Geometry independent planar manipulation by multiple cooperating mobile robots

Abstract

Manipulation is one of the main tasks performed by the robots which strive to replace human effort in every possible way. Manipulation tasks have evolved from the industrial robots which performed pick and place operations to the present era of co-operative manipulation by multiple robots. The work presented here would focus on the problem of planar manipulation of objects in a plane. The obvious difficulties of manipulating heavy and complex shaped objects by a single robot has led to the increasing research in areas of co-operative manipulation. Moreover, employing multiple robots increases the sensing capabilities through sensor integration, facilitates aggregation of effort and opens up possibilities of forming closures around the object to be manipulated. Most of the previous research works in the area of cooperative manipulation focus on a certain type of object geometry or a narrow range of prey. The recent shift of research to closure based techniques have increased the range of prey considerably. Closure based technique focuses on establishing a configuration of robots around the prey such that the prey can never escape through the robots. Such a configuration, commonly referred to as the inescapable configuration is derived from the geometry and orientation of the prey. Moving the robots, maintaining this configuration results in transport of the prey. Thus it reduces the problem of manipulation to a geometric plane. The major drawback of a closure based methodology is the excessive dependence on orientation and shape of the object and the positions of other robots in the group. Estimating the geometry of the prey, tracking the prey orientation and tracking the positions of other robots are big challenges in a practical scenario while they are prerequisites for closure formation. In this work we focus on the development of a geometry independent methodology for manipulation of arbitrary objects in a plane. The suggested algorithm...