity predictions. For other methods that use nonlinear curve fitting or genetic algorithm for parameter searching, the successful implementation greatly depends on the proper setting of initial values and searching space. A novel method of parameter identification for the equivalent circuit model is presented in this paper. It makes use of a regression equation which is linear in variables that can be measured or calculated from the test. With this approach, all testing data during the relaxation period of a constant current pulse discharge or charge test is used towards obtaining the model parameters and the calculation is in the sense of least squared error. Application of the method to real battery testing data is presented. The example indicates that the method gives very good results with modeling error of less than 0.5%.
Variable compression ratio and variable displacement technologies are adopted in internal combust... more Variable compression ratio and variable displacement technologies are adopted in internal combustion engines because these features provide further degrees of freedom to optimize engine performance for various operating conditions. This paper focuses on a multiple-link mechanism that realizes variable compression ratio and displacement by varying the piston motion, specifically the Top Dead Center (TDC) and Bottom Dead Center (BDC) positions relative to the crankshaft. It is determined that a major requirement for the design of this mechanism is when the control action changes monotonically over its whole range, the compression ratio and the displacement should change in opposite directions monotonically. This paper presents an approach on how to achieve multiple-link mechanism geometric designs that fulfill this requirement. First, a necessary and sufficient condition, and a stronger sufficient condition are obtained on how the TDC and BDC positions should change with respect to the control action to fulfill the design requirement. Then Design of Experiments (DoE) methodology is used for creating sets of geometric designs of the mechanism, for which kinematics are calculated and checked against the conditions. A feasible design that satisfies the conditions is selected and detailed study on such characteristics as piston motion, stroke length, displacement, combustion chamber volume, and compression ratio etc. is performed. The design approach and obtained results serve as a basis for further analysis and optimization of the multiple-link mechanism.
To fulfill ever increasingly stringent emission regulations, a great many studies on engine contr... more To fulfill ever increasingly stringent emission regulations, a great many studies on engine control and catalytic converter performance have been made. Topics of great interest in this area, to name a few, include: the relationship between catalyst light-off time and air-fuel (A/F) ratio; the relationship between forced A/F ratio modulation and catalyst efficiency; the effects of phaseshifted A/F ratio modulation between banks of a dual bank engine, or among cylinders of a single manifold engine on catalyst efficiency; and methods of modeling and measuring the oxygen storage capacity of a catalytic converter by rich-lean transition, A/F ratio sweeping, or other on-line estimation methods. To undertake this type of research, an engine control system with necessary functions, especially with very flexible A/F ratio control capabilities, is needed. Mass production ECU does not provide the flexibility desired and it is also hard to develop and integrate the control algorithms needed for catalyst testing into the existing ECU software. An engine rapid control prototyping system is set up in an engine dynamometer test cell environment to overcome the limitations of mass production ECU and fulfill the requirements for catalyst research and testing. Model-based development methodology is adopted for the design and implementation of necessary software. Control algorithms, including individual bank control of a dual bank engine, A/F ratio modulation of different frequencies and amplitudes, with and without phase shift between banks, A/F ratio rich-lean transition and sweeping etc, are designed using graphical language, automatically converted into executables to run on the real-time target. UDP communication for real-time command and variable exchange between the engine controller and the test cell controller is developed to facilitate testing. The system provides the flexibility and good control performance desired for catalyst research and evaluation testing. Application and results of the system on a 4.6L V8 gasoline engine is given.
The Electronic Throttle Control (ETC) system is more and more used and increasingly becoming a st... more The Electronic Throttle Control (ETC) system is more and more used and increasingly becoming a standard part of the engine. It controls the amount of air intake into the cylinders by precisely positioning the throttle plate at the desired opening. An ETC system provides the possibility of improving the overall engine and vehicle performance because with such a mechanism, the engine controller can decide and set the throttle position not only based on driver intention, but also taking into consideration the specific engine operation mode information, such as safety factors, emission constraints, etc. After the throttle position target is determined, the requirement for the ETC system is that the throttle plate should achieve the commanded position as accurately and as quickly as possible. In many cases the controller is designed by first establishing a model of the electronic throttle system using experimental identification. However, due to such nonlinear effects as static friction, dynamic friction, and nonlinear return springs etc., identification of a model for the electronic throttle system sometimes does not give good results. This makes a controller design based on the model far from optimal. Iterative Feedback Tuning (IFT) is a method for directly tuning the controller parameters based on the data of closed loop experiments without the need for an explicit model of the system. This property makes IFT an attractive method for ETC design. In this paper a Two-Degree-of-Freedom (2-DOF) Proportional-Integral-Derivative (PID) controller for an engine electronic throttle system is designed and the PID control gains are optimized using IFT. The application shows that the IFT method gives very good performance for controller tuning.
