喷油器用超磁致伸缩致动器多自由度模型

为满足高压共轨喷油器球阀的驱动要求，设计喷油器用超磁致伸缩致动器。考虑超磁致伸缩棒轴向磁场强度分布的不均匀性，计算磁场强度为电流和轴向尺寸的二元函数，并基于J-A模型、二次畴转理论和振动理论建立致动器的多自由度模型；确定合理的自由度取值，并给出模型的阶跃信号稳态响应解、状态空间形式，并采用Matlab软件进行求解；计算得到致动器直流稳态响应和低频正弦响应，并与试验结果对比验证模型的准确性；将油液负载近似为弹性-阻尼负载，利用文中的模型预测致动器在喷油器中的响应特性。结果表明，多自由度模型计算的直流稳态响应与试验结果误差较小，低频正弦响应曲线在形状和数值上与试验结果吻合，说明模型比较准确；经过模型计算，所设计的喷油器用致动器加载后输出位移大，响应时间快，能够满足驱动要求。

Multiple Degrees of Freedom Model of Giant Magnetostrictive Actuator Used on High-pressure-common-rail Injector

Giant magnetostrictive actuator used on high-pressure-common-rail injector is designed to control the bullet valve opening and closing. The axial magnetic field on giant magnetostrictive rod is not so uniform that the magnetic field value is the function of not only the current input but the axial coordinate. And the actuator displacement’s multiple degrees of freedom model is established based on J-A model, quadratic domain-transfer model and vibration theory, and the degree value of freedom is given appropriately. Steady step response and state space format of the model are presented and solved through Matlab software. The responses of direct and sinusoidal current in low frequency input calculated by the model are contrasted with test results to verify the model’s accuracy. Actuator’s behavior putting on the injector is forecasted through this model with the assumption of oil’s equivalent load being seen as elastic damping load. The results show that the direct current steady responses achieved by multi-degree of freedom model have little errors contrast with test results, and displacement-current curves under sinusoidal signals calculated through this model are similar to the test results. So the model’s precision is validated. With the injector, the actuator has large displacement and short responding time and can satisfy the driving requirement.