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Soft pneumatic actuators used in robotic rehabilitation gloves are classified into two types: whole-finger actuators with air chambers that cover the entire finger and modular actuators with chambers only above the finger joints. Most existing prototypes provide enough finger flexion support, but insufficient independent thumb abduction or opposition support. Even the latest modular soft actuator realized thumb abduction with a sacrifice of range of motion (RoM). Moreover, the advantages and disadvantages of using the two types of soft actuators for thumb assistance have not been made clear. Without an efficient thumb assist, patients' options for hand function rehabilitation are very limited. Therefore, the objective of this study was to design a modular actuator (M-ACT) that could support multiple degrees of freedom, compare it with a whole-finger type of thumb actuator with three inner chambers (3C-ACT) in terms of the RoM, force output of thumb flexion, and abduction, and use an enhanced Kapandji test to measure both the kinematic aspect of the thumb (Kapandji score) and thumb-tip pinch force. Our results indicated superior single-DoF support capability of the M-ACT and superior multi-DoF support capability of the 3C-ACT. The use of the 3C-ACT as the thumb actuator and the M-ACT as the four-finger actuator may be the optimal solution for the soft robotic glove. This study will aid in the progression of soft robotic gloves for hand rehabilitation towards real rehabilitation practice. [ABSTRACT FROM AUTHOR]

Resin tubes made of epoxy base material and fibers are widely used in the transportation, and aeronautics industries due to their high mechanical properties. Different reinforcing fibers and resins are usually used in making these tubes and lead to various properties. In this study, tubes made by using a 45-degree unilateral winding method and reinforced by Glass, Carbon, and Kevlar fibers and their hardness and wear behaviors were investigated. The results showed that the highest hardness was obtained for the carbon fiber reinforced composite tube (CFR), equal to 65HV, which was 109% more than the Kevlar fiber reinforced composite tube (KFR). Higher hardness indicates greater resistance of the material to local deformation and also stronger bonding between the base material and the reinforcing fibers. The wear test results showed that the wear rate of CFR was 6 mg/m, which was 26% and 55% lower than the glass fiber reinforced composite tube (GFR) and KFR, respectively. The obtained result can be explained as a result of good bonding and compatibility between carbon fibers and used resin. Scanning electron microscope (SEM) images were taken to evaluate the results.

Soft pneumatic actuators used in robotic rehabilitation gloves are classified into two types: whole-finger actuators with air chambers that cover the entire finger and modular actuators with chambers only above the finger joints. Most existing prototypes provide enough finger flexion support, but insufficient independent thumb abduction or opposition support. Even the latest modular soft actuator realized thumb abduction with a sacrifice of range of motion (RoM). Moreover, the advantages and disadvantages of using the two types of soft actuators for thumb assistance have not been made clear. Without an efficient thumb assist, patients’ options for hand function rehabilitation are very limited. Therefore, the objective of this study was to design a modular actuator (M-ACT) that could support multiple degrees of freedom, compare it with a whole-finger type of thumb actuator with three inner chambers (3C-ACT) in terms of the RoM, force output of thumb flexion, and abduction, and use an enhanced Kapandji test to measure both the kinematic aspect of the thumb (Kapandji score) and thumb-tip pinch force. Our results indicated superior single-DoF support capability of the M-ACT and superior multi-DoF support capability of the 3C-ACT. The use of the 3C-ACT as the thumb actuator and the M-ACT as the four-finger actuator may be the optimal solution for the soft robotic glove. This study will aid in the progression of soft robotic gloves for hand rehabilitation towards real rehabilitation practice.

In this study, the reactive extrusion mechanism of fiber-reinforced polyamide 66 materials with added carbodiimide was clarified, and the mechanical and tribological properties of the materials were evaluated. Increasing the molecular weight of resin is one of the methods that has been proposed to improve the wear resistance and toughness of fiber-reinforced materials. This study proposes a reactive extrusion method using poly-carbodiimide compounds. The effects of the feeding position of the poly-carbodiimide compounds in the twin screw extruder, type of carbodiimide compounds, and proportion of carbodiimide compounds on the extrusion reaction and static mechanical properties were elucidated. The toughness of the glass fiber-reinforced polyamide 66 was improved by the increase in molecular weight of the polyamide 66 related to the addition of the carbodiimide compounds. The wear resistance properties were significantly improved by the addition of carbodiimide compounds for both glass fiber-reinforced polyamide 66 and aramid fiber-reinforced polyamide 66 materials. In addition, a synergistic improvement in the toughness was also observed with the addition of both carbodiimide compounds and a maleic anhydride modified olefin polymer to the glass fiber-reinforced polyamide 66 material. The results of this study will be beneficial for improving the mechanical and tribological properties of extruded resins. Unlabelled Image • Addition of carbodiimide to fiber reinforced polyamide 66 can increase the molecular weight and improve the toughness. • Using aromatic carbodiimide can control the reaction velocity, allowing the carbodiimide to remain unreacted in the pellets. • The wear resistance of reinforced polyamide 66 materials could be improved significantly by the addition of carbodiimide. • A synergistic improvement in toughness was obtained by adding carbodiimide and a maleic anhydride modified olefin polymer. [ABSTRACT FROM AUTHOR]