面向纱管抓取的仿生末端执行器手指设计与分析

Design and analysis of bionic end effector finger for bobbin grasping

针对络筒工序纱管自动化上料时,纱管上料设备未端夹持不稳定、自适应不佳的问题,提出一种新颖的仿人肌腱欠驱动三指手的设计方案。首先,基于人手功能机制,设计手指的腱-轮布局与肌腱路径,构建末端执行器结构模型,并且通过关节弹簧的合理配置,使手指结构具备被动顺应性;其次,应用接触力学理论建立抓取刚度模型,评估指尖结构对抓取稳定性的影响,进而优选指尖结构参数;在此基础上,定量化分析指尖抓取合力中心点对抓取稳定性的影响,进一步验证手指布局的合理性;最后采用3D打印技术制作实物样机并进行试验。结果表明:指尖抓取细纱管、粗纱管、网球的平均成功率分别达到87.33%、91.67%、90.00%,能够完成包络抓取直径110 mm纱筒的任务,设计的仿生末端执行器能够实现纱管的稳定抓取。

Aiming at the problems of unstable top clamping and poor self-adaptation of the end equipment of automatic loading of yarn tube in winding process,a novel design scheme of three-finger hand with simulated tendon under-actuation was proposed to realize stable gripping of multi-size yarn tubing.Firstly,based on the functional mechanism of the hand,the tendine-wheel layout and tendon path of the finger were designed,the end-effector structure model was constructed,and the finger structure had passive compliance through the reasonable configuration of the joint spring.Secondly,a grasping stiffness model was established using contact mechanics theory to evaluate the influence of fingertip structure on grasping stability,and then the fingertip structure parameters were optimized.On this basis,the influence of fingertip grasping force center on grasping stability was quantitatively analysed,and the rationality of finger layout was further verified.Finally,3D printing technology was used to make a prototype and the test was carried out.The results show that the average success rate of fingertip grasping yarn tube,roving tube and tennis ball reaches 87.33%,91.67%and 90.00%respectively,and the task of enveloping and grasping yarn tube with diameter of 110 mm can also be completed.The biomimetic end effector designed can realize the stable grasping of the yarn.