Gang Li

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Mississippi State University | MSU · Michael W. Hall School of Mechanical Engineering

This paper presents an ultimate motion methodology of a face-milling spiral bevel gear pair to synthesize the mating tooth surfaces with a predesigned fourth-order motion curve. The methodology is to control some contact points along the contact path in the process of tooth contact analysis via application of an extended local synthesis which permi...

A gear form-grinding optimization method is proposed to obtain an optimal shape of a form-grinding wheel by solving a transcendental equation of the contact line between a form-grinding wheel and a helical gear workpiece. Since the equation of the contact line is transcendental, the relationship between the installation angle of the form-grinding w...

This study presents a flume flow experimental investigation of operational performances of a tidal current energy converter (TCEC) with a horizontal-axis tidal turbine and an infinitely variable transmission (IVT). A closed-loop speed ratio controller of the IVT is developed to continuously adjust its speed ratio with variable water speeds for a de...

Gear shaping causes processing characteristics on gear tooth surfaces (PCGTS), e.g., gear tooth surface deviation (GTSD) and processing textures (PT), which can affect gear meshing performances. Gear shaping simulation is operated to obtain PCGTS with different indexing feeds. An improved contact stiffness method of gear tooth surfaces is develope...

Pipe-type cable systems, including high-pressure fluid-filled (HPFF) and high-pressure gas-filled cables, are widely used for underground high-voltage transmission. These systems consist of insulated conductor cables within steel pipes, filled with pressurized fluids or gases for insulation and cooling. Despite their reliability, faults can occur d...

This study presents a gearbox wear prediction method by introducing a particle swarm optimization (PSO) enhanced smoothed variable-weight grey model (PSO-SVWGM(1, N)). The PSO-SVWGM(1, N) model improves upon conventional grey models by incorporating a smoothing generation factor with variable weights, optimized through PSO. Applied to oil debris an...

Pipe-type cable systems, including high-pressure fluid-filled (HPFF) and high-pressure gas-filled (HPGF) cables, are widely used for underground high-voltage transmission. These systems consist of insulated conductor cables within steel pipes, filled with pressurized fluids or gases for insulation and cooling. Despite their reliability, faults can...

A tidal current energy converter (TCEC) is a device specifically designed to harness the kinetic energy present in tidal energy and convert it into stable mechanical rotational energy, which can then be used to generate electricity. The core component of the TCEC is an infinitely variable transmission (IVT), which adjusts the speed ratio to maintai...

The paper presents a new condition monitoring method for distributed wind systems (DWSs) by combining federated learning with supervisory control and data acquisition (SCADA) data. Federated learning facilitates training of a global model across decentralized SCADA datasets without actual data exchange. This method allows multiple DWSs to collectiv...

Failure analysis and fatigue life prediction are important steps in the design procedure of industrial products to assure the safety and reliability of their components. A model to calculate the heat generation by the hysteresis loss in natural rubber subjected to cyclic loads in a uniaxial direction was introduced and the fatigue life prediction m...

This paper proposes a novel numeric tooth contact model of hypoid gears which combines the conjugate approach and a special method of contact search operations. The model performs the tooth contact analysis at different contact curvatures, and demonstrates better computational accuracy than the finite element method. The model is capable of quickly...

A tidal current energy converter including an infinitely variable transmission (IVT) control system and a hybrid vertical axis wind (or water) turbine (VAWTs) apparatus. The hybrid VAWT apparatus includes a modified-Savonius (MS) rotor in the central region and a straight bladed H-type Darrieus rotor in the surrounding annular region. The IVT contr...

As an abundant, clean, and predictable source of renewable energy, tidal current energy provides a cost-effective alternative to fossil fuels. Tidal current energy harvesting technologies are still at their early stages of development. Even some advanced demonstration projects with full-scale tidal current energy converters (TCECs) still face consi...

The present disclosure describes innovations to improve the use of noncircular gear pairs in a transmission, e.g., an infinitely variable transmission. The noncircular gear pair includes a first noncircular gear with a first pitch curve; and a second noncircular gear with a second pitch curve. The first pitch curve includes a plurality of elliptica...

This paper presents a flume flow experimental investigation of operational performances of a tidal current energy converter (TCEC) with a horizontal-axis tidal turbine (HATT) and an infinitely variable transmission (IVT). A closed-loop speed ratio controller of the IVT is developed to continuously adjust its speed ratio with variable water speeds f...

