Programmable Matter and Applications

Date 4th April 20161/

• Introduction• History• Approaches to programmable matter• Basic component/Examples• Metamaterials• Electropermanent magnet• Claytronics

Content

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Programmable matter is matter which has the ability to change its physical properties (shape, density, moduli, conductivity, optical properties, etc.) in a programmable fashion, based upon user input or autonomous sensing

Programmable matter is thus linked to the concept of a material which inherently has the ability to perform information processing, networking capability, power, actuation, programmable adhesion, sensing, and display capabilities

Programmable matter

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water - changing states in response to temperature isn't programmable.

movie screen - appears to have adjustable optical properties based on optical inputs, but it's just reflecting.

quartz - really does have electrically adjustable shape, but no memory or processing.

Misconceptions

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Programmable matter is a term originally used to refer to an ensemble of fine-grained computing elements arranged in space

In the early 1990s, there was a significant amount of work in reconfigurable modular robotics with a philosophy similar to programmable matter

As semiconductor technology, nanotechnology, and self-replicating machine technology have advanced, the use of the term programmable matter has changed to reflect the fact that it is possible to build an ensemble of elements which can be "programmed" to change their physical properties in reality, not just in simulation.

History

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In one school of thought the programming could be external to the material and might be achieved by the "application of light, voltage, electric or magnetic fields e.g. liquid crystal display(LCD)

A second school of thought is that the individual units of the ensemble can compute and the result of their computation is a change in the ensemble's physical properties e.g. Claytronics

There are many proposed implementations of programmable matter. Scale is one key differentiator between different forms of programmable matter

At one end of the spectrum reconfigurable modular robotics pursues a form of programmable matter where the individual units are in the centimeter size range

At the nanoscale end of the spectrum there are a tremendous number of different bases for programmable matter, ranging from shape changing molecules to quantum dots

Approaches to PM

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Electromagnet: a simple coiled wire driven by a hefty electrical current gives a fully-programmable magnetic field strength (on, off, and everything between)

But such controlled magnet causes enormous power consumption while in Working mode

This led to idea of controlled magnet which should operate in exactly reverse way i.e. Magnetism mode without any power consumption and OFF state with help of triggering power

Electropermanent Magnet

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Thus an electropermanent magnet is a solid-state device which allows an external magnetic field to be modulated by an electrical pulse

Cont…

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To implement such matter duo of electromagnet as well as permanent magnet is required where magnetism caused by electromagnet is used to nullify the magnetic field created by permanent magnet

The permanent magnet consists of magnetically hard and semi-hard(low coercivity) material, capped at both ends with a magnetically soft material (e.g. Iron)

The magnetically semi-hard material is coiled with wire to form electromagnet which causes change in its magnetic behavior with change in direction of current

Construction

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The Soft iron core surrounding the permanent magnets are used to concentrate the magnetic field within its core as they have higher permeability than air

The magnetic field generated by the EPM is produced by the permanent magnets not by electric currents and this is the main difference with the electromagnets

Construction

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In first image(ON) no magnetic field inside U-shaped soft iron bar surrounding two permanent magnet

When one of the permanent magnet is reversed manually(image 1 OFF), all magnetic field inside the core only

Similar analogy achieved using coil around one of the bar magnet without mechanically reversing the magnet

One of the permanent magnet should have lower coercivity so that its magnetic field can be changed easily by supplying current well within its current holding capacity

Operating Principle

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Magnetic Circuit

The solid magnetic structure can be described into electrical circuit where MMF represents magnetic strength of permanent magnet and is analogous to voltage in electrical domain

Similarly permeability of core/air act as resistance to magnetic flux

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Force on external magnet From the previous circuit we can find out the force exerted by EPM

on any external magnet core using following description

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EPM DesignAppropriate designing of solenoid is necessary as it causes the

reversal in magnetic field of magnetically semi hard magnetAt least it should be able to create magnetic field equal to

magnetizing field created by MSHM

Where

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Electromagnetic Lock Electromagnetic Lock are used for security purposes in

doors and platforms to maintain them closed by using the force created by the permanent magnets

These locks are very bulky and with big magnets the

system can generate forces of several newtons making breaking the door easier than breaking the lock mechanism

Application

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Project Ara is an open hardware initiative by Google to create a modular phone where all the components are interchangeable and can be replaced meanwhile the device is on

This product is still underdevelopment and prototypes are available for developers

The project was originally announced as using EPMs as the method used to fasten the phone's modules to its endoskeleton

Project ara

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Drone package delivery systemGripping systems for drones have been starting to use

EPM for their configuration

Reconfigurable matter

Using a dice of six sides and in each side include an EPM is the concept behind this Pebbles robots that are capable of interpret a simple shape and reproduce it by selecting which blocks must be attached to the other

Cont…