Rishika Trivedi
@iiitdmj.ac.in
Post Doc Fellow
IIT Delhi
RESEARCH, TEACHING, or OTHER INTERESTS
Control and Systems Engineering, Modeling and Simulation
Scopus Publications
Scopus Publications
Kurnam Gnaneshwar, Rishika Trivedi, and Prabin Kumar Padhy
Wiley
AbstractThis article presents a novel approach to the robust design of fractional order IMC controller for the fractional‐order (FO) plus time delay processes. The proposed methodology provides the flexibility to adjust the controller performance based on the application requirement using a single parameter. Also, it does not require any external filter. Thus, it ensures a better response over existing methods. A mathematical analysis is provided to select the tuning parameter to obtain the optimal solution. The effectiveness of the proposed methodology is measured for different FO processes with time delay using time‐domain specifications, performance indices and frequency domain parameters. Load disturbance analysis under various disturbances and robust analysis under uncertainty in process gain in the presence of the disturbances is carried out to study the sensitivity and robustness of the controller. The performance parameters are estimated in both analyses and compared with the different approaches available in the literature.
Rishika Trivedi and Prabin Kumar Padhy
Institute of Electrical and Electronics Engineers (IEEE)
In this brief, indirect design estimation of fractional order systems is proposed. In indirect fractional order approach, fractional order plant is shifted in the frequency domain and the equivalent plant is modeled by employing binomial approximation. The equivalent fractional order plant obtained is used for the design of the controller. While designing fractional order controllers, robustness and handling sensitivity to parametric variations are of key importance. Therefore, indirect fractional order approach is used, which gives the flexibility to adjust the maximum sensitivity according to the system requirements and eliminates the need for external IMC filter. IMC filter added externally results in an additional phase lag of the system. The proposed design method excludes external IMC filter and the binomial expansion used helps in achieving the internal filter which results in better transient response. This is termed as Indirect Fractional order IMC based fractional order PID controller.
Rishika Trivedi, Bharat Verma, and Prabin K. Padhy
Wiley
AbstractIn this article, the tuning rules of fractional order PID controller are derived using Indirect Design Approach‐1. In Indirect Design Approach‐1, the plant is shifted in the frequency domain using the shifting parameter ψ. The tuning rules of stochastically optimized fractional order PID controllers exist in literature for the fixed values of maximum sensitivity. Maximum Sensitivity or robustness of the process is application dependent. Due to complex fractional order mathematics, the design of fractional order PID controller is complex. Therefore, in this article, new optimal tuning rules for FOPID controller are proposed using the shifted version of the plant. The adjustable robustness is achieved by varying tuning variable ψ which has a linear relation with the Maximum Sensitivity, Gain margin and Phase Margin. The range of ψ within which it can be varied is also proposed for both stable and unstable processes. Simulation is carried out in the MALTAB environment for validating the proposed methodology. A stable and an unstable first order process with time delay is considered for simulation. For the practical viability and novelty, a real‐time experiment on the level control of Canonical Tank using the proposed methodology is shown.
Kurnam Gnaneshwar, Rishika Trivedi, Bharat Verma, and Prabin Kumar Padhy
IEEE
In this paper design of fractional order controller for stable systems based on the IMC approach is presented. The proposed method creates a filter internally; therefore, phase lag obtained by an external filter in the system response can be avoided with the proposed method. It has the capacity to regulate the transient response and robustness of the system with a single parameter. This parameter plays a vital role to obtain the optimum response. Hence, a metaheuristic algorithm is considered. Numerous performance parameters and performance are considered to examine the proposed methodology efficacy. The proposed methodology performance has been carried out under load disturbance, robustness analysis. Also, its performance has been compared with various existing techniques.
Rishika Trivedi and Prabin Kumar Padhy
Informa UK Limited
Kurnam Gnaneshwar, Rishika Trivedi, and Prabin Kumar Padhy
IEEE
An approach to sustain the Automatic Voltage Regulator (AVR) system voltage at the desired level using the Fractional Order PID controller (FOPID) were described in this article. Numerous optimization techniques are used for the optimal tuning of FOPID parameters with the proposed objective function. The performance of this objective function has been compared with existing ones to validate its effectiveness. Moreover, load disturbance analysis is carried out on the FO-PID controller along with the robustness analysis under uncertainties of exciter parameters.
