Objective The biological characteristics and action mechanisms underlying the excellent performance of skeletal muscles were studied through experiments to provide a scientific basis for the development of flexible actuators with performance comparable to that of skeletal muscles.Methods A frog skeletal muscle sample was contracted by applying electrical stimulation,and then tensile load was applied to it to analyze the relationship between the driving properties(such as contraction length and output force)of skeletal muscle and its structure from three aspects:skeletal muscle dimensions,tendon,and epimysium.Results The contraction lengths of these skeletal muscle samples were approximately 28.92％and 20％under unloaded conditions and under 50％of their maximum output force,respectively.When the load on the skeletal muscles did not exceed 20％of their maximum output force,they also exhibited the property of rapid reduction(approximately 1.25 s).The active tendon increased contraction by approximately 19.68％compared with the inactive tendon,and the integrity of the epimysium protected the force transfer efficiency of skeletal muscles.Conclusions By simulating the structural and biomechanical properties of skeletal muscles,flexible actuators can achieve better driving performance,thus greatly promoting the development of bionic robots.

Objective The biological characteristics and action mechanisms underlying the excellent performance of skeletal muscles were studied through experiments to provide a scientific basis for the development of flexible actuators with performance comparable to that of skeletal muscles.Methods A frog skeletal muscle sample was contracted by applying electrical stimulation,and then tensile load was applied to it to analyze the relationship between the driving properties(such as contraction length and output force)of skeletal muscle and its structure from three aspects:skeletal muscle dimensions,tendon,and epimysium.Results The contraction lengths of these skeletal muscle samples were approximately 28.92％and 20％under unloaded conditions and under 50％of their maximum output force,respectively.When the load on the skeletal muscles did not exceed 20％of their maximum output force,they also exhibited the property of rapid reduction(approximately 1.25 s).The active tendon increased contraction by approximately 19.68％compared with the inactive tendon,and the integrity of the epimysium protected the force transfer efficiency of skeletal muscles.Conclusions By simulating the structural and biomechanical properties of skeletal muscles,flexible actuators can achieve better driving performance,thus greatly promoting the development of bionic robots.