Design Of Two-Dimensional Scanning Probe For Measuring The Crankshaft

The crankshaft is one of the key components of the engine. The requirement to ensure processing quality is the precision measurement of the axial and radial size. In order to solve the problems of low precision efficiency and incomplete measurements of the traditional measurement methods, it is necessary to carry out the related research and technological development on dedicated crankshaft measuring probe to create the ideal conditions for further development of CNC integrated crankshaft measuring machines.The characteristics of domestic and foreign crankshaft measurement technology are analyzed and the research program of two-dimensional scanning probe is proposed in this paper. This two-dimensional scanning probe can measure both radial and axis parameters of the crankshaft. The high-precision guide mechanism is designed basing on Flexible hinge. A constant force structure is designed with the dynamic balance between guide mechanism and permanent magnetic force. The radical and axial constant-force expressions are inferred by analyzing the stress state of the probe, and the theoretical value of mechanical parameters are deduced when the probe under constant stress state. In order to achieve high-resolution measurement, the dual-channel precision detection circuit based on LVDT is designed, which consists of STM32, AD7190 and other chips. Besides, the detection circuit system communicates with the host using USB. The prototype of two-dimensional simulation probe is built. The system calibration of two-dimensional analog probe is initially completed after comprehensive testing.After the test verification, the probing resolution is 0.0127μm, the standard deviation estimated value is ± 2.06μm, the non-linearity of measurement results is 0.337% within lmm measuring range, the fluctuations range of measuring power is less than ±10% within the effective measurement range.