Architecture, performance and stability analysis of a formula-based fuzzy I?fuzzy P?fuzzy D controller
In this paper, a formula-based fuzzy integral minus fuzzy proportional minus fuzzy derivative (FI?FP?FD) controller is proposed based on the modified conventional parallel PID controller, i.e. parallel integral minus proportional minus derivative (I?P?D) controller, in order to avoid some practical industrial process problems. It freezes the linear structure of conventional parallel I?P?D controller, with analytical formulas. The final shape of the controller is a discrete-time fuzzy version of conventional parallel I?P?D controller. Computer simulation is performed to evaluate the performance of FI?FP?FD controller for setpoint tracking and load-disturbance rejection for some complex processes, such as, first- and second-order process with delay, inverse response process with and without delay and higher order processes. The simulation is done using National Instrument software (LabVIEW). The response of FI?FP?FD controller is compared with the conventional parallel I?P?D controller, tuned with the ZieglerNichols tuning technique. It is observed that the FI?FP?FD controller performed much better than conventional I?P/I?P?D controller. Simulation results demonstrate the effectiveness and usefulness of proposed formula-based FI?FP?FD controller. Also, the bounded-input bounded-output (BIBO) stability of the overall fuzzy control system is established with sufficient conditions, using the famous Small Gain Theorem.
pid i?p?d fi?fp?fd controller inverse response process dead time