Simulation Method for Hydraulic Tensioning Systems in Tracked Vehicles Using Simulink–AMESim–RecurDyn
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsGeneral Comments
The simulation of complex mechanical systems using software tools such as Simulink, AMESim, and RecurDyn has gained traction due to their respective strengths in various simulation domains. These tools provide complementary functionalities, enabling effective modelling and co-simulation that enhance the performance analysis of mechanical systems. The authors chose AMESim, which offers high-fidelity hydraulic transient modelling and robust libraries for hydraulic nonlinear modelling. Simulink is well-suited for designing control systems and offers real-time simulation capabilities. Supports various dynamic systems modelling, including linear, nonlinear, discrete, continuous, and hybrid systems. RecurDyn is renowned for its multibody dynamics (MBD) simulation capabilities, making it a preferred choice for modelling complex mechanical interactions involving multiple linked systems. Moreover, RecurDyn allows for seamless co-simulation with Simulink, which can manage controller designs for such dynamic systems.
From this point of view, the manuscript is well-suited to the author's main objective, as presented in the abstract section. There are several cross-domain comparables, where Table 1 summarises the pros and cons of each tool. Therefore the selection is well-done.
Finally, an experimental section demonstrates the strong coupling between simulation results and real-world applications.
There several works where this integration allows Simulink to benefit from AMESim’s capabilities while utilising its own strengths in control system design.
In conclusion, the combined use of Simulink, AMESim, and RecurDyn for simulating complex mechanical systems leverages the unique strengths of each tool. Through effective co-simulation, engineers can conduct detailed analyses that provide insights into the dynamic behaviour of multifaceted systems, leading to informed design decisions and improved performance across various engineering domains.
Major Comments
There are other tools with extensive experience in multibody dynamics (MBD) simulation, such as MSC ADAMS. What reasons have been applied to decide the use of RecurDyn in front of MSC ADAMS?
Line 115: Seems that a missing equation was forgotten. The paragraph talks about the orifice equation. Review the paragraph.
The following paragraph from lines 116 to 119 is also not clear. They talk about pressure p7 and p10, but there is no supporting scheme.
A circuit scheme is needed to understand the chambers in the hydraulic circuit of the steering system.
In line 144, the authors discuss the track chain as an equivalent Euler-Bernoulli beam. A reference should be made to inform the readers who are not informed.
How can this model be applied to a linked chain? Especially where in line 147 says I is the moment of inertia of the cross-section. We are talking about a rigid bar.
Paragraphs from line 198 to 204 are complicated to follow. What does “ … structural deficiency in the system …” or “... the disruption affects the continuity of the pressure–flow–force–displacement power transmission chain” mean? Please rewrite it.
In line 236, give a reference to the Facet–Facet contact algorithm.
Why is DP-A consistently overestimated in different tests?
There is no information about the computational cost of calculating the different cases. As well as missing information about the platform needed to use this model's integration.
Minor Comments
- Line 110, 111: there are extra characters addressed to LaTex that must be removed.
- Table 1 should use some symbols in each box in order to identify green cells (line 293) when the article is printed in B/W.
- The same improvement should be made on the Figures to identify the different curves. The use of symbols is mandatory.
Author Response
Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for Authors1. The authors' names are followed by numbers; they should be superscripted.
2. The review is relatively well-written. However, I have reservations about its sources – most of the works cited by the authors were developed in one part of the world. Please expand the review to include the rest of the world.
3. The references to the literature in the text are inconsistent with MDPI requirements.
4. Line 104 should begin with "abstrakt." This entire paragraph is too wide relative to the rest of the text.
5. The font in Figure 2 is too large. It should be similar in size to the text in the article.
6. In line 127, A(u) should be italicized. I've noticed similar errors elsewhere.
7. The font in the graphs depicting the results (Chapter 3) is too small, making analysis difficult.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsSummary:
The study proposes a novel tri-platform strongly coupled co-simulation framework that unifies hydraulic, mechanical, and control domains for electro-hydraulic tensioning in tracked vehicles. Through energy-consistent modeling, unified time-step synchronization, and NMPC-based control, the framework achieves high-fidelity, experimentally validated dynamic accuracy across diverse operating conditions. It significantly outperforms conventional dual-platform methods in tracking precision, robustness, and energy efficiency. The authors position the method as a new theoretical and practical paradigm for multi-domain modeling of complex electro-hydraulic systems.
