Asymmetric Dual-Arm Task Execution using an Extended Relative Jacobian
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Dual-armed coordination is a classical problem in robotics, which gained an added relevance as robots are expected to become more autonomous and deployed outside structured environments. Classical solutions to the coordination problem include leader-follower or master-slave approaches, where the coordinated task is assigned to one arm, while the other adopts a passive role, such as the regulation of contact forces. Alternatively, cooperative task space approaches represent the task space of the dual-armed system in terms of absolute and relative motion components, where, for the most part, the relative task is split evenly between the manipulators. Relative Jacobian methods offer an alternative approach where the task space of the system contains only its relative motion. This is an attractive approach for tasks which do not require an absolute motion target, as a larger degree of redundancy becomes available for the optimization of secondary goals of the cooperative system. However, existing relative Jacobian solutions do not allow for a particular degree of collaboration to be set explicitly. In this work, we present a task-space analysis of common cooperation strategies and propose a novel, asymmetric, definition for the relative motion space. We show how this definition enables a user to prescribe a specific degree of cooperation between arms while using a relative Jacobian solution. Simulation results are provided to illustrate some properties of this novel cooperation strategy.
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