89 results found
Arif J, Rehman-Shaikh MA, Evangelou SA, 2022, Novel evaluation and testing of technology qualification process of subsea oil and gas products, Journal of Petroleum Science and Engineering, Vol: 208, Pages: 1-11, ISSN: 0920-4105
Use of robust products is of utmost importance in the subsea production systems to ensure the maximum utilization of the energy resources available under the seabed. To achieve highly reliable products, a comprehensive technology qualification program is proposed in this paper for the subsea electrical and electronics-based products. The recommended qualification program is specifically focused on a novel technology readiness level 4 (TRL4) process of the product used in an intended environment condition, which guarantees the product availability on the seabed without any operational failures. The analytical assessment on the products’ design, operating conditions and compliance stress tests are proposed following the internationally recognized standards, e.g. The American Petroleum Institute (API) , International Electrotechnical Commission (IEC), Institute of Electrical and Electronics Engineers (IEEE), International Organization for Standardization (ISO), European Standards (EN) and European Union (EU-directives). Modified environmental tests methods and novel product safety procedures are introduced for the first time to ensure that products meet the acceptance criteria set in the proposed TRL4 process. Finally, the proposed TRL4 process and its recommended test methods are exercised on the various functional units of the subsea electronic module. The experimental results show that the product is fit for use in the subsea environment after going through the proposed extensive qualification test program.
Yu M, Evangelou S, Dini D, 2021, Parallel active link suspension: full car application with frequency-dependent multi-objective control strategies, IEEE Transactions on Control Systems Technology, ISSN: 1063-6536
Yu M, Cheng C, Evangelou S, et al., 2021, Series active variable geometry suspension: full-car prototyping and road testing, IEEE-ASME Transactions on Mechatronics, ISSN: 1083-4435
In this paper, afull-car prototype of the recently proposed mechatronic suspension, Series Active Variable Geometry Suspension (SAVGS), is developed for on-road driving experimental proof of concept, aiming to be adopted by suspension OEMs (original equipment manufacturers) as an alternative solution to fully active suspensions. Particularly, mechanical modifications are performed to both corners of the front double-wishbone suspensionof a production car, with active single-links attached to the upper-ends of the spring-damper units, while both corners of the rear suspension remain inthe original (passive) configurations.The mechanical modifications involve innovatively designed parts to enable the desired suspension performance improvements, while maintaining ride harshness at conventional levels.Areal-time embedded system is further developed to primarily implement:1) power supply, data acquisition and measurementsof the vehicle dynamics related variables, and 2) robust control application for the ride comfort and road holding enhancement, which is based on a derived linearized model of the full-car dynamics and a newly synthesizedH-infinity control scheme. Results obtained from on-road driving experiments are inessential agreement with numerical simulation results also produced. Overall, the full-car prototypeof SAVGS demonstrates promising suspension performance,with anaverage 3 dB attenuation (or equivalently 30% reduction) of the chassis vertical acceleration at aroundthe human-sensitive frequencies (2-5Hz),as compared to the original vehicle with the passive suspension system. More importantly, the prototype also indicatesthe practicality of the solution, as the SAVGS retrofit to a real car is achieved by simple mechanical modifications, compact actuator packaging, smallmass increment(21.5kg increase with respect to the original vehicle), limited power usage
Arif J, Rehman-Shaikh MA, Evangelou S, 2021, Comprehensive technology qualification process for subsea electronics assemblies, IEEE Transactions on Industrial Electronics, Vol: 68, Pages: 6358-6368, ISSN: 0278-0046
Subsea production systems technologies are being developed steadily to address the technological issues associated with the deep-sea environment, primarily pressure and temperature. To ensure the reliable operation of electrical/electronic systems for at least 25-years on theseabed, a comprehensive technology qualification program is proposed in this paper. In relation to this, Technology Readiness Level of the Subsea electrical/electronics assembly is achieved after conducting devised environmental stress tests compliant to the internationally recognizedstandards, e.g. API, ISO, IEC and IEEE. The comprehensive tests methods of the qualification program are explained to achieve the technology readiness level 3 of the Subsea printed circuit board and sub-assemblies. Finally, experimental test results of a standalone Subsea Ethernet Switchand also functional verification with 100 meters of electrical flying lead undergoing the prescribed test methods show that the Subsea electronics comply with the international standards and is fit for use in the Subsea environment.
