Sma control for bio-mimetic fish locomotion

In this paper, we describe our current work on bio-inspired locomotion systems using smart materials. The aim of this work is to investigate alternative actuation mechanisms based on smart materials, exploring the possibility of building motor-less and gear-less robots. A swimming underwater robot is being developed whose movements are generated using such materials, concretely Shape Memory Alloys. This paper focuses on the actuators control in order to generate the desired motion pattern

Free vibration analysis of a robotic fish based on a continuous and non-uniform flexible backbone with distributed masses

This paper presents a differential quadrature element method for free transverse vibration of a robotic-fish based on a continuous and non-uniform flexible backbone with distributed masses (represented by ribs) based in the theory of a Timoshenko cantilever beam. The effects of the masses (Number, Magnitud and position) on the value of natural frequencies are investigated. Governing equations, compatibility and boundary conditions are formulated according to the Differential Quadrature rules. The compatibility conditions at the position of each distributed mass are assumed as the continuity in the vertical displacement, rotation and bending moment and discontinuity in the transverse force due to acceleration of the distributed mass. The convergence, efficiency and accuracy are compared to other analytical solutions proposed in the literature. Moreover, the proposed method has been validate against the physical prototype of a flexible fish backbone. The main advantages of this method, compared to the exact solutions available in the literature are twofold: first, smaller time-cost and second, it allows analysing the free vibration in beams whose section is an arbitrary function, which is normally difficult or even impossible with analytical other methods

Fish physiology put into practice: A robotic fish model

Underwater creatures are capable of high performance movements in water. Thus, underwaterrobot design based on the mechanism of fish locomotion appears to be a promising approach.Over the past few years, researches have been developing underwater robots based on underwatercreatures swimming mechanism

Shape memory alloy-based high phase order motor

In this paper, we present our current work in the design and characterisation of a new shape memory alloy (SMA)-based High Phase Order Motor (HPOM). The motor can be used either in stepping mode or in servo mode of operation. Each phase of the motor consists of an SMA wire with a spring. The principle of operation of the HPOM is presented. In its operation the motor resembles a stepper motor though the actuation principles are different and hence has been characterised similar to a stepper motor.This motor can be actuated in either direction depending on which SMA is actuated, which are presented in this work. The motor is modelled and simulated and the results of simulations and experiments are presented

Aerial Remote Sensing in Agriculture: A Practical Approach to Area Coverage and Path Planning for Fleets of Mini Aerial Robots

In this paper, a system that allows applying precision agriculture techniques is described. The application is based on the deployment of a team of unmanned aerial vehicles that are able to take georeferenced pictures in order to create a full map by applying mosaicking procedures for postprocessing. The main contribution of this work is practical experimentation with an integrated tool. Contributions in different fields are also reported. Among them is a new one-phase automatic task partitioning manager, which is based on negotiation among the aerial vehicles, considering their state and capabilities. Once the individual tasks are assigned, an optimal path planning algorithm is in charge of determining the best path for each vehicle to follow. Also, a robust flight control based on the use of a control law that improves the maneuverability of the quadrotors has been designed. A set of field tests was performed in order to analyze all the capabilities of the system, from task negotiations to final performance. These experiments also allowed testing control robustness under different weather conditions

A motor-less and gear-less bio-mimetic robotic fish design

In this paper, we describe our current work on bio-inspired locomotion systems using a deformable structure and smart materials, concretely Shape Memory Alloys, exploring the possibility of building motor-less and gear-less robots. A swimming underwater robot has been developed whose movements are generated using such actuators, used for bending the backbone of the fish, which in turn causes a change on the curvature of the body. This paper focuses on how standard swimming patterns can be reproduced with the proposed design, using an actuation dynamics model identified in prior work