Effect of Mass-Center Position of Spinal Segment on Dynamic Performances of Quadruped Bounding with a Flexible-Articulated Spine

Round 1

Reviewer 1 Report

The paper is devoted to studying how the position of the center of mass (CoM) affects the dynamic performance of a 4-legged planar galloping robot with a flexible spine.

The paper starts with a detailed literature review. Particularly it is underlined that flexible spine motion can increase the performance of a robot, especially better horizontal velocity and energy efficiency.

According to the author, most of the researches assume that the centers of mass of spinal segments are constant. The author decided to study how the position of CoM changing affects dynamic performance. The main idea seems reasonable. In terms of the design of a robot, this information will be helpful to be aware were on-board equipment is supposed to be located: actuators, batteries, CPU, cargo, and others. 

It is proven that stride period and stride length are higher for CoM located in the hip joint and in terms of that characteristic it is the best configuration. It looks like the author has found that the common SLIP model is the best option. However, it was proven that the duty factor and motion stability is better for the configuration, when CoM is located near centers of spinal segments.

The author has carried out a comprehensive study, but the main discussion makes me feel like all in vain. I recommend rewriting it. I suppose there is a better position for CoM and it is the position between a joint and the middle of a spinal segment.

Also, I think it will be interesting if the author makes some comparisons of his results and designs of existing galloping robots, for example, MIT Cheetah (1st generation) and Cheetah robot from University of Twente.

Minor questions:

What do you think about the robot’s ability to change the position of CoM actively? Are there any benefits? I recommend fixing images: use different colors for the robot parts and the signs and letters. The spine is passive: “…no inputs and controls are added”. How do you control it? How does the robot move?

Some typos and grammar mistakes: “But the results shows…”, “…quadruped model in his study is with…”, “…in sagittal plane as Figure…”, “ground is no slip”, “The anterior and posterior spinal segment…”, “configured by pitch angle”. Also, a lot of articles are missed. Use “:” instead of “-” in the following sentence “… of two equal rigid segments – the anterior …”. “The first” instead of “First” and so on. I recommend reading the text carefully with a native English speaker.

Author Response

Please see the attachment.

Author Response File: Author Response.doc

Reviewer 2 Report

In this paper, author investigated effect of MCPSS on dynamic motion of quadruped robot.

I agree that this study helps to design of quadruped robot.

 

1, Quadruped robot was modeled as sagittal-plane model. However, motion in a lateral direction (swing and tilt) may also be important.

 

2, MCPSS is arranged symmetrically around the spine joint. I think it is useful to investigate effect of MCPSS arranged in asymmetry.

 

3, Adequacy of result can not be evaluated because experiment was not conducted.

 

4, Bounding motion of robot in result section should be shown diagrammatically for intuitive understanding.

Author Response

Please see the attachment.

Author Response File: Author Response.doc