Pan X, Chen B, Evangelou SA, et al., 2020, Optimal Motion Control for Connected and Automated Electric Vehicles at Signal-Free Intersections, Pages: 2831-2836, ISSN: 0743-1546
Traffic congestion is one of the major issues for urban traffic networks. The connected and autonomous vehicles (CAV) is an emerging technology that has the potential to address this issue by improving safety, efficiency, and capacity of the transportation system. In this paper, the problem of optimal trajectory planning of battery-electric CAVs in the context of cooperative crossing of an unsignalized intersection is addressed. An optimization-based centralized intersection controller is proposed to find the optimal velocity trajectory of each vehicle so as to minimize electric energy consumption and traffic throughput. Solving the underlying optimization problem for a group of CAVs is not straightforward because of the nonlinear and nonconvex dynamics, especially when the powertrain model is explicitly modelled. In order to ensure a rapid solution search and a unique global optimum, the optimal control problem (OCP) is reformulated via convex modeling techniques. Several simulation case studies show the effectiveness of the proposed approach and the trade-off between energy consumption and traffic throughput is illustrated.
Evangelou S, Rehman-Shaikh MA, 2020, Comprehensive energy efficiency analysis of series hybrid electric vehicles with dual-phase-shift-controlled DC-DC converter, Journal of the Franklin Institute, Vol: 357, Pages: 8761-8799, ISSN: 0016-0032
By considering converter fundamental operating principles, the paper first derives a complete set of analytic expressions of theoverall power losses of a conventional Dual Active Bridge (DAB) bi-directional DC-DC converter under Dual Phase Shift (DPS)control. Expressions for conduction and switching losses in the electronic devices acting as the converter switches, and copperand core losses in the isolation transformer, are derived and accounted for in the DC-DC converter model. DPS control involvesmany more converter operating conditions, in comparison tothe more common single-phase-shift (SPS) control, which makes theanalytic power loss characterization of a DPS-controlled converter an arduous task. Subsequently and by employing thederivedanalytic converter power loss model with exemplary parameter values, the paper analyzes the efficiency of a high-fidelity fullhybrid electric vehicle (HEV) model that includes a DAB DC-DC converter, under a wide range of realistic driving conditions andconverter operation, including low- to high-speed driving, and converter DPS operation. Two popular hybrid powertrain energymanagement schemes, the Thermostat and Power Follower control strategies, are used to simulate the vehicle model to reinforcethe range of realistic vehicle operating conditions. The results show that in series HEV applications more accurate modeling ofDC-DC converter models than conventional constant efficiency models is required to predict converter losses, and also the fidelityin the characterization of converter losses can have a significant impact on the vehicle fuel consumption prediction.
Georgiou A, Tahir F, Evangelou S, et al., 2020, Robust moving horizon state estimation for uncertain linear systems using linear matrix inequalities, 59th IEEE Conference on Decision and Control - CDC 2020, Publisher: IEEE
The paper investigates the problem of state estimation for a linear-time-invariant (LTI) discrete-time system subject to structured feedback uncertainty and bounded disturbances. The proposed Moving Horizon Estimation (MHE) scheme computes at each sample time tight bounds on the uncertain states by solving an LMI optimization problem based on the available noisy input and output data. In comparison with conventional approaches that use offline calculation for the estimation, the suggested scheme can achieve an acceptable level of performance with reduced conservativeness, while the online computational time is maintained relatively low. The effectiveness of the proposed estimation method is assessed via a numerical example, where an output-feedback Model Predictive Control (MPC) scheme is utilised in the control problem.
Chen B, Li X, Evangelou S, et al., 2020, Joint propulsion and cooling energy management of hybrid electric vehicles by optimal control, IEEE Transactions on Vehicular Technology, Vol: 69, Pages: 4894-4906, ISSN: 0018-9545
This paper develops an optimal control methodology for the energy management (EM) of a series hybrid electric vehicle (HEV) with consideration of ancillary cooling losses, to minimize fuel consumption. Both engine and battery thermal management (TM) models are integrated into the HEV powertrain model as they interact with each other during operation. By collecting all components for propulsion and cooling, a control-oriented model is established, which enables the joint EM and TM optimization problem to be solved simultaneously. Experimental driving cycles are utilized to reveal the impact of the cooling losses on the fuel economy under different driving circumstances. The case study shows the effectiveness of the proposed strategy in finding the optimal power sharing of the hybrid powertrain with consideration of both propulsion and overall cooling requirements. Moreover, a benchmark method based on separately optimized EM and conventional thermostat and PI controlled cooling systems is introduced to verify the solution quality of the proposed approach. It is demonstrated that the proposed method outperforms the benchmark by 0.7%-2.49% in terms of fuel economy, depending on the driving scenarios.
