Error Analysis And Application Research Of Ship Shaft Power Measurement System

There are many ways to measure shaft power. Every testing instrument with a certain value in different occasions and environment has different properties and different structures. Before using them, a lot of preparatory work is necessary, such as:installation of sensors, signal transmission. So, improving shaft power measurement accuracy and the reliability of data is particularly important. From a practical point of view, errors in measurement of optical non-contact shaft power measurement system which is being developed based on phase difference are researched, in order to improve the accuracy of the shaft power test and provide a guide for follow-up instrument development and use in vessels.The reasons to cause the FPGA counting error is theoretically analyzed. Effective measures to reduce FPGA counting error are provided, that is frequency of pulse signal is divided and choosing the counter frequency by experiment. Shaft power is measured on the shaft experiment platform. Select312.5kHz counter frequency and verify the stability of angle measurement data of the photoelectric encoder.Environment error of photoelectric non-contact shaft power measurement system is researched. A special logic operations is provided to reduce or eliminate the impact of temperature on the measurement. Vibration error of optical non-contact shaft power measurement system is researched and error is amended by "Compensation Act":one is a front and rear along the compensation method, the second way is to install additional a photoelectric switch sensor to reduce or eliminate the measurement error caused by the vibration.Mechanical installation of the photoelectric encoder is analyzed. Average method and3σ rules are used to reduce the measurement deviation caused by the photoelectric encoder installation tilt. Using the median filtering method and the arithmetic mean filtering method to finish filter to reduce the measurement error caused by the asymmetry of shaft.Tests on the shafting test platform are operated by photoelectric non-contact shaft power measurement system, in oder to verify torque-speed characteristic error of measurement system. The results show that photoelectric non-contact shaft power measurement system has not torque-speed characteristic error. The nonlinear error of the shaft is analyzed, and using linear interpolation to correct torque measurement. Uncertainty analysis of photoelectric non-contact shaft power measurement system is researched by statistical analysis method. The results show that uncertainty analysis of photoelectric non-contact shaft power measurement system is able to achieve the requirements of the measurement.