【作者】 张伟；

【导师】 田为军；

【作者基本信息】 吉林大学 ， 农业机械化工程， 2021， 硕士

【摘要】 四足机器人具有良好的稳定性和环境适应性,随着应用范围的不断拓展,对其结构与性能提出了更高要求,如何提高四足机器人的运动与承载能力是四足机器人的研究热点之一。通过合理的躯干设计可以提高四足机器人的运动性能,同时增加其承载能力。猫科动物具有出色的运动缓冲能力与承载特性,为四足机器人躯干机构的承载设计提供了新的思路。本文基于猫胸腔生物学特性进行四足机器人仿生胸腔结构设计,以提高四足机器人运动时的缓冲与承载能力。基于医学图像(MRI&CT)和逆向工程技术,测量并表征猫胸腔宏观构型和各关节结构尺寸,并确定各部位间的关联和运动方式;基于医学图像观察,明晰胸椎椎体之间连接方式以及肋骨与胸椎椎体连接方式;结合关联与运动方式进行生物组装,构建胸腔生物模型;基于医学图像分别对肋骨、胸骨进行轴线提取并进行轴线方程拟合与建模。对猫不同运动下胸腔弯曲角变化规律进行试验研究。采用高速摄像系统对猫进行小跑、跨越、连续翻越、跳跃运动学试验,胸椎运动分析结果表明,猫在小跑运动的过程中,为了获得更为稳定的运动状态胸腔弯曲幅度较小;在连续翻越试验过程中,连续翻越阶段时猫胸腔弯曲幅度大于小跑运动时弯曲幅度,有利于其连续翻越运动,在落地时其胸椎关节角变化幅度增加;在跨越过程中,胸腔在承载重要器官的同时实现胸椎长度变化比为22.6%;通过对比不同高度的跳跃运动,猫胸腔最大弯曲角以及最大弯曲角出现时间具有较大差异性。运动学试验结果表明,猫通过主动调节胸腔形态来保护自身机体不受损伤。对猫跳跃着陆过程进行动力学研究,采用压力板测试系统以及高速摄像机系统采集猫1m、2m高度跳跃着陆过程的足底压力变化、COM位置变化、质心角变化。通过计算机械能、动能、转动能、重力势能以及前肢吸收能量来获取胸腔在跳跃着陆过程中所吸收的冲击能。对比不同高度的跳跃着陆试验发现:随着跳跃高度的增加,胸腔所吸收的冲击能会增大,机体通过调节质心角的角速度来延长冲击时间,减小冲击力。基于猫胸腔的结构以及运动学和动力学特性,进行了胸腔机构仿生设计,并进行仿猫胸腔机构仿真对比分析,结果表明:仿生机构具有承载和缓冲功能。更多还原

【Abstract】 Quadruped robot has good stability and environmental adaptability,but its structure design and performance still have a lot of improvement.The load-bearing construction of quadruped robot is one of the research focuses of robot.The emergence and development of bionics provides a new idea for mechanism design and performance improvement of quadruped robot.Cats have excellent jumping ability,climbing ability and balance ability.Based on the research on the characteristics of cat chest,this paper designs the structure of imitating cat chest,and puts forward a new solution for the problem of load-bearing construction of quadruped robot.The jumping motion of quadruped robot is not only a common motion of robot,but also a unique motion mode of quadruped robot.By imitating the special structure design of cat chest,the quadruped robot has stronger buffering ability.Based on medical imaging(MRI&CT)technology,reverse engineering technology and combined with gross anatomy,the macro configuration and joint structure size of cat thoracic cavity were tested and characterized,and the relationship and movement mode between various parts were determined;based on biological anatomy,the connection mode between thoracic vertebrae,the connection mode between ribs and thoracic vertebrae,and the number and connection mode of soft tissues such as tendons and muscles were clarified;combined with the relationship analysis,the structure of cat thoracic cavity was characterized The biological coupling model of thoracic vertebrae was constructed based on the joint and movement mode;the axis of rib and sternum was extracted based on the image sub comparison,and the axis equation was used for modeling.In this paper,the changes of chest bending angle of cats under different running conditions were studied.The high-speed camera system was used to test the trot,stride,continuous somersault and jumping kinematics of cats.The results of thoracic vertebra motion analysis showed that in the process of trot,in order to obtain a more stable movement state,the chest bending angle of cats was small;in the process of stride test,the chest was in the same position as carrying important organs The length change ratio was 22.6%;in the process of the rollover test,the chest of the cat changed little during the continuous rollover process,but the change range of the thoracic vertebra angle increased when landing;through the comparison of different height jump process,the maximum bending angle and the maximum bending angle time of the cat chest had great differences.Therefore,we conclude that cats protect themselves from injury by actively adjusting the shape of their chest.The dynamics of cat’s jumping landing process was studied.The plantar pressure,the position of the center of mass(COM)and the angle of the center of mass were collected by the pressure plate test system and the high-speed camera system.By calculating the mechanical energy,kinetic energy,rotational energy,gravitational potential energy and energy absorbed by the forelimb,the impact energy absorbed by the chest during the jump landing process is obtained.It is found that the impact energy absorbed by the chest increases with the increase of jumping height,and the impact time is prolonged and the impact force is reduced by adjusting the angular velocity of the center of mass angle.Based on the structure,kinematics and dynamics of the cat chest,the bionic design of the four segment three joint chest was completed.Based on the bionic prototype structure,the connection mode between the rib and the thoracic vertebra is adjusted appropriately.The results show that the bionic mechanism has the function of bearing and buffering.更多还原