This paper presents a review-based comparative study of state-of-the-art technologies, technical challenges and research barriers, and development trends of gearboxes used in tidal current energy converters (TCECs). Currently, the development of commercial projects using TCECs is still in the demonstration phase. While many drivetrain designs and c...

A tidal current energy converter including an infinitely variable transmission (IVT) control system and a hybrid vertical axis wind (or water) turbine (VAWTs) apparatus. The hybrid VAWT apparatus includes a modified-Savonius (MS) rotor in the central region and a straight bladed H-type Darrieus rotor in the surrounding annular region. The IVT contr...

A nonlinear closed-loop control combined with an integral time-delay feedback control is disclosed to adjust a speed ratio of an infinitely variable transmission (IVT) system. A speed ratio control for an IVT system involves a forward speed controller and a crank length controller for different speed ranges. The time-delay control is designed to re...

Wooden utility poles are one of the most commonly used utility carriers in North America. Even though they are given different protection treatments, wooden utility poles are prone to have defects that are mainly caused by temperature, oxygen, moisture, and high potential hydrogen levels after decades of being exposed in open-air areas. In order to...

This paper presents a nonlinear closed-loop control combined with an integral time-delay feedback control of an infinitely variable transmission (IVT) to adjust its speed ratios with respect to variable input speeds that are induced by variable tidal speeds. A speed ratio closed-loop control for the IVT system involves a forward speed controller an...

A nonlinear closed-loop control combined with an integral time-delay feedback control is disclosed to adjust a speed ratio of an infinitely variable transmission (IVT) system. A speed ratio control for an IVT system involves a forward speed controller and a crank length controller for different speed ranges. The time-delay control is designed to re...

A nonlinear closed-loop control combined with an integral time-delay feedback control is disclosed to adjust a speed ratio of an infinitely variable transmission (IVT) system. A speed ratio control for an IVT system involves a forward speed controller and a crank length controller for different speed ranges. The time-delay control is designed to re...

A nonlinear closed-loop speed ratio control combined with an integral time-delay feedback control is developed to adjust the speed ratio of an infinitely variable transmission (IVT) for a desired output speed with any variable input speed. The speed ratio control of the IVT system is developed based on its nonlinear dynamic model, which involves a...

High operation performance of a tidal current energy converter (TCEC) requires a gear transmission with a continuously variable speed ratio for high-torque and low-speed conditions. A nonlinear closed-loop control combined with an integral time-delay feedback control is developed to adjust the speed ratio of an infinitely variable transmission (IVT...

Gear bending strength is a core indicator to indicate reliability and operation performances of automotive transmissions. Fillet curve design of dedendum of gear teeth can improve their bending stress and complex tooth contact performance. Geometrical parameters of gears are considered important for the variation of stresses in the design of gears....

Finite element based tooth contact analysis of a rack and pinion system of an impulse continuously variable transmission is performed in this study. The rack and pinion system are designed with involute profile herringbone tooth profiles. The involute profile herringbone tooth profile is a type of concave-convex profiles, which can be used for heav...

A novel noncircular gear design method is proposed in this work based on a modified high-order elliptical pitch curve for an infinitely variable transmission (IVT), and power loss evaluation of a noncircular gear pair is investigated. Modified high-order elliptical pitch curves of noncircular gears are developed by using kinematic equations of the...

Vertical-axis wind turbines (VAWTs) are compact and efficient and have become increasingly popular for wind energy harvesting. This paper mainly focuses on free and forced vibration analysis of two different types of VAWTs, i.e., an H-type VAWT and a new hybrid VAWT. The H-type VAWT has a lower cost, while the hybrid VAWT has a better self-starting...

A novel mechanical impulse continuously variable transmission (ICVT) is developed to provide continuously variable speed ratios and smooth acceleration for drivetrains based on a rotational swashplate, and its design principle is illustrated. A swashplate-guide linkage mechanism is used in the ICVT; the speed ratio of the ICVT is changed with the s...

This paper describes the main types of the state-of-the-art wind energy harvesting technologies and their commercial prospects, and presents shortcomings of Betz’s limit and misleading of the blade element-momentum theory for aerodynamic design and computational fluid dynamic simulation of vertical-axis wind turbines. A new aerodynamic design metho...

