Pneumatic rubber actuators for a rehabilitation device to prevent contractures of finger joints

There has been increased interest in use of pneumatic actuators in many fields, such as medical care and welfare. In particular, a pneumatic rubber actuator with soft material has many advantages such as low mass, flexibility, safety and user-friendliness. We therefore focus on pneumatic rubber actuators as a drive source of a rehabilitation device. This paper presents pneumatic rubber actuators for a rehabilitation device to prevent contractures of the finger joints. We propose two types of actuators. The fabrication of the actuators was based on molding silicon rubber. The actuators can not only operate in flexion and extension but can also twist and stretch out the finger. The actuators force and motion were characterized at different supply pressures. In addition, we investigated different possible methods of rehabilitation for fingers using the actuators. The metacarpophalangeal (MP) and the proximal interphalangeal (PIP) joint motion were measured with the supply pressure of 150 kPa. The range of MP/PIP joint motion was from minus 3/9 degrees to 53/55 degrees. It was shown about 40 percent of its normal range. As a result, we confirmed the viability of the actuators for a finger rehabilitation device.