To meet the ever increasing requirements for engines and vehicles in the areas of performance, fu... more To meet the ever increasing requirements for engines and vehicles in the areas of performance, fuel economy, emission, and meanwhile reduce product development time, Hardware-in-the-loop (HIL) simulation is increasingly used in automotive control system development. Engine-in-the-loop (EIL) vehicle simulation, which is a specific form of HIL simulation, is an approach in which a physical engine (together with its control unit) is coupled to virtual vehicle and driver models through a high power, low inertia engine dynamometer in the engine test cell environment. EIL can be used to perform powertrain control development, as well as engine and vehicle performance evaluation. Because of its advantages in repeatability and flexibility etc., especially for transient operating mode study, EIL has become a powerful tool and will be more widely used in the near future. Design and implementation of an EIL vehicle simulation system is described. Driver and vehicle simulation models are developed and executed in real time on a high-speed system controller. A highly responsive permanent magnet AC engine dynamometer and a vehicle acceleration pedal are controlled such that the dynamometer loads the connected engine as a real vehicle would and the simulated vehicle speed trace follows the targeted driving cycle. With this system, developers can perform transient engine control development before whole vehicle integration is available. Vehicle parameters, including driveline configurations can be easily modified and the effect on engine and vehicle performance can be studied. An application example of simulating a 10-15 mode emission test cycle is given. The result verifies the effective performance of the system in simulating vehicle dynamics and shows its great potential in engine and vehicle system development.
Due to growing interest in hybrid and electric vehicles, the battery, being one of the critical c... more Due to growing interest in hybrid and electric vehicles, the battery, being one of the critical components, is receiving a lot of attention from designers and researchers. Two batterymodeling approaches, though seemingly different, share the same mathematical challenge of robust non-linear curvefitting. The two methods are battery equivalent circuit model and battery system level thermal modeling using the linear time-invariant (LTI) method. Both modeling approaches involve curve-fitting testing data or data from advanced models to identify four parameters in a circuit model consisting of two pairs of RC elements. Such curve-fitting is mathematically a non-linear least-squares (LS) problem. Standard methods like the Levenberg-Marquardt (LM) method can be used for non-linear curve-fitting, but the LM method is known to be sensitive to initial conditions. Due to the unique features of the two pairs of RC values in the model, the curve-fitting problem can be reformulated into a linear LS problem. Solution from the linear LS problem can then be used as an initial condition for the LM method for greater accuracy. Since the initial conditions from the linear LS problem are already close to the minimum, the sensitivity issue associated with the LM method is mitigated.
To meet the ever increasing requirements in the areas of performance, fuel economy and emission, ... more To meet the ever increasing requirements in the areas of performance, fuel economy and emission, more and more subsystems and control functions are being added to modern engines. This leads to a quick increase in the number of control parameters and consequently dramatic time and cost increase for engine calibration. To deal with this problem, the automotive industry has turned to model-based calibration for a solution. Model-based calibration is a method that uses modern Design of Experiments (DoE), statistical modeling and optimization techniques to efficiently produce high quality calibrations for engines. There are two major enablers for carrying out this method-fully automated engine control and measurement system, and advanced mathematical tools for DoE, modeling and optimization. This paper presents a case study of adopting this methodology for the determination of optimum steady state calibrations of ignition timing, air-fuel ratio and intake cam phasing for a gasoline engine. ORION automated engine control and measurement system is used for testing data collection. EasyDoE Toolsuite is used for DoE, engine response modeling and control parameter optimization. Major features of these tools are described. Each step in performing this process, including definition of factors and responses, DoE, automatic measurement on engine test bench, creation of engine models of sufficient accuracy, and generation of control maps using optimization techniques, is covered. The results demonstrate that the model-based approach is a well suited method for engine calibration, and the integrated system provides an effective solution for implementing model-based calibration.
2010 IEEE/ASME International Conference on Advanced Intelligent Mechatronics, 2010
... Dr. Shugang Jiang, Dharshan Medonza, James Kitchen and Dr. Michael Smith are with A&D... more ... Dr. Shugang Jiang, Dharshan Medonza, James Kitchen and Dr. Michael Smith are with A&D Technology Inc., Ann Arbor, MI. Rahul Ahlawat is a PhD candidate at the University of Michigan, Ann Arbor and was with A&D during this work. ... 689 Page 3. MSe Tm 1 ωe I : Je − Jim ...
