GMA的温度特性分析及热形变被动补偿方法研究

Temperature characteristics of GMA and passive compensation method for its thermal deformation

利用超磁致伸缩材料的磁致伸缩效应特性制成的磁致伸缩智能构件,位移输出精度可达亚微米级,这为精密与超精密加工领域提供了新的驱动解决方案,这种精密微驱动过程是依靠智能材料的功能性实现的。然而,在磁致伸缩智能构件工作过程中,线圈的焦耳热损耗、材料磁滞与涡流损耗等因素会导致其温度升高,并伴随着材料出现热变形、磁致伸缩系数不稳定等问题,从而严重影响系统的输出性能。为降低温升对磁致伸缩智能构件工作性能的影响,对超磁致伸缩致动器的温度变化特性进行了深入分析,提出一种热形变被动补偿机构,完成了具有热形变自补偿功能的超磁致伸缩致动器设计。实验结果表明,磁致伸缩致动器的主要发热形式和发热源,取决于激励电流形式、工作频率;所设计的超磁致伸缩致动器在工作过程中能够对热形变自动进行补偿。研究结果为提高磁致伸缩智能构件在精密与超精密驱动领域应用过程中的工作精度提供了一种途径。

Smart magnetostrictive device based on magnetostrictive effect of giant magnetostrictive materials has a displacement output precision of submicron level to provide a new driving solving scheme for precision and ultra precision machining fields. This precision micro-driving process is realized with the functionality of smart materials. However, in working process of a smart magnetostrictive device, coil’s Joule heat dissipation, materials’ hysteresis and eddy current dissipation may make its temperature rise and may be accompanied by thermal deformation of materials and instability of magnetostrictive coefficient to seriously affect the system’s output performance. Here, temperature variation characteristics of a giant magnetostrictive actuator(GMA) were analyzed deeply. A passive compensation mechanism for thermal deformation was proposed to design a GMA with thermal deformation self-compensation function. Test results showed that GMA’s heating forms and heat sources depend on excitation current forms and working frequency;the designed GMA can automatically compensate its thermal deformation in its working process;the study results can provide a way to improve working accuracy of magnetostrictive devices applied in precision and ultra precision machining fields.