Dynamic Analysis And Collaborative Optimization Of The Wheel Driving System In Electric Drive Mining Trucks

Wheel drive system is the core of electric drive mining vehicles. Suspension of electric drive vehicle is connected to the drive motor shell directly and the motor’s excitation force will have influence on ride comfort. Previous studies usually made road roughness as excitation and ignored the coupling relationship between the motor excitation force and the road roughness. Besides, the hydro-pneumatic suspension of mining truck is nonlinear and the conclusions of linear suspension shouldn’t be directly adopted. On the other side, the structure of wheel reducer and motor were designed as monomers instead of as a whole in the past, and previous studies neglect the dynamic characteristics of curve and torsion vibration. This article studies the dynamics and optimization of the wheel drive system, aims to study the law of wheel drive system as well as the influence on the ride comfort, and finally provides a theoretical basis for the design.Based on the requirements of complete vehicle dynamic of electric drive mining truck, the article proposes a design method of wheel drive system. The analysis calculates and plots the tractive characteristic curve of traction force, gets the ideal external characteristic curve of motor and designs the high-efficiency induction motor. Combining with the electromagnetic finite element software, the method is simulated and verified.In order to evaluate the influence of motor vibration on ride comfort, considering the impact of road and motor excitation, this paper builds a vehicle suspension vibration system model and nonlinear differential equations. Combined with the gas state equation and the outflow equation of oil orifice, the nonlinear mathematical model of single-chamber hydro-pneumatic suspension is built. The Maxwell stress method is used to solve and analyze the vertical vibration force of asynchronous motor. Considering motor vibration, this paper studies the input and output characteristics of system at the sinusoidal excitation pavement, and also discusses indicators of the system acceleration as well as the relative dynamic of wheel load.According to the electromagnetic structures of motor, this paper solves the motor excitation force under the static and fixed eccentric by combining with the finite element method. Road surface irregularity is constructed to solve the equations. Vibration system is solved by the road roughness and eccentricity electromagnetic composite excitation. This paper explores the exciting force changing with eccentric characteristics in each direction and analyzes the vibration response of the vehicle.The physical model of in-wheel motor system is built, and then Lagrange equation is used to build the system’s electromechanical coupling dynamics model. The vibration response of motor in-wheel motor system is analyzed under the electromagnetic excitation. Nonlinear response of electric wheel system under the unbalanced electromagnetic excitation and torque fluctuations is analyzed. The accuracy of numerical modeling is verified by the use of multi-body dynamics software. This paper summarizes the wheel drive system’s vibration law and makes recommendations about system design and control.The sample vehicle manufacturing is carried out during the study process. The author conducts the vehicle dynamics test and suspension system coupled vibration test to verify finite element method of motor design. On the other side, suspension vibration is analyzed on the common road conditions to verify the coupling system model and the influence of motor vehicle vibration force on ride comfort was analyzed.Multidisciplinary collaborative optimization is used to design the wheel drive system and an overall optimization method taking the vehicle dynamics and ride comfort into account is proposed. The author writes script files to achieve the interactive simulation of finite element software and multidisciplinary optimization software and establish system-level and subsystem-level optimization model. The multi-island genetic algorithm is used to solve the equations by directly reducing unsprung mass to improve vehicle ride comfort. The results show that the motor and the wheel reducer can achieve optimization and both evaluations will be improved to meet the requirements.This study focuses on the vibration characteristics of the drive system and their influence on the vehicle’s wheel ride. Collaborative optimization which considers vehicle dynamics and various parts of their own advantages is proposed. It provides some theoretical guidance and basis for electric drive mining truck design and research.