A eutectic-alloy-infused soft actuator with sensing, tunable degrees of freedom, and stiffness properties

Hao, Yufei; Wang, Tianmiao; Xie, Zhexin; Sun, Wenguang; Liu, Zemin; Fang, Xi; Yang, Mujin; Wen, Li

doi:10.1088/1361-6439/aa9d0e

Cited by 90 publications

(61 citation statements)

References 40 publications

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“…All such robot structures can be categorized into two models, i.e., multifingered hand robots ( Figure 5) and multijoint extendable arms ( Table 3). All the multifingered hand robots [132][133][134][135][136][137][138][139][140][141][142][143][144][145][146] were developed to have a similar structure, with a metal or plastic base and fingers made up of hardened polyamide material.…”

Section: Manipulation Flexibilitymentioning

confidence: 99%

Continuum Robots for Manipulation Applications: A Survey

Kolachalama

Lakshmanan

2020

Journal of Robotics

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This paper presents a literature survey documenting the evolution of continuum robots over the past two decades (1999–present). Attention is paid to bioinspired soft robots with respect to the following three design parameters: structure, materials, and actuation. Using this three-faced prism, we identify the uniqueness and novelty of robots that have hitherto not been publicly disclosed. The motivation for this study comes from the fact that continuum soft robots can make inroads in industrial manufacturing, and their adoption will be accelerated if their key advantages over counterparts with rigid links are clear. Four different taxonomies of continuum robots are included in this study, enabling researchers to quickly identify robots of relevance to their studies. The kinematics and dynamics of these robots are not covered, nor is their application in surgical manipulation.

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Section: Manipulation Flexibilitymentioning

confidence: 99%

Continuum Robots for Manipulation Applications: A Survey

Kolachalama

Lakshmanan

2020

Journal of Robotics

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“…The research about piezoelectric sensor-actuators involves the development of composite materials with integrated sensing functions [ 1 ], structural health detection and correction [ 2 ], flexible actuators with variable stiffness [ 3 , 4 ], nano-level manipulators [ 5 , 6 ], medical robots and micro grippers [ 7 , 8 ]. Piezoelectric sensor-actuators can be divided into two types: structure-integrated and function-integrated.…”

Section: Introductionmentioning

confidence: 99%

A Dynamic Hysteresis Model and Nonlinear Control System for a Structure-Integrated Piezoelectric Sensor-Actuator

Shan

Song

Cao

et al. 2021

Sensors

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The piezoelectric sensor-actuator plays an important role in micro high-precision dynamic systems such as medical robots and micro grippers. These mechanisms need high-precision position control, while the size of the sensor and actuator should be as small as possible. For this paper, we designed and manufactured a structure-integrated piezoelectric sensor-actuator and proposed its PID (Proportion Integral Differential) control system based on the dynamic hysteresis nonlinear model and the inverse model. Through simplifying the structure of the piezoelectric sensor-actuator by the centralized parameter method, this paper establishes its dynamic model and explores the input–output transfer function by taking the relationship between the output force and displacement as the medium. The experiment shows the maximum distance of the hysteresis curve is 0.26 μm. By parsing the hysteresis curve, this paper presents a dynamic hysteresis nonlinear model and its inverse model based on a 0.5 Hz quasi-static model and linear transfer function. Simulation results show that the accuracy of the static model is higher than that of the dynamic model when the frequency is 0.5 Hz, but the compensation accuracy of the dynamic model is obviously better than that of the static model with the increase of the frequency. This paper also proposes a control system for the sensor-actuator by means of the inverse model. The simulation results indicate that the output root mean square error was reduced to one-quarter of the original, which proves that the structure-integrated piezoelectric sensor-actuator and its control system have a great significance for signal sensing and output control of micro high-precision dynamic systems.

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“…[42] There have been quite a number of studies focusing on this approach. [17,39,[43][44][45] Although progress has been achieved, similar to other FEA grippers, these continuums, helical grippers generally exhibit inherent low-load capacity soft grippers. As a result, it will be beneficial to have a gripper that possesses advantages of both being continuum to fit a wide range of object sizes and strong enough to handle large loads while providing highly sensitive force feedback to manipulate objects safely.…”

Section: Introductionmentioning

confidence: 99%

Bio‐Inspired Conformable and Helical Soft Fabric Gripper with Variable Stiffness and Touch Sensing

Hoang

Phan

Thai

et al. 2020

Adv Materials Technologies

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compliance of constituent materials enables soft grippers to safely work with flexible, fragile, and delicate objects. A great number of actuation methods have been investigated, including cable-driven mechanisms, [19] fluid elastomer actuators (FEA), [20,21] dielectric elastomer actuators, [22,23] magnetic actuators, [24-26] and shape memory materials including metal alloys [27,28] and polymers. [29] Among these actuation methods, FEA is one of the oldest and the most widespread technologies employed for soft robotic grippers owing to a number of advantages such as lightweight, high power-to-weight ratio, large stroke and force production, ease of fabrication, robustness, and low-cost materials. [30,31] FEA-based soft grippers have been mostly developed based on claws or human-like structures consisting of multiple inward-bending fingers. This design is suitable for gripping objects spanning a wide range of sizes. However, existing FEA-based grippers are ill-suited for applications that require high conformability or high-load sustainability. The integration of electro-adhesion, [23,32] gecko adhesion, [33,34] or variable stiffness structures (VSSs) can help improve the load capacity. Several studies also address both the issues by designing robotic fingers that can adjust their effective length via the use of segments of VSS. [21] Two main types of VSSs for soft grippers include vacuum-driven jamming of granules [35,36] or layers, [6] and phase-change materials such as thermoplastics, [12,37] shape memory polymers (SMPs), [20,21,38] and low-melting-point alloys (LMPAs). [22,39,40] In another approach, grippers with closed structures have been investigated in an attempt to improve both conformability and load capacity. [23,24,38-40] However, grippers with closed structures are not able to grip objects that are either smaller or larger than the opening orifice of the gripper. Another approach that has also been investigated involves the use of helical winding to enclose objects. This gripping strategy was inspired by natural instances such as elephant trunks, python body constriction, or cephalopod tentacles that use a continuum finger to helically grasp around the objects, thereby increasing the area of contact and stability between the gripper and objects. [41] Continuum, helical grippers that are not constrained by any host have the advantage of being free to wrap around objects and adapt to a wide range of object sizes, shapes, and orientations. There are many instances in nature where continuum, helical manipulators are used to efficiently grasp different objects with various shapes and sizes. Inspired by nature, this paper introduces a continuum, flat, scalable, helical soft-fabric robotic gripper that is thin and lightweight with stiffness tunability and sensory feedback. The gripper is fabricated by a facile method of simple insertion using a computerized technique from apparel engineering and controlled by a miniature hydraulic source to grasp different objects at different scales and weights. It uses a ...

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A eutectic-alloy-infused soft actuator with sensing, tunable degrees of freedom, and stiffness properties

Cited by 90 publications

References 40 publications

Continuum Robots for Manipulation Applications: A Survey

Continuum Robots for Manipulation Applications: A Survey

A Dynamic Hysteresis Model and Nonlinear Control System for a Structure-Integrated Piezoelectric Sensor-Actuator

Bio‐Inspired Conformable and Helical Soft Fabric Gripper with Variable Stiffness and Touch Sensing

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