| The nano-science and technology has showed its fantastic attraction as well as prosperity of application. It has essential influenced modern society's development of technology and economy. In addition, people pay far more attention on the development of nano-science and its relative fields. Almost all the countries in the world devote plenty of human resource and money to this popular area, in order to win the challenge of this new opportunity. In order to recognize and make good use of nano-world, people must use something directly which could observe nano-scale such as AFM (Atomic Force Microscope) and which could operate in nano-scale such as PZT actuator. Though PZT has been widely use in worldwide, it still has some shortcomings, for instance, hysteresis, creep and non-linearity, which impact static and dynamic performance of nano-driving systems. This is the reason that we could not use PZT actuator in the condition of nano-scale freely. When we use the PZT actuator in micro-positioning circumstance, the traditional control mode based on drive voltage would lead to poor repeat positioning accuracy, non-linear displacement, which made positioning and the drive system based on the piezoelectric ceramic-driven into a complicated nonlinear systems, and this restrict the further application of the piezoelectric ceramic. So, in this paper, we design three generation displacement sensor according to the characteristics of PZT, and with which we could bring close-loop control based on displacement to deal with non-linear characteristic of the PZT actuator in nano-drive environment. This is a ratter simple way to realize real time control of PZT accurately and efficiently.This paper is supported by the National Nature Science Foundation key projects "the robotic operating system theory and implementation in the nano-environment". It is also based on the research foundation of force sensor in robot sensor laboratory over years in Chinese Academy of Sciences Hefei Institute of Intelligent Machines. A force sensor, which can access real-time PZT driving force information is designed.The main studies of the paper are expressed as follows:1. Design theory of the sensors based on mechanics expansion for measuring the displacement of the PZT actuator: According to features of the PZT driver: High stiffness, Small displacement, Large driven force, as well as the installation method, we design a force sensor which is based on flexible hinge- mechanics expansion's framework structure. We also finish the design and test work of the next two generations displacement sensors.2. Mathematic model building: Due to the complicate structure and multi-factors influences of this displacement sensor, building a accurate mathematic model is necessary. In this paper, we use mathematical and mechanical method to build the mathematical model for sensors from simple model to accurate model. With the help of this novel model we could have a better realized about the sensors, and also the model builds firm theoretic foundation for us about designing next generation sensor.Software and hardware system design:3. Sensor performance test platform building and experiment results analysis: In terms of features of sensor date process system: real-time, high-speed signal acquisition, analysis and two-way communications of microprocessor and PC. The MCU achieves the function of the AD sampling and communication with PC by using C8051F040, and PC is mainly the software system which includes the acquirement of the sensing information, signal processing and the design of the RS232 port. Through the nanometer scan position platform produced by PI co., we calibrate the three generations of displacement sensors. In this paper we also introduce the process of platform building, calibrate experiment process and as well as the optimize method for adjusting dates. |
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