Yu M, Cheng C, Evangelou S, et al., 2020, Robust control for a full-car prototype of series active variable geometry suspension, 2019 IEEE 58th Conference on Decision and Control, Publisher: IEEE
The Series Active Variable Geometry Suspension (SAVGS) which has been recently proposed shows promising potential in terms of suspension performance enhancement, limited power consumption and so on. In this paper, the control aspects of a full-car prototype with the front axle retrofitted by the SAVGS, which is developed to validate the practical feasibility of the novel mechatronic suspension, are addressed. Two 12 Vdc batteries and one DC/AC inverter constitute an independent power source that supplies the overall embedded mechatronic system, with two AC rotary servo motors driving the single links (in the SAVGS) at two front corners, respectively.A robust control scheme, with an outer-loop H-infinity control and an inner-loop actuator velocity tracking control, is synthesized to enhance the vehicle ride comfort and road holding performance. Numerical simulations of the full-car prototype, withthetypical road events of a 2 Hz harmonic road, and a speed humptested, are performed. Nonlinear simulation results provide the potential suspension performance improvement contributed by the SAVGS and the power usage in the batteries, which will be compared in the future with the upcoming experimental testing results of the prototype on-road driving.
Georgiou A, Evangelou S, Jaimoukha I, et al., 2020, Tracking control for directional drilling systems using robust feedback model predictive control, 1st Virtual IFAC World Congress, Publisher: Elsevier, ISSN: 2405-8963
A rotary steerable system (RSS) is a drilling technology which has been extensively studied and used for over the last 20 years in hydrocarbon exploration and it is expected to drill complex curved borehole trajectories. RSSs are commonly treated as dynamic robotic actuator systems, driven by a reference signal and typically controlled by using a feedback loop control law. However, due to spatial delays, parametric uncertainties and the presence of disturbances in such an unpredictable working environment, designing such control laws is not a straightforward process. Furthermore, due to their inherent delayed feedback, described by delay differential equations (DDE), directional drilling systems have the potential to become unstable given the requisite conditions. This paper proposes a Robust Model Predictive Control (RMPC) scheme for industrial directional drilling, which incorporates a simplified model described by ordinary differential equations (ODE), taking into account disturbances and system uncertainties which arise from design approximations within the formulation of RMPC. The stability and computational efficiency of the scheme are improved by a state feedback strategy computed offline using Robust Positive Invariant (RPI) sets control approach and model reduction techniques. A crucial advantage of the proposed control scheme is that it computes an optimal control input considering physical and designer constraints. The control strategy is applied in an industrial directional drilling configuration represented by a DDE model and its performance is illustrated by simulations.
Feng Z, Yu M, Cheng C, et al., 2020, Uncertainties Investigation and mu-Synthesis Control Design for a Full Car with Series Active Variable Geometry Suspension, International Federation of Automatic Control
Pan X, Chen B, Evangelou SA, 2020, Optimal Vehicle Following Strategy for Joint Velocity and Energy Management Control of Series Hybrid Electric Vehicles, 21st IFAC World Congress on Automatic Control - Meeting Societal Challenges, Publisher: ELSEVIER, Pages: 14161-14166, ISSN: 2405-8963
Li X, Chen B, Evangelou SA, 2020, Optimized Design of Multi-Speed Transmissions for Parallel Hybrid Electric Vehicles, 21st IFAC World Congress on Automatic Control - Meeting Societal Challenges, Publisher: ELSEVIER, Pages: 14147-14153, ISSN: 2405-8963
Chen B, Pan X, Evangelou SA, et al., 2020, Optimal Control for Connected and Autonomous Vehicles at Signal-Free Intersections, 21st IFAC World Congress on Automatic Control - Meeting Societal Challenges, Publisher: ELSEVIER, Pages: 15306-15311, ISSN: 2405-8963
Frezza G, Evangelou SA, 2020, Ecological Adaptive Cruise Controller for a Parallel Hybrid Electric Vehicle, 18th European Control Conference (ECC), Publisher: IEEE, Pages: 491-498
Chen B, Evangelou SA, Lot R, 2019, Series hybrid electric vehicle simultaneous energy management and driving speed optimization, IEEE/ASME Transactions on Mechatronics, Vol: 24, Pages: 2756-2767, ISSN: 1083-4435
The energy management (EM) and driving speed co-optimization of a series hybrid electric vehicle (S-HEV) for minimizing fuel consumption is addressed in this article on the basis of a suitably modeled series powertrain architecture. The paper proposes a novel strategy that finds the optimal driving speed simultaneously with the energy source power split for the drive mission specified in terms of the road geometry and travel time. Such a combined optimization task is formulated as an optimal control problem that is solved by an indirect optimal control method, based on Pontryagin's minimum principle. The optimization scheme is tested under a rural drive mission by extensive comparisons with conventional methods that deal with either speed optimization only or EM strategies with given driving cycles. The comparative results show the superior performance of the proposed method and provide further insight into efficient driving.
