Obstacle Avoidance by a Hyperelliptic Potential and a Virtual Spring Method for Omnidirectional Cooperative Transportations

Abstract

Robots can be expected to make our work efficient by covering transportation tasks in factories and warehouses. However, it is not easy to transport a long object in a narrow space. In our previous research, an omnidirectional cooperative transportation system was developed to transport a long-sized object with two lift-up robots. Then, an obstacle avoidance method was implemented with a virtual spring method when passing through a narrow space, so as to realize transportation even though some uncertainties are included in the prior map and localization. However, the model of the repulsion acted between the robot and the obstacle is not considered the shape of the carrying object. If the shape of the transported object is can be represented by a simple mathematical formula, such as a point or a circle, the robot can easily calculate the distance of the transported object and obstacles. However, the long rectangular object can’t be easily modeled. In this research, the shape of the transported object is modeled by the hyperellipsoidal approximation. Then, obstacle avoidances in the narrow space are realized by using repulsion with hyper-elliptic potential. The path to be followed is totally generated by the hyperelliptic potential and the virtual spring potential to obtain an efficient and shorter path. Finally, the usefulness of the proposed method is confirmed through some simulations by omnidirectional cooperative transportations of the long rectangular object in the narrow space.