Exoskeletons and other assistive robotics can never truly takeoff until they can be controlled properly. Even the best robots in the world can’t out-walk a toddler. This problem only gets worse when the robot is attached to a human. Humans and machines will always argue until the day they die over who is in charge.
Frustration occurs whenever a machine disobeys a direct order. Over-aggressive abs and traction control in a car, aim assist in video games, a wheelchair defeated by a half inch curb, all examples of machines gone wrong. All machines should aspire to be a microwave, you enter 30 seconds you get 30 seconds. If you tell a machine to jump it should not ask how high, it should just jump. If you wanted a certain height you would have specified.
There needs to be a way to control more outputs than current means. It takes two human arms to control one robot arm, see an excavator, and that does not include fingers. It would be much better if we had access to the spinal cord’s output to our limbs.
Reading intent from muscle movement is hard because we cant put sensors inside where they are needed.
Our body is controlled by opposing muscles, each pulling a joint up or down. Lets use the elbow as an example. The bicep pulls your forearm up, and the tricep pulls it down. However this is not all they do, your brain can also vary the stiffness of your limbs. It does this by pulling both the bicep and tricep at the same time, in order to lift more weight or have more precise control.
Muscles by themselves are not precision instruments but this effect makes them so. Now imagine if your brain had direct control over a electric motor.
Propose you had a device that could measure the intended power of every muscle in the human body. And you wanted to control the elbow motor of an exoskeleton. This motor is attached to a variable gearbox.
To gear the motor up or down we need simply to use the variable stiffness built in to our brain. When the bicep and tricep are both pulling hard, gear down, when they’re relaxed, gear up. Use the difference between the bicep and tricep for motor direction. Effectively the same mix for tank drive on a single joystick.
This would also save power because gearing down keeps joints in place without powering the motor. Also gearing down gives more torque, allowing for greater deadlifts and other feats of “strength”.