Lending a Hand: Design of a Modular Wearable Robotic Arm with a Foot Control System

The “Maestro Arm,” presented in this paper, is a modular wearable robotic arm with a five-fingered hand and wrist, elbow, and shoulder joints. The arm attaches to a waist belt to serve as a wearable third arm and can detach from its shoulder interface for mounting on external platforms such as a table or wheelchair. The dexterous, underactuated hand features a biomimetic joint design with 6 degrees of freedom and can output 18.4 N of grip force and 66.7 N of pulling force. A generatively designed forearm internal structure houses all necessary electronics. Cycloidal gear actuation systems control the arm’s vertical (shoulder joint) and horizontal (elbow joint) motions, providing 17 Nm and 8.5 Nm of lifting torque, respectively. The modular attachment architecture also provides a basis for future investigation of prosthetic configurations; however, this study does not cover socket design, residual-limb attachment, suspension, or clinical prosthetic use. The arm is fully controlled by an insole-based custom foot controller, called “Maestro Step.” This foot controller has two push buttons that control finger actuation and the grip pattern. The user’s ankle motion controls the shoulder, elbow, and wrist joints, with gesture recognition to switch between joints.