| The nonlinear dynamic behavior of nonbackdrivable transmissions, typically associated with low lead angle gear components, has not been established in literature. To study the dynamic behavior of two proposed variable stiffness upper arm prostheses [English, 1996] which require nonbackdrivable transmissions, a simple dynamic model of non-intersecting, non-parallel axes gears was developed. The model includes the nonlinear effects of backlash, Hertzian damping and friction and can be used to study both backdrivable and nonbackdrivable gear sets. The development of this model involved investigations of DC dynamo operation and nonbackdrivable characteristics of several gear types. Dynamic simulations of the two proposed variable stiffness upper arm prostheses were conducted involving nonbackdrivable components and motors that were selected in this thesis. The results from these simulations using the gear model appeared reasonable and accurate. |
