Robustness Analysis of a Closed-loop Controller for a Robot Manipulator in Real Environments

The need to design a robot manipulator that can complete tasks satisfactorily in the presence of significant uncertainties brought about the continued advance research in robust system design. This paper focuses on the robustness analysis of a closed-loop controller for robot manipulator in real environment. The neglect of wide range of uncertainties and failure to study the fundamental behavioral responses during design stage of a control system result to the system failure in real environments. The robustness analysis studies these essential behavioral responses of a controlled system considering the significant uncertainties that exist in real environment in order to design a robust controlled system. It was concluded that the robot manipulator controlled system can only achieve robustness when it can maintain low sensitivities and zero steady state error, stable over the range of parameter variations and its performance continues to meet the specifications of the designer in the presence of wide set of uncertainties. Robustness and optimization of the robot manipulator can be achieved using closed-loop control technique. Bode plot can be used to ascertain the performance and robustness behavior of the controlled system in frequency domain. The disturbance rejection and disturbance rejection settling time describe how well and fast the controlled system can overcome disturbances.