The adaptive telescope based on a deformable secondary mirror can effectively simplify the system structure, enhance the telescope’s utilization of light energy, reduce background radiation, and improve the telescope’s observation ability for dim and infrared targets. This paper presents our latest research on adaptive telescopes utilizing piezoelectric deformable secondary mirrors (PDSM). We have developed a 241-unit PDSM with small actuator spacing and installed it on the 1.8-meter adaptive telescope at the Lijiang Observatory in Yunnan, China. This system has successfully captured high-resolution visible near-diffraction limit images of astronomical targets. The imaging Strehl ratio of the system in the visible light band (approximately 640nm) reaches about 0.5, and the tracking accuracy is approximately 0.02 arcseconds. These results suggest that adaptive telescopes utilizing piezoelectric-driven deformable secondary mirrors outperform traditional ’telescope + adaptive optics’ system architecture, enabling significant improvements in high-resolution visible imaging.
KEYWORDS: Digital signal processing, Signal processing, Servomechanisms, Sensors, Control systems, Operating systems, Field programmable gate arrays, Optoelectronics, Process control, Computer programming
When Opto-Electronic Tracking system operates in complex environments, every subsystem must operate efficiently and stably. As a important part of Opto-Electronic Tracking system, the performance of PMSM(Permanent Magnet Synchronous Motor) servo system affects the Opto-Electronic Tracking system’s accuracy and speed greatly[1][2]. This paper applied embedded real-time operating system μC/OS to the control of PMSM servo system, implemented SVPWM(Space Vector Pulse Width Modulation) algorithm in PMSM servo system, optimized the stability of PMSM servo system. Pointing on the characteristics of the Opto-Electronic Tracking system, this paper expanded μC/OS with software redundancy processes, remote debugging and upgrading. As a result, the Opto- Electronic Tracking system performs efficiently and stably.
As the Photoelectric tracking system develops from earth based platform to all kinds of moving platform such as plane based, ship based, car based, satellite based and missile based, the fault tolerance control system of phase current sensor is studied in order to detect and control of failure of phase current sensor on a moving platform. By using a DC-link current sensor and the switching state of the corresponding SVPWM inverter, the failure detection and fault control of three phase current sensor is achieved. Under such conditions as one failure, two failures and three failures, fault tolerance is able to be controlled. The reason why under the method, there exists error between fault tolerance control and actual phase current, is analyzed, and solution to weaken the error is provided. The experiment based on permanent magnet synchronous motor system is conducted, and the method is proven to be capable of detecting the failure of phase current sensor effectively and precisely, and controlling the fault tolerance simultaneously. With this method, even though all the three phase current sensors malfunction, the moving platform can still work by reconstructing the phase current of the motor.
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