Design and test of wirelessly powered IPMC artificial muscle for aquatic ecosystem health applications

Aquatic environments and water resources face a variety of risks from numerous sources of pollution. In this paper, we propose a preliminary mechanism for realizing robotic technology practically and cost-effectively for monitoring these pollutions. The presented system is a small robotic fish propelled by a beam of ionic polymer-metal composite (IPMC) artificial muscle that imitates the motion of a small Scorpis Georgiana fish. One of the superiorities of the proposed model is the IPMC actuation mechanism powered by a battery that is charged wirelessly from a solar panel source. This approach enables us to produce a robotic fish that works ceaselessly without being forced to carry the solar panel load. Moreover, we present a method to control the flapping motion of a robotic fish by taking advantage of a tiny Wi-Fi module that yields more working range, bulky data sending, low power consumption, simple programing, and convenient communication for creating a network with other similar robots. All these beneficial characteristics make the proposed structure a promising candidate for detecting pollution on the surface of aquatic environments and sending/recording necessary data in collaboration with desirable sensors. Theoretical considerations support experimental results reported in the paper.

Experimental and numerical investigation of metal-polymer riveted joints

This paper presents the modeling and analysis of the joints of metal inserts with polyamide 6 using the injection technique. Based on the conducted experiments, modeling and numerical calculations of joints were carried out for various joint configurations. Metal parts, made of steel grade DC 04, are mechanically locked with polyamide 6 (PA6) with rivets. The mechanical connection with rivets of both elements was achieved by filling the holes in the metal parts in the injection process. As part of the work, mechanical-clamp connections made of steel / PA6 were mechanically tested in a single-axis joint tensile test using appropriate tabs. The main goal was to study and numerically analyze the number of rivets and their location on the metal plate for the strength of the connector. An important element of the work was the modeling process of both the PA6 material behavior and the joint itself. As part of the experimental research, the rivet deformation was also observed using computer thermography with the use of an IR camera. The tests and simulation showed that for the sample, the polymer-metal connected with less than three rivets was destroyed by shear. On the other hand, when the polymer-metal junction was made of three rivets, the jamming mechanism was mainly related to damage to the polymer part. For these joints, the maximum values of the breaking force of the joint were obtained in uniaxial tensile and shear tests where three rivets were used. Similar values were obtained during the numerical calculations performed with the use of Abaqus software.

Approximate field measures for ionic polymer-metal composite Materials and a simplified Order-of-magnitude actuator model

As the field of soft robotics grows and new applications for this technology are discovered, the use of simplified models for the soft actuators found in these devices will be critical. In this study we explore arguments based on the magnitude of field gradients that arise in the ionic polymer-metal composite under large applied voltages and their use for approximating measures of the fields inside the polymer. Using the order-of-magnitude based arguments provides exceptional results for quantifying the field measures of maximum ionic concentration and electric potential within the bulk of the polymer. These measures are leveraged to reconstruct the fields themselves in such a way that the internal bending moments generated inside the actuator may be approximated. With the internal moments, a simplified kinematic model may be used to formulate the steady-state actuator response of the IPMC. This actuator model shows a great deal of accuracy as compared to a full multiphysics model, and we discuss the prospects for future development of this model to account for dynamic actuation.