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2000
Volume 18, Issue 1
  • ISSN: 2212-7976
  • E-ISSN: 1874-477X

Abstract

Background

The variable stiffness joint (VSJ) is a kind of inherent flexible actuator with independent controllable position and stiffness. Among various types of VSJs, the VSJs based on equivalent lever mechanisms and relying on changing the position of the lever pivot to adjust the transmission rate between input and output have the characteristic of low energy consumption for stiffness adjustment. Therefore, many patents have been applied for this type of VSJ. As the structural design of VSJs is an open research field, it is necessary and meaningful to explore novel structural designs of VSJs based on equivalent lever mechanisms.

Objective

The purpose of this article is to design a variable stiffness joint that changes the joint stiffness by adjusting the position of the lever pivot.

Methods

By referring and combining existing mechanical design ideas of some series configuration VSJs with good stiffness adjustment mechanism schemes, a novel series configuration VSJ based on an equivalent lever mechanism and relying on adjusting the position of the lever pivot to change joint stiffness has been implemented through CAD drawing, 3D printing, and assembly.

Results

Due to the wide movable range of the lever pivot, the designed VSJ has a wide adjustable range of stiffness. Moreover, assembly design and modular design have been achieved in terms of elastic output and power transmission, for easy installation and maintenance. The movability and stiffness adjustability of the designed VSJ were preliminarily verified through manual adjustment.

Conclusion

The assembly model of the VSJ demonstrates the feasibility of structural design. The stiffness adjustment experiment showed the variable stiffness ability of the designed VSJ.

