DYNAMIC CHARACTERISTICS OF MICROMACHINE COMPONENTS IN BIONIC LIQUID

为了研究仿生液体中微悬臂梁的动力学特性，本文重点研究了微悬臂梁的静态和动态特性。主要结果如下。（1）从Si_3N_4薄膜在空气中的共振特性中提取了薄膜的杨氏模量。用激光束激励悬臂梁，用光学方法测量悬臂梁的振幅。(2)To针对微悬臂梁在三维静电场作用下大变形问题，基于薄膜大变形弹性理论和静电场理论，开发了微悬臂梁在三维静电场作用下大变形的计算机分析系统。得到了多晶硅悬臂梁的杨氏模量与施加在悬臂梁和衬底之间的电压之间的关系。（3）建立了基于力平衡法的AFM（Atomic Force Microscopy）力曲线测量系统的控制模型。在此基础上，设计了原子力显微镜验证系统的PID控制器，使快速测量周期接近1/100秒。（4）利用激光激发光杠杆测量了微悬臂梁在水中的谐振特性。水中的共振频率比空气中的共振频率低1/10左右。采用串珠模型估算粘性流体的拖曳力，理论推导了基于串珠模型的共振特性，计算结果与实验结果吻合较好。

For investigation of dynamic characteristics in bionic liquid, static and dynamic behaviors of micro cantilever are typically studied. The main results were as follows.(1)Young's modulus of thin Si_3N_4 films are extracted from the resonance characteristics in air. The cantilevers are excited by Laser beams and the amplitudes are measured by optical methods.(2)To study large deflection of micro cantilever in 3-dimensional static electric field, computer analysis system is developed based on large deflection elastic theory in thin films and electrostatic field theory. Relations between the Young's modulus of the poly-Si cantilever and the applied voltages, which is applied between the cantilever and the substrate, are obtained.(3)Analytical model is proposed to control the force curve measurement system for AFM (Atomic Force Microscopy) proves based on the force balanced method. Based on this method, PID control system for AFM prove is designed to approach quick measurement period within 1/100 seconds.(4)Resonance characteristics in water are measured for micro cantilevers by optical lever, which is excited by Laser beam. The resonance frequency in water shows around 1/10 times lower than that of in air. Using the string of beads model for estimating the drag force by viscous fluids, the resonance characteristics are theoretically derived based on the strings of beads model and the results show good agreements with the experimental results.