Contents
Generalities
Challenges
- Performance requirements
- Force Control in Displacement (>1 cm)
- Smoothness, minimum vibration needed to perceive a stimulus (ideal 250Hz)
- Speed and Bandwidth: Response time (<1 sec)
- Resolution (<3 cm)
- Fabrication issues
- Parts (< 10 euro/taxel)
- Labor (??)
- Assembly (time and difficulty)
- Durability (child-proofness)
- Maintenance
- Efficiency: Power consumption
- Quiescent power consumption should be low
- Active power consumption should be not too high
- Especially for electrical actuators (<10W?)
- Consider limiting the number of possibly simultaneously active taxels to <100%
- Heat dissipation (see Power above)
- Safety
- Physical Dimension
Prototype Materials Supply
Actuators
(More information, links, and specifics on these below
SMA
http://www.mondotronics.com/catalog/list.asp?cid=50
- Demo kit $20
- Mondotronix Electric Piston SMA actuators:
http://www.mondotronics.com/catalog/list.asp?cid=42
- A 5-pack costs $100 = $20 x 5. Presumably in volume we could do better.
- Mondotronix Nanomuscle actuators:
http://www.mondotronics.com/catalog
- Mondotronix Bulk SMA Filament/NiTi Springs/Etc:
Pneumatic
[[http://www.anver.com/document/bottling_end-effectors/end_effect_ip_series.htm]] * (http://www.anver.com/document/bottling_end-effectors/end_effect_ip_series.htm
- Air Bladder Actuators
[[http://www.anver.com/document/bottling_end-effectors/hi_res_end_effect_pic.htm]] * (http://www.anver.com/document/bottling_end-effectors/hi_res_end_effect_pic.htm
- Bottling Pick-Up Actuators
- Unlike some similar products, these might be cheap enough.
[[http://www.shadow.org.uk/products/airmuscles.shtml]]
* (http://www.shadow.org.uk/products/airmuscles.shtml
[[http://www.mutr.co.uk/Pneu/Pneu_musc.htm
* Shadow model is available here:
http://www.mutr.co.uk/Pneu/Pneu_musc.htm
- Shadow Air Muscles
http://www.imagesco.com/catalog/airmuscle/AirMuscle.html
- In single quantities, $17 plus $18 for a (SMA-based) valve.
- Another model
- Air Muscles
- Robot store UK
http://www.robotstoreuk.com/ACTUATORS/ACTUATORS.htm
- Other Pneumatic Suppliers
- as used in current muscles
http://www.halkey-roberts.com/moreinfo.asp?pic=1&ID=355
- similar but smaller (and much more expensive i think
- Flow Control Valves
Piezo
- Piezo Motor/Actuator Kit: $499
- Piezos: Piezo-Industrial Meisters : See http://www.piezo.com
- Piezoelectric Composites (Actuators+Sensors): Active piezoelectric composites are constituted of uniaxially oriented piezoceramic fibres sandwiched between two interdigitated electrodes and embedded in a polymer matrix http://www.empa.ch > Materials > Adaptive Materials Systems
http://www.empa.ch/plugin/image/empa/2156
image: 2156
RC Servo
- Mondotronics sells a servo controller and 6 servo trial kit ($120): http://www.mondotronics.com/catalog/display.asp?pid=93
Polymer
- kits and samples of different polymer based artificial muscles: https://www.world-congress.net/registration1.htm
- polymer actuators: http://www.eamex.co.jp/index_e.html
Pressure Sensor
Piezo
- Piezo Generator/Sensor Kit: $499
- Piezos: Piezo-Industrial Meisters : See http://www.piezo.com
- Probably we can find something cheaper here.
Other Electrical
Displacement Encoder
Other?
- Power Supply, Mounting Hardware, Electronics..
Actuators
Biorobotics
Insect Robot resources:
SMA
http://www.cimss.vt.edu/shape_memory_database.html
http://www.alloys-metals-ez.com/alloys-metals/0005023_0015665_1.html
- Shape Memory Alloy Manufacturer's Databases:
- L'image:
- Mondotronix electric piston SMA actuators:
- Activation requires about 1V/5A (5W)
- 2 cm throw
- Moderate actuation time should allow some rough positioning.
Very sturdy looking.
Temperature
Actuation time
- Drawbacks: (hot, 60-90C), Several seconds
- Conclusion: Tricky balance between power, heat, and actuation time.
