Dan MaloneyThe encoder costs around 150 Euro including the scale.....
Affordable to some - not so affordable to others.
(See y'all -- I'll have to read the rest in the transcripts)
yeah.....more flexiblity for research institutes....
how large a max displacement can those measure?
Which series encoder did you use? The accuracy seems to be "+/- 1um"
... oh per meter?
The encoder has two different types of scale: glass, metal tape. The metal tape can go meters
150euro, that's quite a bit less than I expected. That's definitely doable! Especially since a comparable piezo stage from Newport or Thor or whatever is like 2-5k USD
We are using interferometry in the way that both @Edwin Hwu and @Jakob Wulfkind suggest. @Edwin Hwu - tell us a little about your global view for how to accomplish the nanopositioning. I have done scanning tunneling and atomic force microscopy for a long time. In those systems, you have a stepper motor to get the coarse motion and a piezoelectric motor to get the fine motion. How are you doing this?
Let me check the model...because I use them 6 years ago...things chaged
I built UHV STM, AFM and nano TXM before....I use my home made positioner for approaching and scanning
I seem to be unable to download a full text version of the u-LBIC conference contribution :/
@Edwin Hwu I guess for the long travel range you demonstrated, encoders are the right choice. I thought about something with 0.5mm travel and 200nm repeatability or so... Do you have any experience with Hall sensors? Not sure if the resolution is high enough... But they are likely super cheap.
https://www.instructables.com/A-Low-Cost-Atomic-Force-Microscope-%E4%BD%8E%E6%88%90%E6%9C%AC%E5%8E%9F%E5%AD%90%E5%8A%9B%E9%A1%AF%E5%BE%AE%E9%8F%A1/ one of my hobby work
Out of curiosity how are those metal tapes encoded?
I am not so familiar with the magnetic one...but my student told me that they are robust
Those metal tapes has microscale marks....so be careful not to touch them
What is the best way to get in get in touch with you to collaborate on closed loop positioning?
This is the one I am using
1.2 nm
I am amazed at the positioning speed in your videos, were those using your open source controller?
@placethesundontshine you can contact me by email: etehw@dtu.dk
or my gmail: whoand@gmail.com
I also have some colleagues in DTU like to build one
I really like to open source closed loop system, because it is more valuable and useful
Have you done any force measurements on these? I assume they are pretty low force output before the magnet starts to slip?
also, any plans for a goniometer or tip/tilt device? :)
@polyfractal you are right, but if we use different mechanism for heavy weight
I built tip till also...let me find photo
Have you explored the possibility of using photoelectric effect to fine-tune a piezo actuator's extension?
very cool! Looks like the tweezers are piezo-actuated with a flexure too. neat! is the tip/tilt mechanism flexure based as well?
photoelectric effect? not yet touched ;P
(unless that "tweezer" is an afm cantilever or something?)
So are hard drive head positioners essentially "out of the box" nanopositioners? Or do they need some fine tuning?
This 7 axes system was my fun work haha!
😄
Yes, all flexture based rol/tip/til by 3 linear actuator
OIW, are the tracks nanoscale apart on a disk platter?
yes they are
really fantastic work, hope you publish something about that 7ax system (or a blogpost or something 🙂)
@Dan Maloney you are right! the hard drive arm is super precise!
Thanks! My bad habit was not to do proper testing then moved to next one...so the 7 axes system is not publishable...
Let me find the 7 axes sysetm video
♥ thanks!
I think hdd arms also have the superpower of higher bandwidth than a lot of "nano" scale actuators, no?
Play Video
oh! that's very clever
Would you be interested in open sourcing those 7 axis for others to chip at?
I dig those flexures!
I found this interesting: https://documents.westerndigital.com/content/dam/doc-library/en_us/assets/public/western-digital/collateral/tech-brief/tech-brief-hgst-micro-actuator.pdf
ah yep that is somewhat reminiscent of a hard drive head flexure
@Edwin Hwu - It looks like you might have been part of the LEGO2NANO contest many years ago? Am I correct? I had a student start working toward that, but he veered off and focused on developing a metal 3D printer instead. That was a fascinating contest. Part of the focus of the maker education textbook that I am writing is how most of my work evolved out of trying to build and/or repair nanotechnology equipment. It looks like you have a very similar background.
@placethesundontshine for sure! I hope you guys can help me to test the performance and publish in HardwareX
How do you make the flextures? Wire EDM?
What did you use the 7 axis stage for out of interest? very cool!
