Miga Cascade™ is a lightweight, portable, and silent massaging system made by applying Shape Memory Alloy (SMA) wires to a mesh lumbar support frame or other suitable seating component.
SMA wires are special alloys of Nickel and Titanium that contract when heated with electrical current. When applied to a curved seatback or cushion, they produce a warm and very pleasing compression waves, something like a Shiatsu massage effect.
Since the SMA wires are very thin (only as thick as 5 sheets of paper), the entire massaging surface is vanishingly thin and lightweight. These surfaces then need to be applied to a curved seatback and supported on the sides so that when the SMA wires contract, the chord-length is shortened, and the SMA wires press into the soft tissue of your back. Elastic fabric elements help to spread out the force so that each wire produces a pleasing 1.5” wide ‘zone’ of compression.
Shape Memory Alloy wires are ‘thermal’ actuators in that they contract about 5% of their length when heated with electrical current. As a result, a very pleasing heat pulse is generated at the same time the wires contract: producing a warm compression wave along the soft tissue of your back. When current is removed, the wires cool and lengthen back to their neutral position. Another result of thermal actuation is that the contraction is totally silent. This adds significantly to the ‘ambiance’ of the effect, in that there are absolutely no distracting noises. Existing chair massage devices have whining and whirring motors, with gears grinding up and down plastic tracks in the thick and heavy units. All of which is very distracting, and could not be used in a work-office environment, for example.
Miga is the world leader in the development of devices that utilize SMA wires, and has been designing and building SMA wire actuators for over 15 years. Miga has a sophisticated physics-based model of SMA motion that allows us to carefully control the timing and length of the SMA wires during heating. Our control schemes have allowed us to control multiple SMA wire ‘zones’ – spanning the entire seatback or cushion with a network of SMA wires. We are even able to provide vibration effects of various frequencies, from a slow ‘throb’ to higher frequency ‘buzzes’, and can apply a range of operating modes from quick and assertive ‘invigorating’ massage, to slow and gentle ‘relaxing’ massage. All of this can be done using a typical laptop adapter as a power supply. High-energy Lithium Polymer batteries can also be used, of course, as well as typical automotive power adapters.
A tiny microprocessor is used in the device, to control the timing and distribution of current pulses to the multiple compression zones. This is done with a bank of high current P-Channel MOSFET switches, individually addressed by the processor.
Like other massage units, the Miga Cascade provides several orchestrated ‘treatments’ of around 10 minutes each, then goes into low-power auto-shutdown until restarted.
Miga Cascade™ was designed to operate in office chairs, waiting rooms, or car seats (with an optional 12v adapter). They can even be used in living room or other furniture.
Miga has multiple issued and pending international patents covering this new technology.
Features:
- The SMA wires do not make any noise or sound of any kind, so Cascade® can be used in office environments without disturbing office mates or neighbors. (We can add a pleasant ‘humming’ sound to indicate the motion.) Unlike those bulky motor-powered devices there are no motor sounds.
- Remote Control. Can be controlled with RF remote, Bluetooth, or simple on/off switch. Chosen wireless control methods must be compatible with potentially many different installations in an office environment.
- Unlike thick, bulky motor-powered devices, Cascade® can provide pleasant motion to nearly any contoured surface.
- Cascade ® warms up slowly: providing a slightly higher force and motion as the device and your back muscles warm up and loosen up. The effect is not as jarring as traditional massagers.
- Cascade® automatically powers off after a 7.5 minute ‘treatment’. You can restart after a 3-minute cooling period, but we do not recommend more than 15-minutes of treatment every two hours. Or more than 7.5 minutes per hour.
- Heat is generally pleasing for most users, but is disturbing to some. We can add a thin cover or other fabric layers to ‘turn down’ the heat generated by the SMA wires. We can also provide a constant heater mode (as in car seat heaters) by adding just enough power to warm the SMA wires without contracting them.
- Top/Down vs Bottom/Up. Studies have shown that Top/Down massage tends to relax, while Bottom/Up tends to stimulate. We can easily add software or switch control for any desired mode.
- We can apply pressure waves from 1-5 seconds in duration. The slowest compressions tend to dump a lot of waste heat into the system, so are not very efficient. And rapid compressions are not very relaxing. So we standardize on roughly 2-second compressions with 1.5-second wait period between ‘zones’. And a 5-second wait period before starting a new cycle.
- We can provide 2-6 zones of compression, in many different shapes. Horizontal line shapes or ‘V’ or ‘X’ shaped zones are the most effective. Vertical zones do not work because the SMA wires need to be in a concave curved shape to provide ‘squeeze’ when they straighten out. And vertical concaves cannot be done with chair-back shapes.
- Size & Shape. The typical Lumbar Support Mesh is roughly 17” wide by 21” tall, and has an aggressive curvature in the lumbar area. This makes it difficult to provide effective squeezes to the lowest zone in the lumbar region. According to research provided by Peter Vink at Delft University, the most pleasing chair-back has a ~70% ‘golden rectangle’ shape, so the ideal size may be 17” wide by 24” tall. I tend to think that 17” x 22” is the ideal shape for most backs.
- According to Peter Vink, the mesh chair-back is the best way to distribute forces, so provides the most comfortable chair-backs. Thus all of the mesh-back chairs on the office furniture market today.
- Rigid (molded plastic) vs. flexible (wire) frame. I believe that there is additional ‘action’ that arises from using a wireframe that cannot be duplicated with a rigid frame. The wireframe tends to ‘wrap’ around you when you sit in it: providing additional curvature, which is so important to the action of the SMA wires upon straightening.
Engineering Design Guidelines
- Portable, lightweight, silent sort-of-a massage
- Intended use: office chairs, waiting room chairs, automotive and aircraft seats, potentially living room furniture
- Voltage requirements: 12-24 volts depending on model, powered by 110/220 VAC adapters, Automotive 12VDC jacks, or LiPo battery packs
- Current requirement: ~1-4 amps depending on circuit, typically 2.0 amps. 70-Watt adapters are more than sufficient for even vibration operation.
- Controller: ON/OFF switch, over-temp protection using temperature sensors and/or fuses, Bluetooth LE or RF remote (must be compatible with multiple chairs in close environments), potential tilt and/or weight sensors, even biorhythmic sensors such as stress sensors.
- Controller box: ON/OFF switch, potentially UP/DOWN switch, and potentially HIGH/LOW temp/squeeze switch.
- Spring steel wire frame or molded plastic frame, roughly 17” wide by 21” tall by <5” deep
- Most critical design feature: frame shape produces large curvature of mesh or fabric (typically 2” ‘sagitta’ in no-load ‘rest’ position from forward-most surface to fabric surface)
- Frame supports mesh or other fabric layers and SMA circuits and wire harness
- SMA circuits mechanically mount to sides (edges) of frame (requires high force attachment, in excess of 15 pounds)
- 3-6 circuits in various patterns: horizontal lines, X-shapes, or overlapping V-shapes.
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