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2024-05-10
2025-09-25

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References

  1. GrosuV. Rodriguez-GuerreroC. GrosuS. VanderborghtB. LefeberD. Design of smart modular variable stiffness actuators for robotic-assistive devices.IEEE/ASME Trans. Mechatron.20172241777178510.1109/TMECH.2017.2704665
     [Google Scholar]
  2. MoltedoM. CavalloG. BačekT. LataireJ. VanderborghtB. LefeberD. Rodriguez-GuerreroC. Variable stiffness ankle actuator for use in robotic-assisted walking: Control strategy and experimental characterization.Mechanism Mach. Theory201913460462410.1016/j.mechmachtheory.2019.01.017
     [Google Scholar]
  3. GlanzerE.M. AdamczykP.G. Design and validation of a semi-active variable stiffness foot prosthesis.IEEE Trans. Neural Syst. Rehabil. Eng.201826122351235910.1109/TNSRE.2018.287796230371376
     [Google Scholar]
  4. CestariM. Sanz-MerodioD. ArevaloJ.C. GarciaE. An adjustable compliant joint for lower-limb exoskeletons.IEEE/ASME Trans. Mechatron.201520288989810.1109/TMECH.2014.2324036
     [Google Scholar]
  5. DežmanM. GamsA. Rotatable cam-based variable-ratio lever compliant actuator for wearable devices.Mechanism Mach. Theory201813050852210.1016/j.mechmachtheory.2018.09.006
     [Google Scholar]
  6. TryggvasonH. StarkerF. ArmannsdottirA.L. LecomteC. JonsdottirF. Speed adaptable prosthetic foot: Concept description, prototyping and initial user testing.IEEE Trans. Neural Syst. Rehabil. Eng.202028122978298610.1109/TNSRE.2020.303632933151884
     [Google Scholar]
  7. ShepherdM.K. RouseE.J. The VSPA foot: A quasi-passive ankle-foot prosthesis with continuously variable stiffness.IEEE Trans. Neural Syst. Rehabil. Eng.201725122375238610.1109/TNSRE.2017.275011328885156
     [Google Scholar]
  8. CalancaA. MuradoreR. FioriniP. A review of algorithms for compliant control of stiff and fixed-compliance robots.IEEE/ASME Trans. Mechatron.201621261362410.1109/TMECH.2015.2465849
     [Google Scholar]
  9. XuJ. LiY. XuL. PengC. ChenS. LiuJ. XuC. ChengG. XuH. LiuY. ChenJ. A multi-mode rehabilitation robot with magnetorheological actuators based on human motion intention estimation.IEEE Trans. Neural Syst. Rehabil. Eng.201927102216222810.1109/TNSRE.2019.293700031443038
     [Google Scholar]
  10. ChenQ. ZiB. SunZ. LiY. XuQ. Design and development of a new cable-driven parallel robot for waist rehabilitation.IEEE/ASME Trans. Mechatron.20192441497150710.1109/TMECH.2019.2917294
     [Google Scholar]
  11. LiuQ. ZuoJ. ZhuC. MengW. AiQ. XieS.Q. Design and hierarchical force-position control of redundant pneumatic muscles-cable-driven ankle rehabilitation robot.IEEE Robot. Autom. Lett.20227150250910.1109/LRA.2021.312374735582110
     [Google Scholar]
  12. SunY. TangP. DongD. ZhengJ. ChenX. BaiL. Modeling and experimental evaluation of a pneumatic variable stiffness actuator.IEEE/ASME Trans. Mechatron.20222752462247310.1109/TMECH.2021.3116871
     [Google Scholar]
  13. VanderborghtB. Albu-SchaefferA. BicchiA. BurdetE. CaldwellD.G. CarloniR. CatalanoM. EibergerO. FriedlW. GaneshG. GarabiniM. GrebensteinM. GrioliG. HaddadinS. HoppnerH. JafariA. LaffranchiM. LefeberD. PetitF. StramigioliS. TsagarakisN. Van DammeM. Van HamR. VisserL.C. WolfS. Variable impedance actuators: A review.Robot. Auton. Syst.201361121601161410.1016/j.robot.2013.06.009
     [Google Scholar]
  14. TagliamonteN.L. SergiF. AccotoD. CarpinoG. GuglielmelliE. Double actuation architectures for rendering variable impedance in compliant robots: A review.Mechatronics20122281187120310.1016/j.mechatronics.2012.09.011
     [Google Scholar]
  15. WolfS. GrioliG. EibergerO. FriedlW. GrebensteinM. HoppnerH. BurdetE. CaldwellD.G. CarloniR. CatalanoM.G. LefeberD. StramigioliS. TsagarakisN. Van DammeM. Van HamR. VanderborghtB. VisserL.C. BicchiA. Albu-SchafferA. Variable stiffness actuators: Review on design and components.IEEE/ASME Trans. Mechatron.20162152418243010.1109/TMECH.2015.2501019
     [Google Scholar]
  16. KluteG. GorgesJ. Controlled coronal stiffness prosthetic ankle.US Patent 2016151175A12016
  17. RouseE. J. ShepherdM. K. Biomimetic and variable stiffness ankle system and related methods.US Patent 2018092761A12018
  18. HerrH. M. AuK. W. S. PaluskaD. J. DilworthP. Artificial ankle-foot system with spring, variable-damping, and series-elastic actuator components.US Patent 2019321201A12019
