Command-Filtered Adaptive Prescribed-Time Tracking Control with Application to Output-Constrained Hydraulic Servo Systems

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

In this manuscript, a command filter-based adaptive prescribed-time control method is proposed for hydraulic servo systems subject to time-varying parameters, external disturbances, and output constraints. The effectiveness of the proposed method is validated through simulation results. Although the work is interesting, the following revisions and questions are suggested to be considered and answered:

1. Please highlight the key differences between the proposed method and traditional control approaches. Provide a more rigorous and precise comparison between the proposed approach and existing methods to clearly demonstrate the specific contributions of this work.

2. Regarding the positive bounded functions w_i(t)=(i=1,2) and l_i=(i=2,3), please clarify whether their functional forms are identical. Also, explain the reason for choosing these specific functions. Furthermore, please clarify whether alternative functions could be employed and outline the general rules for their selection.

3. Please explain how to choose the control parameters in the two examples.

4. Please provide more details regarding the trajectory plots shown in Fig. 3.

5. Finally, there are some unclear symbol definitions and missing punctuation. Please carefully polish the overall English writing and organization of the paper.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The manuscript addresses the design of a command-filtered adaptive prescribed-time control strategy for nonlinear hydraulic servo systems with output constraints. The topic is relevant and fits well within the scope of the journal. The integration of prescribed-time control, adaptive mechanisms, and command filtering is potentially interesting and applicable to practical systems. However, the manuscript in its current form suffers from several issues related to clarity, methodological transparency, and validation, which limit its overall quality and reproducibility.

I have the following comments for the authors:

1. The mathematical formulation is not sufficiently clear. Several equations contain unclear notation, formatting issues, and inconsistencies, which make the derivations difficult to follow. All variables and functions should be clearly defined and consistently used throughout the paper.
2. The controller design and stability analysis are presented in a condensed manner, with several intermediate steps omitted. More detailed explanations and derivations (possibly in an appendix) are needed to improve transparency and reproducibility.
3. The novelty of the proposed approach is not clearly justified. The manuscript appears to combine existing techniques (prescribed-time control, command filtering, adaptive control), but the specific original contribution should be highlighted more explicitly.
4. The assumptions (e.g., bounded disturbances, known system structure) are standard but not sufficiently discussed in terms of their practical implications and limitations for real hydraulic systems.
5. The validation is based solely on simulations. The lack of experimental results or of more realistic simulation scenarios (e.g., measurement noise, actuator saturation) weakens the study's practical relevance.
6. The comparison study is limited. Although several controllers are included, most are variants of the proposed method. Comparisons with well-established control strategies (e.g., PID, sliding mode, or MPC) would strengthen the evaluation.
7. The controller includes many tuning parameters, but no systematic tuning procedure or sensitivity analysis is provided. This makes practical implementation difficult.
8. The overall presentation quality needs improvement. The manuscript contains typographical errors, unclear sentences, and formatting issues that should be carefully revised.
9. The reference list is incomplete in terms of citation metadata. In particular, most references do not include DOI identifiers. The authors are strongly encouraged to revise the reference list and provide DOIs for all cited journal articles where available, in accordance with MDPI formatting guidelines.

The manuscript can be accepted after revision, provided that the authors adequately address the above comments and improve the clarity and rigor of the presentation. I wish the authors success in revising their work.

Comments on the Quality of English Language

The English language quality is generally understandable; however, it should be improved to enhance clarity and readability. Several sentences are grammatically incorrect or awkwardly formulated, and some technical descriptions are not clearly expressed. A careful revision of the language by a fluent English speaker is recommended. It is also recommended that authors try out the Grammarly tool.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

I thank the authors for addressing all my comments and improving the quality of the paper. I have no further comments for the authors. I suggest that the revised manuscript be accepted for publication.