- L'image:
- Nanomuscle SMA actuators
- mondotronics also distribute in quantity.
- The nanomuscle version embeds key parts of the electronics, simplifying integration.
- Low power consumption (about 2 W, or 4V at 475 mA
- One may vary the applied voltage between 2.5 and 12V to control the rate of contraction.
- Note: 5-pack costs $100 = $20 x 5. Presumably in volume we could do better.
- Manufacturer's page:
- L'image:
- Bulk SMA Filament/NiTi Springs/Etc:
- available here
http://www.mondotronics.com/catalog
- L'image:
- SMA actuator products from Ti Ni Aerospace:
http://www.tiniaerospace.com/actuators.html
- One concern with these devices: they cannot be left powered for too long, or they will overheat.
Pneumatic
- A Shadow robot company project PNEUMATIC INSECT. Interesting and specific demonstration:
http://www.shadow.org.uk/projects/zephyrus.shtml
beautiful
- Shop by picture:
http://catalog.festo.com/enu/asp/start.asp
- Fluidic muscles:
http://catalog.festo.com/enu/asp/DefaultBAResult.asp?ID=187594&L=001
- FESTO has some stuff:
- L'image:
- Merlin's Pneumatic Humaniform Muscles:
http://www.merlinsystemscorp.com/pages/html/humaniformmuscle.html
- Unlike some similar products, these might be cheap enough.
[[http://www.shadow.org.uk/products/airmuscles.shtml]] * (http://www.shadow.org.uk/products/airmuscles.shtml * L'image:
- “Air Muscles”
- Also
http://www.imagesco.com/catalog/airmuscle/AirMuscle.html
- These latter run, in single quantities, $17 plus $18 for a valve.
- L'image:
- Robot store UK
http://www.robotstoreuk.com/ACTUATORS/ACTUATORS.htm
- Other Pneumatic Suppliers
http://www.robotstoreuk.com/SENSORS%2BVISION/MerlinStretchSensor/MerStretchSensor.htm
- Changes resistance as it stretches (100 Ohm/cm)
- The Merlin stretch sensor:
only
This last item raises an interesting possibility that would be quite easy to implement: displacement of Wall1 at x1,y1 relative to equilibrium is z1. Suppose we fix wall 2 at x2, y2 to be z2 = -z1 always. Provided the air muscles may be freely pressed upon and contracted by the users, no additional pressure sensor would be needed (and no protection), and the
taxel components we would need are these:
- Small air muscle (Maybe $10 at 1ea
- Stretch sensor ($15 at 1ea
- Electrically controlled valve ($15 at 1ea
- Microcontroller or similar (to scan displacement and balance
- Compression
- Noise
- Valve cost
- Possible problems:
Piezo
- Piezo Motor/Actuator Kit: $499
- Une Image:
- Piezos: Piezo-Industrial Meisters : See http://www.piezo.com
RC Servo
- Mondotronix servo kits:
- Many other RC servo suppliers
- RC servo basics:
http://www.geocities.com/BourbonStreet/3220/servobasics.html
- Une Image:
Electric other
- A linear motor primer:
http://capital2.capital.edu/admin-staff/dalthoff/lim.html
- Brushless linear actuators:
http://www.servomag.com/lin/linear.htm (5-6 mm displacement, 4 pounds force, about 16W consumed, positionable
- Lovely electric linear actuator
- Linear Push-Rod Actuators are used to control blinds:
- These seem to draw a great deal of power, however.
- Another Linear push-rod actuator from the same company :
- These are used in slat/blind adjustment, tilting things, etc. Has many great features and options, but, again, suspect power consumption (operating at 24V DC or 230V AC) may be too high.
- Coil Solenoids from Detroit Coil:
- Vibro Tactile Actuators: Tacter, VIBROTACTILE TRANSDUCERS: Currently, boards driving up to 12 tactors are available with serial or parallel interfaces, and in a PC104 format. USB and PCI compatible boards will be available in early 2003. All EAI’s driver/interface boards incorporate an on-board processor which can be pre-programmed to provide a variety of tactile outputs, or “patterns”, in response to simple processor commands.