An elastic transmission error (TE) compensation method for a rotary vector (RV) speed reducer is proposed to improve its transmission accuracy based on error sensitivity analysis. Elastic and geometric TEs of the RV speed reducer can be compensated by tooth surface modification of cycloidal gears. Error coefficients of the TE of the RV speed reduce...

Aiming at the difficulty of feature extraction for gear fault diagnosis and the problem of traditional classification methods cannot diagnose the faults in wind turbine gearboxes adaptively, a new fault diagnosis method based on ensemble empirical mode decomposition (EEMD) energy entropy and SOM neural networks (SOM-NN) is proposed. Firstly, the EE...

Sliding door is an important part of commercial vehicle. Aiming at the problem of damage caused by the resonance of chuck and wheel in sliding guideway. The three-dimensional force and smoothness of sliding mechanism are studied. An improved guide rail system is designed in the grey model. In the non-linear optimization design [1], the trust domain...

A new active ease-off topography modification approach is proposed to improve the meshing performance of hypoid gears based on a fourth-order predesigned transmission error (PTE) model and a modified error sensitivity analysis method. Ease-off topography modifications that describe local deviations of pinion tooth surfaces can be conducted by conve...

An active form-grinding method is proposed to obtain excellent and stable contact performance of cylindrical gears by designing modification forms based on a predesigned controllable second-order transmission error function. First of all, a predesigned second-order transmission error polynomial function is assigned to the gear drive. Mathematical m...

Blockchain advantages, such as decentralised tamper-proof and smart contracts, are naturally suitable for the trading needs of energy internet, dealing with the problems of low efficiency, waste of resources, privacy leakage, etc. In this paper, an energy trading method is proposed based on blockchain expansion technology. The lightning network is...

A new wear prediction method of tooth surfaces of involute gears based on a real tooth surface model and a modified fractal method is developed. The real tooth surface model of an involute gear pair is introduced, and microgeometry feature detection of tooth surfaces is achieved by monitoring variations of normal vectors of each discrete data point...

In order to study the tooth root crack initiation lifes for the helical gears of high-speed EMU， a three-dimensional model of helical gear pair was established using UG software，and the crack initiation positions were determined by ABAQUS. Based on the fatigue cumulative damage theory，nominal stress method and local stress-strain method were used t...

This paper proposes a function-oriented form-grinding approach to obtain excellent and stable contact performance of cylindrical gears by designing modification forms based on a predesigned controllable fourth-order transmission error (TE) function and error sensitivity evaluation. First of all, a predesigned fourth-order TE polynomial function is...

The formula based on the gear pump flow pulsation rate is a multi-parameter function, which cannot get the optimal solution of parameters by the general function method. The paper introduces a new flow pulsation rate formula for the geometric parameters for the straight conjugate internal gear pump. The genetic algorithm is introduced to optimize t...

In order to improve the accuracy of tooth profile deviation in the machine a method that can get the radial error based on the actual working condition is proposed． According to the principle of polar coordinates measuring and tooth profile deviation calculation, an optimization model with the purpose of minimum tooth profile and variable parameter...

Accurately and rapidly evaluated the error-sensitivity of actual tooth surfaces of hypoid gears can be a significant foundation for a variety of dynamic preference analysis and machine tool setting readjustments. Due to the complexity of local geometric features as well as the limitations of the data measurement on tooth surfaces of hypoid gears, a...

Thermal error compensation technology is a cost-effective way to improve the machining accuracy. The key point to determine the optimum temperature measurement arrangement positions and quantity will greatly improve the accuracy and robustness of the machine tool error model. A thermal experiment is performed on a vertical machining center. Based o...

Accurately and rapidly evaluated error sensitivity of actual tooth surfaces of hypoid gears can be a significant foundation for a variety of dynamic preference analysis and machine tool setting readjustments. Due to the complexity of local geometric features as well as the limitations of the data measurement on tooth surfaces of hypoid gears, autom...

In allusion to the difficulties to determine dynamic characteristic parameters of sliding joints, and the complexity and large calculation quantity of the current method, a new method combining the response surface and experimental modal analysis was proposed to identify the dynamic characteristic parameters. The sample points were acquired by expe...

A method for reconstructing the digital real tooth surfaces of hypoid gears can be a significant foundation for a variety of dynamic performance and lifetime prediction. This study demonstrates a new digital real tooth surfaces modeling approach for hypoid gears based on non-geometric-feature segmentation and interpolation algorithm. In this method...

