Damping of Oscillations of a Rotary Pendulum System

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The paper deals with a problem of examining underdamped dynamics of the model of rotary pendulum systems as well the effect of nonlinearities on the spectrum of the final signal. Therefore, the traditional shaping techniques based on linear theory was replaced and the innovative application of nonlinear shaper occurs to be more efficient.

The paper is written in eight parts. Traditionally, it starts with Introduction where the needs of controlling flexible structures are explained. It also shows a review of several related works within the discussed topic. In my opinion this review is too short and more references could be provided.

Next part is dedicated to input shaping with time delays. This is a good part showing the theoretical background to the problem. It also shows the shaper constraints where a discussion is provided and input shaping of multiple vibration modes which was just briefly introduced.

Next, problem formulation and system description was done. It was shown in block diagram version as well all the required equations were provided. Next, shaper design was discussed separately. I think, it can be simply another subpart to the previous chapter as this part also shows a structure of shaper and discussion over it.

Next part showed the verification of the method. Again, it was done in subparts. First, simulation verification was done – in my opinion very briefly. Apart from the graphical presentation it should be discussed with details. In my opinion it should be done more precisely. Next, real-system verification was provided. In this case it is much clearer for me.

Another chapter is dedicated to the results. As it was in case of simulation verification – this very important part of the paper is simply too short. Although, it contains the important information it requires more analysis and description. The same situation with Discussion chapter which could be simply joint with the “Results” part.

The final part showed the conclusions.

The paper is interesting. The proposed approach is also a good idea. However, more references should be used in “Introduction” part and more information should be provided in “Verification of the method”, “Results” and “Discussion” parts. Also, the construction of the whole paper can be changed as I wrote above.

Final verdict – major revision.

Author Response

Hello,

• 1. It is possible to supplement the literature in the introduction with an adaptive method (in general) https://www.researchgate.net/profile/Yiannis-Stergiopoulos/publication/4156044_Adaptive_Input_Shaping_for_Nonlinear_Systems_A_Case_Study/links/54f0d0da0cf2b36214aae5d2/Adaptive-Input-Shaping-for-Nonlinear-Systems-A-Case-Study.pdf
  2. It is also possible to supplement the introduction with heuristic methods (in general)
  3. Adaptive approaches can also be used for several vibration modes https://www.sciencedirect.com/science/article/pii/S0005109803003832
  4. Another possible solution to the problem of multiple vibration modes is a solution based on the Zero-placement nominal mode technique, which means that all modes are placed in the allowed range (two EI shapers) https://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=524629
• We do not find it appropriate to edit the chapters
• 1. It is also in our interest to state that that we are considering a rope that is solid, inelastic, inelastic and not subject to any twisting, friction or other non-ideal properties.
  2. We will also state that the dynamics of the motor can affect the dynamic properties, but if the dynamics of the motor (response) is faster than the dynamics of the load, there is no significant influence on the position of zeros in the transfer function of the system. Then the motor should be able to effectively control the load without significantly changing the dynamic characteristics of the overall system. Its contribution to the overall system response can only be in the rounding of the waveforms, which means that the response is smoother and thus the motor is unlikely to be a limiting factor in controlling the system's response. If the bandwidth of the motor servo is much higher than the natural frequency of the load, it means that the motor responds quickly to changes in the control signal, which will ensure fast and accurate control of the load.
• 1. the contribution will be supplemented by further experiments, while in the first case we consider the original weight of the load, in the second case five times the weight compared to the first case and the third experiment is carried out with a load 10 times compared to the original case
  2. As for the discussion, it could be developed by emphasizing the limitation of this specific approach and the proposed shaping methods. While the article emphasizes the importance of nonlinear effects in shaping, the discussion could go into more detail about the importance and impact of these nonlinearities on real-world applications. The influence of the physical properties of the system could also be discussed.
  3. It is possible to add additional photos that present the components used in more detail

 

 

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Comments for author File: Comments.pdf

Comments on the Quality of English Language

Author Response

Hello,

• In the article, the real model can be described in more detail.
• the contribution will be supplemented by further experiments, while in the first case we consider the original weight of the load, in the second case five times the weight compared to the first case and the third experiment is carried out with a load 10 times compared to the original case
• Future link to videos URL

 

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

I accept the Authors attitude and remarks. Therefore, the paper can be published.

Author Response

Thank you, videos from the phone have been added to the publication, and photos of the real system have been expanded with a text description

Reviewer 2 Report

Comments and Suggestions for Authors

Comments for author File: Comments.pdf

Comments on the Quality of English Language

Author Response

Videos from the phone will be added to the publication (g-drive) on Tuesday around lunchtime, and the photos of the real system have been expanded with a text description.