Objectives: The control of the robotic manipulator arm under a variety of faults has been studied and the performance is compared using PID and other technique. Methods/Statistical Analysis: In a highly nonlinear environment such as manipulator of a robot, employing more than one control techniques yields desirable results. Here, a combination of PID along with pole-placement control of linear model has been designed. The feedback control gains have been obtained offline using equivalent

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... zation of the nonlinear coupled robot dynamic system. The input torque has been obtained from PID. The combined torque has been applied to the joints. This scheme has been implemented online in a standard PUMA manipulator with the payload. Findings: It has been observed that PID as compared to modified pole placement method is more efficient to control a robotic arm. Application/Improvement: The proposed hybrid control approach involving offline designs and their online implementation on six degrees of freedom robot has been found to be efficient and capable of accommodating common types of faults represented as an exponential or sine or a constant function but sudden or abrupt in nature.