A Novel Discrete Wire-Driven Continuum Robot Arm with Passive Sliding Disc: Design, Kinematics and Passive Tension Control

Round 1

Reviewer 1 Report

the authors have presented the design, kinematic modeling and control of a discrete continuum robotic arm with a passive pretension mechanism. the latter has the objective to avoid the problem of losing tension inside the cables, especially when the arm is in bending configuration. 

Some suggestions:

* In my opinion, the class of soft continuum robot arms should also include the mechanisms whose central backbone is constituted by rods of elastic material. 

* related work: many recent papers on kinematic modeling of continuum robots are missing: the authors should include recent works  

* the authors are encouraged to explain the basic motivations which have led to the use of a continuum-like robot as a tool for a farming CNC platform (why continuum robots in agriculture tasks?)  

* the authors should better explain the input commands used in the performed experiments, and in which terms the used input trajectories are appropriate to validate the design (in particular for the passive pretension mechanism)

* many typos along the manuscript

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

This is an interesting paper, but other than the novel backbone design, there is nothing new to the manipulator design. That said, the major point of concern is that the backbone for each segment is only 10 mm. This severely limits the extensibility of the sections, but not only that, its curvature - these limitations are seen in the accompanying video. The authors provide one possible application as the harvesting of fruit, which they hope to try in the future. However the authors do not incorporate any external forces in the kinetics modeling. How will the robot behave when dealing with a fruit of significant weight? How does the robot behave/react when external are applied on it? This information needs to be provided in order to determine the feasibility of the application. As for the kinematic modeling, that has been covered by Walker et al and numerous other published works, and the authors provide nothing substantially new in that regard. Finally, the authors developed the system using Arduino - there appears to be no feedback. How did the authors verify that the manipulator shape was exactly as intended? Do the authors intend to incorporate feedback - and how would that be done. The authors will do well the clean up the paper in terms of the English grammar (this reviewer recognizes that English is not the authors' primary language and would recommend using an editorial service to help). Along with that, this reviewer would recommend the use of tables to provide information on the manipulator specifications, extension lengths, curvature etc. while also answering the questions/issues this reviewer has provided. Until that time, this reviewer recommends major revisions for this paper before being reconsidered for publication.

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

This paper presents the design and analysis of discrete robotic manipulator. I found the design of the robot to be interesting in that it included some features intended to improve control of such devices, which is often a problem for this type of manipulator.

In the literature review section, the authors presented a good overview of the literature on continuum devices. Though there were some examples missing and I didn't see any discussion of the fluid powered class of devices.

The kinematics section was dense. I think this section could be improved by providing some explanation for the various pieces of the kinematic model and perhaps streamlining some of the mathematical notation. Some of the derivation could perhaps be contained in an appendix or supplementary file instead.

I have included a copy of the manuscript with some additional suggested edits.

Comments for author File: Comments.pdf

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

the authors have answered the requests.