Variable Stiffness Actuator and Variable Stiffness Flexible Gripper Based on Differential Gear Train

doi:10.3901/JME.2023.01.091

Abstract

Abstract: Combined with differential gear train and lever principle, a variable stiffness actuator with stiffness adjustment range from 0 to +∞ is designed, and its structure optimization design and energy consumption optimization design are completed. The variable stiffness actuator has the advantages of large range of variable stiffness, low energy consumption demand for stiffness adjustment, small space occupation, easy control, fast response speed, strong reliability, high feasibility of technical implementation, and has certain practical application significance. On this basis, an underactuated flexible claw with variable stiffness is designed. The variable stiffness actuator is taken as the driving unit of the claw joint, and the stiffness of the claw is changed by adjusting the stiffness of the variable stiffness actuator. Finally, the hardware platform of variable stiffness flexible claw was built, and the stiffness of the variable stiffness actuator was measured, which verified the feasibility of the variable stiffness actuator designed for stiffness regulation. The force control experiment of flexible hand claw with variable stiffness is carried out, and the grasping of soft object is realized successfully. The performance of the single finger of the variable stiffness flexible claw is analyzed, and the positive correlation between the finger stiffness and the stiffness of the variable stiffness actuator is verified, and the performance experimental verification of the variable stiffness flexible claw is completed.

Key words: variable stiffness actuator, the differential gear train, flexible gripper, gripper stiffness, under-actuated

CLC Number:

TG156

LONG Yilin, WANG Binluan, JIN Hongzhe, XU Weiming, ZHAO Jie. Variable Stiffness Actuator and Variable Stiffness Flexible Gripper Based on Differential Gear Train[J]. Journal of Mechanical Engineering, 2023, 59(1): 91-102.

References

[1] GREBENSTEIN M, ALBU-SCHAFFER A, BAHLS T, et al. The DLR hand arm system[C]//Robotics and Automation (ICRA), 2011 IEEE International Conference on IEEE, 2011.
[2] MIGLIORE S A, BROWN E A, DEWEERTH S P. Biologically inspired joint stiffness control, 2005[C]//IEEE, 2005.
[3] LOTTI F, TIEZZI P, VASSURA G, et al. Development of UB hand 3:Early results[C]//IEEE International Conference on Robotics & Automation. IEEE, 2006.
[4] MELCHIORRI C, PALLI G, BERSELLI G, et al. Development of the UB hand IV:Overview of design solutions and enabling technologies[J]. IEEE Robotics & Automation Magazine, 2013, 20(3):72-81.
[5] CARPI F, FREDIANI G, GERBONI C, et al. Enabling variable-stiffness hand rehabilitation orthoses with dielectric elastomer transducers[J]. Medical Engineering & Physics, 2014, 36(2):205-211.
[6] WANG W, AHN S. Shape memory alloy-based soft gripper with variable stiffness for compliant and effective grasping[J]. Soft Robotics, 2017, 4(4):379-389.
[7] WEI Y, CHEN Y, REN T, et al. A novel, variable stiffness robotic gripper based on integrated soft actuating and particle jamming[J]. Soft Robotics, 2016, 3(3):134-143.
[8] ASHTIANI M, HASHEMABADI S H, GHAFFARI A. A review on the magnetorheological fluid preparation and stabilization[J]. Journal of Magnetism and Magnetic Materials, 2015, 374:716-730.
[9] TONIETTI G, SCHIAVI R, BICCHI A. Design and control of a variable stiffness actuator for safe and fast physical human/robot interaction[C]//IEEE International Conference on Robotics & Automation. IEEE, 2006.
[10] SCHIAVI R, GRIOLI G, SEN S, et al. VSA-II:A novel prototype of variable stiffness actuator for safe and performing robots interacting with humans[C]//Robotics and Automation, 2008. ICRA 2008. IEEE International Conference on. IEEE, 2008.
[11] FUMAGALLI M, BARRETT E, STRAMIGIOLI S, et al. The mVSA-UT:A miniaturized differential mechanism for a continuous rotational variable stiffness actuator[C]//IEEE Ras & Embs International Conference on Biomedical Robotics & Biomechatronics. IEEE, 2012.
[12] TSAGARAKIS N G, SARDELLITTI I, CALDWELL D G. A new variable stiffness actuator (CompAct-VSA):Design and modelling[C]//Intelligent Robots and Systems (IROS), 2011 IEEE/RSJ International Conference on. IEEE, 2011.
[13] OKUBO T, OHMORI H. Energy saving by extremum-seeking control using an Actuator with Adjustable Stiffness (AwAS)[C]//Sice Conference. IEEE, 2014.
[14] JAFARI A, TSAGARAKIS NG, SARDELLITTI I, et al. Caldwell. A new actuator with adjustable stiffness based on a variable ratio lever mechanism[J]. IEEE/ASME Transactions on Mechatronics, 2012, 19(1):55-63
[15] JAFARI A, TSAGARAKIS N G, CALDWELL D G. AwAS-II:A new Actuator with Adjustable Stiffness based on the novel principle of adaptable pivot point and variable lever ratio[C]//IEEE International Conference on Robotics & Automation. IEEE, 2011.
[16] JIANG P, YANG Y, CHEN M Z Q, et al. A variable stiffness gripper based on differential drive particle jamming[J]. Bioinspiration & Biomimetics, 2019, 14(3):36009.
[17] MITSUI K, OZAWA R, KOU T. An under-actuated robotic hand for multiple grasps[C]//IEEE/RSJ International Conference on Intelligent Robots & Systems. IEEE, 2014.
[18] SHAO Y, ZHANG W, SU Y, et al. Design and optimisation of load-adaptive actuator with variable stiffness for compact ankle exoskeleton[J]. Mechanism and Machine Theory, 2021, 161:104323.
[19] CARPI F, KORNBLUH R, SOMMER-LARSEN P, et al. Electroactive polymer actuators as artificial muscles:are they ready for bioinspired applications?[J]. Bioinspir Biomim, 2011, 6(4):45006.
[20] VISSER L C, CARLONI R, STRAMIGIOLI S. Energy-efficient variable stiffness actuators[J]. IEEE Transactions on Robotics, 2011, 27(5):865-875.
[21] JIN H, YANG D, ZHANG H, et al. flexible actuator with variable stiffness and its decoupling control algorithm:principle prototype design and experimental verification[J]. IEEE/ASME Transactions on Mechatronics, 2018, 23(3):1279-1291.
[22] HAM K, HAN J, PARK Y. Soft gripper using variable stiffness mechanism and its application[J]. International Journal of Precision Engineering and Manufacturing, 2018, 19(4):487-494.
[23] VANDERBORGHT B, ALBU-SCHAEFFER A, BICCHI A, et al. Variable impedance actuators:A review[J]. Robotics and Autonomous Systems, 2013, 61(12):1601-1614.
[24] WOLF S, GRIOLI G, EIBERGER O, et al. Variable stiffness actuators:Review on design and components[J]. IEEE/ASME Transactions on Mechatronics, 2016, 21(5):2418-2430.
[25] SCHIAVI R, GRIOLI G, SEN S, et al. VSA-II:A novel prototype of variable stiffness actuator for safe and performing robots interacting with humans[C]//Robotics and Automation, 2008. ICRA 2008. IEEE International Conference on. IEEE, 2008.