Design of a FailSafe Wearable Robot with Novel Extendable Arms for Ergonomic Accommodation during Floor Work Aircraft manufacturing, construction, and agricultural production often involve workers maintaining uncomfortable postures, such as stooping and kneeling, for extended periods of time. We present a wearable robot, called MantisBot Alpha, that consists of two expandable robotic arms that brace a worker near the ground and allows them to perform bimanual tasks. The key component of this new design is a novel linkage mechanism that provides adjustment of both the workerxe2x80x99s distance to the ground and their torso tilt. The mechanism link parameters are optimized such that a) its expansion rate is high enough to push off the human body from the ground and fully contract the scissor arm when not used, and b) it allows the worker to reach within a large space while c) it is light enough for wearability. The linkage mechanism also avoids the singularity problem in standard scissor mechanisms. The actuator design provides a failsafe system. A prototype has been fabricated to demonstrate the feasibility of the system.

Development of Adjustable Knee Assist Device for Wearable Robot based on Linkage and Rolling Joint This paper presents an adjustable knee joint for a wearable robot for the elderly, to provide physical gait assistance. In order to compensate for the translational and rotational movements of the knee in the sagittal plane as well as aligning the frontal plane, the proposed knee joint is implemented with a rolling joint, two aligning passive joints, fourbar linkage, and a sliding mechanism. Because the sliding mechanism, fourbar linkage, and rolling joint exist between the actuator and the joint mechanism, the rotation angle of the actuator and the flexion angle of the rolling joint do not change equally due to the kinematic characteristics. In order to define the flexion angle change of the rolling joint with respect to the change to the actuator angle in the flexionextension motion of knee, the design parameters and flexion model are proposed in this paper. The proposed artificial knee joint effectively delivers the torque required for assistance while adapting to the joint motion of the wearer. This paper describes the mechanical design of this knee mechanism and its implementation on a wearable robot and in preliminary experiments. The performance of the proposed mechanism was verified by simulations and experiments. Finally, preliminary experiments were performed to demonstrate the possibility of reducing the metabolic cost of using a knee assist.