Self-sensing magnetostrictive actuator based on ΔE effect: design, theoretical modeling and experiment

Abstract

Giant magnetostrictive material (GMM) has the smart potential to be integrated as a self-sensing actuator. This paper presents a novel self-sensing giant magnetostrictive actuator (SSGMA), by sensing the on-line stiffness of the actuator upon the ΔE effect. A self-sensing signal is generated by superimposing a set of high-frequency small sensing excitation magnetic fields on low-frequency static or quasi-static driving magnetic fields. The fully coupled magneto-elastic-thermal nonlinear constitutive model of GMM is derived, and then the self-sensing response model of the SSGMA based on the nonlinear equivalent piezomagnetic equation is proposed. On the theoretical basis, the influences of magnetic field, prestress and temperature on the ΔE effect, the equivalent piezomagnetic equation parameters and the SSGMA sensing signal are investigated in detail, respectively. Moreover, a prototype of the SSGMA is fabricated and tested for self-sensing performance. The experimental results demonstrate the effectiveness of the theoretical analysis, and further show that the proposed SSGMA achieves self-sensing output displacement within a stroke of nearly 50 μm, with a sensitivity of 2.49 mV/μm. The self-sensing displacement resolution of the SSGMA by far may reach 63.4 nm after experimental determination. This novel self-sensing actuator with micron-level self-sensing drive capability can be integrated into an external sensorless execution system in the future.

Experimental study on synchronous detection of output force in a self-sensing giant magnetostrictive actuator

“…When the output force changes under the coupling action of H, load force and prestress, the stiffness and the internal magnetic field of Terfenol-D will change synchronously. It is well known that the Young's modulus of Terfenol-D is not a constant under changing external magnetic field and the stress, also known as the ∆E effect [22]. Therefore, the frequency of H s is set to close to the natural frequency of Terfenol-D rod, and then the change of the stress in the SSGMA will cause the change of V s in real time due to the ∆E effect and Villari effect.…”

“…Disregarding the effect of operating temperature, V s is produced under the coupling influence of H and σ. In [22], the expression of V s is derived based on the nonlinear equivalent piezomagnetic equation, which is obviously not accurate enough for describing the hysteresis with magnetic-mechanical coupling under dynamic load. Therefore, the static and dynamic output forces of the SSGMA are solved by re-derivation in this paper.…”

“…Chen et al [21] developed a self-sensing actuator based on magnetostrictive powder composites to detect the low-frequency displacement output by extracting the voltage signal of its driving circuit. Recent work [22] proposed a self-sensing actuator based on the variable stiffness effect (i.e. the ∆E effect) of GMM, which requires only mono-material to realize self-awareness and outputs micrometer-level accuracy.…”

Self-sensing model of low-frequency magnetostrictive composites actuator based on Jiles-Atherton theory

“…Afterwards, methods of applying the bridge circuit to solve the self-sensing nonlinear problem of GMA were studied [15,16]. A novel self-sensing giant magnetostrictive actuator utilizing a tiny sensing coil based on the traditional GMA was proposed to sense the online stiffness of the actuator on the basis of the ∆E effect [17]. An optical fiber bragg grating coated with a layer of magnetostrictive composite materials is used to measure DC and AC magnetic fields [18][19][20].…”

Domain Switching-Based Nonlinear Coupling Response for Giant Magnetostrictive Materials

“…In modern industry, on the one hand, magnetostrictive materials are used in functional devices with high-precision displacement control based on quasi-static magnetic field driving with prominent strain characteristics [1][2][3][4], such as rotating giant magnetostrictive vibrating tool handles and transducers. On the other hand, they are used in functional devices with dynamic characteristics based on their fast response speed, wide frequency band, and low voltage drive characteristics [5], such as giant magnetostrictive thin-film actuators.…”