An in-pipe wireless swimming microrobot driven by giant magnetostrictive thin film

In this work, the nonlinear vibration characteristics of bimorph giant magnetostrictive thin film (GMF), TbDyFe/PI/SmFe, are measured and analyzed, firstly. Thereafter, by employing the primary resonance and superharmonic resonance performance of GMF cantilever, and simulating the ostraciiform locomotion of boxfish, an in-pipe wireless swimming microrobot is developed, whose caudal fin is fabricated by GMF microactuator. On the basis of the equivalent load model of magnetostrictive effect of GMF, the governing equations for swimming microrobot are established and solved by the method of multiple scales. Experiments on the swimming characteristics of this GMF microrobot in gasoline pipe show that the microrobot can swim at a mean speed of 4.67 mm/s with the external magnetic field driving frequency of 4.7 Hz, which is close to the first primary resonance frequency in gasoline. Besides, the mean swimming speed can reach 2.8 mm/s with the external magnetic field driving frequency of 2.4 Hz, which is close to the superharmonic resonance frequency of order two of GMF cantilever actuator in gasoline.