Design and analysis of a novel octopod platform with a reconfigurable trunk

Abstract In order to enhance the terrain mobility of the close-chain leg mechanism and maximize its advantages, a novel dual degree-of-freedom (DoF) octopod platform with a reconfigurable trunk is proposed. The walking strategy of the close-chain multi-legged mechanism is adjusted through the spatial close-chain trunk mechanism. These two single-DoF close-chain mechanisms are designed and coupled to constitute whole close-chain mechanism as the walking platform. The locomotion modes of the trunk are discussed with the mobility analysis. In steering mode, the motion characteristic is analyzed under the combined action of steering linkage and elastic deformation. In climbing mode, the kinematic analysis and dimensional optimization are carried out, and the obstacle-climbing ability is evaluated through the probability model. To enhance climbing smoothness and efficiency, the assisted appendage is developed with the inner loop of Watt-Ⅰ leg linkage. A series of dynamic simulations is conducted and analyzed to test the platform performance, and a prototype is fabricated to testify the walking speed, steering property and obstacle-climbing capability. This study provides a new reference for close-chain legged platform development.