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1.
This paper mainly focuses on the development of pressure tracking control logic of electro-hydraulic actuators for vehicle application. This is done to improve and ensure the performance of a precise lower-level controller for evolving modern shift control logic. The required performance is obtained by hysteresis model-based feed-forward control and additional feedback control. The hysteresis and the time delay, which adversely affect pressure control, are well known nonlinear behaviors in electro-hydraulic actuators. In order to cope with the hysteresis, a novel hysteresis model is proposed based on a physical phenomenon. A mathematical model based on a characteristic curve obtained in preliminary experiments is presented using only one tuning parameter, and this model can be inverted easily to construct a feed-forward controller. In addition, a feedback controller is designed considering the stability margin of a time delay system. The feedback control inputs ensure compensation of the feed-forward errors caused by model error and uncertainty. The proposed controller is designed to lower computational cost considering applicability for production vehicles. As a result, the developed pressure controller is applied to a transmission control unit of a production vehicle and verified experimentally for various driving scenarios. 相似文献
2.
La-substituted M-type barium ferrites, Ba1 − x
La
x
Fe12O19, with x = 0.00–0.30 were successfully prepared via a citrate combustion process. Properties of the ceramics were characterized by
powder X-ray diffraction, vibrating sample magnetometry and scanning electron microscopy. XRD patterns revealed only magnetoplumbite
structure without minor phases. With increasing the La substituted content, the saturation magnetization (M
S
) was increased and reached to a maximum at x = 0.15 and then decreased but coercivity (H
C
) was increased. SEM micrographs of the dense ceramics showed the hexagonal platelet shape at low La content and the irregular
shape at high La content. 相似文献
3.
本文通过对偏转磁芯用的铁氧体材料的磁滞损耗特性的分析 ,提出了通过改变偏转磁芯外表面形状以减小磁滞损耗的方法。优化计算结果表明 ,对于Philips 17″CMT的 3C2材料 5mm壁厚的磁芯 ,改用椭圆外表面的磁芯后 ,磁滞损耗降低了 2 7 5 %。 相似文献
4.
5.
A finite element parametric study on the mechanical properties of J-shaped steel hysteresis devices 总被引:1,自引:0,他引:1
Shiro Kato 《Journal of Constructional Steel Research》2006,62(8):802-811
The present paper discusses the mechanical properties of J-shaped steel hysteresis devices, abbreviated to “J-dampers”, interposed between the upper structure of a spatial structure and its substructure. The mechanical properties of a J-damper, which are characterized by its key geometrical and material parameters, are evaluated through parametric analyses using an in-house Finite Element program. The hysteresis behavior of a J-damper is also modeled by a bi-linear elasto-plastic hysteresis model with the strain-hardening effect. Its elastic stiffness, yield strength and dimensionless hardening ratio, which are expressed as functions of the parameters, are formulated on the basis of mathematical models and the results of parametric studies. Finally, some remarks relevant to the application of the proposed hysteresis model are made for the design of the J-damper. 相似文献
6.
Jiang-Li Chen Zhuo Xu Shao-Bo Qu Xiao-Yong Wei Xiao-Hui Liu 《Ceramics International》2008,34(4):803-807
The NiFe2O4 and Pb(Zr0.52Ti0.48)O3 ceramic composites are prepared by conventional solid state reaction method. The microstructural and morphological properties of the composites are studied by X-ray diffraction analysis and scanning electron microscopy. Results indicate that the ferrite and piezoelectric phases can co-exist in the composites. The relationship between the dielectric constant and frequency (40 Hz–40 MHz) as well as temperature is also investigated. It is noted that the transition temperature of the composites is about 380 °C. A double electric hysteresis loop is observed in our composites. The magnetic properties are relatively weak according to the magnetic hysteresis loop. With increase in the content of the ferrite phase, the permeability increases. The electromagnetic properties of the as-prepared composites are tunable according to the content of the NiFe2O4 phase. 相似文献
7.
Angular-dependent magnetic Barkhausen noise measurements were performed on ASTM 36 steel samples for various values of applied uniaxial stress. The maximum differential permeability and the coercive field are obtained from this Barkhausen signals. The angular dependence of these macroscopic magnetic properties is studied. The tension for which the magneto-elastic energy balances the anisotropic energy is estimated. The results are discussed based on the domain wall theory. 相似文献
8.
Fuel injection rate shaping is a strategy to improve fuel efficiency and reduce harmful emissions in diesel engines. Due to their fast response, piezoelectric fuel injectors are capable of rate shaping operation. This paper describes a model-based closed-loop controller of injection flow rate for a piezoelectric fuel injector. This within-an-engine-cycle control strategy utilizes a dynamic surface control scheme and shows an injection flow rate tracking capability. Practical issues with LabVIEW FPGA control implementation are also addressed. The performance of the controller is verified with simulation and experimental results at different rail pressures and desired injection rates. The experiments show a maximum error of total fuel per one injection event of 2.5%. A stability analysis is also included. 相似文献
9.
针对二极管中点钳位型(neutral point clamped,NPC)三电平逆变器直流侧电容电压不平衡问题,提出一种混合空间矢量脉宽调制技术(Space vector pulse width modulation,SVPWM)和虚拟空间矢量脉宽调制技术(Virtual space vector pulse width modulation,VSVPWM)的控制策略。采用60°坐标系,通过大扇区旋转模型和小扇区重新划分以简化计算,即在低调制比时,通过一系列处理简化SVPWM算法,并设计PI控制器以调节小矢量作用时间平衡中点电压;在高调制比时,改进VSVPWM,重新定义小、中矢量在降低共模电压的同时设计滞环比较器以平衡中点电压。仿真和实验验证了该方法的正确性和有效性。 相似文献
10.
针对基于滞环非线性参数未知的多涡卷混沌系统,提出了一种自适应反步变结构的控制方案来实现其同步。通过逐步修正的方法设计镇定控制器,在每一步把状态坐标的变化、不确定参数的调节函数和一个Lyapunov函数的虚拟系统的镇定函数联系起来,以达到实现系统的全局调节。采用所设计的控制器实现了两个混沌系统的同步控制,使得误差系统在有限时间内到达所设定的滑模面,并沿着滑模面渐进收敛到原点,同时估计出系统中存在的未知参数。由于自适应算法和滑模方法的使用,控制器对参数扰动和外部干扰具有较强的抑制作用,理论分析和仿真结果验证了所提出方法的有效性。 相似文献