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Author

Zhao Leilei

Bio: Zhao Leilei is an academic researcher from Shandong University of Technology. The author has contributed to research in topics: Suspension (vehicle) & Spring (device). The author has an hindex of 9, co-authored 169 publications receiving 415 citations. Previous affiliations of Zhao Leilei include Beijing University of Posts and Telecommunications.

Papers published on a yearly basis

Papers
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Patent
27 Apr 2016
TL;DR: In this paper, a method for designing gaps of end straight sections of diagonal few-leaf main springs and auxiliary springs is proposed, and the main and auxiliary spring gaps between contact points of the end-straight sections of the main spring and the auxiliary spring according to the thicknesses h of roots of the N main springs, the endpoint force F and the deformation coefficients G.
Abstract: The invention relates to a method for designing gaps of end straight sections of diagonal few-leaf main springs and auxiliary springs, and belongs to the technical field of suspension steel plate springs. The method includes determining endpoint deformation coefficients of the various main springs and deformation coefficients G of contact points of the end straight sections of the N main springs and the auxiliary springs according to structure sizes and elastic modulus of the various diagonal variable-section main springs; acquiring endpoint force F of the N main springs according to acting load of the auxiliary springs and the endpoint deformation coefficients of the various main springs; designing the main and auxiliary spring gaps between contact points of the end straight sections of the main springs and the auxiliary springs according to the thicknesses h of roots of the N main springs, the endpoint force F and the deformation coefficients G . The method has the advantages that as known from simulation verification, design values of the gaps of the end straight sections of the diagonal few-leaf variable-section main springs and the auxiliary springs can be accurately and reliably obtained by the aid of the method, and accordingly the product design level and performance and the vehicle ride comfort can be improved; the design and experiment costs can be reduced, and the product development speeds can be increased.

39 citations

Journal ArticleDOI
TL;DR: The dynamic characteristics of an electric vehicle with and without motor exciting force and bearing nonlinear force are compared and analyzed and the ride comfort of the electric vehicle can be effectively improved by choosing appropriate parameters of the vehicle suspension system.
Abstract: In order to analyze the influence of the rotor-bearing coupling vibration on the dynamic performance of electric vehicles driven by an in-wheel motor, taking a typical four-phase 8/6-pole switched reluctance motor driven electric vehicle without deceleration mechanism as an investigated object, a nonlinear dynamic model of an electric vehicle with the in-wheel motor driving system is established on the basis of considering the motor exciting force and the bearing nonlinear force. Through the numerical simulation, the influence of the rotor-bearing coupling vibration on the dynamic behavior of electric vehicle driven by the in-wheel motor is studied. Here, in this paper, the dynamic characteristics of an electric vehicle with and without motor exciting force and bearing nonlinear force are compared and analyzed. In addition, the influence of the suspension parameters on the dynamic performance of electric vehicle driven by the in-wheel motor is analyzed. According to the results, the influence of the rotor-bearing coupling vibration on the dynamic behavior of the electric vehicle is mainly embodied in the tire vibration acceleration and tire dynamic load. Moreover, the existence of the in-wheel motor driving system will deteriorate the evaluation index of the electric vehicle vibration performance. By choosing appropriate parameters of the vehicle suspension system, the ride comfort of the electric vehicle can be effectively improved.

24 citations

Patent
18 May 2016
TL;DR: In this article, an auxiliary spring work load checking method of a non-end part contact type end part strengthened few-leaf main and auxiliary springs belonging to the suspension steel plate spring technical field is presented.
Abstract: The invention relates to an auxiliary spring work load checking method of a non end part contact type end part strengthened few-leaf main and auxiliary springs belonging to the suspension steel plate spring technical field. According to the method of the invention, firstly, according to the structure size and the elastic modulus of each end part strengthened few-leaf cross-section variable main spring, the end point deformation coefficient Gx-Ei and the half rigidity KMi of each main spring, and the deformation coefficient Gx-BC at the contact point of the Nth main spring and an auxiliary spring on a parabolic segment can be determined; then, according to the half rigidity KMi of each main spring, the thickness h2 of a root straight section, the Gx-BC of the Nth main spring and a main and auxiliary spring interval Delta design value, the auxiliary spring work load of the non end part contact type end part strengthened few-leaf cross-section variable main and auxiliary springs is checked. Through the emulation proof, in adoption of the method of the invention, the accurate and reliable auxiliary spring work load checking value can be obtained; therefore, the design levels and performances of the few-leaf cross-section variable main and auxiliary springs and the smoothness of a vehicle are improved; moreover, the design and test cost is saved; and the product development speed is accelerated.

23 citations

Patent
04 May 2016
TL;DR: In this paper, a method for designing few-leaf oblique line type variable-section main springs in the gaps between oblique lines segments and an auxiliary spring is presented, where the main and auxiliary spring gap design value meeting the auxiliary spring acting load requirement can be obtained by means of the method, and the product design level, product performance and vehicle smoothness are improved.
Abstract: The invention relates to a method for designing few-leaf oblique line type variable-section main springs in the gaps between oblique line segments and an auxiliary spring, and belongs to the technical field of suspension steel plate springs. According to the structural sizes and the elasticity moduli of the oblique line type variable-section main springs, the endpoint deformation coefficient Gx-Di of each main spring and the deformation coefficient Gx-BC of the Nth main spring at the contact point of the corresponding oblique line segment and the auxiliary spring are determined first; then, according to the required auxiliary spring acting load design value and the endpoint deformation coefficient Gx-Di of each main spring, endpoint force FN of the Nth main spring is obtained; then, according to the thickness h of the root straight section of the Nth main spring, the Gx-BC and the FN, main spring and auxiliary spring gaps between the oblique line segment of the main springs and the contact point of the auxiliary spring are designed. Through simulation verification, it can be known that the main and auxiliary spring gap design value meeting the auxiliary spring acting load requirement can be obtained by means of the method, and the product design level, product performance and vehicle smoothness are improved. Meanwhile, design and testing cost is reduced, and product development speed is increased.

