What is the future potential of exoskeletons ? What should be achievable in reality compared to the fictional Iron Man ?
Here is what I think are the most realistic ways to solve the motor power and energy storage issues for far more powerful exoskeletons. Something that could power fairly high speed flight and be able to lift 8-20 tons of weight.
High power density levels are one of the main hurdles to very powerful exoskeletons.
Various studies and design of high temperature superconducting motors suggest that power densities beyond turbine engines are possible. These superconducting engines would be even lighter if room temperature superconductors are achieved. The cryo-cooling would not be needed.
Detailed design studies for HTS propulsion motors supported by experimental validation have convinced us that superconducting rotating machines today can achieve power densities comparable with that of turbine engines (3-8 kW/kg).
This remarkable achievement, however, is still not enough for deployment into commercial aircraft. Electrically-propelled airliner aircraft would become feasible when power densities approach 25 kW/kg for motors and 50 kW/kg for generators, which appears to be achievable with fully superconducting machines (both inductor and armature).
A kilowatt of power is equal to about 1.3 horsepower. The Tesla Model S electric car has 85 kilowatt hours of batteries.
A P51 Mustang fighter plane engine had 1.3 megawatts of power (1790 horsepower) and had a range of 1140 miles (2200 miles use two 150 gallon drop tanks.
An 18 wheel (semitrailer) truck typically has a 400 kilowatt engine (520 horsepower).
A superconducting electric engine with 50 kW/kg would need 10 kg to equal the power of a semitrailer truck and 27.5 kg to match the engine of a P-51 Mustang. A Tesla Model S has a 416 horsepower engine which would need about 8 kg of future superconducting engine.
Batteries with 1000 watt hours/kg are possible with lithium sulfur, lithium water and lithium air batteries. Lithium air batteries have theoretical far higher densities but the general current thinking is 2000 watt hours should become practical.
50 kilograms of batteries with 2000 watt hours /kg would have 100 KWh. This would be more than a Tesla Model S.
50 kilograms of batteries with 10000 watt hours/kg would have 500 KWh. This would enable 1.2 hours for a full power for a semitrailer truck engine.
30 KW (40 horsepower) can lift about 2 tons
74 KW (101 horsepower) can lift about 8 tons.
80 KW would be ok for one person exoskeleton to fly at 270 km/h but it would need wings
A far lower power sport plane is the lightweight Virus SW 80/100. It is lightweight, robust and features and a useful payload of more than 300 kg. Virus SW 80/100 cruises at over 260 km/h (140 kts), easily overflying terrain higher than 4500 meters (15.000 ft) and covering distances of over 1500 km (800 NM).
The Virus SW 80/100 aircraft can be equipped by either the Rotax 912 UL2 (80 hp) or 912 ULS (100 hp) powerplants and a large variety of avionics options. The new 80 HP Virus SW 80/100 cruises at 246 km/h (133 kts), burning less than 13.6 liters per hour (3.6 gph). At 75% cruise-power-setting the 100 HP version speeds over the skies at 273 km/h (147 kts)
An exoskeleton with tiny wings would missile like propulsion and aerodynamics.
Brian Wang is a Futurist Thought Leader and a popular Science blogger with 1 million readers per month. His blog Nextbigfuture.com is ranked #1 Science News Blog. It covers many disruptive technology and trends including Space, Robotics, Artificial Intelligence, Medicine, Anti-aging Biotechnology, and Nanotechnology.
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