Prediction of the mechanical performance of McKibben artificial muscle actuator

In this study, the deformation mechanism of McKibben artificial muscle actuator is investigated through experimental and theoretical approaches. Especially, the relationship among the applied load, the actuatorʹs length and the internal pressure for the actuator is analyzed by considering several types of energy losses associated with the actuatorʹs deformation. The relationship between the applied load and the internal pressure of the actuator under both pressurization and decompression process can be predicted well by using our theoretical model. Also the effects of the sleeveʹs geometry on the performance of the actuator are discussed by using the proposed model. The contraction ratio of the actuator is the key for evaluating the actuatorʹs performance, but enhancing the contraction ratio may result in increasing the possibility of the rubberʹs protrusion between threads. Moreover, based on our results, the appropriate number of threads, the way of braiding and the cross-sectional shape of a thread are proposed for improving the performance of the actuator.