NanoMuscles

Citation

(2002), "NanoMuscles", Assembly Automation, Vol. 22 No. 1. https://doi.org/10.1108/aa.2002.03322aaf.002

NanoMuscles

NanoMuscles

Keywords: Motion, Technology, Electromagnetics

NanoMuscle, Inc., designs and manufactures a new miniature motion technology that displaces conventional electromagnetic motors and solenoids in a wide range of applications. The NanoMuscle Actuator is silent, smaller, more affordable and more energy efficient than existing solutions. This innovative product has a digital interface, thus reducing the overall design cycle and time to market (Plate 2).

Plate 2

NanoMuscle has developed over 30 actuator models to meet the demands of a wide variety of application categories. It can be utilized in a wide variety of devices ranging from computer and office equipment to toys and robotics, automobiles, and medical instruments.

NanoMuscles combine advanced materials, hardware and software to create a miniature replacement for electromagnetic motors. They are based on a class of materials that exhibit the "Shape Memory Effect". This effect was first discovered over fifty years ago, but never saw widespread commercial deployment due to a number of inherent flaws in the materials. NanoMuscle has solved these problems creating for the first time a viable high volume alternative to small motors.

Alloys that exhibit the Shape Memory Effect are called Shape Memory Alloys (SMA). When these alloys are heated their crystalline structures rearrange, producing a mechanical contraction. In a NanoMuscle, SMA is formed into tiny strands a mere fifty micrometers across. These wires behave like a "delayed reaction" rubber band. In their initial state, they can be stretched out using very little force, much like pulling on a rubber band with your hand. Unlike a rubber band, when the external force is removed, SMA wires do not return to their original length. Instead, they remain in the elongated state until they are heated past their transition temperature – only then do they return to their original length. The SMA strands in a NanoMuscle are small enough that they can be resistively heated by passing a current through them.

By carefully controlling the application of current to an SMA wire, the speed of contraction can be controlled, as can the final position. The SMA wire does not need to return all the way to its original length, but can be precisely stopped at an intermediate length. With six pending patents, NanoMuscle has harnessed the power and potential of SMA. When compared to the raw SMA material itself, NanoMuscle Actuators have a much larger stroke, higher speed, much higher reliability and a wider operating temperature range. Compared to a miniature motor of equivalent size a NanoMuscle is orders of magnitude less expensive, hundreds of times faster, one third the weight and five times the energy efficiency.

Since the force output of a NanoMuscle is invariant with speed no gearbox is required further reducing overall system complexity, size and cost.

Customers from a wide variety of industries are finding innovative ways to use NanoMuscles Actuators in their products. The benefits are numerous:

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  Size – NanoMuscle Actuators are miniature – about the size of a paperclip.

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  Silent – NanoMuscle Actuators' fluid motions replicate the natural movement of animal muscles and are completely silent.

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  Affordable – miniature motion on a scale comparable to a NanoMuscle is only available at a very high cost, effectively making motion inaccessible for high volume consumer devices. NanoMuscle Actuators offer capabilities previously found in low volume, high- end products.

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  Suitable for Battery Powered Equipment – NanoMuscle Actuators use much less current than pervious SMA devices, making them ideal for use in alkaline battery-powered, portable consumer devices.

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  Integrated Power Drives – Reflecting the trend towards "smart devices", NanoMuscle Actuators are available with integrated power electronics, enabling them to be directly connected to digital systems, thus reducing overall system cost and time to market.

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  Digital Interface – The NanoMuscle Digital Interface provides logic level control and feedback from the NanoMuscle motor.

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  Direct Linear Motion – Electromagnetic motors produce rotary motion, yet over 60 percent of all small motor applications require linear motion. This requires system designers to design complex mechanical systems to translate rotary to linear motion. In contrast, NanoMuscle Motors produce linear motion directly and avoid the need for such complex mechanisms, further reducing product size and design time.

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  No Gearing Required – Unlike an electromagnetic motor, the force output of a NanoMuscle Actuator is independent of its speed. NanoMuscle products can be used without a gearbox, reducing overall system size, complexity and cost.

Each NanoMuscle Actuator is a complete motion system designed to make adding movement to digital systems easier and more affordable. A NanoMuscle Actuator consists of a NanoMuscle Motor and a NanoMuscle Interface integrated into a tiny, low cost package containing all required drive electronics, position sensors, and control logic. With numerous models available today, NanoMuscle Actuators span a wide performance envelope (see Table I).

All NanoMuscle Motors are available in Economy Grade or Commercial Grade. Economy Grade units are designed for applications with less stringent cycle life and environmental tolerances.

The NanoMuscle Digital Interface (DI) provides seamless integration with 3V and 5V digital systems by incorporating high current drivers that are activated by logic level signals. End stop signals are also exported as logic level signals on a high density Flex Circuit connector (see Table II).

The NanoMuscle Analog Interface (AI) provides control and end stop detection via analog signals on a high density Flex Circuit connector.

The NanoMuscle Open Loop Interface (OL) is intended for use in systems with external end stop or position sensors, and enables analog control via a high density Flex Circuit connector.

Table I
Actuator performance envelope
Operating voltage	2.5-40+ V
Operating current	80+ mA
Nominal force	30 gf – 70 gf
Activation speed	10 msec – 1 sec
Stroke	4 mm
Ambient temperature	70° C to +75° C
Cycle life	1M – 5M Cycles

Table II
Interface	Flexcircuit	End stopsensors	Integrateddrivers
Digital	x	x	x
Analog	x	x	x
Open loop	x
Lead wire connection

The NanoMuscle Lead Wire (LW) Interface provides low cost connectivity in a variety of configurations.

Industrial Uses

Customers from a wide variety of industries are finding innovative ways to use NanoMuscle Actuators in their products.

Automotive

There are a large number of small motors in a modern automobile. A model year 2000 economy car contains over 50 small motors, and a luxury vehicle contains as many as one hundred. This number will only increase as competitive pressures mount within the industry to shrink the size, weight, and cost of devices that drive these applications.

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  Air conditioning vent controls

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  Rear and side view mirror adjustment

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  Door and accessory locks

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  Air conditioning vents and louvers

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  Tactile feedback on user controls

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  Seat adjustments

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  Instrumentation gauges

Consumer Electronics

Consumer Electronics devices contain a myriad of small motors which often define the ultimate size, weight and cost of the device. The existence of affordable miniature linear actuators opens up the possibility of devices with much more capability than those we use today.

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  Cameras

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  Camcorders

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  Rotating media players (CD, DVD, MiniDisk)

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  Personal Digital Assistants

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  Digital photo printers

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  Cell phones

Selected Consumer Electronic Applications

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  Camera film advance

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  Camera auto-focus / zoom

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  Media eject (compact flash, memory sticks)

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  Portable printer paper feed and positioning

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  Lens positioning

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  Microphone positioning

Computer Peripherals

Office equipment and computer peripherals contain a large number of small motors. NanoMuscle Actuators are an excellent alternative to small motors and solenoids currently used in these devices.

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  CD / DVD-ROM Mechanisms

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  CD-ROM, Disk drive, PCMCIA style ejectors

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  Chassis temperature controls

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  Microphone positioning

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  Lens positioning

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  Electronic locks

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  Fax machine actuations

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  Micro circuit breakers

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  PC mount pilot valves

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  PC mount relay

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  Printer / copier paper feed and positioning

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  Read / write head lifters

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  Tape deck solenoid replacement

For more information about NanoMuscle Actuators, or to purchase a Developer's Kit, please go to their website at www.nanomuscle.com or call +1 925-776- 4700.