Simulation and Analysis of a FullActive ElectroHydrostatic Powered Ankle Prosthesis This paper presents the design and control architecture of a novel fullactive powered ankle prosthesis which uses integrated forcecontrollable electrohydrostatic actuator (EHA) to provide both initiative compliance and sufficient positive power output at terminal stance to assist walking in whole gait cycle. A 100W brushless DC motor driving a 0.45 ccrev bidirectional gear pump operates as the power kernel. Based on finitestate machine (FSM), a hierarchical controller was designed to ensure the control system performance while different control strategies were implemented on each individual gait phase. Three independent force sensing resistor (FSR) mounted under sole, two pressure transducers and a displacement sensor used as ankle rotation sensor provide feedback signal for both state detection and lowlevel impedance control. A simulation model of the ankle prosthesis system was established with the help of MatlabSimulink to validate its feasibility. Using presampled biomechanics profile as input variable and matched group, the conceptual ankle prosthesis turns out to be able to restore the dynamic interaction response of a wholesome anklefoot to a great extent.

Hydraulic Damping and Swing Assistance Control of A Robotic Electrohydraulic Transfemoral Prosthesis: Preliminary Results This paper presents a robotic electrohydraulic transfemoral prosthesis that consists of a controllable bidirectional hydraulic damping and an electrical actuator. The embedded finitestate based controller enables the prosthesis with hydraulic damping adaptation in the stance phase and motorized swing assistance control in the swing phase during level walking. The proposed prosthesis was shorter in length than a fully powered transfemoral prosthesis. Additionally, the prosthesis with swing assistance and bidirectional hydraulic damping control could restore a better gait symmetry on knee angle assessment during level walking, compared with a hydraulic microprocessor controlled transfemoral prosthesis. Preliminary experimental results from a transfemoral amputee demonstrate the potential benefit of the proposed transfemoral prosthesis.