NEXT-GENERATION SOFT ROBOTIC SOCK FOR ASSISTIVE DUAL-PLANE ANKLE EXERCISES
Fan-Zhe Low, Denise Kai Ying Eng, Jeong Hoon Lim, Chen-Hua Yeow
National University of Singapore, Singapore
Patients who suffer from stroke are often at risk of contracting the following medical conditions; Deep Vein Thrombosis where venous thrombus develops in the venous circulation of the lower extremity and occludes the normal flow profile, as well as increase spasticity of the joints of the lower limbs as seen by an increase in resistance to joint motion. These two conditions can affect the time to recovery post stroke resulting in necessary long term care provided by caregivers. One of the main reasons that these conditions can occur is due to long term lower extremity immobility as patients are bedridden, especially in the ankle joint where active ankle motion in a healthy person prevents such conditions from occurring. In this study, a new generation of soft robotic sock is presented where the device is able to provide assisted ankle dorsiflexion-plantarflexion and inversion-eversion exercises in a supine position to assist in the post-stroke recovery process. By using a combination of pneumatically controlled extension and bending actuators, the exercises can be provided to the patients starting from the moment the patients are warded in the hospital. Initial characterization of the actuators showed that when the actuators were inflated at 60kPa, the extension actuator constrained in a denim sheath extended by 62% of its original length and exerted a force of 29.8 ± 0.4N while the bending actuator exerted a force of 9.4 ± 0.3N. Subsequently, the device was tested on healthy subjects, where the device was able to achieve dorsiflexion-plantarflexion and inversion-eversion range of motion of 10.2 ± 3.2° and 19.7 ± 6.6° respectively. These data will be useful to determine the efficacy of such soft robotic targeted rehabilitation and its subsequent testing on stroke patients.