Pneumatic artificial muscles are pneumatic devices with practical and various applications as common actuators. They, as human muscles, work in agonistic-antagonistic way, giving a traction force only when supplied by compressed air. The state of the art of soft pneumatic actuators is here analyzed: different models of pneumatic muscles are considered and evolution lines are presented. Then, the use of Pneumatic Muscles (PAM) in rehabilitation apparatus is described and the general characteristics required in different applications are considered, analyzing the use of proper soft actuators with various technical properties. Therefore, research activity carried out in the Department of Mechanical and Aerospace Engineering in the field of soft and textile actuators is presented here. In particular, pneumatic textile muscles useful for active suits design are described. These components are made of a tubular structure, with an inner layer of latex coated with a deformable outer fabric sewn along the edge. In order to increase pneumatic muscles forces and contractions Braided Pneumatic Muscles are studied. In this paper, new prototypes are presented, based on a fabric construction and various kinds of geometry. Pressure-force-deformation tests results are carried out and analyzed. These actuators are useful for rehabilitation applications. In order to reproduce the whole upper limb movements, new kind of soft actuators are studied, based on the same principle of planar membranes deformation. As an example, the bellows muscle model and worm muscle model are developed and described. In both cases, wide deformations are expected. Another issue for soft actuators is the pressure therapy. Some textile sleeve prototypes developed for massage therapy on patients suffering of lymph edema are analyzed. Different types of fabric and assembly techniques have been tested. In general, these Pressure Soft Actuators are useful for upper/lower limbs treatments, according to medical requirements. In particular devices useful for arms massage treatments are considered. Finally some applications are considered.

Static and dynamic characteristics of externally pressurized gas journal bearings with four supply orifices positioned at the central cross section for rotating shaft displacements near the bearing center are investigated. Results for transfer functions and for gas-film coefficients derived using the developed mathematical model are compared with the results derived from numerical computations of a nonlinear distributed parameter model of the gas bearings. Averaging and corrective coefficients are elaborated. The results obtained demonstrate that analytical data are in good agreement with the numerical data for the wide range of parameters and the mathematical model developed makes the simple calculation of static and dynamic characteristics of this type of externally pressurized gas bearings possible. Derived analytical relations for transfer functions and for gas-film coefficients of gas bearings provide an efficient means for designing rotor-bearing systems.

A method to experimentally evaluate and mathematically indicate the energy loss connected -with friction forces in pneumatic semi-rotary actuators is presented in this paper. A proper test bench was designed and constructed. Results obtained for a group of semi-rotary actuators are presented.