A planning method for efficient mobile manipulation considering ambiguity

Abstract

In this study, we propose a system to enable robots to navigate more efficiently to target objects in order to carry out mobile manipulation tasks. Because a robot arm has limited reach, a target object cannot be grasped if the distance to the object exceeds the reach. At the same time, navigation errors may increase as the robot moves around in an environment. To mitigate these problems, we propose the use of maps that express the arm reachability and navigation reachability. Places with minimum probability of navigation errors and maximum tolerable navigation errors for the reach of the arm can be determined by integrating these two maps. We also consider the fact that the target object position is not always known. To cope with this problem, we introduce an object existence map that represents the ambiguity of the target object position, considering the past position. If the ambiguity is large, it is possible to select a place from where the object searching task can be performed with a wide angle of view by the robot. Efficient object searching can be achieved by changing the task objective from searching to grasping and vice versa. We conducted some mobile manipulation tasks to evaluate the proposed method. The results showed that the proposed system can perform such tasks effectively.