Application of NS-FOG25 in tank stabilization system
1. Fiber optic gyroscope
The fiber optic gyroscope is a fiber optic interferometer based on the Sagnac effect, that is, two beams of light that are transmitted in opposite directions in the same fiber sensing ring to form a fiber Sagnac interferometer, as shown in FIG. 2 .
Figure 2 Schematic diagram of fiber optic gyro
The light beam from the light source is split into two beams by the splitter/combiner, which are respectively coupled into the fiber sensitive coil from both ends of the fiber loop, and propagate in the forward and counterclockwise directions. The two beams coming out from the two ends of the fiber loop are superimposed by the splitter/combiner to generate interference, resulting in a phase difference. Rotational angular velocity with the ring In proportion to:
L fiber length;
The average diameter of the D fiber optic ring;
The wavelength of light in a vacuum;
The speed of light in a vacuum.
By detecting the phase difference (ie the interference light intensity) can get the angular rate Information, of which The term is the scale factor of the gyro.
Figure 3 fiber ring physical map
Fiber optic gyroscopes are photoelectric sensors that differ from conventional electromechanical gyroscopes. It has the advantages of no moving parts, wide dynamic range, direct digital output and networking with computer interface, and is ideal for mobile carriers and military applications. The feature is that the fiber optic gyroscope is directly connected to the carrier and can directly bear the various working environments of the carrier.
2. The main role of fiber optic gyroscope in attitude measurement system
Through the motion information of the fiber optic gyroscope's sensitive motion device around its center of mass, it is ensured that the motion device can achieve stable flight under the action of internal and external interference, and its attitude change is controlled within the allowable range. The motion of the motion device around the centroid can be decomposed into angular motions around its three axes. Therefore, the corresponding three basic measurement channels measure and stabilize the pitch, yaw and roll axes of the motion device. The three measurement channels are basically the same, and each consists of a single-axis fiber gyroscope and its information processing system (or three-axis fiber gyroscope and information processing system) to achieve continuous measurement of the output attitude information of the motion device.
Then there is the fiber optic gyroscope as a rate gyro, whose output information can be directly used as the attitude control signal of the artillery or tank; at the same time, as an important part of the carrier attitude control, it passes the sensitive angular velocity signal to the carrier attitude stabilization system. Advance control provides conditions. It mainly plays the following roles:
1) Through the three angular angular velocities of the pitch, yaw and rolling of the sensitive carrier, and outputting an analog voltage proportional to the angular velocity through the signal conversion, and sending the signal to the carrier computer, adjusting the carrier attitude through servo control to achieve Stable flight or operation of the carrier.
2) Provide sufficient damping ratio for the attitude control loop. The damping coefficient is generally not more than 0.10~0.15, and the overshoot of the attitude angle is generally not more than 30%.
3. The main requirements of fiber optic gyroscopes used in attitude control loops:
1) Determine the kinematics of the carrier, including the height, velocity and overload of the carrier, to determine the open-loop transfer coefficient of the system loop and the stability margin of the system.
2) The system has a certain bandwidth bandwidth requirement, which is mainly determined by the operating conditions of the system.
3) The system should be able to effectively suppress external interference on the carrier and stabilize internal interference of the system equipment.
4) The system also needs to limit the maximum overload of the carrier to a given value, which is determined by the structural strength of the carrier and the structural components of the system equipment.
5) For carriers with a large angle of attack, limit the maximum use angle of attack to ensure system stability and other performance requirements.
6) The fiber optic gyroscope is connected to the angular velocity command system as a rate gyro. The attitude control loop system gain provides unity acceleration transmission gain. Normally, the loop gain is less than 1. The system is particularly sensitive to speed changes. In addition, any noise of the system command is amplified by high gain, and in order to avoid noise saturation, The actuator electronics have a large dynamic range.
4. Introduction to NS-FOG25
Low-precision NS-FOG25 fiber optic gyroscope with five optical components, one set of structures, one signal detection front panel, and one light source control circuit board. Structurally, the optical system and the circuit system are integrally packaged, and the installation is simple, convenient to use, stable and reliable. The user only needs to provide power supply through an external plug, and external motherboard and receive gyro output data can be used. This product can be used in the fields of attitude measurement, navigation, guidance and so on.
4.1, main performance indicators (typical values)
a) Measurement range: not less than 500 ° / s, can be adjusted according to user requirements;
b) zero deviation stability (1σ): 1°/h;
c) Resolution: 0.5 ° / h;
d) scale factor nonlinearity (1σ): 300ppm;
e) Random walk coefficient: 0.1 (° / √ h);
f) frequency band: not less than 400Hz;
g) Power consumption: less than 3W;
h) Working temperature: M1A: -40 ° C ~ +60 ° C;
M2: -55 ° C ~ +85 ° C;
4.2 mechanical and electrical interface
Table 1 NS-FOG25 fiber optic gyroscope mechanical and electrical
10ÍM2 can choose any 3 or more screw holes to install
Mounting surface accuracy
Cylindricity ≤0.01mm, flatness ≤0.01mm
±5V DC (power supply accuracy ±5%, ripple less than 30mV)
Meet the RS-422 interface standard;