A Mobile Extendable Robot Arm: Singularity Analysis and Design* Inspection and maintenance of equipment inside buildings, such as exit signs, bared pipelines, air vents, and fire alarms often requires a robot to reach high, hidden, or confined areas that are difficult for humans to access. Even though these tasks are easy and repeatable, they are still not automated. The Mobile Extendable Robot Arm (MERA) is a movable robot arm with a novel 2DOF scissor mechanism for reaching a high place and positioning an endeffector. MERA is composed of a locomotion vehicle with a rotation table and a 4DOF extender arm, itself made of two layers of the 2DOF scissor mechanism arranged in series. Placing the endeffector at an arbitrary point in space, the 4DOF arm possesses two degrees of redundancy, allowing access to a point from various directions and enabling obstacle avoidance. In this paper, we present the design and analysis of the 2DOF scissor mechanism. The 2DOF scissor mechanism has two rotary actuators for driving the base links individually; consequently, the mechanism can elongate the entire body and tilt at the center of the base shaft. However, we found that the 2DOF scissor mechanism had a singularity; after analyzing the singularity, we propose two novel solutions to the problem.

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.