Controller design for natural and robotic systems with transmission delays

Robust stability and two-dimensional trajectory following problems are considered for n-link robotic systems with transmission delays. Such problems appear in telerobotics, where the controller is physically far from the robot, and in neural control of musculoskeletal (biological) systems, where muscle actuation and neural sensing are subject to time delays. A typical second-order nonlinear dynamical model is taken with input and output time delays. In a prior work by the authors, a control strategy was developed for stable movement of the planar linkage system, using the standard Q-parameterization and solving an H∞ control problem to determine the free parameter. In this article, a new control scheme is proposed to eliminate the steady-state errors seen in the tracking performance of the controller derived in the earlier work. Simulation examples are shown to demonstrate the effectiveness of the proposed control methodology.