Design and Study of a Stair Climbing Robots with Two Wheels and a “4R+2P” Pattern

Round 1

Reviewer 1 Report

General comments

The paper is well written but the prototype used must be fully described (hardware & software) and the ROS modules used or configured must be clearly described. Additionally, the graphical description of the downstairs performances must be improved as it is not convincing.

 

Specific comments

L29: Please add a space before the references. -> mobile robots [1,2],

 

L126: The numbers 0 to 6 are difficult to read and locate, please consider using another color for the font of the numbers.

 

L149 & L155 & L165 please consider the use of an equation instead of text to describe the equations.

 

L426 Please add more information of the wheel. Is there any standard definition or reference for this wheel? Is the 507 mm wheel used in junior mountain bikes?  Maybe a specific photo showing a detail of the tires will help to understand the wheel type used.

 

L446 Please improve the description of the mobile robot. Is it powered using batteries ? type, Ah ?
Please also include a description of the hardware and software of the prototype.

 

L456 Please accurately describe the controllers used in the motors or add a reference of the controllers used.

 

L 473 Please describe the method used to measure the position/posture of the wheels, using encoders ?

 

Figure 19. This is the results and the most interesting part of the paper so please split this image in two (the upper and lower) and maximize the size of the images.

 

Figure 20. This image is unclear, please use another images showing clearly the steps of the sequence.

 

Figure 21 is not convincing, it seems that the position of the robot is the same in all images. Please improve this photo-description.

Author Response

Please refer to the attachment

Author Response File: Author Response.pdf

Reviewer 2 Report

The paper presents the design and mathematical model of the two wheels climbing robots. The paper topic is timely, interesting, and important in the context of the development of autonomous robots capable of negotiating stairs and other obstacles. Very importantly, in addition to the design and mathematical model was developed of a prototype robot tested in real conditions. In my opinion, in addition to the strengths, the article also contains weaknesses that the authors should improve. I present critical (discussion) comments in the following paragraphs.

 

1. The article describes in general terms the various sub-systems of the climbing robot. I suggest, to consider whether the article should not be divided into several parts, e.g:

 

First one: paper describing in detail the design of the robot (mechanical structure, components used such as cameras, sensors, motors etc.).

 

Second one: An article describing in a detailed way the mathematical model together with the verification of this model, in the presented paper there is no measurement verification of results obtained by simulation, e.g. verification of articulated torques. The only information that the mathematical model is correct is provided by photographs showing that the robot can climb stairs.

 

Third one: is a paper describing in detail the control system, control algorithms, their implementation, and how to use the results of the mathematical model in the real control system. Measurement verification of the model, the influence of changing the control system parameters on the climbing, etc.

 

Of course, the article could be expanded to include this detailed information

 

2. Chapter four presents the results of simulation studies for two cases: with and without the Ts parameter. This parameter should be described in more detail, exactly what the parameter is, what values it takes, and only then present the results. In chapter four units should be added to the time curves (especially for the Y-axis).

 

3. Why the height-to-diameter was the coefficient chosen as 0.7, when based on other papers this coefficient is much lower.

 

4. No marking of contact points C and D in Fig. 5.

 

 

Author Response

Please see the attachment. 

Author Response File: Author Response.pdf

Reviewer 3 Report

This paper is about the design, development and testing of a two-wheeled stair climbing robot. The paper is very interesting, well structured, generally well written and there are few points that needs revisions:

·         The main contributions of the paper should be highlighted more.

·         The structure of the paper should be added at the end of the introduction.

·         The D-H modeling introduction (beginning section 3.1) should be valid with fig.3.Since in fig3 the numbering of the frames is Arabic please use the same in the text.

·         It should be highlighted here that the robot is 6 DoF and why those number are needed.

·         In section 3.3.1 the force analysis is better shown in fig.4. Fig 5 seemed to be useless. What is angle \alpha in line 246.

·         L_max and R are closely related in Eq(10) and affect the design of the robot. This should be explained in more detail.

·         Section 3.3.2 is not clear. I don’t understand in eq (12) why the half gravitational force G_2 is used and not the full load. This should be explained in more depth.

Author Response

Please refer to the attachment

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The paper has been improved in this reviewed version.