The Titan Arm system costs under $3,000 to make. It can hold a static load via a braking system, or lift at 3 rad/s (for a 44 cm forearm+hand length, this works out to about 132 cm/s or 4.3 ft/s — pretty fast. The motor is mounted in the backpack area; the elbow joint is driven by a cable system.
TitanArm was developed by a team at the University of Pennsylvania. It is a powered upper body exoskeleton for use in physical therapy and assistive mobility applications.
The exoskeleton system is made mostly of CNC-milled 6061-T6 aluminum. The lightweight aluminum cuts the weight of the entire system to 20 lb.
The system can lift 165W in a bicep curl. Assuming the bicep curl is a full half-circle, that works out to a lift capacity of around 20 kg or about 44 lb (the MEAM Team calculates the capacity at 50 lb, close to this napkin estimate). An aluminum backplate in the backpack-part of the device gives the user support during their lifting.
This suit uses a powerful DC motor, coupled with a novel cable drive system for joint actuation at the elbow of the user. Using the suit, the user is able to easily curl up to 40 pounds! We utilize sheathed cables – just like bike brake cables, but larger – allow force transfer from the elbow to the back of the user (where the motor is mounted). This allows our suit to be extra mobile and flexible, making its applications even more versatile. All of the mechanical components were analyzed, designed, and manufactured by our team here at UPenn.
Our suit runs off a BeagleBone microcomputer running the main control loop for the exoskeleton. It communicates with an ATmega32-based microcontroller, the M2, over serial UART to do the low level sensor data acquisition and motor control. The BeagleBone also has a wireless dongle that transmits joint angle data (captured through Hall effect sensors, motor encoder values, and rotary potentiometers) from the suit to a base station computer. This would be especially useful in a physical therapy scenario where a doctor could remotely monitor a patient, track improvement, and give meaningful feedback.