Design and Finite Element Modeling of Novel Flat Pneumatic Artificial Muscles

With the rapid development of soft exoskeletons, traditional cylindrical pneumatic artificial muscles (PAM) can no longer meet people's needs of wearable exoskeleton for hand rehabilitation. We propose a novel flat pneumatic artificial muscle with the advantage of lightweight, small size, and fitting on the skin without squeezing, made of silicone rubber and embedded fibers. The fibers embedded in the silicone substrate can convert a radial expansion into axial contraction. By finite element modeling (FEM), we obtain the deformation and stress distribution of the PAM preliminary designed under different air pressures. Finally, the flat PAM with better structure and performance is fabricated. Some experiments were carried out to measure the contraction rate and output force. The PAM has a maximum output force of 20.4N and a maximum contraction rate of 9.8% and with a weight of only 19.8g. Finally, a simple wrist exoskeleton is made to verify its availabilit.