摘要
外骨骼能够帮助截瘫患者行走和康复训练。动力助行外骨骼对患者自身的肌肉力量要求较低,但其驱动电机尺寸、重量较大;无动力储能助行外骨骼不需要电机,但对患者的肌力有一定要求,长时间行走容易导致患者疲劳。该文结合两者优势,设计了一种基于棘轮棘爪机构的离合式弹性驱动器,作为助行外骨骼机器人的髋关节驱动器。在支撑期,截瘫患者依靠自身肌力和拐杖转移重心,同时电机将能量储存在扭簧里;在摆动期,已充分储能的扭簧迅速释放能量帮助患者向前迈腿。该文建立了驱动器在支撑期(扭簧储能)和摆动期(扭簧释能)的动力学模型,并以峰值功率为优化目标,优化参数包括电机角加和减速度。仿真结果显示,对比直接用电机和减速器驱动患者髋关节,该驱动器可显著减小电机平均功率和峰值功率,因此可以通过离合式弹性驱动器特殊的设计,选用额定力矩和功率低的小电机,达到减小电机、关节驱动器乃至外骨骼整体结构的尺寸和重量的目的。
Lower limb exoskeletons can help paraplegic patients walk through rehabilitation.Powered exoskeletons do not require much muscle strength in the affected limbs,but the drive motors are rather large and heavy.Unpowered energy-storage exoskeletons do not require motors,but require more patient muscle strength which may cause fatigue during continuous use.This paper describes a clutched elastic actuator based on a ratchet mechanism that can be used as the hip joint driver for a lower limb of an exoskeleton.Patients rely on their upper limb and trunk muscles and crutches to slowly transfer the center of gravity during the support phase.The motor then stores energy during this motion in a torsional spring.During the swing phase,the torsional spring then quickly releases energy to help the patient step forward and complete a gait cycle.This paper presents a model for the driver during the support phase(spring energy storage)and the swing phase(spring energy release).The angular acceleration and deceleration are selected to minimize the peak power.Simulations show that the clutched elastic actuator significantly reduces the average power and the peak power compared with a motor and gearbox driving the patient’s hip joint.Therefore,the system can have small low torque,low power motors to reduce the size and weight of the actuators and the entire exoskeleton.
作者
刘宇霖
李银波
卢仁浩
关鑫宇
季林红
LIU Yulin;LI Y in bo;LU Renhao;GUAN Xinyu;JI Linhong(Division of Intelligent and Biomechanical System,State Key Laboratory of Tribology,Department of Mechanical Engineering,Tsinghua University,Beijing 100084,China)
出处
《清华大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2021年第1期42-49,共8页
Journal of Tsinghua University(Science and Technology)
基金
国家自然科学基金青年基金项目(51905291)
国家自然科学基金中德合作交流项目(51761135121)。
关键词
外骨骼
柔性驱动器
离合式驱动器
棘轮棘爪
截瘫助行
exoskeletons
compliant actuators
clutched actuators
ratchet mechanisms
paraplegic
