A novel piezoelectric actuated underwater robotic finger

To eliminate the problem of the structural damage of traditional manipulators caused by deep water pressure, a novel piezoelectric actuated underwater robotic finger is proposed in this study. The robotic finger, adopting an open configuration, is composed of three phalanges and two joints. A novel bonded-type piezoelectric transducer employed as the actuator in each phalanx pushes the joints by friction. The geometrical parameters of the bonded-type piezoelectric transducer are determined by the finite element method, and a prototype of the proposed robotic finger is manufactured and tested. Experiment investigation is conducted to confirm the calculation results and evaluate output performances of the robotic finger prototype. Experimental results indicate that water has little effect on the driving frequency of the piezoelectric transducer. The maximum average velocities of the phalanges A and C driven by the phalanx B and the phalanx C driven by itself in water are 638 deg s(-1), 676 deg s(-1), and 689 deg s(-1), respectively, under the excitation voltage of 500 V-pp . The maximum output torque of the phalanges A and C driven by the phalanx B and the phalanx C driven by itself in water are 10.98 mN m, 13.18 mN m, and 11.38 mN m, respectively, under the excitation voltage of 450 V-pp . The proposed robotic finger exhibits potential to be employed as underwater manipulators.