面向中间尺度零件精密装配的微夹持器

Micro-gripper for Precision Meso-scale Assembly

中间尺度零件广泛地被应用于复杂微小型武器系统的研发和生产中。中间尺度零件的尺度范围跨度大,形状种类多样,结构易被损坏,在目前我国武器装备科研生产中主要以手工装配为主,效率低,可靠性差。因此,如何在自动化操作和装配过程中对中间尺度零件进行安全可靠的夹持,一直是微小型武器系统精密装配领域的一个难点。研制了一种针对特征尺寸在亚毫米级至厘米级的轴类和块类零件的跨尺度微夹持器,通过成对的刚性-柔性夹爪以及精密直线运动平台的驱动来实现夹持动作,用粘贴于柔性夹爪上的应变片传感器所构成的电桥来实时测量零件所受夹持力作为控制依据。对柔性夹爪的结构参数进行了优化设计,提出同类夹爪关于所面向零件尺寸的优化设计模型。对柔性夹爪进行仿真分析,确定应变片最佳粘贴位置,推导针对柔性夹爪的特殊结构的应变-夹持力计算模型。夹持-释放实验结果表明,该夹持器能够对中间尺寸零件进行稳定、无损伤的夹持并可获得准确的夹持力信息。

Meso-scale parts are widely used in the complex miniature weapon systems.On account of a large dimension range,a variety of shapes and vulnerable structures of the meso-scale parts,the weapon systems are mainly assembled by hand,bringing poor efficiency and reliability.A challenging issue in the precision assembly of miniature weapon systems is how to safely and reliably grip the meso-scale parts in the automatic handling and assembly.A micro-gripper for gripping the sub-millimeter and millimeter scale shafts and parts is developed,including a pair of rigid and flexible gripping jaws and a precision linear motion stage.A Wheatstone bridge,which consists of strain gauges stuck on the flexible gripping jaw,is used to detect a clamping force on a part in real time.The structural parameters of flexible gripping jaw are designed optimally,and an optimal design model of gripping jaws is proposed.A simulation analysis is carried out to determine the best sticking positions of the gauges.A strain-force model for the special shape of flexible gripping jaw is derived.Grip-release experiments indicate that the micro-gripper is capable to grip the meso-scale parts stably and nondestructively.