Robot manipulators, which are nonlinear structures and have uncertain system
parameters, are complex dynamically when operated in an unknown environment.
To compensate for estimate errors of the uncertain system parameters
and to accomplish the desired trajectory tracking, nonlinear robust controllers
are appropriate. However, when estimation errors or tracking errors are
large, they require large input torques, which may not be
satisfied due to torque limits of actuators such as driving
motors. As a result, their stability cannot be guaranteed. In
this paper, a new robust control scheme is presented to
solve stability problems and to achieve fast trajectory tracking of
uncertain robot manipulators in the presence of torque limits. By
using fuzzy logic, new desired trajectories which can be reduced
are generated based on the initial desired trajectory, and torques
of the robust controller are regulated so as to not
exceed torque limits. Numerical examples are shown to validate the
proposed controller using an uncertain two degree-of-freedom underwater robot manipulator.
A 3D Path Following Control Scheme for Robot Manipulators
