Development of Microscopic Hardness and Stiffness Investigation System with Microrobot 2nd Report, Vision Based Precise Navigation

Abstract

A microsurface measurement system that is composed of the microrobot with the indenter and a vision based navigation system is proposed for investigating hardness and stiffness of such microparts. Here the tiny robot with the electromagnetic legs and the piezo elements incorporates with an electromagnetic driven microforce generator. This force generator can provide small forces up to 17 mN with 50 µN resolutions and push down the microindenter to the surface. The displacement of the indenter head can be also measured by the Linear Valuable Differential Transformer (LVDT) on machine. Thus, this mechanism can generate the small force and monitor the depth behaviour of the indenter during whole dwell time. Since the overall size of this mechanism is small enough to implement on the piezo-driven microrobot, the tiny robot with the microindenter is capable tomove precisely step by step with 1 µm per step so that the microindenter could be penetrated anywhere on the sample surface. With the help of an image processing technique, the vision based coordination system with the local close-up view and the overall global view has been developed to identify the locations of small robot and the indenter precisely within ±3 µm accuracy over the working range. In the experimental results, several results that the indentation load-depth characteristics of the unhealthy human tooth are measured automatically at the specified point are discussed.