1. School of Automation Engineering, University of Electronic Science and Technology of China, Chengdu 610054, China; 2. School of Mechanical and Electrical Engineering, University of Electronic Science and Technology of China, Chengdu 610054, China
Abstract:The causes and solutions of high crutch pressure generated by paraplegia patients in sit-to-stand (STS) movement with lower-limb exoskeleton assistance are studied. In order to explore the relationship between ankle stiffness and crutch pressure, a human-exoskeleton coupled dynamic model is established, and the crutch pressure is introduced as an external force. An exoskeleton STS movement verification experiment is designed to verify the importance of ankle stiffness for reducing crutch pressure. By adjusting the ankle stiffness of a walking assistance exoskeleton named "AIDER", the subjects' average loss energy and the changes of the sole pressure center during the entire STS movement are observed. The results show that the subjects' average loss energy is reduced by 45.18% and the stability is improved by 34.99% after adjusting the ankle stiffness. It is verified that a proper ankle stiffness can effectively reduce the subject's pressure on crutches during STS movement assisted by the lower-limb walking assistance exoskeleton.
[1] Reinhardt J D, Zheng Y, Xu G, et al.People with spinal cord injury in China[J]. American Journal of Physical Medicine & Rehabilitation, 2017, 96(2): S61-S65. [2] Riley P O, Schenkman M L, Mann R W, et al.Mechanics of a constrained chair-rise[J]. Journal of Biomechanics, 1991, 24(1): 77-85. [3] Shih T Y, Wu C Y, Lin K C, et al.Effects of action observation therapy and mirror therapy after stroke on rehabilitation outcomes and neural mechanisms by MEG: Study protocol for a randomized controlled trial[J]. Trials, 2017, 18(1). DOI: 10. 1186/s13063-017-2205-z. [4] Strausser K A, Swift T A, Zoss A B, et al.Mobile exoskeleton for spinal cord injury: Development and testing[C]//ASME Dynamic Systems and Control Conference. New York, USA: ASME, 2012: 419-425. [5] Esquenazi A, Talaty M, Packel A, et al.The ReWalk powered exoskeleton to restore ambulatory function to individuals with thoracic-level motor-complete spinal cord injury[J]. American Journal of Physical Medicine & Rehabilitation, 2012, 91(11): 911-921. [6] Kawamoto H, Lee S, Kanbe S, et al.Power assist method for HAL-3 using EMG-based feedback controller[C]//IEEE International Conference on Systems, Man and Cybernetics. Piscataway, USA: IEEE, 2003: 1648-1653. [7] Lee K, Liu D, Perroud L, et al.A brain-controlled exoskeleton with cascaded event-related desynchronization classifiers[J]. Robotics and Autonomous Systems, 2017, 90: 15-23. [8] Smith A J J, Fournier B N, Nantel J, et al.Estimating upper extremity joint loads of persons with spinal cord injury walking with a lower extremity powered exoskeleton and forearm crutches[J]. Journal of Biomechanics, 2020, 107. DOI: 10.1016/ j.jbiomech.2020.109835. [9] Fournier B N, Lemaire E D, Smith A J J, et al.Modeling and simulation of a lower extremity powered exoskeleton[J]. IEEE Transactions on Neural Systems and Rehabilitation Engineering, 2018, 26(8): 1596-1603. [10] Wu C, Zhang T, Liao Y Q, et al.Self-adaptive control strategy for exoskeleton to help paraplegic patients stand up and sit down[C]//35th Chinese Control Conference. Piscataway, USA: IEEE, 2016: 6189-6194. [11] Dehail P, Bestaven E, Muller F, et al.Kinematic and electromyographic analysis of rising from a chair during a "sit-to-walk" task in elderly subjects: Role of strength[J]. Clinical Biomechanics, 2007, 22(10): 1096-1103. [12] Bahrami F, Riener R, Jabedar-Maralani P, et al.Biomechanical analysis of sit-to-stand transfer in healthy and paraplegic subjects[J]. Clinical Biomechanics, 2000, 15(2): 123-133. [13] Daines K, Lemaire E D, Smith A, et al.Sit-to-stand and stand-to-sit crutch use for lower extremity powered exoskeletons[C] //IEEE International Symposium on Robotics and Intelligent Sensors. Piscataway, USA: IEEE, 2017: 358-363. [14] Bhardwaj S, Khan A A, Muzammil M.Lower limb rehabilitation using multimodal measurement of sit-to-stand and stand-to-sit task[J]. Disability and Rehabilitation: Assistive Technology, 2019. DOI: 10.1080/17483107.2019.1629701. [15] Tsukahara A, Kawanishi R, Hasegawa Y, et al.Sit-to-stand and stand-to-sit transfer support for complete paraplegic patients with robot suit HAL[J]. Advanced Robotics, 2010, 24(11): 1615-1638. [16] Tsukahara A, Hasegawa Y, Sankai Y.Standing-up motion support for paraplegic patient with robot suit HAL[C]//IEEE International Conference on Rehabilitation Robotics. Piscataway, USA: IEEE, 2009: 211-217. [17] Huo W, Mohammed S, Amirat Y, et al.Active impedance control of a lower limb exoskeleton to assist sit-to-stand movement[C]//IEEE International Conference on Robotics and Automation. Piscataway, USA: IEEE, 2016: 3530-3536. [18] Alouane M A, Huo W, Rifai H, et al.Hybrid FES-exoskeleton controller to assist sit-to-stand movement[J]. IFAC-Papers OnLine, 2019, 51(34): 296-301. [19] Chen B, Zhong C H, Ma H, et al.Sit-to-stand and stand-to-sit assistance for paraplegic patients with CUHK-EXO exoskeleton[J]. Robotica, 2018, 36(4): 535-551. [20] 尚雅珍.脑卒中患者站起和坐下的训练[J].中外健康文摘, 2012, 9(10):145-147. Shang Y Z. Stroke patients stand-up and sit-down training[J]. World Health Digest, 2012, 9(10): 145-147. [21] Schenkman M, Berger R A, Riley P O, et al.Whole-body movements during rising to standing from sitting[J]. Physical Therapy, 1990, 70(10): 638-648. [22] González Rojas H A, Cuevas P C, Zayas Figueras E E, et al.Time measurement characterization of stand-to-sit and sit-to-stand transitions by using a smartphone[J]. Medical & Biological Engineering & Computing, 2018, 56(5): 879-888. [23] Craig J J.Introduction to robotics: Mechanics and control[M]. 3rd ed. India: Pearson Education, 2009. [24] Haufe F L, Hassani R H, Riener R, et al.The InSight crutches: Analyzing the role of arm support during robot-assisted leg movements[J]. IEEE Robotics & Automation Magazine, 2020, 27(1): 103-113. [25] Herman I P.Physics of the human body[M]. Cham, Switzerland: Springer, 2016.