The PI and PID controllers are the most widely accepted controllers in process industries. Simplicity, robustness, a wide range of applicability and near-optimal performance are some of the reasons that have made PI and PID controllers so popular in the academic and industry sectors. Henee, even a small percentage improvement in design of PI and PID controller could have tremendous impact worldwide. The knowledge of the system and its behavior can be used to characterise the model of the physical system. However, there will be characteristic deviations between the actual plant and the mathematical model developed for controller design. This mismatch may be due to many factors and it is the engineer"s role to ensure the required performance levéis exist despite plant/model mismatches. But the conventional controllers design techniques cannot withstand the uncertainties. Most of the conventional controller design technique fails to maintain the steady state after the oceurrence of the load disturbance. The internal model control (IMC) proportional integral derivative (PID) controller tuning rules provide an excellent tracking of setpoint, but sluggish disturbance rejection, as the conventional IMC filter introduces slow process pole. Disturbance rejection is significant than set-point tracking in many industrial applications. In process control, one often encounters systems described by transfer fimetions with time delays, which become transcendental functions. The design of the controller demands the rational transfer function approximation of the time-delay term. It"s been observed that a PID controller with a lead - lag filter pro vides better insight into load disturbance rejection which can be achieved with conventional IMC filter with 2/2 Padé -approximation or a 1/1 Padé approximation with a proposal for new IMC filter. Thus this work/system presents the design and development of IMC-PID controller, cascaded with lead-lag filter, with a new improved IMC filter to provide effective disturbance rejection and robust operation of the first-order process with time delay, the design is extended to first order process with no delay, first order process with right half plañe zeros and puré integrating processes with time delay. The Controller performance assessment or the control robustness assessment can be viewed in terms of performance robustness and stability robustness. The good design parameter for performance robustness can be achieved with Máximum Sensitivity (Ms) as a design parameter. The experimental study on real time processes constituting self regulating and non-self regulating systems with various time delay time constant ratios is conducted to show the effectiveness of the proposed method on various structures of the first order processes with delay and also without delay, calculating the controller parameters, maintaining similar robustness in terms of máximum sensitivity Ms.
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