Research And Development Of Marine Non-contact Multi-functional Digital Instrument

Rotation rate, torsion and shaft power are the major performance parameters of rotational equipment on board, and they are also the necessary test index of the marine power system. Non-contact digital instrument can carry out real time monitoring of the major performance of the marine power system and find out the operating condition of the marine transmission system, guaranteeing the safe operation of shipes. In view of the current conditions of traditional contact tachometer, this paper proposes the method of using infrared reflectance technology to realize non-contact rotation speed measurement. Through measuring the torque of the marine rotational equipment, shaft power of shafting can be got so as to realize multifunctional measurement.Based on the research of principles of the speed and torque measurement, this paper has analyzed the measurement methods of the speed and torque, and developed non-contact multi-functional digital measurement system. By comparing the measured results with traditional method, measurement of shaft speed and shaft power of marine have been realized.This paper carries out the following tasks:(1) The speed and torque measurement principles and measurement methods are researched. On the basis of the requirements of non-contact measurement, the infrared photoelectric sensor is adopted as the final selection after the comparison of the performance of a variety of speed sensors. The advantages and disadvantages of each measurement method are analyzed, and the error analysis is carried out. The method of speed measurement and torque detection is determined.(2) The overall framework of non-contact multi-functional digital measurement system is designed for the hardware. The circuit design is finished for the system sub-modules, including the infrared signal acquiring circuit, signal processing circuit, LCD displaying circuit, serial communication, printed circuit, etc. and the corresponding circuit design schemes are presented.(3) Main program, key processing program, LCD display program, speed measurement program and shaft power calculation program are written. Through calling the program, functions of signal acquisition, LCD display, and calculation of speed and shaft power are achieved.(4) In laboratory of marine main engines, the non-contact multi-functional digital instrument is tested. The accuracy of the measuring instrument is verified through comparing with the measurement data. The results show that this multifunctional digital instrument can achieve multi-functional measurements.