Design and Testing of a Soft Robot with Variable Stiffness Based on Jamming Principles

doi:10.3901/JME.2020.23.067

Abstract

Abstract: A soft robot has high flexibility when performing tasks with moving and high stiffness, so it has important application in exploring and detecting complex environments. Based on the advantages of driving Pneu-Net and driven jamming mechanism, a soft robot with real-time variable stiffness and dynamic modeling methods is proposed. Firstly, the model of the soft actuator coupling pneumatic structure and jamming mechanism is established. Secondly, by using Hertzian contact model, a mathematical model of robot motion and theoretically investigated formation mechanisms of variable stiffness is built. Moreover, the pneumatically-driven structure is analyzed by using the finite element as well as the influences of pressure in cavities, considering shape and size of cavities on the bending angle of the soft robot are studied. Based on this, the pneumatically-driven structure is optimized. Finally, A prototype and testing of the soft robot arm with variable stiffness is implemented, which verified the variable stiffness and motion performances of the soft actuator. This study provides new theoretical and technical support for the design and stiffness control of a soft robot with variable stiffness.

Key words: variable stiffness, particle jamming, soft robot, three-dimensional printing, experimental research

CLC Number:

TP242

XU Fengyu, JIANG Quansheng, JIANG Fengyou, SHEN Jingjin, WANG Xingsong, JIANG Guoping. Design and Testing of a Soft Robot with Variable Stiffness Based on Jamming Principles[J]. Journal of Mechanical Engineering, 2020, 56(23): 67-77.

References

[1] AMEND J R,BROWN Jr E,Rodenberg N,et al. A positive pressure universal gripper based on the jamming of granular material[J]. IEEE Trans. Robotics,2012,28(2):341-350.
[2] HOU Taogang,YANG Xingbang. Design and experiment of a universal two-fingered hand with soft fingertips based on jamming effect[J]. Mechanism and Machine Theory,2019,133:706-719.
[3] ZHU Mingzhu. A fully multi-material three-dimensional printed soft gripper with variable stiffness for robust grasping[J]. Soft Robotics,2019,6(4):1-13.
[4] LI Yingtian,CHEN Yonghua,LI Yunquan. Distributed design of passive particle jamming based soft grippers[C]//2018 IEEE International Conference on Soft Robotics (RoboSoft),April 24-28,2018,Livorno,Italy,Malaysia:IEEE,2018:547-552.
[5] LI Yingtian, CHEN Yonghua,YANG Yang. Soft robotic grippers based on particle transmission[J]. IEEE/ASME Transactions on Mechatronics,2019,24(3):969-978.
[6] AMEND J,CHENG N,FAKHOURI S,et al. Soft robotics commercialization:Jamming grippers from research to product[J]. Soft Robotics,2016,3(4):213-222.
[7] WEI Ying,CHEN Yonghua,YANG Yang,et al. A soft robotic spine with tunable stiffness based on integrated ball joint and particle jamming[J]. Mechatronics,2016,33:84-92.
[8] WU Zhaoping,LI Xiaoning,GUO Zhonghua. A novel pneumatic soft gripper with a jointed endoskeleton structure[J]. Chinese Journal of Mechanical Engineering,2019,32(1):78-89.
[9] WEI Dunwen,GAO Tao,MO Xiaojuan,et al. Flexible bio-tensegrity manipulator with multi-degree of freedom and variable structure[J]. Chinese Journal of Mechanical Engineering,2020,30(3):56-66.
[10] KIM Y J,CHENG S,KIM S,et al. A novel layer jamming mechanism with tunable stiffness capability for minimally invasive surgery[J]. IEEE Trans. Robot,2013,29(4):1031-1042.
[11] CHENG N G,LOBOVSKY M B,KEATING S J,et al. Design and analysis of a robust,low-cost,highly articulated manipulator enabled by jamming of granular media[C]//2012 IEEE International Conference on Robotics Automation,May 14-18,2012,RiverCentre,Saint Paul,Minnesota,USA:IEEE,2012:4328-4333.
[12] LIN Nan. IMU-based active safe control of a variable stiffness soft actuator[J]. IEEE Robotics and Automation Letters,2019,4(2):1247-1254.
[13] 张明,房立金,孙凤,等.永磁变刚度柔性关节的力学分析与控制器设计[J].机械工程学报,2019,55(5):89-96. ZHANG Ming,FANG Lijin,SUN Feng,et al. Mechanical analysis and controller design of the permanent magnetic variable stiffness flexible joint[J]. Journal of Mechanical Engineering,2019,55(5):89-96.
[14] WALL V,DEIMEL R,BROCK O. Selective stiffening of soft actuators based on jamming[C]//2015 IEEE International Conference on Robotics Automation,May 26-30,2015,Seattle,Washington,USA:IEEE 2015,252-257.
[15] WEI Ying,CHEN Yonghua,REN Tao,et al. A novel,variable stiffness robotic gripper based on integrated soft actuating and particle jamming[J]. Soft Robotics,2016,3(3):134-143.
[16] STELTZ E,MOZEIKA A,RODENBERG N,et al. JSEL:Jamming skin enabled locomotion[C]//2009 IEEE/RSJ International Conference on Intelligent Robots and Systems,October 11-15,2009,St.Louis,USA:IEEE 2009:5672-5677.
[17] JIANG Pei. A variable stiffness gripper based on differential drive particle jamming[J]. Bioinspiration& Biomimetics,2019,14(5):1-14.
[18] WANG Tao,ZHANG Jinhua,LI Yue,et al. Electrostatic layer jamming variable stiffness for soft robotics[J]. IEEE/ASME Transactions on Mechatronics,2019,24(2):424-433.
[19] 姚立纲,李敬仪,东辉.气动软体机械臂模块变刚度性能分析[J].机械工程学报,2020,56(9):36-44. YAO Ligang,LI Jingyi,DONG Hui. Variable stiffness analysis on a pneumatic soft manipulator[J]. Journal of Mechanical Engineering,2020,56(9):36-44.
[20] 王田苗,郝雨飞,杨兴帮,等.软体机器人:结构、驱动、传感与控制[J].机械工程学报,2017,53(13):1-13. WANG Tianmiao,HAO Yufei,YANG Xingbang,et al. Soft robotics:Structure,actuation,sensing and control[J]. Journal of Mechanical Engineering,2017,53(13):1-13.
[21] ANDREW D,MARCHESE,ROBERT K,et al. A recipe for soft fluidic elastomer robots[J]. Soft Robotics,2014,2(1):7-25.
[22] MARCHESE A,TEDRAKE R,RUS D. Dynamics and trajectory optimization for a soft spatial fluidic elastomer manipulator[J]. International Journal of Robotics Research,2016,35(8):1000-1019.
[23] MARCHESE A,RUS D. Design,kinematics,and control of a soft spatial fluidic elastomer manipulator[J]. International Journal of Robotics Research,2016,35(7):840-869.
[24] GENT A N. On the relation between indentation hardness and Young's modulus[J]. Rubber Chemistry and Technology,2008,31(4):896-906.