Rishika Trivedi and Prabin Kumar Padhy
Elsevier BV
Rishika Trivedi and Prabin Kumar Padhy
IEEE
Relay is one method employed for identification, but it introduces error in the identification process. Therefore, in this paper, fractional order controller is introduced in parallel with the ideal relay. In proposed fractional order relay, obtaining the accurate value of is a primary concern. Hence, an analytical approach is employed to design the value of accurately. The proposed scheme is validated by making the comparison in the harmonic contents present in the output signal of the proposed relay, the existing modified relay proposed in literature and ideal relay by considering two stable processes and one unstable process through simulation.
Roshan Bharti, Rishika Trivedi, and Prabin Kumar Padhy
IEEE
In this paper, a new fuzzy proportional-integral-proportional-derivative (FPI-PD) controller is designed, in which fuzzy PI controller is in the forward path and conventional PD controller is in inner feedback loop. The gain parameters of the proposed controller are calculated by gradient descent optimization method. The performance evaluation of this controller is performed for speed control of brushless DC motor in MATLAB/Simulink. The obtained responses are compared with conventional PID controller and the existing fuzzy PID controller. It reveals that proposed FPI-PD controller is more efficient than both the above mentioned controllers.
Roshan Bharti, Rishika Trivedi, and Prabin k. Padhy
IEEE
In this paper, a new structure of PID type fuzzy logic controller is proposed in which Fuzzy PI controller and conventional PD controller are connected in parallel. The gains of the proposed controller are calculated by Gradient descent optimization method. Illustrative examples are considered to validate the performance of the proposed structure. The proposed controller outperforms the Conventional PID Controller and existing fuzzy PID Controllers in terms of performance indices for a different plant.
Sudeep Sharma, Bharat Verma, Rishika Trivedi, and Prabin K. Padhy
IEEE
This research work develops a discrete time method for identification as well as modelling of stable unknown process dynamics in the form of first order plus dead time (FOPDT) process models. A linear three layered Feed-foreword Artificial Neural Network (ANN) is used to yield the relationship between input and output data from unknown plant. Thereafter, this relationship between input and output in terms of ANN weights is represented in mathematical equations for unknown plant characteristics to be identified. Some literature examples are used to test and compare the proposed method on MATLAB platform.
Rishika Trivedi, Bharat Verma, Sudeep Sharma, and Prabin K. Padhy
IEEE
In this paper, tuning of fractional PIλ controller using maximum sensitivity and stability criteria is proposed for First Order Plus Dead Time processes that assure robustness of the process. Maximum Sensitivity is employed for robust control of process variations and model uncertainty. The PIλ controller improves the set point tracking. The effectiveness of the controller is verified by an example.
Bharat Verma, Sudeep Sharma, Rishika Trivedi, and Prabin K. Padhy
IEEE
The coupling among the loops is a primary challenge in MIMO processes over the SISO processes. In this work, a new Relative Derivative Normalised Gain Array (RDNGA) is proposed that be derived from the error and its derivatives. Proposed method helps in input-output paring and gives improved controller design than the existing RNGA based method that uses only Integral error to calculate the normalisation factor. The proposed method is validated by PI controller design for two FOPDT-TITO process that uses RNGA matrix and equivalent transfer function approach, and it is shown that the proposed RDNGA based controller gives a better ISE than the existing RNGA based controller design.
Rishika Trivedi, P. K. Padhy, and S. K. Jain
IEEE
In this paper, a method has been proposed for better tuning of the parameters of Fuzzy PID. The work also proposes a modified firefly optimization algorithm for generating the values of the Scaling Factors for the Fuzzy PID. The performance of the proposed configuration is evaluated through extensive simulations. The result reveals that the proposed scheme converges significantly faster and performs better over conventional PID controller and existing Fuzzy PID controllers in terms of several performance indices, such as, overshoot, settling time for the plant and integral square error (ISE).
Rishika Trivedi and P. K. Padhy
IEEE
This paper presents implementation of an optimization method based on Firefly algorithm (FA) for better tuning of the parameters of Fractional PID Controller (FOPID). The values of all the parameters of FOPID are computed using Modified Firefly Algorithm with random initial conditions. Numerical results obtained from simulations illustrate the performance of the proposed configuration. The results of the examples exhibit that the proposed Modified FA converges significantly faster. It outperforms in terms of overshoot, settling time for the plant and integral square error (ISE).