Research On Improving The Key Technology Of The Performance Of The Photoelectric Detection Target

The sky screen target was an instrument of the exterior trajectory tests, it was used for testing speed of projectile launching with elevation and horizontal, which provided the start signal for other instruments. In the practical application,due to the existence of influence factors,which include the sky light illumination,the size of optical components, noise, the interference of the mosquito and shock wave, and so on, which affected the sensitivity and the stability of detection performance of the sky screen target. Therefore, in order to meet the requirement of exterior trajectory tests for performance of the sky screen target, it is necessary to overcome the influence of external factors and then improve the detection performance of the sky screen target.The thesis is on the basis of the working principle of the sky screen target detection system, the mathematical model of detection sensitivity of the sky screen target is established, researching the main factors affecting the sensitivity of the sky screen target and their regular. On the basis of these analysis,in order to improve the detection performance of photoelectric detection target,the methods of adaptive control and target recognition based on the pulse width is putting forward. The thesis use the fuzzy control method to realize the adaptive control system, the sky brightness and noise are the input control factors of the fuzzy controller, the control voltage of the AGC is the output control factor, the control factors are set fuzzy language variables, including bright, dark; high, low; high gain, middle gain, low gain; and combined with the human long-term accumulated experience and the intuition to design the fuzzy rule base, the fuzzy control rule table of the control system is deduced by Mamdani, then the fuzzy control rule table is programmed. The realization of the automatic adjustment about the circuit gain, the threshold voltage and slit diaphragm are controlled by single chip microcomputer.At the same time, The thesis design target identification algorithm based of the pulse width, design target identification circuit of different interference signals by CPLD,and verify target identification circuit can filter out different interference signals by simulating.The thesis design the system control circuit with the single chip microcomputer as the core controller, verify which the fuzzy control algorithm and control circuit are feasible through simulation and experiment.When the lens focal length is 85 to 125mm, the slit diaphragm is 0.8mm and the projectile flight height is 3M, the results are contrasted under the condition of the fixed parameters circuit and the adaptive control circuit,the results show that the adaptive control method is used to improve the detection sensitivity and stability of the sky screen target.