Nonlinear adaptive control of robot manipulators

The mathematical model of a robot manipulator is described by a set of ordinary, coupled nonlinear differential equations. Present theory is insufficient to obtain the exact solution of the equations to control the manipulator. The complexity of the problem is reduced by proposing a model reference system where the Coriolis terms are ignored and where the system of nonlinear differential equations is almost decoupled by a careful selection of input torques. It is shown that the proposed control scheme for the model reference system is stable about a known equilibrium point. A simulation study is presented for a two-link rotary manipulator where a model system and control scheme are developed. The simulation results indicate that the solution is stable around a predetermined equilibrium point and that the addition of Coriolis terms in the nonlinear differential equation does not change the overall stability of the system