Robust Control of Underactuated Manipulators: Analysis and Implementation

Marcel Bergerman and Yangsheng Xu
tech. report CMU-RI-TR-94-12, Robotics Institute, Carnegie Mellon University, May, 1994


Download
  • Adobe portable document format (pdf) (282KB)
Copyright notice: This material is presented to ensure timely dissemination of scholarly and technical work. Copyright and all rights therein are retained by authors or by other copyright holders. All persons copying this information are expected to adhere to the terms and constraints invoked by each author's copyright. These works may not be reposted without the explicit permission of the copyright holder.

Abstract
Underactuated manipulators are robot manipulators composed of both active and passive joints. The advantages of using such systems reside in the fact that they weigh less and consume less energy than their fully-actuated counterparts, thus being useful for applications such as space robotics. Another interest resides in the reliability or fault-tolerant design of fully-actuated manipulators. If any of the joint actuators of such a device fails, an entire operation may have to be aborted because of the loss of one or more degrees of freedom. The methodology proposed in this paper uses the dynamic coupling between the passive joints and the active joints, and controls the active ones in order to bring the passive joint angles to a desired set-point. Therefore, the control law and the performance of the system are completely dependent on the dynamic model. Since it is difficult to obtain the exact dynamic model of the system in general, considerable position errors and even instability can result in some cases. In this paper, we propose a variable structure controller to provide the system with the robustness necessary to perform tasks regardless of the modelling errors. Case studies are provided as a mean of illustration.

Notes
Sponsor: CNPq
Grant ID: DACA76-89-C-0014, DAAE07-90-C-R059
Associated Center(s) / Consortia: Vision and Autonomous Systems Center
Number of pages: 22

Text Reference
Marcel Bergerman and Yangsheng Xu, "Robust Control of Underactuated Manipulators: Analysis and Implementation," tech. report CMU-RI-TR-94-12, Robotics Institute, Carnegie Mellon University, May, 1994

BibTeX Reference
@techreport{Xu_1994_331,
   author = "Marcel Bergerman and Yangsheng Xu",
   title = "Robust Control of Underactuated Manipulators: Analysis and Implementation",
   booktitle = "",
   institution = "Robotics Institute",
   month = "May",
   year = "1994",
   number= "CMU-RI-TR-94-12",
   address= "Pittsburgh, PA",
}