Datong Qin

A Systematic Model for Dynamics and Control of Dual Clutch Transmissions

This paper focuses on the dynamic modeling and analysis of dry dual clutch transmissions (DCTs) during vehicle launch and shifts. The system model incorporates the clutch torque control strategies for DCT vehicle launch and shifts. This model is capable of quantitatively analyzing and predicting dual clutch transmission dynamic characteristics and performance metrics, such as launch response and shift patterns, thus providing an analytical tool for DCT torque control and calibration. The model is applied for a test vehicle equipped with a dry dual clutch transmission. The simulation data on vehicle launch and shift dynamic characteristics are highly agreeable to the data obtained on the test vehicle.

Flexible Multibody Dynamic Modeling of a Horizontal Wind Turbine Drivetrain System

A mathematical model of a horizontal wind turbine drivetrain is developed by applying the flexible multibody dynamics theory based on the Lagrange formulation. The proposed model accounts for the variation in the number of teeth in contact and support bearing elasticity, which are known to influence the dynamic behavior of drivetrain significantly. The derivation of the system governing equation by Lagrange equations requires the formulations of the kinetic energy terms of both orbiting and rotating gears, the potential energy terms of time-varying tooth stiffness and bearing compliance, and the work from input torque. From the resultant governing equations, the natural frequencies and modes of interest are calculated, and the effect of bearing stiffness on those modes is examined. The rotational vibrations of the sun gears as well as the tooth contact forces between the sun and planet and the ring and planet are analyzed in detail. Result of the dynamic transmission error as a function of gearbox speed is also predicted to understand the overall dynamic behavior of the drivetrain system.

Meshing control of the double-enveloping hourglass worm gearing under the conditions of existing the errors and the load

An approach of localizing the contact zone of the double-envelope hourglass worm gearing has been proposed to reduce the sensitivity to the errors and the load. The influence of the errors on the contact zone is systematically investigated. The contact deformation, the shift of contact zone and load share among the meshing tooth-pairs has been analyzed using 3D contact FEM. After synthetically considering the influence of the errors and the load, the worm surface is modified into the crowning in height direction in comparison with the hob. The results from the loaded contact analysis demonstrate that this modification drive can absorb the influence of the errors and the load on meshing performance.

Shift schedule optimization for dual clutch transmissions

Shift schedules both for optimal dynamic performance and fuel economy are proposed in this paper for vehicles equipped with dual clutch transmissions. A range simulation model for DCT vehicles has been established to evaluate the effects on dynamic performance and fuel economy. A fuzzy logic controller for engine throttle and a PID controller for brake force are used for vehicle operation. The simulation results of the ECE driving cycle show that the designed shift schedules are effective and can be used as the basis for DCT shift control and calibration.

Application of computerized numerical modeling in multi-state wet wheel hub heat simulations

This study documents the use of computers and computational fluid dynamics (CFD) software in numerical modeling of a multi-state wet wheel hub for thermal analysis. First, ANSYS software is used to construct 3D models of a wet wheel hub with internal cooling/lubricating oil and the surrounding air. These are processed with GAMBIT meshing. Subsequently, bond graph theory is used to create heat source system models. Working conditions and heat system boundary conditions for theoretical analysis are established using test data from an actual vehicle. This is followed by using FLUENT software to perform multi-core and parallel heat calculations of coupled heat flow fields under normal and high intensity working conditions. Finally, MATLAB and Control Desk universal modular experiment and instrumentation software are used to verify the results of the simulation on an actual vehicle. The results indicate good agreement between the results of the numerical model simulation and the measurements from the test vehicle. The relative error is less than 5%. This verifies the accuracy and appropriateness of the analysis methods. The study demonstrates the capability of computers and software to aid in the optimizing the design performance of complex mechanical systems.