Chen B, Evangelou S, Lot R, 2019, Hybrid electric vehicle two-step fuel efficiency optimization with decoupled energy management and speed control, IEEE Transactions on Vehicular Technology, Vol: 68, Pages: 11492-11504, ISSN: 0018-9545
Hybrid electric vehicles (HEVs) offer an effective solution for emissions reduction and fuel energy savings. The pursuit of further improvements in their energy efficiency has led to the two fundamental optimization challenges of vehicle speed and powertrain energy management (EM), which are inherently coupled. This paper examines the vehicle speed and powertrain EM co-optimization problem for fuel economy for a series HEV following a prescribed route with expected traveling time. In order to overcome the computational burden of a large scale optimal control problem (OCP), this work presents a novel two-step optimal control strategy that suitably separates the co-optimization problem on the basis of involving the characteristics of the HEV powertrain power split and losses in the speed optimization step without an explicit use of a powertrain model. A benchmark method that simultaneously solves the optimal driving speed and the energy source power split is introduced, which is used to show the solution quality of the proposed approach. It is illustrated that the proposed method yields a driving speed solution close to the benchmark method, and additionally it outperforms the benchmark fuel economy, with much higher computational efficiency. The simplicity and effectiveness of the proposed two-step approach make it a practical and implementable EM control strategy.
Moreno-Ramirez C, Tomas-Rodriguez M, Evangelou S, 2019, Effects of interconnected suspension systems on the in-plane dynamics of sport motorcycles, Symposium on the Dynamics and Control of Single Track Vehicles
The effects of interconnected front and rear suspension systems on the in-plane dynamics of sportmotorcycle is investigated. The interconnected suspension mathematical description is presentedand included in a high-fidelity motorcycle model. The suspension behaviour under road step bumpinputs is studied for different values of stiffness and damping interconnection coefficients. Optimalvalues of interconnection coefficients are proposed for the current motorcycle model. Finally, theoscillating dynamics of the motorcycle at straight running conditions is studied through its normalmodes.
Yu M, Evangelou S, Dini D, 2019, Position control of parallel active link suspension with backlash, IEEE Transactions on Industrial Electronics, Vol: 67, Pages: 4741-4751, ISSN: 0278-0046
In this paper, a position control scheme for the novel Parallel Active Link Suspension (PALS) with backlash is developed to enhance the vehicle ride comfort and road holding. A PALS-retrofitted quarter car test rig is adopted, with the torque flow and backlash effect on the suspension performance analyzed. An elastic linear equivalent model of the PALS-retrofitted quarter car, which bridges the actuator position and the equivalent force between the sprung and unsprung masses, is proposed and mathematically derived, with both the geometry and backlash nonlinearities compensated. A position control scheme is then synthesized, with an outer-loop H∞ control for ride comfort and road holding enhancement and an inner-loop cascaded proportional-integral control for the reference position tracking. Experiments with the PALS-retrofitted quarter car test rig are performed over road cases of a harmonic road, a smoothed bump and frequency swept road excitation. As compared to a conventional torque control scheme, the newly proposed position control maintains the performance enhancement by the PALS, while it notably attenuates the overshoot in the actuator’s speed variation, and thereby it benefits the PALS with less power demand and less suspension deflection increment.
