电磁力驱动的微夹持技术

Micro-Tweezer Technology Driven by Electromagnetic Force

在生物操作和微装配中,需要微力传感器控制操作过程,以保证操作的有效性.为此,设计了集电磁力驱动和压电传感于一体的夹钳,利用螺线管与小永磁体产生的排斥力驱动夹钳闭合,通过改变螺线管电流的大小来控制夹钳夹持力.夹钳夹持物体时,聚偏二氟乙烯(PVDF)产生压电效应输出电压,电压的数值确定了夹持力.利用共振频率方法测量PVDF膜片刚度,结合显微视觉系统测量膜片变形,可以确定夹钳受到的力,从而获得夹钳受力与输出电压的关系.实验结果表明,采用共振频率方法精确测量出的膜片刚度为110.7,μN/μm,夹钳力传感分辨率为1.1,mN.

In bio-manipulation and microassembly, micro-force sensors must be used to ensure validity of operation. In this paper, the repulsion force between solenoid and small magnet was used to close the micro-tweezer, and the change of electric current of the solenoid could control closed force of micro-tweezer. When an object was operated by the micro-tweezer, the polyvinylidene fluoride（PVDF） membrane of micro-tweezer exported voltage under the piezoelectric effect, and the value of voltage was decided by closed force of the micro-tweezer, finally, the micro-tweezer driven by electromagnetic force was integrated with micro-force sensor. A resonance frequency method was used to measure rigidity coefficient of PVDF membrane, the distortion of membrane was measured by microscope vision system. According to rigidity coefficient and distortion of membrane, the pressure of membrane and the relation between pressure and output voltage of membrane were obtained. The experimental result shows that the resonance frequency method can accurately measure the rigidity coefficient of membrane as 110.7 μN/μm and the resolution of micro-force sensor as 1.1 mN.