Research On The Method And Device To Measure Small Angular Displacement Based On Optical Sensor

The angle parameter is an important physical value, which always needs to be confirmed. In practice, we not only measure angular displacement directly, but also change other physical values into angular displacement to measure it for convenience and reliability. There are several methods of angular measurement, such as mechanical, optical, electromagnetic. However, compared these methods, angular measuring based on linear CCD (Charge Coupled Devices) image sensor can realize intelligence and automation in dimension measurement.Combined with the technology of CCD, a new kind of angular measurement principle and device were put forward. The system can achieve one dimensional angular displacement on-line without contact.First, principle of the linear CCD was introduced and one suitable type of CCD was selected. Then, the measurement principle for small angular displacement based on twice reflections was introduced detailedly, and the mathematical model of the system was established. The outer mechanical measurement structure and photic structure were also designed. The time order driving circuit of CCD was designed and debugged with VHSIC Hardware Description Language and Complex Programmable Logic Device under the circumstance of MAX+plusII, it improved the system's reliability and agility. At the same time, the video signal processing circuit realized the primary catching, prepositive and differential signal amplifying and filtration. Variable threshold binarization processing circuit which can obviously restrain the main noise and output steady binarization wave was also designed. The high speed counter 8253 was used to count the sample pulse to binarization processed output signal, and designed the communication interface circuit with the computer, transfered the information of light dot position to the microprocessor, which was processed, deposited, displayed and saved which recurred to the controller MSComm with Visual Basic.At last, the experiment results on this device provided that the measurement principle is feasible, small angular displacement can be measured which is non-contact and online based on the device.