Supernumerary Robotic Limbs for Human Augmentation in Overhead Assembly Tasks

Abstract

-Design and control of a novel extra robotic arm attached to the shoulder of a worker for performing tasks in the overhead area are presented. The wearable robot, a Supernumerary Robotic Limb (SRL), can lift an object and hold it while the wearer is securing the object using a tool with both hands. The worker does not have to take a laborious posture for a long time, reducing fatigue and injuries. Furthermore, a single worker can execute the task, which would otherwise require two workers. Two technical challenges and novel solutions are presented. One is to make the wearable robot simple and lightweight with use of a new type of Granular Jamming Gripper (GJG) that can grasp diverse objects from an arbitrary direction. This eliminates the need for orienting the gripper against the object with three-axis wrist joints, reducing the number of degrees of freedom (DOF) from 6 to 3. The other is an effective control algorithm that allows the wearer to move freely while the robot on the shoulder is holding an object. Unlike a robot sitting on a floor, the SRL worn by a human is disturbed by the movement of the wearer. An admittance-based control algorithm allows the robot to hold the object stably and securely despite the human movement and changes in posture. A 3 DOF prototype robot with a new GJG and an ergonomic body mounting gear is developed and tested. It is demonstrated that the robot can hold a large object securely in the overhead area despite the movement of the wearer while performing an assembly work.

Human augmentation by wearable supernumerary robotic limbs: review and perspectives

“…Early work on supernumerary arms also focused on devices to be mounted on the user's shoulders [15,16] and led to SRLs designed for overhead operations [17]. In [17], Bright and Asada developed an arm with a reduced number of DoFs (three) endowed with a soft Granular Jamming Gripper which can easily grasp objects from different directions without needing to be precisely oriented. The total weight of the device is around 5.5 kg.…”

“…Shoulder-Mounted SRL (2017), Bright and Asada [17] Fully actuated arm with 3 DoFs. Granular Jamming Gripper as end-effector.…”

“…A promising application of supernumerary robotic arms is the manufacturing of large objects (e.g. assembling planes [14,17]). This activity requires human workers to perform extremely complicated and fatiguing tasks (e.g.…”

Research on Simulation System for Human-SRL Collaborative Motion Planning

“…It is connected to the human body through straps and acts as an upper limb or a lower limb of the human to enhance the original working space and operation ability of the human. For example, SRL can be used to assist soldiers to complete the simultaneous shooting of multiple guns, to assist installation workers to clamp panels to be installed [4,5], to assist building workers, farmers, and welders to support their body [6], to assist supporting cleaning tools [7], and to assist the disabled to walk [8].…”

“…Tere are relatively few studies related to SRL. At present, there have been studies involving prototype structure design [5][6][7][8][9], joint control technology [4,6,8,10], human-machine collaborative motion planning [11], SRL operation methods [12][13][14][15][16][17], human-machine dynamics modeling [18][19][20], etc. Current operation methods for SRL include EMG mapping [12], EEG mapping [13], foot mapping [14,15], head mapping [16], and eyeball mapping [17].…”