  19. LahiffC.-A. K. ReedK. B. KimS. H. RamakrishnanT. Knee orthosis with variable stiffness and damping.US Patent 10736765B12020
  20. ChenB. WangB. ZhengC. ZiB. Design and simulation of a robotic knee exoskeleton with a variable stiffness actuator for gait rehabilitation. Proceedings of the 27th International Conference on Mechatronics and Machine Vision in PracticeShanghai, China202110.1109/M2VIP49856.2021.9665028
     [Google Scholar]
  21. ZhuY. WuQ. ChenB. XuD. ShaoZ. Design and evaluation of a novel torque-controllable variable stiffness actuator with reconfigurability.IEEE/ASME Trans. Mechatron.202227129230310.1109/TMECH.2021.3063374
     [Google Scholar]
  22. AhmadA. MohammadI. A. MohamedB. IrfanH. Design optimization of a variable stiffness actuator for knee exoskeleton application.IEEE Access2023115274052749
     [Google Scholar]
  23. SongJ. ZhuA. TuY. ZhangX. CaoG. Novel design and control of a crank-slider Series elastic actuated knee exoskeleton for compliant human–robot interaction.IEEE/ASME Trans. Mechatron.202328153154210.1109/TMECH.2022.3204921
     [Google Scholar]
  24. WangB. XuD. WangZ. Variable stiffness lower extremity exoskeleton power assist robot.WO Patent 2019CN710832019
  25. LeeS. R. KangO. H. YunJ. H. YiH. Reaction force adjusting device and method using variable stiffness actuator of exoskeleton system.KR Patent 20180037619A2019
  26. KongK. C. WooH. S. KimY. S. Wearable robot having variable stiffness structure.KR20200020853A2021
  27. HerrH. BlayaJ. PrattG. A. Motorized limb assistance device.US Patent 201715584289A2017
  28. LecomteC. G. StarkerF. TryggvasonH. Variable stiffness mechanism and limb support device incorporating the same.US Patent 201816132004A2021
  29. ChoiH. RamezaniS. Method and apparatus for enhancing operation of leg prosthesis.WO Patent 2021US639782022
  30. LiX. HaoY. ZhangJ. WangC. LiD. ZhangJ. Design, modeling and experiments of a variable stiffness soft robotic glove for stroke patients with clenched fist deformity.IEEE Robot. Autom. Lett.2023874044405110.1109/LRA.2023.3279613
     [Google Scholar]
  31. BaeJ. B. JoI. S. Force reflecting system using variable stiffness drive system including magneto-rheological elastomer.KR Patent 101907584B12018
  32. WeiH. ShanY. ZhaoY. QiL. ZhaoX. A soft robot with variable stiffness multidirectional grasping based on a folded plate mechanism and particle jamming.IEEE Trans. Robot.20223863821383110.1109/TRO.2022.3183533
     [Google Scholar]
  33. RenH. Variable stiffness actuator.CN Patent 108724166A2018
  34. EsfahaniE. T. Robotic gripper with variable stiffness actuators and methods for same.US Patent 20200147813A12020
  35. KimS. SungE. ParkJ. ARC joint: anthropomorphic rolling contact joint with kinematically variable torsional stiffness.IEEE Robot. Autom. Lett.2023831810181710.1109/LRA.2023.3243439
     [Google Scholar]
  36. NagamanikandanG. ShashankR. AsokanT. Design of a variable stiffness joint module to quickly change the stiffness and to reduce the power consumption.IEEE Access20208138318138330
     [Google Scholar]
  37. BraunD. KimS. Variable stiffness mechanisms for low energy cost stiffness modulation.US Patent 2022118603A12022
  38. HuB. LiuF. ChengK. ChenW. ShanX. YuH. Stiffness optimal modulation of a variable stiffness energy storage hip exoskeleton and experiments on its assistance effect.IEEE Trans. Neural Syst. Rehabil. Eng.2023311045105510.1109/TNSRE.2023.3236256
     [Google Scholar]
  39. KimS.Y. BraunD.J. Variable stiffness floating spring leg: Performing net-zero energy cost tasks not achievable using fixed stiffness springs.IEEE Robot. Autom. Lett.2023895400540710.1109/LRA.2023.3292584
     [Google Scholar]
  40. ChenJ. DingQ. YanW. YanK. ChenJ. ChanJ.Y-K. ChengS.S. A variable length, variable stiffness flexible instrument for transoral robotic surgery.IEEE Robot. Autom. Lett.2022723835384210.1109/LRA.2022.3147454
     [Google Scholar]
  41. BarkanU. CorinneD. MasashiH. PaoloF. TatsuyaT. TomoyukiN. JunM. Variable ankle stiffness improves balance control: Experiments on a bipedal exoskeleton.IEEE/ASME Trans. Mechatron.20162117987
     [Google Scholar]
  42. ZhuY. BaiS. Human compatible stiffness modulation of a novel VSA for physical human-robot interaction.IEEE Robot. Autom. Lett.2023853023303010.1109/LRA.2023.3257711
     [Google Scholar]
