Development of a Bench for Testing Leg Prosthetics

The present paper deals with the development of a bench for testing prostheses for legs. The research is supported by INAIL. The bench includes a fake leg (from femur to foot) and it allows rotations of femur (up to 40°) and of tibia with respect to femur (up to 40°). Lockable gas springs allow stopping tibia and femur rotations. An hydraulic actuator applies a load to the hip, while a sled driven by an electric motor moves the foot simulating walking. Attachment between foot and sled has been designed to allow load transfer from heel to forefoot. Once maximum rotations for tibia and femur are reached, the leg is lifted and swings. As a first application, the test bench will be used to test transtibial prosthetics, including the knee socket, but it has been designed so that it could allow testing, with a limited number of adjustments, also of transfemoral, foot and ankle prosthetics. Design of test bench components and definition of control strategy for moving and synchronizing actuators, has been achieved through co-simulation of a Multi-Body model of the bench developed using ADAMS/View and a model of the control system and actuation devices developed using MatLab/Simulink. Results of preliminary experimental tests on a transtibial prosthesis are shown.