Whole body control of a dual-arm mobile robot using a virtual kinematic chain
Dual-arm manipulators have more advanced manipulation abilities compared to single-arm manipulators and manipulators mounted on a mobile base have additional mobilityand a larger workspace. Combining these advantages, mobile dual-arm robots are ex-pected to perform a variety of tasks in the future. Kinematically, the configuration oftwo arms that branches from the mobile base results in a serial-to-parallel kinematic structure. In order to respond to external disturbances, this serial-to-parallel kinematicstructure makes inverse kinematic computations non-trivial, as the motion of the base has to take the needs of both arms into account. Instead of using the dual-arm kinemat-ics directly, we propose to use a Virtual Kinematic Chain (VKC) to specify the common motion of the two arms. We formulate a constraint based programming solution whichconsists of two parts. In the first part, we use an extended serial kinematic chain including the mobile base and the VKC to formulate constraints that realize the desired orientation and translation expressed in the world frame. In the second part, we use the resolved VKC motion to constrain the common motion of the two arms. In order toexplore the redundancy of the two arms in an optimization framework, we also provide a VKC-oriented manipulability measure as well as its closed-form gradient. We verify the proposed approach with simulations and experiments that are performed on a PR2robot, which has two 7 Degrees of Freedom (DoF) arms and a 3 DoF mobile base.
Recommended citation:
@article{wang2016ijhr,
title={Whole body control of a dual-arm mobile robot using a virtual kinematic chain},
author={Wang, Yuquan and Smith, Christian and Karayiannidis, Yiannis and {\"O}gren, Petter},
journal={Int. J. of Humanoid Robotics},
volume={13},
number={01},
pages={1550047},
year={2016},
publisher={World Scientific}
}