Trajectory Tracking and Adaptive Fuzzy Vibration Control of Multilink Space Manipulators with Experimental Validation
Round 1
Reviewer 1 Report
The proposed manuscript titled Trajectory tracking and adaptive fuzzy vibration control of multi-link space manipulator with experimental validation dealt with the problem of modeling and controlling of a space manipulator system with flexible joints and links.
The authors carried out some numerical simulation and experiment to verify the effectiveness of the proposed compound controller, and a comparison with proportional-derivative (PD) controller is given to highlight its superiority in suppressing residual vibration of the tip.
The concluding remarks were supported by the data.
The paper is relevant and interesting and Schematic of adaptive fuzzy controller was done with no errors.
Experimental results ere done with merit.
A relevant point is the Experimental results show that the proposed control strategy may rapidly realize trajectory tracking and effectively suppress the flexible vibration
It seems to be original , according to other results from current literature, The sate of the art may be done with a number of International authors.
It deserves publication after revisions:
The Numerical simulations must show the efficiency of the control methods, as well as the sensitivity of each control strategy to parametric errors.
Author Response
Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The topic of the paper is interesting. The authors can find below some questions and comments:
1) line 53: typo, correct Ricatti in Riccati
2) the introduction can be improved analyzing better the literature (important authors working on flexible arms are missing, e.g., De Luca, Malzhan, etc)
3) passage from eq 17 to eqs 37-39 is not clear. Could you please expand it? In particular, it is not clear to me how tau_s is related to the motor torques.. and what are tau and tau’ which have not been introduced
4) from eq 51, it seems that the output joint position is used for the control. Is it right? Or do you use the motor position? Also when you compared your control strategy with a simple PD, is the PD closed on the motor or output position? Clearly the performance and stability are different in the two cases. Please clarify.
5) how is the link end displacement computed? Integration of accelerometer? Do you experience any drift and could it be a problem? In general, clarify better what are the sensors and actuators you are using and how you derive all the quantities used in the control laws.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 3 Report
The comments can be found in the uploaded file.
Comments for author File: Comments.pdf
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
In this proposed manuscript the authors dealt with a dynamic mathematical model of flexible space manipulator.
To choose a suitable mode, the natural characteristics of the link under three different boundary conditions are compared with each other, and the dynamic response results of the simulation showed the existence of internal resonance in the considered system.
Then,a computed torque controller was post to track the angle of joints.
So, a model of t adaptive fuzzy controller was proposed to suppress the elastic vibration of the considered sysem.
The simulations carried out of two cases were performed on a two-link flexible manipulator system, and the obtained results showed that the proposed control strategy had a good performance in rapidly tracking trajectory and effectively suppressing the flexible vibration.
Experiments were also performed to verify the proposed control strategy and simulation results obtained.
According to the obtained results with Un-control, the RMS of the vibration response with AFC attenuated by 78.3ï¼… and 81.3ï¼… 564 in the two cases, respectively.
In addition, the authors improved the accuracy of the mathematic model of the space manipulator system, the damping of the joint and link can be future be considered in the modeling, and the effect of the internal resonance phenomenon on the stability of control system can be future studied in detail.
In summary, the paper is well written with no mistakes.
The problem proposed by the authors was analyzed with relevant results .
The paper posed figures with quality and pertinent discussions
I recommend publication as is
Reviewer 3 Report
The comments have been well addressed.
