BIOINSPIRED UNDERWATER ROBOT WITH SHAPE MEMORY MET-AL-BASED ACTUATORS

Abstract

A bio-inspired robot was implemented in a fish whose main objective is the analysis of the interaction of the pectoral and caudal fins during the two-dimensional displacement, the pectoral and caudal fins were implemented for rotation and displacement, its pectoral fin has a dimension of 30mm high and 33mm wide, It consists of two parts, its base with cavities to house the actuator and its cover to hold and compact the fin, the caudal fin is created from a mold with cavities to house the actuator with a rigid fin at the end to have a greater movement, its dimension is 91. 69mm long, 30mm wide at the beginning and 40mm wide at the end, the robot as a whole has a dimension of 249.37mm long and 92.5mm wide with a weight of 254.5g. The actuators based on nitinol shape memory metals were used, for which tests were conducted with 2 wire gauges with diameters of 0. 5mm and 1mm, the 0.5mm cable has an activation of 60±10°C and the 1mm of 40±10°C, for which it was first analyzed the force developed by each of the actuators at different temperatures obtaining the following results, the 0. 5mm when subjected to force tests with a configuration of 60°C activation temperature with a voltage of 1.25 V at 2 A manages to lift an intermediate weight in terms of our tests of 20g reaches its final set point but with a not favorable time and having small deformations in its initial engraving, the 1mm material was subjected to the same tests with a configuration of 40°C activation temperature with a voltage of 0. 54 V at 2.25 A having favorable results in terms of reaching its final set point in the desired time and without having any final deformation, for which already established the tests it is analyzed that the two arrive to lift corresponding but the material of 0. 5mm material consumes more energy with a longer time than the 1mm material, so for the displacement of the robot the 1mm material was chosen because it has the necessary force to fulfill its objective, besides not consuming energy in excess. Once analyzed it was possible to achieve the two-dimensional displacement with pectoral and flow fins, with an oscillatory movement of the rigid flow fin, and turns with the pectoral fins, with an activation of 40°C at 0.54V with 2.25A and with the 1mm actuators a speed of 3.33 m/s was obtained.