Hybrid FES-Exoskeleton Control for Walking Gait Correction

Abstract

Walking gait correction is fundamental to restoring body motion function for patients. Functional Electrical Stimulation (FES) is regarded as a promising method and essential to Neurotherapy, and the exoskeleton is fast becoming a key instrument in rehabilitation. Applying FES or exoskeleton alone, however, has its inherent disadvantages. Therefore, the hybrid exoskeleton combined with FES promoted in recent years overcomes the deficiency of more degree of freedom control. In this paper, a hybrid FES-Exoskeleton for walking gait control was first proposed and evaluated. With the Force Sensing Resistors (FSR) sensor, the exoskeleton actively assists in walking. Simultaneously, it also triggers the FES of the soleus, tibialis anterior, and gastrocnemius muscles for dorsilflexion and plantar flexion. Later, three different control strategies are employed for the pulse-width controlled FES. Eventually, an ILC with a PID controller is applied in the hybrid exoskeleton, following the best foot angle trajectory.