Base locationing and workspace mapping for mobile telemanipulators in cluttered envrionment

Abstract

While the perspectives on totally autonomous robots stagnates afar, teleoperation presents a more practical alternative for performing various manipulation tasks in hostile environments. Since telerobotic systems actively adopts human intervention in the essential parts of control and decision making loop, human operator is often burdened with multitude of decision makings in a pressed time. A significant portion of such decision makings attributes to the kinematic reasoning of the slave robot‘s environment, and very powerful aids must be provided to enhance operator‘s transparency to the kinematic complexity. In this regard, the presented work addresses on the extension of manipulator’s workspace analysis techniques to perform such kinematic reasoning in aid of fundamental stages of teleoperation, specifically in the placement of robot base and subsequent manipulation. Using a mobile telemanipulator, the first responsibility of the operator is to adequately place the mobile base so that the manipulator has full access to the specified task trajectories. Such a decision making is difficult because the shape and topology of the workspace varies widely in the presence of obstacles. Thus, off-line methods are developed for generating the optimal base locations in regard to various task capabilities. In all of the methods, the various free workspaces and task trajectories are coded into octree to facilitate enumeration of task capabilities. Subsequently the base locationing problems are formulated into direct optimization processes. For the task of tracking continuous paths, two different methods are presented. One method implements the topological characterization of configuration free space, and it can provide clear visualization of the task capability of workspace. Another method adopts the identification of trajectory feasibility in operation space, and is computationally more efficient. Also, for the tasks consisting of PTP motions, a novel method is presente...