Abstract:For the existing problem that the powered exoskeleton can't squat smoothly due to unclear characteristics of the joint drive, the joint drive of the powered exoskeleton while squatting and its compensation with the human-machine coupling interaction are investigated to enhance squatting reliability and human-machine interactivity. The kinematic equations of all joints are obtained through a somatic data acquisition experiment and nonlinear data-fitting. A human-machine coupling dynamic model during squatting is established, and the driving features of all joints are analyzed. It is found that the driving features and their volatility at knee joint are significantly greater than those at ankle and hip joints, there is a strong coupling between the driving torque and the angular acceleration at knee joint, and the system centrobaric displacement has significant influence on the drive at knee joint only in the first half phase of squatting. These analyses on the joint driving features show that the double-acting linear hydraulic cylinder can be used to drive the knee joint, and the human-machine interaction force can compensate the partial driving torque at ankle joint and the whole driving torque at hip joint.
[1] Dollar A M, Herr H. Lower extremity exoskeletons and active orthoses:Challenges and state-of-the-art[J]. IEEE Transactions on Robotics, 2008, 24(1):144-158.
[2] 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.
[3] Ghan J, Kazerooni H. System identification for the Berkeley lower extremity exoskeleton (BLEEX)[C]//IEEE International Conference on Robotics and Automation. Piscataway, USA:IEEE, 2006:3477-3484.
[4] Kazerooni H, Steger R, Huang L H. Hybrid control of the Berkeley lower extremity exoskeleton (BLEEX)[J]. International Journal of Robotics Research, 2006, 25(5/6):561-573.
[5] Zoss A, Kazerooni H. Design of an electrically actuated lower extremity exoskeleton[J]. Advanced Robotics, 2006, 20(9):967-988.
[6] Walsh C J, Endo K, Herr H. A quasi-passive leg exoskeleton for load-carrying augmentation[J]. International Journal of Humanoid Robotics, 2007, 4(3):487-506.
[7] 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.
[8] 刘放,程文明,赵南.携行式外骨骼机械结构应力测试试验研究[J].机械强度,2012,34(2):198-202.Liu F, Cheng W M, Zhao N. Study on stress testing to the mechanical structure of portable exoskeleton[J]. Journal of Mechanical Strength, 2012, 34(2):198-202.
[9] 赵南,程文明,邬钱涌.穿戴式外骨骼膝关节三铰点机构优化设计[J].机械工程与自动化,2012(1):7-9,12.Zhao N, Cheng W M, Wu Q Y. Optimized design for three-hinge mechanism of wearable exoskeleton knee[J]. Mechanical Engineering and Automation, 2012(1):7-9,12.
[10] 贾山,路新亮,韩亚丽,等.在摆动相中用于下肢外骨骼跟踪人体踝关节轨迹的方法[J].东南大学学报:自然科学版,2014,44(1):87-92.Jia S, Lu X L, Han Y L, et al. Method for lower extremity exoskeleton's ankle joint trajectory to track human's in swing phase[J]. Journal of Southeast University:Natural Science Edition, 2014, 44(1):87-92.
[11] 孙建,余永,葛运建,等.基于接触力信息的可穿戴型下肢助力机器人传感系统研究[J].中国科学技术大学学报,2008,38(12):1432-1438.Sun J, Yu Y, Ge Y J, et al. Research on multi-sensors perceptual system of wearable power assist leg based on interaction force signal and joint angle signal[J]. Journal of University of Science and Technology of China, 2008, 38(12):1432-1438.
[12] Kazerooni H, Steger R. The Berkeley lower extremity exoskeleton[J]. Journal of Dynamic Systems, Measurement, and Control, 2006, 128(1):14-25.
[13] 陈江城,张小栋.人体下肢行走关节连续运动表面肌电解码方法[J].西安交通大学学报,2016,50(6):61-67.Chen J C, Zhang X D. Surface electromyography decoding for continuous movement of human lower limb during walking[J]. Journal of Xi'an Jiaotong University, 2016, 50(6):61-67.
