Analytic nonlinear H/sub ∞/ inverse-optimal control for Euler-Lagrange system

The success in nonlinear H/sub /spl infin// control design is applied to the control of Euler-Lagrange systems. It is known that the existence of H/sub /spl infin// optimal control depends on solvability of the so-called Hamilton-Jacobi-Isaacs H/sub /spl infin// partial differential equation. In the article, the associated HJI equation for nonlinear H/sub /spl infin// inverse-optimal control problem for a Euler-Lagrangian system is solved analytically. The resulting control is referred to as the reference error feedback, which takes conventional PID controller form. Consequently, robust motion control can be designed for robot manipulators using L/sub 2/-gain attenuation from exogenous disturbance and parametric error.