Powered Exoskeleton

Overview

A powered exoskeleton is a wearable robot that straps to a person's legs and adds torque at the joints they cannot drive on their own. It is used in rehabilitation, to let people with spinal injury or stroke stand and walk again, and in industry, to carry load off a worker's body during lifting or overhead work. The machine is a partner rather than a vehicle: it must read what the wearer is trying to do and assist in time, because a step it mistimes is worse than no assistance at all. An Frame & Cuffs transfers weight to the ground through cuffs and struts adjusted to the user, while powered hip and knee joints supply the muscle.

How it works

Each leg carries two actuated joints, an Hip Actuator and an Knee Actuator, built on the same design: a compact Servo Motor feeds a thin, near-zero-backlash Harmonic Reducer so the joint is both strong and back-drivable. A joint encoder reports angle and an Joint Torque Sensor reports the actual torque between the machine and the limb, which is what lets the controller assist a motion the wearer starts rather than forcing one. A local joint drive closes the current loop at each actuator.

The robot infers the wearer's intent from sensing rather than from a joystick. Instrumented Foot Plate soles detect heel-strike and toe-off, and an IMU Suite tracks the orientation of the trunk and limb segments. The Gait Controller fuses these streams into a gait state machine that decides when to flex, extend, and hold each joint through a step. An Battery Pack pack of cylindrical cells supplies a few hours of walking and clips to the spine strut for hot-swapping. The user picks sit, stand, or walk modes from a small User HMI, and the whole body of actuators and sensors is wired together by a flexible Body Harness harness that moves with the frame.