Dual-arm coordinated-motion task specification and performance evaluation

Performing manipulation tasks in human environments often requires coordinated motions. The Extended-Cooperative-Task Space (ECTS) presents a unified representation describing any type of coordinated motions of two end-effectors. This paper focuses on the specification of dual-arm motion tasks based on the ECTS representation and the evaluation of the performance of the specified tasks. We first examine how the ECTS motion variables can be used effectively to specify coordinated motions to manipulate different types of objects. Then we derive new performance indices that can be used to evaluate and optimize the configurations of dual-arm robot systems performing any type of coordinated-motion tasks. The experimental results of coordinated-motion tasks performed by a Baxter robot demonstrate intuitiveness and efficiency of ECTS-based task specifications. We also show that the proposed ECTS performance indices can enable redundancies in a dual-arm system to be effectively utilized for a larger range of workspace as well as desired control objectives.