Polymer
- NASA's Worldwide electroactive polymer actuator webhub:
http://ndeaa.jpl.nasa.gov/nasa-nde/lommas/eap/EAP-web.htm
http://ndeaa.jpl.nasa.gov/nasa-nde/lommas/eap/EAP-material-n-products.htm
- a good page with an overview of manufacturers of EAP (Elelectroactive Polymers):
http://ndeaa.jpl.nasa.gov/nasa-nde/lommas/eap/EAP-material-n-products.htm
http://www.environmental-robots.com/
- An offshoot of a U. New Mexico research lab
- Allegedly makes electroactive polymer actuators
- Environmental Robots Inc.
- Page (in japanese) showing a prototype braille tactile display based on electroactive polymer actuators:
http://micromecha.skku.ac.kr/research/project/brailletactile.htm
- Artificial muscles and miscle fibres made with ion-conductive polymers and EAPs: from http://www.eamex.co.jp/index_e.html
- Prototype actuator arrays made from shape memory alloys and electrorheological sandwiches:
Push-Pull Cables
- Advantage: isolate electromechanical elements from panels
- All mechanical solution (Problem: does not quite satisfy..
- Hybrid electromechanical and cable solution (Problem: this doubles the number of mechanical stages we need!
- There are 2 ideas here:
- Another idea: use actuators selectively – only 1 set of actuators!
Other Actuator Tech
Sensors
http://www.rhodeschroma.com/?id=pressuresensor
{{http://www.rhodeschroma.com/content/pressuresensor/figure03.jpg}}
- Notes regarding the construction of a pressure-sensing matrix such as an electronic keyboard:
- Piezo: http://www.piezo.com
and many other suppliers.
- Linear-Displacement sensors:
http://www.msiusa.com/schaevitz/products/index.html
arrays http://www.steadlands.com
- Force-sensing resistor . Some manufacturers:
- See e.g. http://www.tactex.com
- Fibre optic
- Emfit - permanently charged electret film, converts mechanical stress into proportionate electrical energy (and vice versa):
http://www.emfit.com/technology
http://www.start.t.u.-tokyo.ac.jp/~kazuto/
- - measuring both magnitude and direction of force:
http://www.start.t.u.-tokyo.ac.jp/~kazuto/
* electex - pressure, bend/stretch sensors made from washable fabric:
http://www.eleksen.com/
* active piezoelectric composites for adaptive material systems (both sensing and actuation):
http://www.empa.ch/plugin/template/empa/41/9517/---/l=2
- tactile sensing
- tactile pressure sensors:
Other Sensor Tech
Control
Membrane
shock absorption
- technogel (PU, non toxic): shock absorbant, shape memory, balanced pressure distribution, does not harden or age, can withstand 300000 pressure cycles without deformation; does not expand:
http://www.edizone.com/technologies.html
- fluid foam (floam and z-flo), gelastic, intelligel:
http://www.edizone.com/technologies.html
- liquicell: combination of a low viscosity fluid and strategically placed seal points that control the flow of liquid:
http://www.liquicell.com/technology.html
- different visco-elastic gels:
stretchable materials
- darlexx: Darlexx® Stretch Barrier Laminates Darlexx® is an omni-directional spandex warp knit with a layer of a highly breathable elastic monolithic membrane. Windproof, waterproof, and breathable, Darlexx® provides solutions across a broad spectrum of end-product applications, such as warm water diving suits, ski racing suits, clean room hoods, boots, and gloves. Darlexx® comes in a 2-ply or 3-ply construction.
http://www.shawmutcorporation.com/markets/custom_solutions.php
- CDXA Elastic laminate composite: A breathable, stretch, 3-layer laminate consisting of a nonwoven base, elongated strands of Lycra® XA® ( a man-made elastomeric fiber), and a nonwoven cover, bonded together with a hot melt adhesive. There are two types: MDXA in which the Lycra XA strands are laid down in the machine direction, which gives the resulting laminate good elasticity in the machine direction; and CDXA in which the elongated strands are laid down in the cross-machine direction, which gives the resulting laminate good stretch and recovery in the cross direction plus strength and stability in the machine direction. Both of these elastic laminate composites can be tailored to suit individual applications.
http://www.accratec.com/cdxa.htm
- Filltext powerspan and nyspan: powerspan is developed by using high tenacious yarn and elastic yarn, and designed for high abrasion resistance and Stretchability. suitable for work gloves, bags and heavy garments.
