7
previously developed ideas. Designing the controller about a nominal
trajectory is a standard technique often used in dealing with nonlinear
systems. This technique usually reduces the stability requirements of
the feedback law since it is assumed that the state trajectory will
never deviate far from a prescribed nominal trajectory.
Another topic discussed in Chapter Five is that of using a
discrete-time control law to approximate the already developed
continuous-time control law.
In Chapter Six we consider the robotic manipulator as a system for
which to apply the results derived in this paper. The dynamic equations
modeling the manipulator are analyzed in view of the servomechanism
problem. It is shown that the requirements needed for a solution to the
servomechanism problem are satisfied for the robotic system. Also
considered for the manipulator is an application of tracking where the
signals being tracked are used to compensate for errors in end-effector
location due to link flexibilities.
Chapter Seven shows results, obtained using simulations, of
applying the control scheme to a 2-link manipulator. These results
verify that the method will improve, or sometimes eliminate, steady-
state tracking error.