Soft Humanoid Hands with Large Grasping Force Enabled by Flexible Hybrid Pneumatic Actuators

Liu, Xiaomin; Zhao, Yuping; Geng, Dexu; Chen, Shoue; Tan, Xiaobo; Cao, Changyong

doi:10.1089/soro.2020.0001

Cited by 60 publications

(26 citation statements)

References 35 publications

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“…The flexible finger belongs to the pneumatic composite elastomer, which is composed of an axial elongation type pneumatic artificial (the closed cavity formed among the latex tube, the constraint ring, and the upper and lower covers) and the spring plate in parallel. [28][29][30] The inner part of the finger is supplied with a latex tube, and the outer side of it is provided with a sheet-shaped constraint ring. One side of the constraint rings supplied with an elastic steel plate (Figure 2(a)).…”

Section: Structure and Function Of The Robotic Handmentioning

confidence: 99%

Kinematics modeling and grasping experiment of pneumatic four-finger flexible robotic hand

Liu

Geng

2021

Proceedings of the Institution of Mechanical Engineers, Part C:

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To solve the complex structure, poor flexibility, and heavyweight of the rigid robotic hand, a pneumatic four-finger flexible robotic hand is developed in this paper. The robotic hand is about 1.3 times as large as that of a human hand and each finger is composed of a single multi-drive bending joint. The kinematic model of the robotic hand is established by using homogeneous coordinate transformation matrix. Through the simulation experiment of the robotic hand structure, the trajectory, and workspace of the robotic hand are established. According to the experimental results of grasping performance of the robotic hand, the grasping forces of different geometric positions along the finger axis are obtained. The results show that the robotic hand can realize a variety of grasping modes, has flexible action and strong adaptive ability; it can grasp, hold, and pinch, as well as stably grasp objects such as cylinder, box, and sphere. In pinch grasp mode, the robotic hand can grip objects as thin as 1 mm and the diameter of the grasped object varies from 28 mm to 160 mm; the maximum mass that the robotic hand can grasp an object with a diameter of 90 mm under 0.35 MPa is 1386 g.

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Section: Structure and Function Of The Robotic Handmentioning

confidence: 99%

Kinematics modeling and grasping experiment of pneumatic four-finger flexible robotic hand

Liu

Geng

2021

Proceedings of the Institution of Mechanical Engineers, Part C:

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“…e maximum braking torque provided by the brake for a given air pressure was obtained using the torque calculation formula. Additionally, theoretical braking torque data were obtained by substituting the structural brake parameters into equation (14). Finally, Figure 14 illustrates the comparison between theoretical and experimental data.…”

Section: Mechanical Performance Experiments Of the Brakementioning

confidence: 99%

“…Although the design of rotary joints above fully applies the characteristics of elastic (soft) materials to achieve the rotary function, the joint stiffness cannot be adjusted actively. Additionally, the position cannot be maintained when the external load changes and can easily crack when in contact with the sharp surface [14]. In practical applications, pneumatic rotary joints should not only ensure motion flexibility but also have stable positioning and load-bearing capacity in a specific environment.…”

Section: Introductionmentioning

confidence: 99%

Study on the Structure and Performance of an Antagonistic Pneumatic Bidirectional Rotary Joint

Liu

Sun

Geng

et al. 2021

Mathematical Problems in Engineering

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An antagonistic pneumatic bidirectional rotary flexible joint was developed to improve both safety and environmental adaptability of service robots and associated human interactions. The joint comprises two semicircular rotary actuators with positive and negative symmetrical distributions and a pneumatic brake. As such, it achieves forward and reverse rotations, and its damping and braking are adjustable in real time, enabling it to maintain its position. According to the force/torque balance at the free end of the rotary actuator, the rotation angle static model was established. The relationship between the actuator rotation angle, driving torque, impedance torque, and air pressure was obtained experimentally. The brake airbag was manufactured using additive manufacturing and silicone gel casting technologies. The mathematical model of the braking torque was established next, and the model was verified through experiments. Furthermore, an experimental system was constructed to carry out the air pressure-angle, air pressure-torque, and speed response experiments without the load on the joint. The results have shown that the joint can achieve any position within ± 68.5° when the driving air pressure varies from 0 to 0.30 MPa; the time required to reach the maximum angle was 0.85 s. The joint has shown good adjustable damping characteristics. Lastly, the braking torque reached 4.21 Nm at 0.32 MPa, effectively maintaining the position.

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“…[ 3 ] Examples include pneumatically driven grippers, [ 4 ] soft active material‐based grippers, [ 5 ] octopus‐inspired soft arms, [ 6 ] elephant trunk‐inspired arms, [ 7 ] and humanoid hands. [ 2 ] Compared with traditional rigid robotic manipulators, [ 8 ] these soft counterparts are more compliant, more adaptable, and easier to control, thereby more suitable for safe machine‐human and machine‐environment interactions, such as grasping fragile objects, picking apples, and assisting elderly people and children. Moreover, soft manipulators are unique for physical and distributed computations through their compliance feature, reducing the needs for sophisticated algorithms and mechanisms in planning and control for real‐world applications.…”

Section: Introductionmentioning

confidence: 99%

“…Soft robotics makes full use of the softness, large deformation, and compatibility of various soft materials and actuation principles to achieve unique functionalities as well as safe manipulations. [1,2] Over the past decades, a variety of soft robotic manipulators, i.e., soft grippers and soft arms, have been studied. [3] Examples include pneumatically driven grippers, [4] soft active material-based grippers, [5] octopus-inspired soft arms, [6] elephant trunk-inspired arms, [7] and humanoid been widely used in a broad spectrum of fields, such as smart electronics, robotics, and virtual or augmented reality (VR/ AR).…”

Section: Introductionmentioning

confidence: 99%

Soft Robotic Manipulation System Capable of Stiffness Variation and Dexterous Operation for Safe Human–Machine Interactions

Chen

Pang

Cao

et al. 2021

Adv Materials Technologies

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Soft robots have attracted great attention in the past decades owing to their unique flexibility and adaptability for accomplishing tasks via simple control strategies, as well as their inherent safety for interactions with humans and environments. Here, a soft robotic manipulation system capable of stiffness variation and dexterous operations through a remotely controlled manner is reported. The smart manipulation system consists of a soft omnidirectional arm, a dexterous multimaterial gripper, and a self‐powered human–machine interface (HMI) for teleoperation. The cable‐driven soft arm is made of soft elastomers and embedded with low melting point alloy as a stiffness‐tuning mechanism. The self‐powered HMI patches are designed based on the triboelectric nanogenerator that utilizes a sliding mode of tribo‐layers made of copper and polytetrafluoroethylene. The novel soft manipulation system has great potential for soft and remote manipulation and human machine interactions in a variety of applications from elderly care to surgical operation to agriculture harvesting.

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Soft Humanoid Hands with Large Grasping Force Enabled by Flexible Hybrid Pneumatic Actuators

Cited by 60 publications

References 35 publications

Kinematics modeling and grasping experiment of pneumatic four-finger flexible robotic hand

Kinematics modeling and grasping experiment of pneumatic four-finger flexible robotic hand

Study on the Structure and Performance of an Antagonistic Pneumatic Bidirectional Rotary Joint

Soft Robotic Manipulation System Capable of Stiffness Variation and Dexterous Operation for Safe Human–Machine Interactions

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