[14] 陈江城,张小栋,李睿,等.利用表面肌电信号的下肢动态关节力矩预测模型[J].西安交通大学学报,2015,49(12):26-33.Chen J C, Zhang X D, Li R, et al. Prediction model for dynamic joint torque of lower limb with surface EMG[J]. Journal of Xi'an Jiaotong University, 2015, 49(12):26-33.
[15] Racine J C. Control of a lower extremity exoskeleton for human performance amplification[D]. Berkeley, USA:University of California, 2003.
[16] 张军,李建喜,夏钰坤,等.行走过程中人体下肢受力模型的建立与验证[J].西安交通大学学报,2015,49(9):134-140.Zhang J, Li J X, Xia Y K, et al. Establishment and verification of a mechanical model for analyzing the forces acted on lower limb during walking[J]. Journal of Xi'an Jiaotong University, 2015, 49(9):134-140
[17] 贾山,韩亚丽,路新亮,等.基于人体特殊步态分析的下肢外骨骼机构设计[J].机器人,2014,36(4):392-401, 410.Jia S, HanY L, Lu X L, et al. Design of lower extremity exoskeleton based on analysis on special human gaits[J]. Robot, 2014, 36(4):392-401,410.
[18] 韩亚丽,贾山,王兴松.基于人体生物力学的低功耗踝关节假肢的设计与仿真[J].机器人,2013,35(3):276-282.Han Y L, Jia S, Wang X S. Design and simulation of an ankle prosthesis with lower power based on human biomechanics[J]. Robot, 2013, 35(3):276-282.
[19] 韩亚丽,祁兵,于建铭,等.面向助力膝关节外骨骼的弹性驱动器研制及实验研究[J].机器人,2014,36(6):668-675.Han Y L, Qi B, Yu J M, et al. Development and experimental study of elastic actuator for a power-assisted knee exoskeleton[J]. Robot, 2014, 36(6):668-675.
[20] Wang D H, Lee K-M, Guo J J, et al. Adaptive knee joint exoskeleton based on biological geometries[J]. IEEE/ASME Transactions on Mechatronics, 2014, 19(4):1268-1278.
[21] 陈兵,骆敏舟,孙少明,等.基于仿生原理的节能减振类人机器人膝关节的设计[J].机器人,2014,36(2):218-223.Chen B, Luo M Z, Sun S M, et al. Design of energy-saving and vibration damping knee joint of humanoid robot based on bionic principles[J]. Robot, 2014, 36(2):218-223.
[22] 杨巍,张秀峰,杨灿军,等.基于人机5 杆模型的下肢外骨骼系统设计[J].浙江大学学报:工学版,2014,48(3):430-435,444.Yang W, Zhang X F, Yang C J, et al. Design of a lower extremity exoskeleton based on 5-bar human machine model[J]. Journal of Zhejiang University:Engineering Science, 2014, 48(3):430-435,444.
[23] 贾山,王兴松,路新亮,等.基于踝关节处人机位姿误差的外骨骼摆动腿控制[J].机器人,2015,37(4):403-414.Jia S, Wang X S, Lu X L, et al. Control of the exoskeleton's swing leg based on the human-machine posture error at ankle joint[J]. Robot, 2015, 37(4):403-414.
[24] Escamilla R F, Zheng N, Imamura R, et al. Cruciate ligament force during the wall squat and the one-leg squat[J]. Medicine and Science in Sports and Exercise, 2009, 41(2):408-417.
[25] Robertson D G E, Wilson J M J, St Pierre T A. Lower extremity muscle functions during full squats[J]. Journal of Applied Biomechanics, 2008, 24(4):333-339.
[26] Collins S H, Wiggin M B, Sawicki G S. Reducing the energy cost of human walking using an unpowered exoskeleton[J]. Nature, 2015, 522(7555):212-215.