Frequency Criterion for the Existence of Sliding Processes in Control Systems with an Arbitrary Variable Structure

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

1. Quality of figure 2, figure 9, figure 10 are very low, author must improve.

2. the notation in figure 9, figure 10, equations 4-9 are not explained.

3. What is the power system for LFC in figure 2?

4. What kind of power system for LFC in Figure 6?

5. What conditions for the stability and reachability of  the power system for LFC in Figure 6?

6.  In figure 8, 12, 13, 14, and 15, the real signals are not the same with reference signals, how to improve its?

7. What is the phase margin and gain margin of the system in simulations?

8. In simulation, author must compare with other papers to emphasize new contributions 

9. Is your method can apply for the LFC of multi area power system such as paper (Tran, A.-T.; Minh, B.L.N.; Huynh, V.V.; Tran, P.T.; Amaefule, E.N.; Phan, V.-D.; Nguyen, T.M. Load Frequency Regulator in Interconnected Power System Using Second-Order Sliding Mode Control Combined with State Estimator. Energies 2021, 14, 863. https://doi.org/10.3390/en14040863)

10. the reference list is very old paper, please adding more new papers.

 

Comments on the Quality of English Language

Minor editing of English language required

Author Response

Please see the attachment

Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors The manuscript presents a frequency criterion for identifying the existence of sliding modes in control systems of variable structure, diverging from the conventional analysis techniques of phase trajectories and state space equations. This method, supported by modeling evidence, proposes to facilitate the application of sliding mode control in electromechanical systems, particularly electric drives, by establishing conditions for absolute stability and ideal sliding through frequency characteristics. However, the manuscript's presentation lacks the meticulousness and precision expected in mathematical discourse for a scholarly journal, with a notable deficiency in addressing the impact of saturation and non-linear functions in the frequency domain analysis. Additionally, the discussion could significantly benefit from incorporating a wider range of real-world examples to substantiate the practicality of the proposed criterion, thereby bridging the gap between theoretical analysis and practical implementation. The absence of such examples, coupled with the paper's somewhat casual and imprecise writing style, detracts from the work's credibility and utility in a field where the topic, despite being well-established, demands rigorous and clear exposition.The paper presents a frequency criterion for identifying the existence of sliding modes in control systems of variable structure, diverging from the conventional analysis techniques of phase trajectories and state space equations. This method, supported by modeling evidence, proposes to facilitate the application of sliding mode control in electromechanical systems, particularly electric drives, by establishing conditions for absolute stability and ideal sliding through frequency characteristics. However, the manuscript's presentation lacks the meticulousness and precision expected in mathematical discourse for a scholarly journal, with a notable deficiency in addressing the impact of saturation and non-linear functions in the frequency domain analysis. Additionally, the discussion could significantly benefit from incorporating a wider range of real-world examples to substantiate the practicality of the proposed criterion, thereby bridging the gap between theoretical analysis and practical implementation. The absence of such examples, coupled with the paper's somewhat casual and imprecise writing style, detracts from the work's credibility and utility in a field where the topic, despite being well-established, demands rigorous and clear exposition. Comments on the Quality of English Language The manuscript presents a frequency criterion for identifying the existence of sliding modes in control systems of variable structure, diverging from the conventional analysis techniques of phase trajectories and state space equations. This method, supported by modeling evidence, proposes to facilitate the application of sliding mode control in electromechanical systems, particularly electric drives, by establishing conditions for absolute stability and ideal sliding through frequency characteristics. However, the manuscript's presentation lacks the meticulousness and precision expected in mathematical discourse for a scholarly journal, with a notable deficiency in addressing the impact of saturation and non-linear functions in the frequency domain analysis. Additionally, the discussion could significantly benefit from incorporating a wider range of real-world examples to substantiate the practicality of the proposed criterion, thereby bridging the gap between theoretical analysis and practical implementation. The absence of such examples, coupled with the paper's somewhat casual and imprecise writing style, detracts from the work's credibility and utility in a field where the topic, despite being well-established, demands rigorous and clear exposition.The paper presents a frequency criterion for identifying the existence of sliding modes in control systems of variable structure, diverging from the conventional analysis techniques of phase trajectories and state space equations. This method, supported by modeling evidence, proposes to facilitate the application of sliding mode control in electromechanical systems, particularly electric drives, by establishing conditions for absolute stability and ideal sliding through frequency characteristics. However, the manuscript's presentation lacks the meticulousness and precision expected in mathematical discourse for a scholarly journal, with a notable deficiency in addressing the impact of saturation and non-linear functions in the frequency domain analysis. Additionally, the discussion could significantly benefit from incorporating a wider range of real-world examples to substantiate the practicality of the proposed criterion, thereby bridging the gap between theoretical analysis and practical implementation. The absence of such examples, coupled with the paper's somewhat casual and imprecise writing style, detracts from the work's credibility and utility in a field where the topic, despite being well-established, demands rigorous and clear exposition.

Author Response

Please see the attachment

Author Response File: Author Response.docx

Reviewer 3 Report

Comments and Suggestions for Authors

The contribution of this paper is good at designing a criterion for the existence of sliding processes according to the frequency characteristics of a practical control system. Compared to the conventional method of phase trajectories and state space equations, the proposed strategy is a simple proposal to formulate several applicable engineering provisions with a high-order object. However, there are some suggestions about this paper. Please address the following concerns.

(1) Please provide more detailed discussions for Fig. 12 to Fig. 20 because only simulation waveforms are insufficient.

(2) Please provide a summary table to compare the simulation results, which is easy to understand for readers. 

Author Response

Please see the attachment

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The paper is revised follwing the comments. this is good for publication 

Reviewer 3 Report

Comments and Suggestions for Authors

Thanks for the authors' effort in answering the questions.