A Soft Tactile Sensor Based on Magnetics and Hybrid Flexible-Rigid Electronics

Round 1

Reviewer 1 Report

Dear Authors,

you present a nice piece of work in the paper. I like the sensor principle and all the data provided. Also the text and English are clear and easily readable.

But... I was missing something like a link that would connect the parts and give the reader some support for decisions made during the development. And the are no "sub-conclusions" after discussing some parts, so the reader knows something but there is no clue how it affects the overall tactile sensor performance (I will be more specific in the following text..)

At first - the tactile sensor uses a magnetic sensors to detect a change of a position of a permanent magnet. At the beginning I would expect some discussion what is the range of the magnetic field you will need to detect, what are the possible sensors (range, sensitivity)? How about the influence of some nearby permanent magnets (they are in many normal things now..) or ferromagnetic objects that will maybe influence the local magnetic field in the tactile sensor volume...?

You present a manufacturing of your own spin valve sensors. There should be more information about the sensor properties instead of presenting its manufacturing - your topic is its application in the tactile sensor. I mean - why there are six elements, Fig 4b- I am not sure what is the orientation of the elements, what is the sensitive axis (add to Fig.4), what are the target parameters (range, resistance..)..

section 2.3 FPC - seems to be quite a normal technology used in the electronic industry.. you could comment why you used the conductive epoxy instead of a "normal" soldering?

section 2.5 - you mention 24-bit ADC - no clue what is needed to see some changes in the magnetic field..  1) changes in the field are like this, sensor sensitivity is this.. Influence of the magnetic field of the Earths is this, so we need this resolution...

(1k 0402 100nF capacitor - delete 1k?)

section 3 - sensor characterization - Fig.8 - what it means dH linear? I guess the H was changed linearly in the whole range +-10mT?

section 3.2 - a lot of information about the chip bonding but no information how important is that to detect some changes in the magnet position - force applied to the tactile sensor? Can you compare this electrical noise with other noise sources (magnetic field in a normal office can vary a lot +-50uT..)  do not write peak-to-peak the way you do..(Probably lower index with capital letters?)

3.3 - different ADC speeds mentioned- what is the desired rate for the tactile sensor of the whole hand, does it make any sense with respect to values - changes you need to measure to detect the force?

3.4 - equation 4 %/uT,  in the text %/mT  .. not sure what are the absolute field values measured...

section 3.5 - Figure 15- some text in a very small font, not readable.. (Figure 16 as well)

one of the innovative features you present is the number of sensors per unit of surface. Do you discuss somewhere if the usage of 8 sensors brings some real advantage (supported by measured data) over using only 6-4-2 of your sensors on the FPC?

section 3.6 - Figure 18 - the final comparison - so the change in magnetic field is in the range of +-100uT - could be disturbed very easily by any a bit magnetic objects handled by the robot?

Author Response

Please see the attachment. Thank you.

Author Response File: Author Response.docx

Reviewer 2 Report

The purpose of this study is to report the design of a magnetic-based tactile sensor to be integrated in the robotic hand of the humanoid robot Vizzy. Besides, the authors also provided the details of its experiments. However, I have some suggestions mentioned as follows.

1. What is your main contribution to this study? The abstract is not clear.
2. I would recommend manuscript reorganization and a better explanation of the Tables and Figures. These descriptions were very hard to read. For this research, I have two main considerations: 
   (1). I suggest that the authors add more previous related research work to prove that their research is state-of-art.
   (2). There is a lack of strong explanations and evidence for the reasons for the design and material selection of this study. But judging from the results, it is very innovative and breakthrough. However, I think the description of design and material selection and planning should go further. The author should explain in more depth. I also hope that more specific pictures or experimental results describing the stability and feasibility of Robot Vizzy after importing.  

Author Response

Please see the attachment. Thank you.

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

I agree and suggest that this version can be published in this journal