Active torque control for gear dynamic load suppression in a drum shearer cutting transmission system under impact loads

In order to suppress the impact of a loads-induced gear dynamic load of a drum shearer cutting transmission system, an active torque compensation control method is proposed in this paper based on the active disturbance rejection and adaptive neuro-fuzzy control technologies. Using the speed difference between the motor rotor and the first stage gear as a feedback state variable, an active disturbance rejection torque compensation controller is firstly designed for suppressing the dynamic load of the electromechanical transmission system. The controller uses the speed difference as the tracking control target and sets it to a zero value, thereby transforming the dynamic load suppressing problem into a trajectory tracking problem. Secondly, the active disturbance rejection controller parameters are tuned based on the adaptive neuro-fuzzy control technology. Therefore, the torque compensation can be realized adaptively in accordance with the various cutting conditions. Finally, the suppression effect on the dynamic load of the transmission system under continuous impact conditions with different load mutation rates is analyzed based on the proposed control method. Simulation results indicate that the proposed method exhibits a good control effect in suppressing the dynamic load and an improved adaptive ability to the complex and changeable working conditions. The proposed method also can be useful for the electromechanical transmission systems with similar structure applied in other areas.

Controls development for motor-assisted engine starting in a full hybrid electric vehicle with an integrated starter generator

This paper focuses on the control strategy and the related experiments for motor-assisted engine starting in a full hybrid electric vehicle (FHEV) with an integrated starter generator (ISG). The characteristics of FHEV driving system have been analysed based on the dynamic model of hybrid powertrain system. The control strategy for motor-assisted engine starting during transition from the electric driving mode to the engine driving mode has been proposed. A simulation model of the hybrid powertrain system has been established based on Matlab/Simulink software platform. The results show that the proposed control strategy satisfies the engine starting requirement in terms of transient response and smoothness. Furthermore, both bench test system and prototype vehicle have been developed respectively based on D2P (From Development to Production) rapid prototype developing system. The effectiveness of the engine starting control strategy is validated by the comparison between simulation results and the test data.

Torque coordinated control in engine starting process for a single-motor hybrid electric vehicle:

To tackle the excessive output torque ripple during engine starting process of parallel hybrid electric vehicles, the engine starting process is divided into three phases in this study: engine cranking phase, speed synchronization phase, and after synchronization phase. The expressions of the vehicle jerk are derived from the vehicle dynamic formula in each phase, and the influences of various parameters on the jerk are analyzed. The coordinated control strategy for the clutch pressure and motor torque and that for the motor torque and engine torque are proposed. The simulation model for the single-motor parallel hybrid electric vehicle is established using MATLAB/Simulink, and the effectiveness of the proposed control algorithms is verified. Besides, a bench test is conducted and the test results show that the selected change rates of clutch pressure, motor torque, and engine torque can effectively coordinate the relation between clutch, motor, and engine. It can be concluded that the proposed control strategy satisfies the requirement of vehicle ride performance in engine starting in-motion process.

Control strategy for all the mode-switches of hybrid electric vehicle

This article focuses on the mode-switch control of a new type of full hybrid electric vehicle with a torque-limiting clutch and an overrunning clutch. The working mode regions of hybrid electric vehicle are divided according to the characteristics of the engine and motor. The target-required torque of the power source in each working mode is determined by a rule-based control strategy for optimal system efficiency. To reduce the torque fluctuation and improve the ride comfort of the vehicle, the coordinated torque control strategy has been proposed during the mode-switch process. The fuzzy control strategy of the oil pressure loaded on the torque-limiting clutch has been put forward. To improve the ride comfort during the mode-switch, the motor has been used for compensation of the rest of the vehicle-required torque according to the clutch-transmitted torque and the output torque of the engine. The dynamic model of the system in each mode-switch has also been established. The simulation has been conducted using MATLAB/Simulink platform for all the mode-switches. Furthermore, the experiment of the motor-assisted engine starting process with the proposed control strategy has been carried out. The result of the experiment is consistent with that of the simulation, and the control strategy proposed in this article is effective for the mode-switch control.