Major comments:
- The paper relies on RecurDyn as a multibody “black-box” module, yet no governing equations of the vehicle or the track roller terrain system are provided. Including at least a summarized model description such as the number of degrees of freedom, kinematic constraints, contact formulation, and key assumptions would greatly improve clarity and reproducibility. Alternatively, the authors could supply explicit references to sources where their vehicle model was previously developed, including the DOF structure, governing equations, modeling assumptions and simplifications, and any comparative validation results demonstrating the dynamic fidelity of the vehicle model.
- The manuscript does not clearly state the modeling assumptions adopted for the hydraulic, mechanical, and control domains. Assumptions related to fluid compressibility, leakage modeling, terrain stiffness, contact damping, and friction laws should be explicitly listed. Without a clear set of assumptions, it is difficult to assess model fidelity and generalization.
- The text highlights the importance of preserving ∂F/∂p and ∂v/∂Q, but the paper does not show how these derivatives are computed in the tri-platform setting. A short explanation or illustrative example would help readers understand why these terms improve dynamic consistency.
- Figure 3 is central to the proposed methodology, yet the data-exchange pathways, variable types (e.g., p-Q and F-v pairs), and the interface logic between the three platforms are not described in sufficient detail. A clearer schematic or an expanded explanation of the coupling mechanism would significantly strengthen the contribution. In addition, the labels “zong3”, “den1”, and “den2” are not explained, and their meaning within the hydraulic/control architecture is unclear. Several text elements in the figure are also difficult to read, and improved legibility is recommended.
- The NMPC formulation is presented largely at a conceptual level, and although several key design parameters are listed (prediction horizon, control horizon, weighting matrices, and constraints), the rationale for selecting these values is not discussed. Providing an explanation of the tuning process and indicating whether alternative configurations were evaluated would significantly enhance transparency. Such details are essential for assessing controller robustness, performance sensitivity, and overall reproducibility.
- Hydraulic–mechanical systems are strongly affected by parameter uncertainties (bulk modulus, track stiffness, friction coefficient). A brief sensitivity analysis or at least a discussion of expected sensitivities would improve the completeness of the study.
- The role of the EKF/UKF within the proposed control architecture is only briefly introduced, and key details of the estimation framework are missing. The manuscript should clearly specify the measurement model, the selection of observed states, and the assumed noise characteristics. In particular, the authors do not report the process and measurement noise levels, covariance matrices, or any indication of filtering performance. Providing this information is essential to assess the robustness of the state estimator and to understand how the EKF/UKF contributes to the overall NMPC stability and accuracy.
- While NMPC is clearly advantageous, the manuscript does not provide comparison with simpler controllers such as PID or linear MPC. Including a baseline comparison would illustrate how much improvement the tri-platform NMPC provides relative to conventional approaches.
- Tri-platform co-simulation is computationally intensive, yet the paper provides no information on simulation time, solver settings, or scalability. Reporting average step computation time, hardware used, or profiling results would help assess the method’s practicality for real-time or hardware-in-the-loop application.
- The experimental validation on the LF1352 vehicle lacks information about sensor placement, sampling rate, calibration procedures, and load conditions. Providing this detail would strengthen the credibility of the comparison between simulation and experiment.
- The study focuses on a specific tracked vehicle and tensioning system. It would be beneficial to discuss to what extent the proposed framework is generalizable to other vehicle types, hydraulic systems, or different track geometries. Clarifying whether the methodology is platform-independent would broaden the impact of the work.
Minor Comments:
- Terms such as “tri-platform”, “three-platform”, and “strong coupling” should be standardized throughout the text.
- Several figures (e.g., Figures 3-6) contain small labels. Increasing resolution and font size would improve clarity.
- The naming appears to come directly from the AMESim model. Renaming these to meaningful engineering terms (e.g., V_main, V_L, V_R) would improve clarity, e.g. valve labels zong3, dan1, dan2.
- Ensure consistent SI units (e.g., kN, MPa, mm) and consistent usage of parentheses on figure axes.
- A light proofreading pass would help remove long sentences and improve readability.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 3 Report
Comments and Suggestions for AuthorsThank you for your thorough work on the major revision. The improvements are clearly visible and approved.
