Force task planning of robotic systems with limited actuator capabilities

In this thesis, we study the problem of large wrench application using robotic systems with limited force or torque actuators. It is shown that such systems may be able to apply a wrench in some configurations only; therefore their useful Force Workspace is limited, and may be smaller than their reachable workspace.To improve the force capabilities of a system, base mobility or redundancy can be employed. A planning algorithm is proposed which results in proper base positioning relative to large-force quasi-static tasks. Similarly, the Force Workspace can be used to position such tasks relative to a robotic system. An efficient numerical algorithm is proposed to generate the Force Workspace, based on the 2$ sp{n}$-tree decomposition of the Cartesian space. Its efficiency stems from the variable resolution nature of the Cartesian space representation, and also from the use of four test levels that restrict the search to valid regions of the Cartesian space only. Examples of Force Workspaces are given for redundant and non-redundant planar manipulators, and spatial manipulators.Next, the case of tasks requiring the application of a wrench along a given path is considered. The Task Workspace, the set of Cartesian space locations that are valid starting positions for such tasks, is shown to be a subset of the Force Workspace.To plan redundant manipulator postures during large force-tasks, a new method based on a mini-max optimization scheme is developed. (Abstract shortened by UMI.