22 citations

Journal ArticleDOI
TL;DR: In this article, an analytical estimation method and a practical damping parameters design method for wheel-drive electric vehicles (WDEVs) is presented, where two formulae of the human body vertical acceleration in terms of the power spectrum density (PSD) and the root mean square (RMS) are deduced for WDEVs.
Abstract: To provide initial design values of seat cushion and chassis suspension damping for wheel-drive electric vehicles (WDEVs), this paper presents an analytical estimation method and a practical damping parameters design method. Firstly, two formulae of the human body vertical acceleration in terms of the power spectrum density (PSD) and the root mean square (RMS) are deduced for WDEVs. Then, the coupling effects of the key vehicle parameters on ride comfort are revealed. Finally, with a practical example, the damping parameters of the cushion and the suspension are initially designed and analyzed. The results show that when every 10.0 kg increases for motor mass, the optimal damping values of the cushion and the suspension should be reduced by about 15.0 Ns/m and 50.0 Ns/m, respectively. However, the RMS acceleration increases 0.017 m/s2 with a decrease of 2.5 % for ride comfort.

17 citations


Cited by
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Journal ArticleDOI
TL;DR: In this paper, the authors give a comprehensive state-of-the-art review on the charging technologies available for battery electric vehicles (BEVs): wired charging and wireless charging technologies.
Abstract: The increasing emissions created by the large-scaled number of automobiles around the world pose severe threats to modern life by causing global warming issues and deteriorating air quality. These serious issues stimulate the essential demand for cleaner, safer, and more efficient vehicles, such as battery electric vehicles (BEVs). Unlike other studies on the charging technologies of BEVs, this paper gives a comprehensive state-of-the-art review on the charging technologies available for BEVs: wired charging and wireless charging technologies. First, the wired charging technologies are systematically classified into AC charging (indirect charging) and DC charging (direct charging) methods based on how the BEVs batteries are fed from the grid. Next, the configurations and commonly used topologies of wireless charging technologies for BEVs are thoroughly discussed. The leading institutes/companies driving advancements in both technologies are also acknowledged. Finally, this paper extensively highlights the recent and future research trends along with the industrial applications.

72 citations

Journal Article
TL;DR: In this paper, the authors present an abstract of the ASFA part 2 (ASFA-2), ASFA-3, part 2 part 2, abstracts part 2.
Abstract: ed/Indexed in Applied Mechanics Reviews, Aquatic Sciences and Fisheries Abstracts part 2 (ASFA-2), Compendex, CSA Illumina, Current

58 citations

Journal ArticleDOI
05 Dec 2017-Energies
TL;DR: In this article, the in-wheel motor is considered as a dynamic vibration absorber (DVA), which is isolated from the unsprung mass by using a spring and a damper.
Abstract: This paper presents an integration design scheme and an optimization control strategy for electric wheels to suppress the in-wheel vibration and improve vehicle ride comfort. The in-wheel motor is considered as a dynamic vibration absorber (DVA), which is isolated from the unsprung mass by using a spring and a damper. The proposed DVA system is applicable for both the inner-rotor motor and outer-rotor motor. Parameters of the DVA system are optimized for the typical conditions, by using the particle swarm optimization (PSO) algorithm, to achieve an acceptable vibration performance. Further, the DVA actuator force is controlled by using the alterable-domain-based fuzzy control method, to adaptively suppress the wheel vibration and reduce the wallop acting on the in-wheel motor (IWM) as well. In addition, a suspension actuator force is also controlled, by using the linear quadratic regulator (LQR) method, to enhance the suspension performance and meanwhile improve vehicle ride comfort. Simulation results demonstrate that the proposed DVA system effectively suppresses the wheel vibration and simultaneously reduces the wallop acting on the IWM. Also, the alterable-domain-based fuzzy control method performs better than the conventional ones, and the LQR-based suspension exhibits excellent performance in vehicle ride comfort.

34 citations

Journal ArticleDOI
TL;DR: In this paper , a robust vibration controller design for active suspension system of in-wheel-motor-driven electric vehicles based on unified µ-synthesis framework is proposed.
Abstract: This paper proposes a robust vibration controller design for active suspension system of in-wheel-motor-driven electric vehicles based on unified µ-synthesis framework. First, multiple parameter uncertainties and unmodelled high-order dynamics of the suspension are analyzed and discussed. By applying the mixed uncertainties and linear fraction transformation, model perturbations are separated from the suspension system and their perturbation bounds can be also limited. Then the uncertain quarter-vehicle active suspension model with dynamic damping in-wheel motor driven system is established, in which in-wheel motor is suspended as a dynamic vibration absorber. The resulting robust µ-synthesis feedback controller of generalized closed-loop active suspension system is designed with the concept of structured singular value µ and µ-synthesis theoretics, and solved via comprehensive solution of the D-G-K iteration. The µ analysis results show that the µ controller possesses less conservative stability and performance margins as compared to the H8 method against system uncertainties. Furthermore, simulations of nominal and perturbed suspension systems are implemented and the corresponding frequency and time-domain responses are compared, and then simulations results confirm that the developed µ controller is capable of attenuating the negative vibration of the active suspension system compared with H8 controller and passive suspension.

28 citations