Li X, Evangelou S, 2019, Torque-leveling threshold-changing rule-based control for parallel hybrid electric vehicles, IEEE Transactions on Vehicular Technology, Vol: 68, Pages: 6509-6523, ISSN: 0018-9545
A novel rule-based control strategy is proposed for the energy management of parallel hybrid electric vehicles (HEVs): the torque-leveling threshold-changing strategy (TTS). In contrast to the most commonly used heuristic electric assist control strategy (EACS) that is designed based on the load following approach, the TTS proposes and applies the new fundamental concept of torque leveling. This mechanism operates the engine with a constant torque when the engine is active, thus ensuring the engine works at an efficient operating point. The TTS additionally extends and uses a design concept that has previously been proposed in the context of series HEVs, thethreshold-changing mechanism, to operate the HEV in a chargesustaining manner. By exploiting this new set of design principles for parallel HEVs, the TTS realizes energy source control sharing behavior that is reminiscent to optimization-based methods. To show its effectiveness, the TTS is implemented to a through-theroad (TTR) HEV and benchmarked against two conventional control strategies: Dynamic Programming (DP) and the EACS. The results show that the TTS, despite its simplicity, is able to deliver comparable fuel economy as the global optimization approach DP and thus achieve significant improvement compared to the EACS. In addition, to facilitate real-time application, a simplified version of the TTS (STTS) is also developed, which is able to deliver similar performance as the TTS but is more simple to implement in practice.
Yu M, Arana C, Evangelou S, et al., 2019, Quarter-car experimental study for series active variable geometry suspension, IEEE Transactions on Control Systems Technology, Vol: 27, Pages: 743-759, ISSN: 1063-6536
In this paper, the recently introduced series active variable geometry suspension (SAVGS) for road vehicles is experimentally studied. A realistic quarter-car test rig equipped with double-wishbone suspension is designed and built to mimic an actual grand tourer real axle, with a single-link variant of the SAVGS and a road excitation mechanism implemented. A linear equivalent modeling method is adopted to synthesize an H-infinity control scheme for the SAVGS, with the geometric nonlinearity compensated. Simulations with a theoretical nonlinear quarter-car indicate the SAVGS potential to enhance suspension performance, in terms of ride comfort and road holding. Practical features in the test rig are further considered and included in the nonlinear model to compensate the difference between the theoretical and testing behaviors. Experiments with a sinusoidal road, a smoothed bump and hole, and a random road are performed to evaluate the SAVGS practical feasibility and performance improvement, the accuracy of the model, and the robustness of the control schemes. Compared with the conventional passive suspension, ride comfort improvements of up to 41% without any deterioration of the suspension deflection are demonstrated, while the SAVGS actuator power is kept very low, at levels below 500 W.
Luo C, Shen Z, Evangelou S, et al., 2019, The Combination of Two Control Strategies for Series Hybrid Electric Vehicles, IEEE-CAA JOURNAL OF AUTOMATICA SINICA, Vol: 6, Pages: 596-608, ISSN: 2329-9266
Shabbir W, Evangelou S, 2019, Threshold-changing control strategy for series hybrid electric vehicles, Applied Energy, Vol: 235, Pages: 761-775, ISSN: 0306-2619
This paper proposes a new set of design principles to classify and design rule-based control strategies for the powertrain energy management of series hybrid electric vehicles. The design principles proposed consider the two most established rule-based control strategies for series hybrid electric vehicles, the Thermostat and the Power follower control strategies, and also an optimization-based control strategy, the Equivalent consumption minimization strategy, in terms of the mechanisms they employ to ensure charge sustaining operation and fuel efficient driving. Thus, the work then reflects upon the most effective design principles and derives a novel and superior rule-based control strategy for series hybrid electric vehicles that is claimed to outperform all the existing rule-based schemes in terms of fuel economy: the optimal primary source strategy (OPSS). The OPSS is implemented and then compared on a high fidelity hybrid electric vehicle model to Thermostat, Power follower and Equivalent consumption minimization strategies, as well as to a recently developed rule-based control strategy, the Exclusive operation strategy. As compared to conventional rule-based control strategies, the OPSS is found to deliver significantly improved fuel economy and which is remarkably close to that achieved by the optimization-based Equivalent consumption minimization strategy, while the design of the OPSS is simple and robust as compared to optimization-based strategies. The impressive performance is partly attributed to the recent improvements in engine start stop system technology. It is also shown that the battery is operated in a more steady manner, with a lower depth of discharge, consequently reducing battery degradation.
