Advanced Materials Research Vols. 945-949

Abstract: A multi-axle dynamic steering technology was proposed to solve the steering stability and maneuverability problem of heavy vehicle. Two degrees of freedom linear steering-model and motion-equations of three-axle vehicle was established. Taking the zero sideslip angle as the control target and the proportional rear-front wheel angle as control method, we got the angular scale-factor equation and related matrix of the state space and transfer function. The MATLAB software was used to simulate the different steering modes stability steady-state and transient response. The results show that by using proportional control method the sideslip angle can be stabilized near zero and by using multi-axle dynamic steering technology the stability and maneuverability of the vehicle when steering can be improved effectively.

Abstract: This paper is concerned with the milling instability of spindle-ball bearing milling system. The finite-element analyzes is adopted. It is verified that there existed close relationships between the vibration response and the milling instability contributed by the same spindle mode. The spindle mode, which excites the maximum peak spectrum value, will produce the milling instability most likely. The front bearing preload has much more remarkable influences on spindle modes and milling stability than the rear one. It is therefore very important to adjust the front bearing preload according to the actual processing situations and stability demands in the spindle system design stage.

Abstract: The effect of impact force on vehicle tires is a complex process. Accurately chassis dynamics analysis need to consider the influence of impact force. This paper uses collision model to solve it and then successfully establish Impact function model Hysteretic damping model and Modified hysteretic damping model based on the C language. Analysis the result of impact contact force of tire vertical landing. In the coefficient of restitution close to 1, the simulation results of the three models have no greater difference. While the Hysteretic damping model simulation result is different from the other two models in the coefficient of restitution is relatively small.

Abstract: The complicated motion of the gyroscope includes the rotation, the precession, the nutation and the sliding motion which are coupled, and it is affected by the lash-force by the whip. Taking the gyroscope which is moving stably as the research subject, according to the motion characteristics of the gyro’s rotation and precession, the gyro is assumed to be the two-force bar, and the coupled relationship of the gyroscope is analyzed quantitatively. The three-dimensional complicated motion in the different categories is analyzed. The nonlinear differential equations in the different categories is derived and linearized by the minor variables method, and then the three-dimensional motion equations on the rotation, precession, nutation and slipping of the gyroscope in the different categories is established. Take the big gym gyroscope as the example, the influence of the force, time and position of the whip on the motion state of the gyroscope is analyzed in detail, and provides the basis for the design of the gyroscope.

Abstract: This article discusses the ternary Baker transform dynamic characteristics, the ternary Baker transformation is sensitivity to initial value, when the initial value takes different value, the result is that tending to being restrained in the attractor, the periodic orbit, entering the chaotic state. Baker were subsequently extended to the N-ary, the same dynamics and ternary.

Abstract: Finite element model of track in frog zone is built by vehicle-turnout system dynamics. Considering variation of rail section and elastic support, bending deformation of turnout sleeper, spacer block and sharing pad effects, the track integral rigidity distribution in longitudinal direction is calculated in the model. Vehicle-turnout rigid-flexible coupling model is built by finite element method (FEM), multi-body system (MBS) dynamics and Hertz contact theory. With the regularity solution that different stiffness is applied for rubber pad under sharing pad of different turnout sleeper zone, analysis the variation of vertical acceleration of bogie and wheelset, rail vertical displacement and wheel-rail interaction force, this paper proves that setting reasonable rubber pad stiffness is an efficient method to solve rigidity irregularity problem.

Abstract: The vibratory jaw crusher with double cavities was designed for reducing energy consumption by more crushing and less grinding. The dynamic model is established based on its structural characteristics, and the standard state equations are built by using Lagrange method. Based on MATLAB, the trajectory diagrams of the moveable jaws in the two cavities are obtained by Range-Kutta method. The influence of dynamic characteristics on yield and grain size is gained ,and the optimization design idea for the crusher is put forward.

Abstract: The wind power is increasingly developed, and the tropical weather condition is a challenge for flexible wind turbine structure. It is essential to get the structure response of wind turbine under typhoon conditions, and then solutions to reduce the load should be found. This article firstly discusses characteristics of typhoon suitable for wind turbine loads calculation, and then a simplified model with two degrees of freedom is got in two directions separately, according to the experiences of high-rise structure to mitigate vibration and theory of vibration absorber, passive TMD systems are put to the wind turbine structures in longitudinal and lateral direction. After that a medium complicated aero-elastic software FAST-SC is used to simulate transient and also fatigue conditions, the tower top displacement and tower base bending moment are evaluated, TMD systems can help reduce the transient load and fatigue loads of flexible wind turbine structures.

Abstract: The paper focus on an improved particle swarm optimization (IPSO) used to solve nonlinear optimization problems of steering trapezoid mechanism. First of all, nonlinear optimization model of steering trapezoid mechanism is established. Sum of absolute value of difference between actual rotational angle of anterolateral steering wheel and theoretical rotational angle of anterolateral steering wheel is taken as objective function, bottom angle and steering arm length of steering trapezoid mechanism are selected to be design variables. After that, an improved particle swarm optimization algorithm is proposed by introducing Over-flow exception dealing functions to deal with complicated nonlinear constraints. Finally, codes for IPSO are programmed and parameters of steering trapezoid mechanism for different models are optimized, and numerical result shows that errors of objective function's ideal values and objective function's optimization values are minimal. Performance comparison experiment of different intelligent algorithms indicates that the proposed new algorithm is superior to Particle swarm algorithm based on simulated annealing (SA-PSO) and traditional particle swarm optimization (TPSO) in good and fast convergence and small calculating quantity, but a little inferior to particle swarm algorithm based on simulated annealing (SA-PSO) in calculation accuracy in the process of optimization.

Abstract: Method for the synthesis of timing diagram of mechanisms of machine is presented in this work. This method is based on the vector model and allows take into account the precision of mechanisms, connection of the displacements of mechanisms and errors of timing diagram.