Pre-Charged Pneumatic Soft Gripper With Closed-Loop Control

Pneumatic soft grippers have nonlinear continuum deformation enabling them to adapt to irregular object shapes. Most of the existing pneumatic soft grippers use only open-loop control. Attempts for closed-loop control of soft grippers are all based on air pressure regulation, which is inaccurate and cumbersome due to nonlinear performance of the soft actuator and the compressible nature of air. In this letter, we present a controllable soft gripper based on pre-charged pneumatic soft actuators. The soft actuators, with the same design as a normal bending pneumatic soft actuator, are pre-charged with air to a preset pressure through a one-way check valve. The bending angle and bending speed of soft actuators are controlled by servomotors through tendons based on feedback data from force and proximity sensors. Kinematic models of the soft actuators are developed. Dynamic properties are experimentally studied. A prototype gripper with closed-loop control is developed for controllable grasping demonstration.

[1]  Seungwan Ryu,et al.  Soft robot review , 2017 .

[2]  Carlo Menon,et al.  A Soft-Touch Gripper for Grasping Delicate Objects , 2017, IEEE/ASME Transactions on Mechatronics.

[3]  Sung-Hoon Ahn,et al.  Soft composite hinge actuator and application to compliant robotic gripper , 2016 .

[4]  WeiYing,et al.  A Novel, Variable Stiffness Robotic Gripper Based on Integrated Soft Actuating and Particle Jamming , 2016 .

[5]  Chang Li,et al.  Design and Fabrication of a Soft Robotic Hand With Embedded Actuators and Sensors , 2015 .

[6]  Filip Ilievski,et al.  Soft robotics for chemists. , 2011, Angewandte Chemie.

[7]  D. Floreano,et al.  Soft Robotic Grippers , 2018, Advanced materials.

[8]  D. Rus,et al.  Design, fabrication and control of soft robots , 2015, Nature.

[9]  Ian D. Walker,et al.  Soft robotics: Biological inspiration, state of the art, and future research , 2008 .

[10]  Yonghua Chen,et al.  Precharged Pneumatic Soft Actuators and Their Applications to Untethered Soft Robots. , 2018, Soft robotics.

[11]  Gih-Keong Lau,et al.  Dielectric elastomer fingers for versatile grasping and nimble pinching , 2017 .

[12]  Inho Cho,et al.  Microrobotic tentacles with spiral bending capability based on shape-engineered elastomeric microtubes , 2015, Scientific Reports.

[13]  Fumiya Iida,et al.  Soft Manipulators and Grippers: A Review , 2016, Front. Robot. AI.

[14]  George Nikolakopoulos,et al.  Piecewise Affine Modeling and Constrained Optimal Control for a Pneumatic Artificial Muscle , 2014, IEEE Transactions on Industrial Electronics.

[15]  Kai Tang,et al.  Soft damper for quick stabilization of soft robotic actuator , 2016, 2016 IEEE International Conference on Real-time Computing and Robotics (RCAR).

[16]  D. Floreano,et al.  Versatile Soft Grippers with Intrinsic Electroadhesion Based on Multifunctional Polymer Actuators , 2016, Advanced materials.

[17]  Yong Hu,et al.  Passive and Active Particle Damping in Soft Robotic Actuators *This work is funded by a Basic Research Grant from the University of Hong Kong. , 2018, 2018 IEEE International Conference on Robotics and Automation (ICRA).

[18]  Arianna Menciassi,et al.  Feedback Control of Soft Robot Actuators via Commercial Flex Bend Sensors , 2017, IEEE/ASME Transactions on Mechatronics.

[19]  James E. Bobrow,et al.  Modeling, Identification, and Control of a Pneumatically Actuated, Force Controllable Robot , 1996 .

[20]  YapHong Kai,et al.  High-Force Soft Printable Pneumatics for Soft Robotic Applications , 2016 .

[21]  Gursel Alici,et al.  Soft and smart modular structures actuated by shape memory alloy (SMA) wires as tentacles of soft robots , 2016 .

[22]  Kaspar Althoefer,et al.  Tendon-Based Stiffening for a Pneumatically Actuated Soft Manipulator , 2016, IEEE Robotics and Automation Letters.

[23]  Huichan Zhao,et al.  Flexible and stretchable sensors for fluidic elastomer actuated soft robots , 2017 .

[24]  Robert J. Wood,et al.  Soft robotic glove for combined assistance and at-home rehabilitation , 2015, Robotics Auton. Syst..

[25]  Heinrich M. Jaeger,et al.  Universal robotic gripper based on the jamming of granular material , 2010, Proceedings of the National Academy of Sciences.

[26]  E. Makino,et al.  Thin Film Shape Memory Alloy Microactuators , 2001 .

[27]  Robert J. Wood,et al.  Soft Robotic Grippers for Biological Sampling on Deep Reefs , 2016, Soft robotics.

[28]  Minoru Taya,et al.  A variable stiffness dielectric elastomer actuator based on electrostatic chucking. , 2017, Soft matter.

[29]  Oliver Brock,et al.  A novel type of compliant and underactuated robotic hand for dexterous grasping , 2016, Int. J. Robotics Res..

[30]  Darwin G. Caldwell,et al.  Control of pneumatic muscle actuators , 1995 .