Singularity-free planning for a robot cat free-fall with control delay: Role of limbs and tail

Cat free fall righting maneuverer has inspired many aerial, space and legged robotic research. Conservation of angular momentum principle is used to derive the inverse differential kinematic and TMT vector form dynamics of the motion for three robotic models: a two-link model, a three-link model with tail, and a comprehensive eight-link model with the addition of legs. The path planning problem in the presence of geometric and kinematic constraints is addressed using a novel singularity free single shooting optimization method. While a 2 DOF torso is sufficient to perform a full maneuver, the addition of the tail reduces the time and increases the maneuverability despite the leg motions that has adverse effects. The method performance is investigated numerically and a simulation in MSC.ADAMS software is used to verify the results. The structural parameters are optimized showing the significant advantageous of a light and symmetric body shape. A prototype will be fabricated based on these results in near future.