http://www.filltex.com/channel_02/powerspan.htmlhttp://www.filltex.com/channel_02/nyspan.html
- protective elastic films:
- polyurethane films and sheets:
chromic materials:
- pressure sensitive liquid crystals, elastic liquid crystal films: Dispersed and encapsulated liquid crystals (organic compounds derived from cholesterol that change color with temperature) on elastic films can be used to detect hot spots on irregular or three-dimensional surfaces; shapes can be die-cut or vacuum-formed and treated with a pressure-sensitive adhesive for adhesion to another surface; and other films can be used to detect variances in temperature over a surface area.
http://www.liquidcrystalresources.com/research.cfm
- chromic inks, prints and dyes:
- thermocromic inks and paints:
- thermochromic, photocromic and glow in the dark inks:
- ink from Sherwood technology:
http://www.sherwoodtech.com/ChemiThermal.asp
- microencapsulation and liquid crystals from:
- metamo colour:
http://www.pilotnbd.com/metamo.htm
- thermocolour sheet:
http://www.mutr.co.uk/prodDetail.aspx?prodID=574
- multicolour thermocromic pigment:
http://www.siltex.com.cn/prode2.htm
- Security & Specialty inks from Chromagen corporation : Thermochromic ink(reversible, irreversible), Photochromic ink, Thermochromic Liquid Crystal ink, UV-Phosphour ink, IR ink, Fluorscent ink(Numbering ink), Magnetic ink, Conductive ink, Fugitive ink, Optical Variable ink, Solvent Reactive ink, Chemical Reactive ink, Coin ink(Rubbing ink), Other Security and Specialty ink, Hydrochromic ink, Organic Phosphour ink, UV-IR Absorbing ink r. Blacklight ink, Piezochromic ink, Electrochromic ink, Optoelectrochromic ink, Flavour & Flavour ink, Phase Change Material, Glow in the dark ink
Company details:
- Name of company : Chromagen Corporation
- Address : #202, 218-11, Jangwi 1-Dong, Sungbuk-Ku
- Seoul Korea 136-834
- Tel : +82-2-943-1685
- Mobile : +82-(0)16-9816-8580 ( 24 hours open
- Fax : +82-2-472-9107
- E-mail : chromagen (at) yahoo (dot) co (dot) kr
Rachel received a data sheet for their piezochromic ink Active MaterialFlexible Displays
also see Active Materials , Flexible Displays , Materials Textiles and http://open.loop.ph/
More potentially useful stuff
Electronic Supplies and Parts
Animatronics
- The Animatronic and stop motion studio where Yon's sister works!: http://www.chiodobros.com
- Blue Point Animatronix: http://www.bpesolutions.com/product.html
Crazy Ideas
Electronic whiteboards
These are based either on near-field ultrasound tracking, as in mimio http://www.mimio.com, or on extremely skewed video acquisition. I had in mind the latter, thinking that it might be possible to use video acquisition, with the touchable surface, say, separated from a coated translucent hard sheet of acrylic or something, so that pressure upon the material causes certain regions of the sheep to appear darker (or lighter) than others. Or, in any case, arranging things such that a pattern of light and dark is what would result from pressure upon the surface.
Air or liquid pressure
I was thinking the same could be accomplished with a network of air or liquid filled tubing. http://content.honeywell.com/sensing/prodinfo/pressure
Pressure sensors are small but not necessarily cheap http://content.honeywell.com/sensing/prodinfo/pressure
In a woven array, if we scan, we would only require 2N pressure sensors per wall, where N is the number of taxels along one direction (say, 30-200), but this only locates an isolated centroid. More is possible, as evidenced by http://www.tactex.com
LCD display technology
We might be able to adopt an array based scanning scheme as used in LCDs. See Flexible Displays
for more information on new LCD, OLED and other technologies.
Tactile compression
- Apply a mechanical data compression algorithm
- Apply nonuniform sampling
A Boundary-tensioned mesh
- Could a mesh could be constructed of passive cells which displace only when a tension is applied along both the x and y axes?
Thermal Displays
- temperature can aid a lot in the perception of touch. This extremely interesting research area has not yet yielded satisfactory results for purposes of tactile shape recognition up to the beginning of 2004.
Humidity Displays
- how do we know if the person on the other side of the display is nervous, or has just entered the house after a massive rain-pour?
nik