Pneumatic artificial muscles are pneumatic actuators with elastic structure distinctive for their nonlinear characteristics and hysteresis. In the paper we concentrate on the investigation of hysteresis in one of the recent types of fluidic muscles (DMSP-5). The main objective is to examine the hysteresis with respect to its rate-independence as well as its nonlocality. We used two types of excitation signal (triangular with linearly decreasing amplitude and triangular with randomly chosen amplitude) and two types of tests (quasi-static and dynamic with two different frequencies) to observe the overall quality of hysteresis. It was found out that the hysteresis show intricate behavior in response to the random excitation and well-defined formation of major and minor loops in response to linearly decreasing signal. It can also be described as rate-independent, with the width of hysteresis major loop being maximal for quasi-static measurement (5.26 mm) but with small differences between static and dynamic tests.
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