  43. NiuZ. AwadM.I. ShahU.H. BoushakiM.N. ZweiriY. SeneviratneL. HussainI. Towards safe physical human-robot interaction by exploring the rapid stiffness switching feature of discrete variable stiffness actuation.IEEE Robot. Autom. Lett.2022738084809110.1109/LRA.2022.3185366
     [Google Scholar]
  44. HuangQ. MengL. YuZ. ChenX. MaG. HuangH. A variable stiffness robot joint.CN Patent 104440936A2015
  45. KimS. Y. ChoiS. K. ParkC. H. LeeS. H. HamS. Y. KimB. I. Variable stiffness joint using differential gears and method.KR Patent 20160028676A2016
  46. SchmmelsJ. M. BernhardA. RiceJ. Variable stiffness series elastic actuator.WO Patent 2017180968A12017
  47. JeongH.-H. CheongJ.-N. KangB.-K. Variable stiffness robotic joint system.US Patent 2018009116A12018
  48. JosephM. S. AndrewB. JacobR. Variable stiffness series elastic actuator.CN Patent 109476023A2019
  49. MunozG. J. M. NavarroC. E. ChaconT. E. DiazL. A. Elastic device with variable rigidity.ES Patent 2797550A12020
  50. AhnK. K. ToX. D. VoC. P. Adjustable stiffness actuator.KR Patent 102197484B12020
  51. ShenY. JinJ. XuY. MeiJ. ZhaoJ. BaoG. A variable stiffness joint of a soft manipulator based on layer disturbance.CN Patent 116460887A2023
  52. BraunD. MathewsC. W. Method and apparatus for human augmentation and robot actuation.US Patent 2023036736A12023
  53. LiuL. LeonhardtS. MisgeldB.J.E. Design and control of a mechanical rotary variable impedance actuator.Mechatronics20163922623610.1016/j.mechatronics.2016.06.002
     [Google Scholar]
  54. ShaoY. ZhangW. DingX. Configuration synthesis of variable stiffness mechanisms based on guide-bar mechanisms with length-adjustable links.Mechanism Mach. Theory202115610415310.1016/j.mechmachtheory.2020.104153
     [Google Scholar]
  55. WuJ. WangZ. ChenW. WangY. LiuY. Design and validation of a novel leaf spring-based variable stiffness joint with reconfigurability.IEEE/ASME Trans. Mechatron.20202542045205310.1109/TMECH.2020.2995533
     [Google Scholar]
  56. ZhuY. WuQ. ChenB. ZhaoZ. Design and voluntary control of variable stiffness exoskeleton based on sEMG driven model.IEEE Robot. Autom. Lett.2022725787579410.1109/LRA.2022.3160668
     [Google Scholar]
  57. LiuY. GuoS. YangZ. HirataH. TamiyaT. A home-based bilateral rehabilitation system with sEMG-based real-time variable stiffness.IEEE J. Biomed. Health Inform.20212551529154110.1109/JBHI.2020.302730332991291
     [Google Scholar]
  58. LiuL. MisgeldB.J.E. PomprapaA. LeonhardtS. A testable robust stability framework for the variable impedance control of 1-DOF exoskeleton with variable stiffness actuator.IEEE Trans. Control Syst. Technol.20212962728273710.1109/TCST.2021.3051716
     [Google Scholar]
  59. LiX. ZhuH. LinW. ChenW. LowK.H. Structure-controlled variable stiffness robotic joint based on multiple rotary flexure hinges.IEEE Trans. Ind. Electron.20216812124521246110.1109/TIE.2020.3044795
     [Google Scholar]
  60. LiZ. BaiS. A novel revolute joint of variable stiffness with reconfigurability.Mechanism Mach. Theory201913372073610.1016/j.mechmachtheory.2018.12.011
     [Google Scholar]
  61. MalosioM. SpagnuoloG. PriniA. Molinari TosattiL. LegnaniG. Principle of operation of RotWWC-VSA, a multi-turn rotational variable stiffness actuator.Mechanism Mach. Theory2017116344910.1016/j.mechmachtheory.2017.05.006
     [Google Scholar]
  62. NingY. XuW. HuangH. LiB. LiuF. Design methodology of a novel variable stiffness actuator based on antagonistic-driven mechanism.Proc. Inst. Mech. Eng., C J. Mech. Eng. Sci.201923319-206967698410.1177/0954406219869968
     [Google Scholar]
  63. GroothuisS.S. RusticelliG. ZucchelliA. StramigioliS. CarloniR. The variable stiffness actuator vsaUT-II: mechanical design, modeling, and identification.IEEE/ASME Trans. Mechatron.201419258959710.1109/TMECH.2013.2251894
     [Google Scholar]
  64. AmirJ. NikosG. T. IreneS. DarwinG. C. A new actuator with adjustable stiffness based on a variable ratio lever mechanism.IEEE/ASME Trans Mechatron20141915563
     [Google Scholar]
  65. UsmanM. RazaA. Development of adjustable stiffness actuator by varying lever arm length.Zhongguo Gongcheng Xuekan201740865165810.1080/02533839.2017.1385423
     [Google Scholar]
  66. SunJ. GuoZ. ZhangY. XiaoX. TanJ. A novel design of serial variable stiffness actuator based on an Archimedean spiral relocation mechanism.IEEE/ASME Trans. Mechatron.20182352121213110.1109/TMECH.2018.2854742
     [Google Scholar]
