Design and Development of an Automated Electromechanical Knee Ankle Foot Orthosis: An Innovative Sensor Based Programmable Device

The condition of knee-deficient patients is commonly characterized by quadriceps weakness and knee instability during gait, leading to compensatory walking patterns and reduced functional mobility. Conventional locked knee ankle foot orthoses (KAFOs) provide stance-phase stability but restrict knee flexion during swing and increase metabolic cost. This study aimed to design and develop an Automated Electromechanical Knee Ankle Foot Orthosis (AEMKafo) that ensures stance-phase stability while permitting free knee motion during swing. A custom-molded polypropylene KAFO was integrated with a force sensing resistor, Arduino UNO microcontroller, lithium-ion battery, and a solenoid-based magnetic locking mechanism. Heel contact detection triggered automatic knee locking during stance, while pressure release initiated unlocking to allow swing-phase flexion. The fabricated prototype demonstrated reliable sensing, timely actuation, smooth gait-phase transitions, and stable mechanical engagement during bench testing. These findings confirm the technical feasibility of a sensor-driven stance-control KAFO and support further optimization and clinical validation for knee-deficient patients.