When grinding of helical gears with tooth to tooth, contact lines changed all the time, the additional movement caused the tooth to produce "distortions of modification". Based on the facts, this paper presented a high precision establishment method of tooth flank. Firstly, the actual contact line equation of form grinding was derived by the princi...

A modeling approach of digital real tooth surfaces of hypoid gears based on non-geometric-feature segmentation and interpolation algorithm aiming at hypoid gears with wear of tooth surfaces is proposed. Above of all, the discrete data of real tooth surfaces, which are measured by 3D coordinate-measure-machine, is segmented by segmentation based non...

A method to analyze transmission errors of spiral bevel gears with real tooth surfaces was proposed based on the spiral bevel gear system dynamics and geometric properties. The dynamic transmission errors considering material damping, rotational speed and inertia, etc. were analyzed based on the software of ABAQUS. By comparing the two kinds of dyn...

By importing imaginary whole conjugated tooth surface as the reference tooth surface, namely the reference tooth surface of gear is consisted of theoretical tooth surface with machining tool setting parameters, and the reference tooth surfaces of pinion use the tooth surfaces conjugating with the reference tooth surfaces of gear. The imaginary toot...

A method to analyze dynamic transmission errors of spiral bevel gear, considering the influential factors of inertia, material damping and gear support system, was proposed based on the traditional analysis method. Comparing with the traditional analysis of static transmission error, the proposed method can better reflect the dynamic performances,...

Since the contact line equation is a transcendental equation, the relationship between the installation angle and the shape could not be expressed by explicit functions, which madeitdifficult to obtain the optimal shape, this paper firstly took three evaluation parameters of the shape, over run, shift and offset as the objective function as well as...

Since the contact line equation is a transcendental equation, the relationship between the installation angle and the shape could not be expressed by explicit functions, which madeitdifficult to obtain the optimal shape, this paper firstly took three evaluation parameters of the shape, over run, shift and offset as the objective function as well as...

针对渐开线齿轮稳健优化设计过程中, 存在动载系数难确定, 多参数非线性耦合, 难以实现参数优化等问题, 提出动载系数修正计算方法, 并通过求解设计参数之间的相对增益矩阵, 反映出设计参数之间的耦合关系, 再结合稳健优化设计方法进行优化的方法, 提出渐开线齿轮反馈式优化设计方法. 既改善了一般优化方法稳健性差, 易产生优化失效的情况, 又避免稳健优化设计过程中优化参数难确定的情况. 结果表明, 所提出的反馈式稳健优化设计方法能够齿轮部分外界条件发生波动情况下, 仍能保持较好的齿面接触质量及动态性能, 为渐开线齿轮优化设计提供了一条新途径.

By importing imaginary whole conjugated tooth surface as the reference tooth surface, namely the reference tooth surface of gear is consisted of theoretical tooth surface with machining tool setting parameters, and the reference tooth surfaces of pinion use the tooth surfaces conjugating with the reference tooth surfaces of gear. The imaginary toot...

A chamfering algorithm was put forward to achieve automatic NC programming for chamfering addendum of spiral bevel gears and a NC programming module was developed based on UG/Open through secondary development. Furthermore, a practical example was used to demonstrate the automatic NC code generation process for chamfering addendum according to the...

This paper proposed a remaining useful life prediction model to avoid the original monitoring information due to the influence of the oil monitoring linear regression process, thereby reducing the prediction error. According to the process of equipment wear, we analyzed the impact of the relationship between the wear, the metal particle concentrati...

In order to improve the shift quality of automatic mechanical transmission (AMT), the engine control during gear shifting process is divided into speed control mode and torque control mode based on the analyses on the ideal speed and torque curves of engine, and a CAN bus-based engine control strategy for gear shifting is worked out. The results of...

Based on the gear generation principle, taking the professional software as the tool, the problem of virtual hobbing simulation on involute helical gears was studied, and virtual hobbing simulation of hobbing on the whole gear was completed by using macros of CATIA V5. The validity of this method was validated through analyzing the tooth surface ac...

Drivability and fuel economy are continuously emphasized during the development of automobiles, and shift quality is the most important part of the drivability. To improve the shift quality, the integrated powertrain control strategy for gear shifting is presented in this paper. First of all, the transmission control strategy based on the turbine s...