Rotating member rotation radian detection method based on triaxial magnetometer

[0016] Example 1:

[0017] The invention provides a method for detecting the arc of rotation of a rotating part based on a three-axis magnetometer. A permanent magnet is fixed on the end surface of the rotating part, and a sensor with a built-in three-axis magnetometer is fixed to the machine on which the rotating part is installed through a support. On the rack, the detection end of the sensor faces the direction of the permanent magnet, and the permanent magnet periodically approaches the sensor with the rotation of the rotating part. The sensor detects the magnetic field intensity generated by the permanent magnet and sends it to the sensor’s microprocessor The magnetic field strength and the rotation time of the rotating part meet the sine curve function. When the magnetic field strength reaches the extreme value for the first time and the extreme value for the second time, the microprocessor determines the peak position and valley position of the sine curve and passes the magnetic field The law of intensity change during this period of time analyzes the sinusoidal transformation process of the magnetic field intensity, and then calculates the initial phase of the sinusoidal transformation process based on the sinusoidal transformation process and the measured magnetic field strength in the initial state, and then calculates it based on the current measured magnetic field strength The arc of rotation of the rotating component at the current moment is calculated, and the microprocessor sends the calculated arc of rotation of the rotating component to the external network through the data communication unit.

[0018] The sensor is a three-axis MEMS magnetometer sensor, the sensor is located below the rotating part, the Z-axis component of the magnetic field is used as a detection target, and the end surface of the rotating part is parallel to the Z-axis component. The microprocessor samples the magnetic field intensity detected by the sensor and then performs filtering processing to reduce the fluctuation and interference of the detection result.

[0019] The microprocessor is also provided with an alarm module. When the detection result of the magnetic field intensity does not change for a long time during the detection process or the change trend of the magnetic field detection result does not conform to the sinusoidal function, the microprocessor activates the alarm module, The alarm module sends alarm information to the network through the data communication unit.

[0020] In this method, even if the rotating part rotates at a variable speed, as long as its acceleration during the half-round rotation is less than a certain threshold, the rotation within the half-round time can be regarded as a uniform rotation. This can be based on the half cycle, that is, the half-cycle rotation of the rotating part. The detection result analyzes the sinusoidal transformation process, and calculates the real-time rotation state of the rotating component at the current moment based on this. Re-analyze the new sine transformation process every half cycle to calculate the real-time rotation state of the rotating part. Even if the rotating part rotates at a variable speed, the relatively accurate rotation state can be detected.

[0021] The process of changing the magnetic field strength from one extreme value to the next extreme value satisfies a half cycle of a sinusoidal curve. Each time the magnetic field strength changes from one extreme value to the next extreme value, the microprocessor will pass the magnetic field strength in this section. Analyzing the change law over time The new sine transformation process replaces the sine transformation process obtained by the previous analysis. The microprocessor calculates the arc of rotation of the rotating part at the current moment according to the sine transformation process obtained by the previous analysis and the measured magnetic field strength.

[0022] The analytical process of the sinusoidal transformation process is: each time the magnetic field intensity changes from one extreme value to the next extreme value, one of the extreme values ​​is the maximum magnetic field intensity H max And the other is the minimum magnetic field strength H min , The microprocessor calculates the amplitude of the sine curve A=H max -H min And offset k=(H min +H max )/2, the sine transformation process obtained by the microprocessor is Said Is the initial phase of the sinusoidal transformation process, and the magnetic field strength measured according to the initial state Calculated, Is the arc of rotation of the rotating part.

[0023] Under the principle of the present invention:

[0024] The sensor can detect the change in the intensity of the magnetic field generated by the permanent magnet. The permanent magnet periodically approaches the sensor with the rotation of the rotating part. The measured magnetic field intensity changes from one extreme value to the next extreme value and satisfies a sinusoidal curve. Each time the magnetic field intensity changes from one extreme value to the next extreme value, one of the extreme values ​​is the maximum magnetic field intensity H max And the other is the minimum magnetic field strength H min , The microprocessor calculates the amplitude of the sine curve A=H max -H min And offset k=(H min +H max )/2, the sine transformation process obtained by the microprocessor is Said The initial phase of the sinusoidal transformation process. During the first sine transformation obtained from the first extreme value to the second extreme value of the magnetic field strength Not necessarily set to 0, the first phase Magnetic field strength measured according to the initial state Calculated, The radian for the rotation of the rotating part can be calculated according to the above-mentioned sinusoidal transformation process.

[0025] Even if the rotating part in this method rotates at a variable speed, as long as its acceleration during the half-round rotation is less than a certain threshold, the rotation within the half-round time can be regarded as a uniform rotation. This can be based on the half cycle, that is, the half-turn of the rotating part. The detection result analyzes the sinusoidal transformation process, and calculates the real-time rotation state of the rotating component at the current moment based on this. Re-analyze the new sine transformation process every half cycle to calculate the real-time rotation state of the rotating part. Even if the rotating part rotates at a variable speed, the relatively accurate rotation state can be detected. The analytical process of each sinusoidal transformation process is consistent with the aforementioned method, and in the process of continuous detection Unchanged.

[0026] After adopting this method, the sensor does not need to be connected with the rotating part, and the sensor does not have a rotating part, which solves the technical problems raised before, has a long service life, and the detection result is accurate and reliable.