A framework for reference trajectory generation for mode-free prosthetic limb control

Most state-of-the-art prosthetic controllers define modes of operation corresponding to terrain types such as flat-ground walking or stair ascent. This control policy can create impairments for locomotion when unique situations arise, such as in obstacle avoidance or unstructured terrain. Human locomotion, however, is a continuous motion, fluidly adapting to the environment and not always categorizable into modes. A prominent feature of locomotion is that it exhibits strong inter-joint co-ordination. We show that using body motion from the intact limbs and trunk, a reference trajectory can be generated for a prosthetic joint for every instant in time.