A Vacuum-Powered Artificial Muscle Designed for Infant Rehabilitation

Abstract

The majority of soft pneumatic actuators for rehabilitation exercises have been designed for adult users. Specifically, there is a paucity of soft rehabilitative devices designed for infants with upper and lower limb motor disabilities. We present a low-profile vacuum-powered artificial muscle (LP-VPAM) with dimensions suitable for infants. The actuator produced a maximum force of 26 N at vacuum pressures of −40 kPa. When implemented in an experimental model of an infant leg in an antagonistic-agonist configuration to measure resultant knee flexion, the actuator generated knee flexion angles of 43° and 61° in the prone and side-lying position, respectively.

An Original System for Controlling the Speed of Movement of Pneumatic Drives in Rehabilitation Devices

“…Measurement of displacement of the piston rods of the actuators (Fig. 1) was performed using a potentiometric position transducer (10,11). The measurements of the experimental study were collected and archived via USB 231.…”

“…These units are electrically controlled by power modules (15,16). Near the piston rods of the pneumatic cylinders, there are potentiometric position transducers (10,11), which are mechanically coupled to the piston rods of the cylinders (1, 2).…”

“…Voltage signals (Fig. 2) from potentiometric position transducers (10,11) are transmitted to the inputs of the A/C converter of the microcontroller ( 14), which acts as the controller of the entire system. The signal paths of potentiometric sensors are equipped with properly selected filters eliminating interference.…”

“…Pneumatic muscles [9][10][11] are also used in rehabilitation devices. Pneumatic drives are used in rehabilitation robots [12] due to force control through proper pressure regulation in the actuator cylinder chambers, and also because of the safety of the drives [13].…”

Rehabilitation of the Human Bone-Muscle System

“…The level of CCM depends on several parameters: it is proportional to the speed [70,71], it is variable for the degree of inertia [72], to the muscle group under consideration [73] and maybe partially dependent on sex and age [74][75][76]. Other factors can also be taken into account to explain these variations [25,53,[77][78][79] in the literature, but it is always calculated as a ratio between agonist and antagonist muscles and as a function of the walking sequence (double support, unipodal phase, etc.). From a scientific point of view, TVC has been defined in different ways to facilitate its interpretation.…”