A case study that illustrates the use of nonlinear state feed back to decouple the control of a two-axis polar-coordinate robotic manipulator is presented. One type of position cou pling and two types of velocity coupling are investigated. In each case, the application of decoupling compensation results in marked improvement in the performance of the robotic arm. The implementation difficulties associated with apply ing a nonlinear state-feedback control law to an inexpensive, indirect-drive robotic arm, using a microcomputer controller and low-resolution sensors, are examined.
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