Leveraging the Human Operator in the Design and Control of Supernumerary Robotic Limbs

Guggenheim, Jacob; Hoffman, Rachel M.; Song, Hanjun; Asada, H. Harry

doi:10.1109/lra.2020.2970948

Cited by 28 publications

(28 citation statements)

References 12 publications

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“…Extrinsic muscular null space has been used for the control of a sixth finger using facial muscles [66] or for the control of external devices using torso muscles [67,68]. Others studies have focused instead on the intrinsic kinematic null space, such as a third limb controlled through force sensors on the fingertips [69]. Applications of neural null space for the control of external devices through brain-machine interfaces, such as a third arm [33] or one of the two DoFs of a cursor in a 2D virtual environment [70,71], have also been reported.…”

Section: Discussionmentioning

confidence: 99%

Simultaneous control of natural and extra degrees of freedom by isometric force and electromyographic activity in the muscle-to-force null space

et al. 2022

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Objective. Muscle activation patterns in the muscle-to-force null space, i.e., patterns that do not generate task-relevant forces, may provide an opportunity for motor augmentation by allowing to control additional end-effectors simultaneously to natural limbs. Here we tested the feasibility of muscular null space control for augmentation by assessing simultaneous control of natural and extra degrees of freedom. Approach. We instructed eight participants to control translation and rotation of a virtual 3D end-effector by simultaneous generation of isometric force at the hand and null space activity extracted in real-time from the electromyographic signals recorded from 15 shoulder and arm muscles. First, we identified the null space components that each participant could control more naturally by voluntary co-contraction. Then, participants performed several blocks of a reaching and holding task. They displaced an ellipsoidal cursor to reach one of nine targets by generating force, and simultaneously rotated the cursor to match the target orientation by activating null space components. We developed an information-theoretic metric, an index of difficulty defined as the sum of a spatial and a temporal term, to assess individual null space control ability for both reaching and holding. Main Results. On average, participants could reach the targets in most trials already in the first block (72%) and they improved with practice (maximum 93%) but holding performance remained lower (maximum 43%). As there was a high inter-individual variability in performance, we performed a simulation with different spatial and temporal task conditions to estimate those for which each individual participants would have performed best. Significance. Muscular null space control is feasible and may be used to control additional virtual or robotics end-effectors. However, decoding of motor commands must be optimized according to individual null space control ability.

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Section: Discussionmentioning

confidence: 99%

Simultaneous control of natural and extra degrees of freedom by isometric force and electromyographic activity in the muscle-to-force null space

et al. 2022

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“…For the 3 DoFs device, impedance control with virtual stiffness and damping coefficients tuned experimentally for each task to maximize dynamic response while giving a safe humanrobot interaction [31]. Lightweight Superlimb (2020), Guggenheim et al [22] Two motors are used to actuate the roll and z DoFs and a qb Robotics SoftHand Gripper is used at the end-effector.…”

Section: Controlmentioning

confidence: 99%

Human augmentation by wearable supernumerary robotic limbs: review and perspectives

et al. 2021

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“…To provide more personalized and adaptive assistance, FSM have been combined with either human-model-based or learning-based approaches [25, 105, 106 ••, [120][121][122][123]. The new approaches still divide a task into several states but the trajectory in each state was generated through the biomechanical models of the human joints or machine learning models.…”

Section: High-level Controllermentioning

confidence: 99%

Human Assistance and Augmentation with Wearable Soft Robotics: a Literature Review and Perspectives

et al. 2021

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Purpose of ReviewWearable soft robotics has demonstrated many unique capabilities in human assistance and augmentation. This paper discusses the recent trends and remaining challenges in designing soft actuators, soft sensors, and controllers for wearable soft robots.Recent Findings Different actuation mechanisms for wearable systems were investigated in this review. We include a synopsis on the design of soft sensors and algorithms for sensor fusion and discuss the recent trends for sensing simultaneous deformations and implementing machine learning techniques for soft sensor fusion. We also present a discussion on layered controller design and the evaluation metrics for experiments with healthy and impaired subjects. SummaryWe review three commonly used soft actuation mechanisms and provide their characteristics, in which the balance between material stiffness and functionality is still a challenge. We present the advances in soft sensor design and discuss the challenges in fusion algorithms for wearable soft sensors, such as inter-subject adaptability and sensor location movement. We also discuss the model-based and model-free controller design together with the evaluation criteria for healthy and impaired users, in which autonomous operation for personalized assistance is still an open challenge for controller design.

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Leveraging the Human Operator in the Design and Control of Supernumerary Robotic Limbs

Cited by 28 publications

References 12 publications

Simultaneous control of natural and extra degrees of freedom by isometric force and electromyographic activity in the muscle-to-force null space

Simultaneous control of natural and extra degrees of freedom by isometric force and electromyographic activity in the muscle-to-force null space

Human augmentation by wearable supernumerary robotic limbs: review and perspectives

Human Assistance and Augmentation with Wearable Soft Robotics: a Literature Review and Perspectives

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