  67. YixinS. DiS. WuxiangZ. XilunD. Design and evaluation of variable stiffness actuators with predefined stiffness profiles.IEEE Trans. Autom. Sci. Eng.2023113
     [Google Scholar]
  68. GuoJ. GuoJ. Mechanical structure design and actuation characteristics analysis of the parallel driven variable stiffness actuator with unrestricted rotation range of the output shaft.IEEE Access202210835298356610.1109/ACCESS.2022.3196930
     [Google Scholar]
  69. MatteoF. EamonB. StefanoS. RaffaellaC. The mVSA-UT: A miniaturized differential mechanism for a continuous rotational variable stiffness actuator. Proceedings of the Fourth IEEE RAS/EMBS International Conference on Biomedical Robotics and BiomechatronicsRoma, Italy2012
     [Google Scholar]
  70. JinH. YangD. ZhangH. LiuZ. ZhaoJ. Flexible actuator with variable stiffness and its decoupling control algorithm: Principle prototype design and experimental verification.IEEE/ASME Trans. Mechatron.20182331279129110.1109/TMECH.2018.2791499
     [Google Scholar]
  71. LiuL. LeonhardtS. MisgeldB.J.E. Experimental validation of a torque-controlled variable stiffness actuator tuned by gain scheduling.IEEE/ASME Trans. Mechatron.20182352109212010.1109/TMECH.2018.2854416
     [Google Scholar]
  72. LiuL. LeonhardtS. NgoC. MisgeldB.J.E. Impedance-controlled variable stiffness actuator for lower limb robot applications.IEEE Trans. Autom. Sci. Eng.2020172991100410.1109/TASE.2019.2954769
     [Google Scholar]
  73. LiuL. HongZ. PenzlinB. MisgeldB.J.E. NgoC. BergmannL. LeonhardtS. Low impedance-guaranteed gain-scheduled GESO for torque-controlled VSA with application of exoskeleton-assisted sit-to-stand.IEEE/ASME Trans. Mechatron.20212642080209110.1109/TMECH.2020.3032372
     [Google Scholar]
  74. HarderM. KepplerM. MengX. OttC. HoppnerH. DietrichA. Simultaneous motion tracking and joint stiffness control of bidirectional antagonistic variable-stiffness actuators.IEEE Robot. Autom. Lett.2022736614662110.1109/LRA.2022.3176094
     [Google Scholar]
  75. ChenB. LiuK. LiaoZ. JiangS. ShenY. WuQ. Variable stiffness joints and their working methods and control algorithms.CN Patent 116619438A2023
  76. GargA. AggarwalP. AggarwalY. BelarbiM.O. ChalakH.D. TounsiA. Machine learning models for predicting the compressive strength of concrete containing nano silica.Comput. Concr.20223013342
     [Google Scholar]
  77. GargA. BelarbiM.O. TounsiA. LiL. SinghA. MukhopadhyayT. Predicting elemental stiffness matrix of FG nanoplates using Gaussian Process Regression based surrogate model in framework of layerwise model.Eng. Anal. Bound. Elem.202214377979510.1016/j.enganabound.2022.08.001
     [Google Scholar]
  78. HabichT-L. KleinjohannS. SchapplerM. Learning-based position and stiffness feedforward control of antagonistic soft pneumatic actuators using Gaussian processes. Proceedings of the 2023 IEEE International Conference on Soft Robotics (RoboSoft)Singapore, Singapore2022
     [Google Scholar]
  79. AnsariY. MantiM. FaloticoE. CianchettiM. LaschiC. Multiobjective optimization for stiffness and position control in a soft robot arm module.IEEE Robot. Autom. Lett.20183110811510.1109/LRA.2017.2734247
     [Google Scholar]
  80. AngeliniF. MengacciR. SantinaC.D. CatalanoM.G. GarabiniM. BicchiA. GrioliG. Time generalization of trajectories learned on articulated soft robots.IEEE Robot. Autom. Lett.2020523493350010.1109/LRA.2020.2977268
     [Google Scholar]
  81. ShettyV.S. LeeU.H. IngrahamK.A. RouseE.J. A data driven approach for predicting preferred ankle stiffness of a quasi-passive prosthesis.IEEE Robot. Autom. Lett.2022723467347410.1109/LRA.2022.3144790
     [Google Scholar]
/content/journals/meng/10.2174/0122127976287776240426105333
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Mechanical Design of Variable Stiffness Joint Based on Planetary Gear Train and Modular Elastic Element
Recent Patents on Mechanical Engineering 18, 68 (2025); https://doi.org/10.2174/0122127976287776240426105333
/content/journals/meng/10.2174/0122127976287776240426105333
/content/journals/meng/10.2174/0122127976287776240426105333
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  • Article Type:     Research Article
Keyword(s): mechanical structure design; modular elastic element; planetary gear train; series configuration; stiffness adjustment mechanism; Variable stiffness joint

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