Adaptive microcomputer control of an artificial knee in level walking

An experimental microcomputer controlled prosthesis is discussed, where knee damping is governed by kinematic signals, picked up from both legs. The control algorithm is based on division of the walking cycle into ten stages; each stage characterized by an appropriate damping level which governs the restraining moment at the knee, as functionally required. Stage identification is carried out by the kinematic inputs. The experimental prosthesis was tested on one amputee, the first author of this paper. The control system was found to be more advantageous than a conventional valve system in significantly reducing hip muscular effort on the prosthetic side. Gait symmetry is also improved.