AAFO (Actuated Ankle-Foot Orthosis)
The Active Ankle Foot Orthosis (AAFO) is attached with straps to the subject’s left calf and thigh, as shown in the figure below. The orthosis has an active rotational degree of freedom (DoF) at the ankle joint (driven by a DC motor with a gearbox with a gear ratio of 114.4:1 and a maximum output torque of 15 Nm) and one passive rotational DoF at the knee joint. The total mass of the AAFO is 3.5 Kg , but only 1.5 Kg (the motor and gearbox) are attached to the shank while the rest (the electronics and battery) is securely fastened to the waist. The AAFO is equipped with an incremental encoder to measure the ankle joint angle at a sampling rate of 1 KHz . Two inertial measurement units (IMU) are used to estimate the angle between the shank and the vertical axis as well as the translational accelerations at the ankle level in the horizontal and vertical directions. Three force sensitive resistors (FSR) are embedded in both left and right insoles (a total of six FSR) and are connected to a wireless system. All data are time normalized to 100% of the gait cycle.
References:
[1] V. Arnez-Paniagua, H. Rifai, Y. Amirat, M. Ghedira, J-M Gracies, and S. Mohammed, “ Modified Adaptive Control of an Actuated Ankle Foot Orthosis to assist Paretic Patients", IEEE/RSJ IROS 2018, Accepted
[2] V. Arnez-Paniagua, H. Rifaï, Y. Amirat, S. Mohammed, "Adaptive control of an actuated-ankle-foot-orthosis", IEEE International Conference on Rehabilitation Robotics (ICORR), pp. 1584-1589, 2017
[3] V. Arnez-Paniagua, H. Rifai, S. Mohammed, Y. Amirat, "Adaptive Control of an Actuated Ankle Foot Orthosis for Foot-Drop Correction", Proceeding of the IFAC world congress, Toulouse, pp.1384-1389, 2017