Exactly, LEGO2NANO....I developed atomic force microscope (normally 100k USD) that can be assembled by school kids and get nano resolution imaging
@John exactly! I love EDM ;3
7 axis stage was for graphene deposition and manuplation....
Time for a DIY EDM Hack Chat, methinks...
Play Video
The rotating screw will be very usefull in optics...
how is it working?
I wonder what will happen to motor prices when the first NewScale Squiggle patent expires
(I guess similarly to the picomotor stuff, but I cant imagine)
The rotary one is using two pzt and contact ped to drive the screw in opposite direction...
Actually that's different from picomotor ;p
Does the use of the screw mean it also has high driving force and is it locked when powered off?
ok
@Merijn Otterman exactly! this rotary piezo motor can drive 5 kg load vertically
Are there any low cost commercial controllers you recommend? I'm excited to try to machine one of the axis in my garage!
haha....the commercial controller I like is from AttoCube, but cost 15k USD
You can use Arduino plus DAC board plus piezoDrive HV amplifier
lol, low cost is relative
https://www.adafruit.com/product/935
ADAFRUIT
ADAFRUIT INDUSTRIES
MCP4725 Breakout Board - 12-Bit DAC with I2C Interface
Adafruit Industries, Unique & fun DIY electronics and kits MCP4725 Breakout Board - 12-Bit DAC with I2C Interface [STEMMA QT / qwiic] : ID 935 - Your microcontroller probably has an ADC (analog -> digital converter) but does it have a DAC (digital -> analog converter)??? Now it can!
https://www.piezodrive.com/modules/pdu100-micro-piezo-driver/
PDu100 Micro Piezo Driver | PiezoDrive
The system block diagram is illustrated in Figure 2. A boost converter generates a high-voltage rail to supply a pair of complementary amplifiers. A single output can be used to drive a unipolar load up to +100 V or both amplifiers can be used to produce +/-100 V.
The nanopositioning system I have is a cobbling of a lot of used equipment I bought off of EBay: a Zygo laser and controller; a ThorLabs x-y-z stage, stepper motor controllers to attach to the ThorLabs stage connected to a set of potentiometers (Newport hardware, but easily converted to generic), Newport NewFocus claw grips and piezoelectric Picomotors for the piezoelectric fine motor control. For really large scale work, instead of using the ThorLabs stage, I used the following: Parker/Daedal ViX250IH Electromechanical Positioning Systems Intelligent Digital Servo Drives.
I think the Arduino and boards combination can get you nice control within 200 USD
is the rotary unit published? and is backlash not a problem the thread?
@Prof. Jim Brenner super cool! :D
200USD per axis?
@placethesundontshine not yet... :(
i assume any inertial piezo motor controller would work, right? As long as the pzt voltage aligns with the controller and emits the right waveform? The Thorlabs k-cube inertial controllers are like $800... not cheap, but not 15k :)
200 USD 3 axes....the PiezoDrive board costs 1XX USD, DAC 18 USD, Arduino XXUSD
I actually like yours a lot better @Edwin Hwu. It is far cheaper. At the time that I started this, I was good at making, but not a motor control expert. This project was my introduction to the field. The Picomotors are quite nice hardware, but https://www.piezodrive.com/modules/pdu100-micro-piezo-driver/ is a much better approach. At the time, I had no plans on anyone else using what I built except me.
Nice, do you machine any of your parts in your lab or send them out to be made?
@Hash my institute in Taiwan has super nice workshop with EDM, machine center....
@Dan Maloney: when I scroll up half a message (from the last ones) every second or so the chat scrolls down automatically. Is there a way to disable this behavior?
Would a stepping piezo motor be easier controller-wise, not needing high voltage driver and allowing greater range of motion?
PiezoDrive can replace my previous hv amplifier....100b has two channels
One of the goals of my textbook is to come up with ways to teach making, especially the projects, in a way that makes it possible for nanotech people like us to build our own equipment. If one of my two AFM's die, I want to be able to build the replacement. The same goes for a lot of my other equipment. For Florida Tech's nanotech minor, we really got a lot more job offers for our students when we had a making course to the materials characterization, the synthesis, and the nanotech lecture.
@John yeah...if you don't go Z direction...30 to 50V is enough
$80 for the piezo driver - Wow! At that price, you could seriously build your own AFM. Even a teaching grade AFM is $38 K.
@mh-nexus - Sadly, no. But I will have a transcript ready soon after the chat, so you can refer back to anything you've missed
@Edwin Hwu what's the limit on range of motion in x-y?
@Prof. Jim Brenner one company licensed my patents...they sell AFM for 3k USD ;)
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