Ground-based self-righting using inertial appendage methods

摘要

As robots are deployed in more dynamic and uncertain environments, the ability to recover from tip-over events is critical. Previously, a framework for generating quasi-static self-righting solutions for generic robots was developed. This paper extends that framework to include the use of inertial appendage methods. It begins by reviewing the basic framework and discussing how it may be extended to incorporate dynamic solutions. It then discusses the generation of appendage momentum in the presence of ground reaction forces by utilizing the zero moment point concept. This concept is further extended to controlling the momentum transfer between the appendage and the body such that a desired tip-over event results. After initiating the tip-over event, the motion of the appendage may further be controlled to reduce the energy of the impact to land within the basin of attraction, or to increase the energy to intentionally land outside that basin and continue the roll. Four strategies based on this methodology are introduced, permuting appendage acceleration or deceleration and whether or not the appendage is involved in the resulting ground contact. The strategies are compared based on three optimization metrics: energy required to induce tipping, collision energy, and stability margin. Finally, the proposed methods are validated on a physical robot, demonstrating the improvement to its rightability as compared with quasi-static solutions.