As an important detecting, perception and monitoring equipment, the optoelectronic platform is always equipped with a series of optoelectronic devices such as optical imaging device, photoelectric encoder and fiber optic gyroscope. These devices all require high-precision data acquisition systems. As the basic method of sensing a variety of mass physical changes, data acquisition systems have been increasingly used in optical sensing, photoelectric platform control and many other fields. The traditional optoelectronic platform design method uses distributed device for assembly, which occupies a large volume. In this paper, we take the multi-channel acquisition system in consideration, instead of the acquisition circuit scattered in each device, during the optoelectronic platform design process, which can effectively improve the system integration. The characteristics of multi-channel and high-precision data acquisition system are studied, and a multi-channel, high-precision AD data acquisition system is designed and verified. The system provides 16 parallel channels, each channel supports 32-bit sampling accuracy, we adopts FPGA as the core processing device, with gigabit network port for data reporting, this scheme has been applied in gyro test systems and weak signal acquisition systems.
In order to improve the anti-interference and tracking performance of photoelectric stabilized platform, a sliding mode controller based on reaching law was designed. Since the differential signal of the input was used in the sliding mode controller, if the noise was added in the input signal, its differential signal will amplify the noise, thus affecting the actual effect of the controller. To solve this problem, a method combining nonlinear Tracking Differentiator (TD) with sliding mode controller was proposed ,then the experimental system was built, and the results of the new controller and the traditional PID controller were compared. It is proved that the method this article presented can improve the anti-interference performance of the system by 66.7%, and also can increase the track precision of the input signal by 48.2%.
The PID controller is widely used in two-axis photoelectric platform velocity loop, however the control precision and the stability of controller are contradictory, especially when friction torque is added. In order to solve this problem, the characteristics of PID controller were analyzed detail in this paper, then a sliding mode controller was designed based on the approach law. First, the model of two-axis photoelectric platform velocity loop was established, then the friction model was linearized according to the interval analysis theory, after that the sliding mode function and the controller was designed, next the simulation model was build, finally, the performance of the velocity loop was compared between sliding mode controller and PID controller, the results showed the sliding mode controller has higher control precision and the stability.
Photoelectric stabilization platform is the eye of the aircraft.At present, the two-axis two-gimbal photoelectric platform is widely used in military, commercial and scientific applications due to simple mechanism, low cost and small size. However, the stability performance of the outer gimbal will be reduced at large pitching angle. In this paper the reason was analyzed , the three-axis gyro system was proposed to stabilize the outer gimbal and the mechanism of this method was explained ,then the control system was designed, the outputs of speed loop were compared between the three-axis gyro and the traditional two-axis gyro system, The results showed three-axis gyro system has higher stabilization accuracy than two-axis gyro system.
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