ABSTRACT This paper presents the development of real-time (RT) engine and vehicle models for emul... more ABSTRACT This paper presents the development of real-time (RT) engine and vehicle models for emulating transient loads during transmission-in-the-loop (TIL) experiments. The models emulating these vehicle-components are required to possess sufficient fidelity to simulate engine torque pulse (ETP) and wheel-slip dynamics while being computationally efficient to run in RT. The emulation of ETP is accomplished by decomposing the waveform into inertia and combustion based components, and implemented using the high switching frequency of AC-dynamometer drive. The task of emulating wheel slip is achieved by using a RT physics based hybrid tire model developed to avoid the singularly perturbed dynamics at high velocities. Parameters of the engine model are identified using experimental data, and both models are validated in pure simulation. Finally, closed loop TIL test results are presented to demonstrate successful emulation during experimentation.
The Electronic Throttle Control (ETC) system is more and more used and increasingly becoming a st... more The Electronic Throttle Control (ETC) system is more and more used and increasingly becoming a standard part of the engine. It controls the amount of air intake into the cylinders by precisely positioning the throttle plate at the desired opening. An ETC system provides the possibility of improving the overall engine and vehicle performance because with such a mechanism, the engine controller can decide and set the throttle position not only based on driver intention, but also taking into consideration the specific engine operation mode information, such as safety factors, emission constraints, etc. After the throttle position target is determined, the requirement for the ETC system is that the throttle plate should achieve the commanded position as accurately and as quickly as possible. In many cases the controller is designed by first establishing a model of the electronic throttle system using experimental identification. However, due to such nonlinear effects as static friction, dynamic friction, and nonlinear return springs etc., identification of a model for the electronic throttle system sometimes does not give good results. This makes a controller design based on the model far from optimal. Iterative Feedback Tuning (IFT) is a method for directly tuning the controller parameters based on the data of closed loop experiments without the need for an explicit model of the system. This property makes IFT an attractive method for ETC design. In this paper a Two-Degree-of-Freedom (2-DOF) Proportional-Integral-Derivative (PID) controller for an engine electronic throttle system is designed and the PID control gains are optimized using IFT. The application shows that the IFT method gives very good performance for controller tuning.
ABSTRACT This paper presents the development of real-time (RT) engine and vehicle models for emul... more ABSTRACT This paper presents the development of real-time (RT) engine and vehicle models for emulating transient loads during transmission-in-the-loop (TIL) experiments. The models emulating these vehicle-components are required to possess sufficient fidelity to simulate engine torque pulse (ETP) and wheel-slip dynamics while being computationally efficient to run in RT. The emulation of ETP is accomplished by decomposing the waveform into inertia and combustion based components, and implemented using the high switching frequency of AC-dynamometer drive. The task of emulating wheel slip is achieved by using a RT physics based hybrid tire model developed to avoid the singularly perturbed dynamics at high velocities. Parameters of the engine model are identified using experimental data, and both models are validated in pure simulation. Finally, closed loop TIL test results are presented to demonstrate successful emulation during experimentation.
... Dr. Shugang Jiang, Dharshan Medonza, James Kitchen and Dr. Michael Smith are with A&D... more ... Dr. Shugang Jiang, Dharshan Medonza, James Kitchen and Dr. Michael Smith are with A&D Technology Inc., Ann Arbor, MI. Rahul Ahlawat is a PhD candidate at the University of Michigan, Ann Arbor and was with A&D during this work. ... 689 Page 3. MSe Tm 1 ωe I : Je − Jim ...
To meet the ever increasing requirements for engines and vehicles in the areas of performance, fu... more To meet the ever increasing requirements for engines and vehicles in the areas of performance, fuel economy and emission, and reduce product development time, we see the need for an integrated development environment which combines engine rapid control prototyping (RCP) capability with real-time vehicle simulation capability using an engine dynamometer in the test cell. Design and implementation of such a system with the ADX universal high-speed system controllers are described. An application example of simulating an FTP-75 cycle in the test cell while the engine is under ADX control is presented. This system moves a lot of work from the whole vehicle environment to the engine test cell environment, and is a powerful tool for quick development and testing of control algorithms as well as calibration.
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Papers by Shugang Jiang