In order to design a lower extremity exoskeleton suitable for various common gaits, experiment data of normal gait and 5 common special gaits, including unbalanced, ankylosing, short-limbed gaits, as well as gaits at different walking speeds, and gaits under different loads, are analyzed. On that basis, the integrated hydraulic cylinder-tendon sheath drive systems are configured and optimized for each joint of the lower extremity exoskeleton. Then, the dynamic model of the exoskeleton is established and analyzed. The configuration of drive systems enables each exoskeleton joint to meet the kinematic and dynamic characteristics in various common gaits, and the optimization reduces the maximum working speed of each hydraulic cylinder as far as possible on the premise of guaranteeing the drive efficiency. Finally, The performance parameters of the drive system of each exoskeleton joint, such as torque and power, are obtained via dynamics analysis in case that the maximum walking speed isn' tless than 1.3m/s. The designed exoskeleton satisfies the kinematic and dynamic requirements of various common gaits.
 Kawabata T, Satoh H, Sankai Y. Working posture control of robot suit HAL for reducing structural stress[C]//IEEE International Conference on Robotics and Biomimetics. Piscataway, USA: IEEE, 2009: 2013-2018. Kawamoto H, Taal S, Niniss H, et al. Voluntary motion support control of robot suit HAL triggered by bioelectrical signal for hemiplegia[C]//32nd Annual International Conference of the IEEE EMBS. Piscataway, USA: IEEE, 2010: 462-466. Kazerooni H, Steger R, Huang L. Hybrid control of the berkeley lower extremity exoskeleton (BLEEX)[J]. The International Journal of Robotics Research, 2006, 25(5/6): 561-573. Steger R, Kim S H, Kazerooni H. Control scheme and networked control architecture for the Berkeley lower extremity exoskeleton[C]//IEEE International Conference on Robotics and Automation. Piscataway, USA: IEEE, 2006: 3469-3476. Pratt J E, Krupp B T, Morse C J, et al. The RoboKnee: An exoskeleton for enhancing strength and endurance during walking[C]//IEEE International Conference on Robotics and Automation. Piscataway, USA: IEEE, 2004: 2430-2435. 郭忠武,王广志,丁辉,等.正常青年人步态运动学参数的研究[J].中国康复理论与实践,2002,8(9):532-533.Guo Z W, Wang G Z, Ding H, et al. A study of kinematic parameters of normal youth in gait analysis[J]. Chinese Journal of Rehabilitation Theory & Practice, 2002, 8(9): 532-533. Han Y L, Wang X S. The biomechanical study of lower limb during human walking[J]. Science China, 2011, 54(4): 983-991.  朱晓兰,赵芳,周兴龙.老年人步态特征的分析及其评价系统的初步建立[J].北京体育大学学报,2006,29(2):201-203.Zhu X L, Zhao F, Zhou X L, et al. Research on the analysis on the characteristics of gait and the initial establishment of its evaluation system of the aged[J]. Journal of Beijing Sport University, 2006, 29(2): 201-203. 李伟,周敬滨,陶增羽,等.膝骨关节炎患者步态动力学相关参数分析[J].中国运动医学杂志,2010,29(3):268-271. Li W, Zhou J B, Tao Z Y, et al. The research on kinetic parameters of gait analysis in patients with knee osteoarthritis[J]. Chinese Journal of Sports Medicine, 2010, 29(3): 268-271. 杨雅琴,张通.正常步态和偏瘫步态的特点及对比[J].中国康复理论与实践,2003,9(10):608-609.Yang Y Q, Zhang T. Normal gait and hemiplegic gait characteristics and comparison[J]. Chinese Journal of Rehabilitation Theory & Practice, 2003, 9(10): 608-609. Lim H B, Luu T P, Hoon K H, et al. Natural gait parameters prediction for gait rehabilitation via artificial neural network[C]//IEEE/RSJ International Conference on Intelli-gent Robots and Systems. Piscataway, USA: IEEE, 2010: 5398-5403. Zielinska T, Chew C M, Kryczka P, et al. Robot gait synthesis using the scheme of human motions skills development[J]. Mechanism and Machine Theory, 2009, 44(3): 541-558.  Faure F, Debunne G, Cani-Gascuel M P, et al. Dynamic analysis of human walking[C]//8th Eurographics Workshop on Computer Animation and Simulation. 1997: 53-65. 郭忠武,丁海曙,王广志,等.基于运动学和动力学参数的步态识别研究[J].生物医学工程学杂志,2005,22(1): 1-4.Guo Z W, Ding H S, Wang G Z, et al. A study of gait recognition based on kinematics and kinetics parameters[J]. Journal of Biomedical Engineering, 2005, 22(1): 1-4. 刘德俊,郦鸣阳,沈力行.正常青年人行走步态的实验研究[J].上海理工大学学报,2008,30(1):67-70.Liu D J, Li M Y, Shen L X. Experimental study on walking gait of normal young people[J]. Journal of University of Shanghai for Science and Technology, 2008, 30(1): 67-70. Vaughan C L, Davis B L, CO'Connor J. Dynamics of human gait[M].South African: Human Kinetics Pub, 1999: 16-20. Han Y L, Wang X S, Fu C Q, et al. The study on human walking gait analysis system for the design of walking power-assisted robot[C]//IEEE International Conference on Mechatronics and Automation. Piscataway, USA: IEEE, 2009: 3607-3612. Jia S, Han Y L, Niu W Q, et al. Mechanical design and improvement of the lower extremity joints of the SEU power-assistant exoskeleton (SPAEX)[C]//Mecatronics2010. 2010: 480-485. Mclntosh A S, Beatty K T, Dwan L N, et al. Gait dynamics on an inclined walkway[J]. Journal of Biomechanics, 2006, 39(13):2491-2502. Kazerooni H, Racine J L, Huang L H, et al. On the control of the Berkeley lower extremity exoskeleton (BLEEX)[C]//IEEE International Conference on Robotics and Automation. Piscataway, USA: IEEE, 2005:4353-4360. Kanjanapas K, Tomizuka M. 7 degrees of freedom passive exoskeleton for human gait analysis: Human joint motion sensing and torque estimation during walking[C]//6th IFAC Symposium on Mechatronics Systems. Laxenburg, Australia: IFAC, 2013: 285-292.