Research On Precision Optical Mini-head Of Inradius Measuring And Signal Processing

With the car industry development, the existing technology used in measuring car engine box bores hole could not meet the growing measure requirement. In modern measurement system, photoelectric detection technology is widely used for its superiority. However, owing to the structural dimension construction, this method could not be used in small space. This article analyzed the photoelectric micrometric displacement detection technology and self-designed mini measuring head to realize mini-hole size measurement.According to the measurement requirement, this paper designs a mechanical bar with four separated head uniform distributed on it. Every two interfacing heads are orthogonal and every two opposite heads are co-liner. Each head detects one radial 7displacement, so that two heads can get a diameter and four heads can get two groups of data. Then, get average value by multiple detections. A single detection head take laser triangulation as principle and PSD as displacement sensor. When detecting, a laser sent by fiber-optical collimation fixed in the head takes place diffuse reflection when it get to the object surface. The mirror fixed in the head will collect a part of the diffuse reflection laser and send it to PSD. PSD will generate two electric currents according to the focus position of incident light. So we can get the displacement by calculating the value of the two electric currents.The main content of this article includes:1.Analyze the development situation of photoelectric detection in home and outdoor, elaborate triangulation principle and the necessary of following the condition of Scheimpflug when applying this principle.2.Compare optical displacement sensor PSD and CCD merits and drawbacks, choose PSD as the optical displacement sensor in this article. Research the application characteristic of PSD sensor and the affection caused by the whole detection system. Choose light source according to PSD characteristic.3.Design the mechanical and optical structure according to the detection requirement to make the structure compact and precise and possess strict geometry demand and dimensional coordination relationship.4.Design the sensor circuit board according to the mechanical structure to deal with signals and realize functions such as signal extract, I/V conversion, magnification, A/D conversion, storage and transmission. 5.Design calibration experiments to calibrate solo detection head and bar. Analyze the detection mistake in whole and advance a way to diminish it.