Different from sculling forward of water striders with their hairy water-repellent legs, water spiders walked very quickly on water surfaces. By using a shadow method, the walking of water spiders had been studied. Th...Different from sculling forward of water striders with their hairy water-repellent legs, water spiders walked very quickly on water surfaces. By using a shadow method, the walking of water spiders had been studied. The three-dimensional trajectories and the supporting forces of water spider legs during walking forward were achieved. Results showed that the leg movement could be divided into three phases： slap, stroke, and retrieve. Employing an effective strategy to improving walking efficiency, the sculling legs supported most of its body weight while other legs were lifted to reduce the lateral water resistance, which was similar to the strategy of water striders. These findings could help guiding the design of water walking robots with high efficiency.展开更多
Measuring walking forces of small or tiny insects can help the comprehension of their locomotion principles.However,as their size and force are generally too small,walking forces of small insects in sub-mg mass have n...Measuring walking forces of small or tiny insects can help the comprehension of their locomotion principles.However,as their size and force are generally too small,walking forces of small insects in sub-mg mass have never been actually measured.In this work,a convenient multi-lens and jelly surface based shadow method was developed for simultaneous multiple walking forces measuring,ranged from nN to mN with a sensitivity of sub-nN/pixel under ambient conditions.Walking force of six legs of a 0.3 mg water treader was demonstrated.The obtained results disclosed a rapid and extending middle leg strategy of water treader in walking forward above a jelly surface.This method is cost-effective and high-resolution,which could be easily used in measuring other tiny forces.展开更多
The concept of legged-robot stability training with a training platform is proposed and a serial-parallel mechanism platform with 6 degrees of freedom is designed for this target. The designed platform is composed of ...The concept of legged-robot stability training with a training platform is proposed and a serial-parallel mechanism platform with 6 degrees of freedom is designed for this target. The designed platform is composed of 4-DOF parallel mechanism with spherical joints and prismatic pairs,and 2-DOF serial mechanism with prismatic pairs. With this design,the platform has advantages of low platform countertop,big workspace,high carrying capacity and high stiffness. On the basis of DOF analysis and computation of space mechanism,weight supporting auxiliary mechanism and raceways-balls supporting mechanism are designed,so as to improve the stiffness of designed large platform and payload capacity of servo motors. And then the whole structure design work of the platform is done. Meanwhile,this paper derives the analytical solutions of forward kinematics, inverse kinematics and inverse dynamics. The error analysis model of position and orientation is established. And then the simulation is done in ADAMS to ensure the correctness and feasibility of this design.展开更多
目的自然行走、慢跑是人类最基本的运动,倒走是一些非特异性腰疼病人进行康复训练的一种运动。了解正常人的步态特征,可以为判定患者步态异常的生物力学研究提供对照。方法选取50名大学生作为研究对象,应用0.5 m footscanUSB足底压力分...目的自然行走、慢跑是人类最基本的运动,倒走是一些非特异性腰疼病人进行康复训练的一种运动。了解正常人的步态特征,可以为判定患者步态异常的生物力学研究提供对照。方法选取50名大学生作为研究对象,应用0.5 m footscanUSB足底压力分布测试系统采集受试者自然行走、倒走和慢跑时的步态参数,并应用SPSS 17.0进行数据的统计学分析。结果在3种运动方式下,左右足的支撑期分期均无显著性差异,足弓指数差异明显,足前部所受冲量百分比最大。而慢跑和自然行走相比,足支撑期分期均有显著性差异,T2-T5、M1-M5和MF区域的压强峰值有显著性差异。倒走时,全足支撑期以及足轴角明显大于自然行走和慢跑。结论不同的运动方式改变了足底压力分布状态,在日常运动中,应结合自身体质状况选择运动。展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51323006 and 51425502)the Tribology Science Fund of State Key Laboratory of Tribology(Grant No.SKLTKF17B18)
文摘Different from sculling forward of water striders with their hairy water-repellent legs, water spiders walked very quickly on water surfaces. By using a shadow method, the walking of water spiders had been studied. The three-dimensional trajectories and the supporting forces of water spider legs during walking forward were achieved. Results showed that the leg movement could be divided into three phases： slap, stroke, and retrieve. Employing an effective strategy to improving walking efficiency, the sculling legs supported most of its body weight while other legs were lifted to reduce the lateral water resistance, which was similar to the strategy of water striders. These findings could help guiding the design of water walking robots with high efficiency.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51323006 and 51425502)。
文摘Measuring walking forces of small or tiny insects can help the comprehension of their locomotion principles.However,as their size and force are generally too small,walking forces of small insects in sub-mg mass have never been actually measured.In this work,a convenient multi-lens and jelly surface based shadow method was developed for simultaneous multiple walking forces measuring,ranged from nN to mN with a sensitivity of sub-nN/pixel under ambient conditions.Walking force of six legs of a 0.3 mg water treader was demonstrated.The obtained results disclosed a rapid and extending middle leg strategy of water treader in walking forward above a jelly surface.This method is cost-effective and high-resolution,which could be easily used in measuring other tiny forces.
基金Sponsored by the National High-Tech Research and Development Program(Grant No.2006AA04Z201)
文摘The concept of legged-robot stability training with a training platform is proposed and a serial-parallel mechanism platform with 6 degrees of freedom is designed for this target. The designed platform is composed of 4-DOF parallel mechanism with spherical joints and prismatic pairs,and 2-DOF serial mechanism with prismatic pairs. With this design,the platform has advantages of low platform countertop,big workspace,high carrying capacity and high stiffness. On the basis of DOF analysis and computation of space mechanism,weight supporting auxiliary mechanism and raceways-balls supporting mechanism are designed,so as to improve the stiffness of designed large platform and payload capacity of servo motors. And then the whole structure design work of the platform is done. Meanwhile,this paper derives the analytical solutions of forward kinematics, inverse kinematics and inverse dynamics. The error analysis model of position and orientation is established. And then the simulation is done in ADAMS to ensure the correctness and feasibility of this design.
文摘目的自然行走、慢跑是人类最基本的运动,倒走是一些非特异性腰疼病人进行康复训练的一种运动。了解正常人的步态特征,可以为判定患者步态异常的生物力学研究提供对照。方法选取50名大学生作为研究对象,应用0.5 m footscanUSB足底压力分布测试系统采集受试者自然行走、倒走和慢跑时的步态参数,并应用SPSS 17.0进行数据的统计学分析。结果在3种运动方式下,左右足的支撑期分期均无显著性差异,足弓指数差异明显,足前部所受冲量百分比最大。而慢跑和自然行走相比,足支撑期分期均有显著性差异,T2-T5、M1-M5和MF区域的压强峰值有显著性差异。倒走时,全足支撑期以及足轴角明显大于自然行走和慢跑。结论不同的运动方式改变了足底压力分布状态,在日常运动中,应结合自身体质状况选择运动。
