BIOSIMILAR ARTIFICIAL KNEE FOR TRANSFEMORAL PROSTHESES AND EXOSKELETONS

Artificial knees play an important role in transfemoral prostheses, lower extremity exoskeletons and walking robots. Their designs must provide natural kinematics, high strength and stiffness required in the stance phase of gait. Additionally, modern artificial knee is the principal module by means of which the prosthesis control is performed. This paper presents a prototype of an artificial polycentric knee, designed on the basis of the hinge mechanism with cross links. In order to increase strength and stiffness, the elements of the joint have curved supporting surfaces formed in the shape of centroids in relative motion of links of the hinge mechanism. Such construction is a mechanical system with redundant links but it allows for providing desirable characteristics of the artificial knee. Synthesis of the hinge mechanism is made by a method of systematic study of the parameter space, uniformly distributed in a finite dimensional cube. Stiffness of bearing surfaces elements of knee was determined by solving the contact problem with slippage of surfaces relative to each other.