A Knitro-based real-time locomotion method for imitating the caterpillar-like climbing strategy

This paper presents a novel locomotion method to imitate the caterpillar-like climbing strategy. Caterpillar-like climbing is in fact slow, but a caterpillar's multi-segmented body trunk enhances the climbing versatility and dexterity, which motivates us to develop a caterpillar-like climbing method. In this paper, we introduce the characteristics of the climbing locomotion observed on natural caterpillars first, and then propose a three-stage climbing method to imitate the caterpillar-like climbing patterns. An energy efficient strategy is then formulated, aiming for the minimization of robot joint energy expenditure over a locomotion period. For real-time implementation and singularity avoidance within the energy efficient framework, we incorporate the Knitro method to search for kinematical optimal solutions over a period of time. Successful simulation and experimental results show the effectiveness of the proposed caterpillar-like climbing locomotion strategy.