Background Technology

  1.Wind tunnel is a duct-like experimental equipment used to simulate the flow of gas around a vehicle or entity by artificially generating and controlling the airflow, and to measure the effect of gas on the entity and observe the physical phenomena. The measurement parameters involved in the wind tunnel usually include many, among them, pressure is a very important parameter in the wind tunnel measurement, which is mainly for the measurement of the total pressure, static pressure and model surface pressure of the wind tunnel, through these pressure measurements can solve the wind speed, model flow characteristics and aerodynamic shape design and other important wind tunnel test parameters.      

   2. However, in order to obtain reliable test results, it is especially important to calibrate various sensors and the acquisition channels of various sensors. Wind tunnel test sensor acquisition accuracy generally involves a number of links, such as the acquisition board itself accuracy, acquisition channel accuracy and sensor detection accuracy. Each link calibration methods and methods and different types of sensors calibration methods and calibration equipment are different, resulting in its calibration is mostly manual calibration or semi-automatic calibration.

  3. Based on this, it is necessary to provide a sensor automatic calibration method and system of a general-purpose wind tunnel capable of automatic calibration for the above technical problems.

  4. An automatic sensor calibration method for a universal wind tunnel, said automatic sensor calibration method implemented in a sensor automatic calibration system, said system comprising a plurality of sensors, a signal acquisition board, each of said sensors connected to the signal acquisition board, a signal source, a pressure source, and a control device, respectively, through corresponding signal acquisition channels, wherein said signal acquisition channels include a signal box connected sequentially between each of said sensors and signal box and a signal conditioner connected between each said sensor and the signal acquisition board, said sensor auto-calibration method comprising:

  5. The control device acquires calibration instructions and calibrates said signal acquisition board, each sensor and the acquisition channel, respectively, according to said calibration instructions;

  6. The calibration command is to calibrate the signal acquisition board when said control device controls said signal acquisition board for self-calibration;

  7. When the calibration command is to calibrate said acquisition channel, said control device controls said signal source to send a reference electrical signal to the acquisition channel and receives the output signal of said acquisition channel output through said signal acquisition board to calculate the current channel calibration coefficient, error limit and linearity to calibrate said acquisition channel;       

  8. When the calibration instruction is to calibrate said sensor, said control device controls said pressure source to send a pressure reference value to the sensor and receives the pressure value output from said sensor through said signal acquisition board and calculates the calibration coefficient, error limit and linearity of the current sensor acquisition channel to calibrate said sensor.

  9. Before calibrating said signal acquisition board, each sensor, and acquisition channel, each sensor, signal acquisition board, signal conditioner, and signal source are also tested to see if they are online.

  10. The automatic sensor calibration system further comprising an Ethernet switch, said control device regulating said signal conditioner, signal source, and pressure source according to preset parameters via said Ethernet switch.

  11. A sensor automatic calibration method and system for a general-purpose wind tunnel described above obtains calibration instructions through a control device in the sensor automatic calibration and automatically calibrates said signal acquisition board, each sensor and acquisition channel respectively according to the calibration instructions, so that by improving the acquisition accuracy of the signal acquisition board, the acquisition channel and the sensor itself, reliable wind tunnel experimental results are obtained while reducing the human cost and automation.