A suit called "HAL" produced by a company called "Cyberdyne"

What could possibly go wrong when the suit is named after a murderous computer and the company is named after a company that created Skynet, an AI program that wipes out humanity...?

Now I'll attempt to write this without at shred of jealousy and purely as an objective observer that has somewhat specialized knowledge in the field of human performance robotics.

This major problem I have with this suit is that it does not enhance a normal human upward towards superhuman. This video details the suit in action. It looks pretty cool. However, when they want to show the strength allowed by the suit, they load the user with three 20-lb bags of rice. Wow, 60 lbs. that is so much weight... Now the other problem I have is that if you watch the video carefully you realize the only thing the arms are capable of doing is holding things in that cradled, bicep-curled position. The suit does not appear to be able to articulate more than a few forces. It can walk, stand up from a sqaut, and bend the arm in a bicep curl. Forgive my underwhelming sense of awe.

Overblown Iron Man analogies aside, this suit is a huge step forward in terms of medical rehabilitation. Imagine someone who had lost most of their nervous system activity, and their leg muscles had atrophied as a result. Put them in this suit, and they might walk again. That's an amazing, wonderful thing. But what I want to impress upon all of you is that this suit is not capable of picking up a grand piano and hurling it a half-mile. In terms of raw mechanical strength, this suit is probably no stronger than your average American. In a lot of ways it is much weaker. You cannot do a pushup in this suit.
The other important thing we should all notice is the same problem I had with the Sarcos suit: no hands. The HAL suit requires the user to rely on their own hand strength. Any athlete will tell you that there is no point in having the arm strength to dead lift 900 lbs. if you don't have the grip strength to hold the barbell!

Anyway, if you really take a look past the cool blue circular lights and nifty paint scheme, you realize this suit is not a technological leap into the future. The video tells us that a suit will cost $20,000 US dollars once they get done with it, and they'll only be able to make ~500 a year. So it won't exactly be selling like the iPhone.

Why the strength limitation? Joint-located servos. The legs have servos at the knee, which is nearly the worst design plan you could do. It works great for 12 lb. Asimo robots, because they don't require a lot of force to move. But what the Japanese seem unable to give up is the idea that a servo can power a robotic joint as powerfully as human muscle can. A servo works by rotation two discs in relationship to each other. The problem with this is not that a servo cannot generate enough force to move the joint. The problem is that the torque is directly proportional to the current draw of the servo. In order for a servo to rotate with the torque and speed of a human leg, it quickly draws a huge amount of power and overheats. Cyberdyne has solved circumvented this problem with large, high-torque servos that are one directional. However, I must repeat that Cyberdyne's suit does not appear to render the wearer any strength beyond what a normal human would have. Despite all our grandiose schemes, Nature has evolved the most efficient, strongest method for moving your bones. Muscles attached to ligaments, attached at points along your bones to create lever arms. Servos, though simpler in function, simply cannot produce the force per unit energy expended that muscle can. A possible solution is a linear actuator, which can mimic the movement of a muscle.

A personal issue I have with the suit is that the anchors, that is, the parts of the suit that attach to the body, are not efficient. Application of force is tied to the body using double straps wrapped around the muscles. A properly built suit should only strain itself, almost like a person wrapped around you. Ideally, designers should want the suit to dynamically balance itself, the same way the body does, so that the wearer carries a load like normal, and then the suit carries an additional load with no effect on the lifter. The Sarcos suit has achieved this design, the wearer really doesn't feel any strain on their body even though they could be lifting 400 pounds.

One thing the HAL suit does right is that the amount of augmentation power is modular. It can be set to assist the wearer 50/50 with loads, or for severely handicapped users, it can be upped as high as 90/10. This is a good idea.
My powered arm design is a slight departure from this. The arm's force actuators are pre-calibrated to move from 0-100% of their force curve as the wearer goes from ~30-100% of their muscle force. Squeeze a can of vegetable soup as hard as you can, you can't break it. Squeeze a can of vegetable soup as hard as you can while wearing the powered arm, the can is crushed. However, squeeze a can only hard enough to lift it, and the suit doesn't kick in and crush the can, it simply lets the wearer do their thing. Under normal circumstances, like the act of holding a can of soup, there is no need for the augmented strength, so the suit has an input threshold, i.e. a minimum amount of muscle tension required before the suit says "I ought to help out here." The basic premise here is that you don't need the suit to help you all the time, but when you do, you don't want it to lag behind. So the suit has a shorter force curve than you do.

It's all very simple, in my head.

Anyway, cheers to Cyberdyne for their suit, it looks neat. But let's not all jump on the "wow, Iron Man lives!" bandwagon just yet.


_