Research Of Direct Cardiac Assist Devices Based On Artificial Muscles

Dilated cardiomyopathy or DCM is a serious heart disease, which is one of the main causes of heart failure. It is a condition in which the heart becomes weakened and enlarged and cannot pump blood efficiently. In this paper, our purpose is to design a cardiac assist device with artificial muscles, which could help hearts to contract and reduce the impact of DCM.We used the BioMetal Helix (BMX) series of Toki Corporation as the artificial muscles, which were coil springs formed by NiTi shape memory alloys. In this paper, we mainly analyzed the mechanical properties of BMX in the practical application processes through two experiments, which were measured in stable states and in dynamic states, respectively. The results of the experiments indicated that, when the current through BMX was unchanged, there was a linear relationship between the tensile force of BMX and the change of BMX in length and the slope of the straight line could be considered as the equivalent elastic coefficient of BMX. The equivalent elastic coefficient increased with the increase of the initial current, and there were three regions. Then we applied the BMX series in cardiac assist devices and somatosensory rings and there were good performance of these applications.In this work, we discussed the properties of BMX in the practical application processes through two experiments and described it with a simple spring model. Finally, efficient cardiac assist devices and somatosensory rings were designed with the results of our experiments. Maybe this paper could provide some references for others and make them have an intuitive understanding of the characteristics of BMX.