Predictive control strategies for image based visual servoing of robot manipulators

Professor Corneliu Lazar
Vice-Dean of Automation and Computers Faculty,
Technical University “Gh.Asachi” Iasi,
ROMANIA
E-mail: clazar@ac.tuiasi.ro
Co-Author:
Adrian Burlacu
Abstract: There is significant motivation to provide robot manipulators
with improved autonomy using image based visual servo (IBVS) control. In
classical approach, an image Jacobian matrix maps image space errors into
errors in Cartesian space. Then, a simple proportional control law can be
applied guaranteeing local convergence to a desired set point. This control
strategy can not deal with delays due to image acquisition and processing and
nonlinear constraints such as joint limits and actuator saturation or
visibility constraint. In this paper, an IBVS control architecture based on
model predictive control (MPC) is presented considering the direct dynamic
model of the robot as a Virtual Cartesian Motion Device (VCMD), its joint and
torque limits, the camera projection model and the visibility constraint.
Considering the VCMD and camera models, the plant model of the visual servo
open-loop was derived and, based on it, two predictive control strategies were
developed. First, the control approach uses the Generalized Predictive
Controller (GPC) to improve accuracy along trajectories in Cartesian space by
employing information on the future reference. The second strategy is a
predictive control algorithm based on EPSAC (Extended Predictive Self Adaptive
Controller) which can take into account the nonlinearities of the plant model.
The effectiveness of the predictive control strategies are successfully
validated by simulations and with real-time experiments on a 6 DOF industrial
robot manipulator.
Brief
Biography of the Speaker: Corneliu Lazar received his M.Sc.
degree in electrical engineering from The Technical University of Iasi in
1976. In 1991 he received Ph.D. degree in automatic control from the same
university. Since 1997 he has been a Professor of Control Engineering in The
Department of Automatic Control and Applied Informatics at Technical
University of Iasi. His research interests include control engineering,
predictive control and visual servoing systems. He is a member of IEEE.
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