Soft Actuated Foot Exoskeleton for Ankle Rehabilitation

Abstract

Technological advancement has made rehabilitation robotics possible. Robots can now help patients to proceed with their physiotherapy treatment with less assistance from physiotherapists. Soft robots are made from material similar to living organisms to improve safety between human and robot interaction. A soft robotic foot exoskeleton using pneumatic fiber braided bending-type actuator was developed in this study. Focusing on dorsiflexion ankle stretching movement, several actuator positioning was performed to gain the maximum ankle angle. MPU6050 sensor was used to detect the ankle dorsiflexion angle. Without any load, the bending-type actuator was able to bend and meet end-to-end of the tip. ITV0031-2ML valve was used as the connecter between air pressure supply and electronic circuit. Several experimental setups have been used in this study to obtain the maximum ankle dorsiflexion angle. The average maximum dorsiflexion angle from healthy volunteers was 8-degree, and Phase II experimental setup was able to drive a maximum of 6-degree dorsiflexion angle.

Application of Wearable Sensors in Actuation and Control of Powered Ankle Exoskeletons: A Comprehensive Review

“…Gurney et al, 2008 [209] integrated a set of FSR sensors into shoe insoles to measure the plantar pressure from the main pressure distribution regions of the foot sole: forefoot, toe, and heel, to identify gait events based on the pressure profile of these regions during different states of a normal gait cycle. Gyroscope [172] Linear displacement sensor [97][98][99] IMU [64,127,152,211] Goniometer [180,183] Attitude sensor [116] Custom strain sensor combined with IMU [174,175] Strain sensor [87] Knee joint angle IMU [206,207] Strain sensor [87] Absolute shank angle IMU [40,85,87,117,118,159,160,177] Orientation of shank, thigh, and trunk IMU [42] Inclinometer [82] Angular velocity Gyroscope [123][124][125][126]128,129,150,151,157,172] IMU [114,119,120] Translational acceleration of wearer IMU [40,[117][118]…”

“…The acquired data then can be used for estimating the anatomical ankle joint kinematics based on the mechanical relationship between the anatomical ankle and the exoskeleton hinge joint. In more recent prototypes, IMU sensors have also been used to measure orientation and angular movement of the user’s foot, ankle, and shank [ 64 , 119 , 127 , 152 , 211 ]. Strain sensors can be another option for measuring joint kinematics.…”

“…Pneumatic actuators are made of pneumatic cylinders or cylinder-like elements with enclosed pistons that can be powered and driven using external air compressors. Four types of pneumatic actuators were used in the reviewed PAEs: pneumatic artificial muscles [ 11 , 38 , 49 , 50 , 62 , 63 , 88 , 89 , 90 , 91 , 92 , 93 , 95 , 96 , 97 , 98 , 99 , 131 , 132 , 133 , 134 , 135 , 146 , 174 , 175 , 176 , 179 , 190 , 191 , 192 , 193 , 194 , 195 , 196 , 197 , 198 , 199 , 200 , 201 , 203 ], pneumatic cylinders [ 43 , 166 , 167 , 168 , 169 , 170 , 171 ], soft fabric actuators [ 156 , 232 ], and soft fiber braided bending actuators [ 211 ]. Pneumatic ac...…”