The Research Of Ship Motion Measurement Instrument

On the research of motion control of ship, to control ship motion, we must know the state of ship motion. So that, the six-DOF motion measurement meter is necessary to be researched. The meter can measure linear acceleration,angle acceleration,linear velocity,angle velocity,and orientation angle,roll angle,pitch angle, provides data evidence for ship motion control.For insuring precision of testing, the meter used 15 sensors, measuring motion state of various physical variable for one-to-one. The paper introduces the theory and essential characteristic of sensor, and chooses sensors which we want to base on the requests of the system, designs corresponding circuit to adjust signal, makes the signal to zero when the corresponding sensor have not input, and zoom in the signal, make them to meet the request of voltage range, that is the request of microcontroller to signal.The six-DOF motion testing meter is made up of the measurement instrument of lower part and measurement software of upper part. The lower part mainly uses the microcontroller W77E58 to consist of the host control device, controls the system to complete data acquisition, data processing, data storage and communicate with upper part. The system has two modes by controlling of outer key-press, namely: the mode of data acquisition and the mode of data transmission. When the system works as the mode of data acquisition, it measures data by sensors, and storages data into external data memory, and transmits data to upper part by using serial interface RS232 at the same time; When working as the mode of data transmission, the system doesn't measure data, only transmits data of external data memory to upper part by using serial interface RS232. To meet different requests, the meter also has an analog output interface, can export analog voltage of every motion state.The software of upper part is built on the basis of C++ Builder, it receives data from lower part, and real-time displays data as curves. The curves can be displayed as the manner of two-dimensional plane, and can also be displayed as the manner of three-dimensional space, and the software can also display a kind or one of the curves which the user concerns. Adjusting sensors achieves dynamic adjusting the parameters of sensors. The meter registers data automatically which it has measured as a file.Finally, according to the experiment result, we know that the system can meet the requests of target.