Higher accuracy of optical surface measurement is needed with the rapid development of optical industry and technology, especially in the field of optical manufacture and optical metrology. Fizeau interferometery is widely recognized as one of the most important measurement techniques currently in use. Results of the Fizeau interferometeric testing contain the reference surface errors and test surface errors. The test accuracy is restricted by the error of reference surface. As a result, so-called absolute flatness testing technology must be used to eliminate the system error such as reference surface error and higher accuracy of the surface profile testing. In this paper, the theory formula of even and odd functions is deduced, and the method are programmed for simulation. Based on HOOL phase-shifting interferometer, experiments are done to achieve high accuracy flatness measurement. The experiment shows that with high-accuracy interferometer, absolute flatness testing technology can effectively calibrate reference surface and improve the accuracy of flatness surface testing. An important result of this experiment is that the accuracy of the test surface can be reached λ/50.
In the experiment of researching the nanometer laser interferometer, our design of laser interferometer circuit system is up to the wireless communication technique of the 802.15.4 IEEE standard, and we use the RF TI provided by Basic to receive the data on speed control system software. The system’s hardware is connected with control module and the DC motor. However, in the experiment, we found that single chip microcomputer control module is very difficult to drive the DC motor directly. The reason is that the DC motor's starting and braking current is larger than the causing current of the single chip microcomputer control module. In order to solve this problem, we add a driving module that control board can transmit PWM wave signal through I/O port to drive the DC motor, the driving circuit board can come true the function of the DC motor’s positive and reversal rotation and speed adjustment. In many various driving module, the L298N module’s integrated level is higher compared with other driver module. The L298N model is easy to control, it not only can control the DC motor, but also achieve motor speed control by modulating PWM wave that the control panel output. It also has the over-current protection function, when the motor lock, the L298N model can protect circuit and motor. So we use the driver module based on L298N to drive the DC motor. It is concluded that the L298N driver circuit module plays a very important role in the process of driving the DC motor in the DC motor speed control system.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.