Nonlinear feedback control of PUMA 560 robot arm by computer

Abstract

It is shown that nonlinear feedback with diffeomorphic state transformation is applicable to dynamic control of PUMA 560 robot arm. This new dynamic control method externally (or exactly) linearizes the whole system and provides simultaneous output decoupling. To render the control robust, the nonlinear feedback is augmented with optimal error correcting controller which operates on the error in the task space. A key feature of this dynamic control method is that the nonlinear gains in the controller do not need readjustment from task to task. In that sense this controller is "intelligent" since it directly responds to changing task commands. A complete dynamic model in state equation form and with the necessary geometric and inertial parameters is also presented for PUMA 560 restricted to motions at the first three joints. This model is necessary to specify the nonlinear feedback and diffeomorphic transformation.