Advanced Materials Research Vols. 712-715

Abstract: Hybrid electric vehicle (HEV) is integrated with the engine, the motor and the battery and so on. HEV has a significantly better fuel efficiency compared with conventional vehicles due to its multiple power sources. To evaluate fuel economy, HEV and its subsystem modeling methodologies were provided through the analysis of energy flow. The Equivalent Consumption Minimization Strategy (ECMS) was built based on the prototype. The ECMS implementation analytical formulation was developed. The equivalency factor, one for charging and the other for discharging, each of them was different during a driving cycle. In a certain drive, only a subset of them generates a trend close to zero, which indicates charge-sustainability.

Abstract: An intelligent control system of wet dual clutch transmission was presented in this paper,and an intelligent control arithmetic based on neural adaptive PSD was established to realize precise control of clutch pressure.The transfer characteristics of clutch torque were analyzed,and the clutch torque model was established Due to the characteristic of the clutch control valve,the clutch pressure was precisely controlled in the neural adaptive PSD controller. The shift tests showed that the intelligent control arithmetic based on neural adaptive PSD had good adaptive ability,which could meet the control requirements of wet dual clutch transmission.

Abstract: A mathematical model and dynamic characteristics simulation model were established based on working principle of stationary combination valve in order to study shift quality of heavy-duty vehicle automatic transmission. Various parameters on buffer characteristics influence and outer diameter of the clutch hydraulic cylinder, the spring stiffness and preload influenced on the buffer time, starting pressure and termination pressure were gained with using batch function. The results show that the smaller the orifice diameter, spring stiffness and preload is, the longer the buffer time is, and the curve of buffer characteristic is downward translation. The larger the outer diameter of the clutch hydraulic cylinder, spring stiffness and preload is, the shorter the buffer time is, while the initial pressure and the termination pressure are relatively lower.

Abstract: EPS is the abbreviation of electric power steering system and reduction device is one of the key parts of the EPS. It determines whether the steering system works normally. This paper studies the deceleration mechanism of EPS and in accordance with its assistance characteristic, designs a new deceleration device that Cycloid steel ball planetary reducer, and gives the specific design and implementation of the program. Combined with steering portability needs, this paper gives the specific reduction ratio calculation and the deceleration mechanism design.

Abstract: In order to improve the performance of jet-pipe servovalve, a novel pilot stage for jet-pipe servovalve driven by giant magnetostrictive actuator is presented, and its working principle is given. On the basis of Jiles-Atherton’s theory of magnetism, the dynamic nonlinear model of giant magnetostrictive actuator is deduced to analyze the characteristics. The simulation results shows the peak time of GMA is less than 0.5ms at the driving current of 1.5A, and the bandwidth can be reached up to 900Hz, but the static performance is worse than the torque motor applied in conventional jet-pipe servovalve.

Abstract: Stopping accuracy is a significant guarantee of the safety of the train's operation. It is mainly impacted by the performance of the electric-pneumatic braking system and the control mode of the braking system. In this paper, the braking deceleration control mode is adopted and a braking model of the urban rail vehicle reflecting the principle of the electric-pneumatic braking system is derived. Dynamic characteristics of the deceleration and dead time of the system are also considered in this model. Furthermore, the impact of the dead time is also analyzed in this work. Based on this nonminimum phase system, a conventional PID controller with the Smith predictor is proposed to control the deceleration of the vehicle. Simulation results verify that this method not only tracks the reference breaking deceleration but also effectively improves the stability of the braking system and the comfort level of the urban rail vehicle.

Abstract: A MEMS(Micro-Electro-Mechanical Systems) scanning mirror with vertical comb actuator was designed, modeled, fabricated and tested, which can be widely applied in scanning micromirrors, optical switches, and variable capacitors. Purposive latching has been successfully applied to the batch fabrication of vertical comb actuators made of silicon on insulator (SOI). The manufacturing process is introduced, and a novel design of latching structure and mechanical spring is also presented. The latching of microstructures is enabled in a controlled manner and significantly reduces the distance between the combs, reducing the driving voltage. The prototype microactuators operate at the driving voltage of 28 V_dc with 9.6 optical angle. A reliability test on an unpackaged actuator with more than 100 million cycles of operation showed extremely small variation in the scanning angle and the driving voltage, showing no sign of degradation in the induced latching interface or the microstructures.

Abstract: In this paper, a microelectromechanical variable optical attenuator (VOA) with grid-type shutter is described. The device is used to control the power in the all optical nelworks. Besides the advantage of good switching performance and the relatively low driving voltage, its fabrication is simple and reliable. In our laboratory, a MEMS VOA with grid-type shutter has been fabricated and setup for investigation. Experimental results have shown that the proposed approaches improve the VOA performance.

Abstract: A 1×6 compound-driven MEMS-based optical device with optical switch and variable optical power attenuating functions has been proposed to optimally serve multifunctional optical fiber-based networking applications. The device manipulates the light with binary-slope mirrors driven by compound electrostatic actuator. The optical models for attenuating are investigated. Performances of the fabricated devices assembled with ball-lensed fibers are measured and discussed. Measurements reveal that the insertion loss of the device is less than 2.7 dB and the controllable attenuation range is more than 40 dB for the switching and attenuation function, respectively.

Abstract: The linear relationship between transfer torque and exciting current of magnetic powder clutch easily achieves to the electronic control and are widely used on the passenger cars. This article established the drive circuit model based on the experiments of excitation current transfer torque for magnetic powder clutch. Aiming at the nonlinear problems of the drive circuit, the article designed a current controller of magnetic powder clutch, which used method of genetic algorithms tuning PID control parameter. The simulation results showed that the drive control dynamic based on the genetic algorithms tuning PID was better than the traditional PID control, and the system had better adaptability.