Robot Ankle Foot Orthosis with Auto Flexion Mode for Foot Drop Training on Post-Stroke Patient in Indonesia

Abstract

Robot Ankle Foot Orthosis (AFO) has been proven to assist the gait impairment, such as the foot drop. However, development challenge is still remains, such as the trade-off between complexity, functionality and cost. High functionality resulted in high cost, bulky, and complex device. But affordability and simplicity may decrease functionality. Therefore, this research proposed a robot AFO, which has the necessary function of auto dorsi-plantarflexion so it can keep the affordability and simplicity. The robot AFO consists of structure, electronics part and algorithm. The structure is custom made according to the user’s anatomy. A brushless DC (BLDC) motor, Force-Sensing Resistor (FSR) and microcontroller builds the electronic parts. The BLDC motor actuates the flexion, while the FSR detects the gait phase to determine the action. Both are integrated by the microcontroller with the P control algorithm that commands the BLDC motor to generate necessary torque so it rotates in a constant speed. A functionality test has been carried out on the robot AFO, where the robot AFO perform a dorsi-plantarflexion continuously in three conditions, such as no load, 1 Kg load, and foot load. The robot AFO successfully performed a constant velocity rotation in both directions, in all conditions. In the case of 1 Kg load, the maximum angular speed is 0.7 rad/s dorsiflexion and -1.8 rad/s plantarflexion. The torque keeps increasing and decreasing from -0.3 Nm to 4 Nm to keep the angular velocity. The result shows that the robot AFO can perform the necessary function to assist the foot drop training. Functionality test on the gait detection has also been done where it shows that the robot AFO can detect the four gait phases accurately. The robot AFO has been tested and future study should test the robot on a real post-stroke patient to see the effect of the gait control in reality.

Field oriented control driver development based on BTS7960 for physiotherapy robot implementation

“…Typically, a robot for physiotherapy purposes is designed to rotate with RPM not more than 50 [33]. Because of that, the open-loop FOC driver shown in this study can be further utilized in developing a physiotherapy robot, such as the previous ankle robot by the authors [14]. However, it is important to note that the required torque for ankle application is at least 1 Nm [18].…”

“…Among them, electric motors are commonly used in both wearable and platform-based ankle physiotherapy robots due to their compact size, high efficiency, and precise control capabilities [13]. Other electrical components also include control systems, sensors, and power supplies [14], [15]. They work together to provide accurate, consistent, and engaging physiotherapy for patients recovering from ankle injuries [8].…”

Immediate Effect Evaluation of a Robotic Ankle–Foot Orthosis with Customized Algorithm for a Foot Drop Patient: A Quantitative and Qualitative Case Report

“…The robotic AFO is a powered AFO with one Degree-of-Freedom developed in [ 36 ], and is shown in Figure 1 a. It has a brushless DC (BLDC) motor right at the ankle, enabling the robot to flex in the dorsi and plantar direction with a constant speed.…”