IEEE Spectrum Robotics Channel

Whitney says the device has greater torque per weight (torque density) than highly geared servos or brushless motors coupled with harmonic drives. And more significant: To build an autonomous robot, you'd need a set of motors and a control system capable of replacing the human puppeteer who's manually driving the fluid actuators [below]. John P. Whitney: The original motivation was the same as for the MIT WAM arm and other impedance-based systems designed for human interaction: Using a lightweight high-performance transmission allows placing the drive motors in the body, instead of suffering the cascading inertia if they were placed at each joint. We are learning that many of the "analog" qualities of this system will pay dividends for autonomous "digital" operation; for example, the natural haptic properties of the system can be of equal service to an autonomous control system as they are to a human operator.