Cheng C, Evangelou S, 2019, Series active variable geometry suspension robust control based on full-vehicle dynamics, Journal of Dynamic Systems, Measurement, and Control, Vol: 141, ISSN: 0022-0434
This paper demonstrates the ride comfort and road holding performance enhancement of the new road vehicle series active variable geometry suspension (SAVGS) concept using an H∞ control technique. In contrast with the previously reported work that considered simpler quarter-car models, the present work designs and evaluates control systems using full-car dynamics thereby taking into account the coupled responses from the four independently actuated corners of the vehicle. Thus, the study utilizes a nonlinear full-car model that represents accurately the dynamics and geometry of a high performance car with the new double wishbone active suspension concept. The robust H∞ control design exploits the linearized dynamics of the nonlinear model at a trim state, and it is formulated as a disturbance rejection problem that aims to reduce the body vertical accelerations and tire deflections while guaranteeing operation inside the existing physical constraints. The proposed controller is installed on the nonlinear full-car model, and its performance is examined in the frequency and time domains for various operating maneuvers, with respect to the conventional passive suspension and the previously designed SAVGS H∞ control schemes with simpler vehicle models.
Chen B, Evangelou SA, Lot R, 2019, Fuel efficiency optimization methodologies for series hybrid electric vehicles, 2018 IEEE Vehicle Power and Propulsion Conference (VPPC), Publisher: IEEE
This paper provides an overview of various optimization formulations that can lead to improved fuel economy for a series hybrid electric vehicle (HEV). The relevance and improvement to the current state-of-the-art are discussed. The formulated optimal control problems (OCP) consist of two individual optimization challenges: vehicle speed optimization and powertrain power-split optimization. These OCPs can be merged leading to a practical and global problem, where all the aspects are optimized simultaneously for a prescribed route and traveling time. Alternatively, the global problem can be approximated by solving individual OCPs, one for each aspect, in steps and combined a posteriori. The optimal solutions in each case are investigated and compared by simulation examples to expose the trade-off between optimality of fuel economy achieved by global optimization and reduction in computational complexity and hence practicality of the two-step solution approximation.
Li X, Evangelou SA, Lot R, 2019, Integrated management of powertrain and engine cooling system for parallel hybrid electric vehicles, 2018 IEEE Vehicle Power and Propulsion Conference (VPPC), Publisher: IEEE
In this work, a supervisory control strategy is pro-posed for parallel hybrid electric vehicles (HEVs). The controlstrategy is based on the equivalent consumption minimizationstrategy (ECMS) but it also considers the power consumedby the engine cooling system to optimize the overall fueleconomy of the vehicle. To verify its effectiveness, the proposedcooling-sensitive ECMS is implemented on a through-the-road(TTR) HEV, after the mathematical model of the TTR HEV isdeveloped based on power flows, and engine thermal dynamicsis also included. Simulations are performed with different drivecycles, and the results show that the cooling-sensitive ECMS isable to improve the fuel economy by 2.7% compared to thebaseline ECMS. Furthermore, it is shown that cooling-sensitiveECMS operates in a charge-sustaining manner provided thatthe equivalence factors are optimally selected.
Chen B, Evangelou SA, 2019, Truncated Battery Power Following Strategy for Energy Management Control of Series Hybrid Electric Vehicles, 18th European Control Conference (ECC), Publisher: IEEE, Pages: 738-743
Lopes DR, Evangelou SA, 2019, Energy savings from an Eco-Cooperative Adaptive Cruise Control: a BEV platoon investigation, 18th European Control Conference (ECC), Publisher: IEEE, Pages: 4160-4167
Luo C, Shen Z, Evangelou S, et al., 2018, A Control Strategy Combined Thermostat Control with DC-Link Voltage Control for Series Hybrid Electric Vehicles, 21st IEEE International Conference on Intelligent Transportation Systems (ITSC), Publisher: IEEE, Pages: 294-299, ISSN: 2153-0009
Chen B, Evangelou SA, Lot R, et al., 2018, Impact of optimally controlled continuously variable transmission on fuel economy of a series hybrid electric vehicle, European Control Conference (ECC), Publisher: IEEE, Pages: 576-581
This paper investigates energy efficiency of a series hybrid electric vehicles (HEV) that utilizes a continuously variable transmission (CVT) to connect the electric motor to the wheels. In contrast with a fixed transmission FT that employs a fixed final drive ratio, the CVT offers variable transmission ratio that can be freely controlled, so that the motor is driven more efficiently. The performance of the CVT is evaluated within an optimal control framework under an urban drive mission, which is specified in terms of the road geometry and the traveling time for the journey. Apart from the CVT operation, vehicle speed and the energy management are also simultaneously optimized by an indirect optimal control method, based on the Pontryagin's minimum principle (PMP). The simulation results illustrate the benefit of the CVT as compared to a fixed transmission in terms of fuel economy.
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