Design optimization and control of a crank-slider actuator for a lower-limb prosthesis with energy regeneration

Recently as technology has progressed, interest in powered prostheses has expanded in an attempt to improve kinematics and kinetics for amputees. The current state of this art is described, noting that most powered knee prosthesis designs do not consider the energy regeneration potential of the natural knee. Three actuator models for the knee joint and its control method are designed, optimized, and evaluated using simulation models. The first model excludes mechanical losses. The second includes a Coulomb friction model. A more coarse efficiency model accounting for the mechanical losses is used in the third case. Energy regeneration of 11.94 J per stride resulted for the first model. The second model gave a total of 7.95 J per stride. Lastly, 1.94 J per stride were regenerated in the third model's simulation. In addition, sufficiently accurate gait tracking was realized with a total RMS error on the order of 10-3 rad or less for all models.