Abstract:
An actuated, bipedal model is developed to investigate lateral plane locomotion dynamics and stability on inclines. Both the point mass case and rigid body case are
considered. Variations in the force-free leg length are determined via inverse dynamics to explicitly and implicitly match prescribed lateral and fore-aft force profiles,
respectively. Forward dynamic simulations incorporating the prescribed leg actuation are employed to identify periodic orbits for gaits in which the leg acts to either push
the body away from or pull the body towards the foot placement point. Gait stability and robustness to external perturbation are found to vary significantly as a
function of slope, velocity, and leg attachment point for each type of leg function. Results of these analyses suggest that the switch in the leg function from pushing to
pulling is governed by gait robustness, and occurs at increasing inclines for increasing velocities.
