A Review of Foot–Terrain Interaction Mechanics for Heavy-Duty Legged Robots

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The authors propose a comprehensive review of heavy-duty legged robots, with particular attention to foot-ground interaction. The paper is of interest to the journal, however there are some points that need further clarification to improve the quality of the work.

The authors considered two different classes: light-duty and heavy-duty legged robots. A more precise definition to distinguish the two classes should be provided (weigh range, size, payload, structural characteristics, …). In Table 1, it is easy to assign the TITAN IX to the class of heavy-duty robots. However, it is not so easy to understand why robots like SILO 4 and SDU Hex are listed and others like Spot, ANYmal, Unitree B2 are not even mentioned.

The review must refer to previous reviews on this topic or similar ones to underline the novelties of the proposed paper.

Even though the authors have provided a useful nomenclature table, the symbols used in the equations should be defined the first time they are introduced. For example, in Equation 1, where sigma and tau are not defined, and similarly for the other equations.

Equation 4 is a copy of equation 1, please either refer to equation 1 or justify this new equation. Also, keep the style of the paper: there is an explicit dependence on time in equation 4, which is omitted in the other equations.

Further discussion of terrain classification and traversability should be reported. Discussions related to learning risk-mediated traversability maps in unstructured terrains navigation through robot-oriented models and Echo State Networks for estimating exteroceptive conditions from proprioceptive states in quadruped robots could also be included.

Furthermore, the importance of reliable control strategies should also be mentioned. Special attention could be provided to new embodied Motor-Neuron architectures that allow to integrate the control layer and the motor layer to improve the adaptability of the robotic system while reducing the computational complexity of the control system.

Throughout the manuscript, there are a number of hyphens within words (e.g., com-plex in line 380, ap-plied in line 390, etc.). Please correct these when reviewing the entire paper.

Comments on the Quality of English Language

The paper still needs to be slightly revised as suggested.

Author Response

Please refer to the attachment.

 

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

It is a fairly complete review of heavy-duty-legged robots, but it is suggested to improve some issues.

Comments for author File: Comments.pdf

Author Response

Please refer to the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Comments for author File: Comments.pdf

Author Response

Please refer to the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The paper has been properly revised following the reviewer's suggestions.