15th Triennial World Congress of the International Federation of Automatic Control
  Barcelona, 21–26 July 2002 
INTEGRATING FUZZY ADAPTIVE AND FUZZY ROBUST FORCE/POSITION CONTROL OF ROBOT MANIPULATORS
Silvério J. C. Marques* José M. G. Sá da Costa**
* Polytechnic Institute of Lisbon, Instituto Superior de
Engenharia de Lisboa
Department of Mechanical Engineering
Avenida Conselheiro Emídio Navarro, 1900 Lisboa, Portugal
Phone: +351-218317136, Fax: 351-218317213
E-mail: smarques@dem.isel.pt
** Technical University of Lisbon, Instituto Superior Técnico
Department of Mechanical Engineering, GCAR/IDMEC
Avenida Rovisco Pais, 1096 Lisboa Codex, Portugal
Phone: +351-218417921, Fax: 351-218498097
E-mail: sadacosta@dem.ist.utl.pt

In this paper is proposed a control structure integrating fuzzy adaptive and fuzzy robust position and force control, in a position based explicit force control strategy, to compensate for modeling uncertainties of the manipulator and environment. The fuzzy robust controller is a position controller in the inner control loop, to compensate for uncertainties in the robot manipulator model. The control surfaces in the boundary layers are designed, so that the region near the origin of the state space can be reached faster. The fuzzy adaptive controller in the outer loop adjust the manipulator tip position to compensate for uncertainties in the environment (stiffness and geometric location) with the purpose of reducing the error force. It uses a fuzzy inverse model and a learning mechanism to adapt the membership functions of the fuzzy logic controller. To show the performance on tracking force and position trajectories and to validate the proposed structure control scheme, simulations results are presented with a three degree of freedom manipulator.
Keywords: Robotics, fuzzy adaptive control, force control, fuzzy robust control
Session slot T-Mo-A14: Robot Controllers/Area code 1d : Robotics