The Iranian National Observatory Telescope is a 3.4-meter Alt/Az optical telescope. MCS (Mount Control System) is developed in such a way that meets the requirements of movements control of all axis. To this end, the end-to-end (E2E) simulations are performed using Matlab software. In this simulation, the telescope is modeled with adequate precision, and the mechanical behavior of the model is tested. Then the results were confirmed with other software independently in some specific positions to make sure that the mechanical behavior is precise and valid. Then in the Matlab software, a controller is developed, and the simulated telescope is controlled. Tracking error is calculated with the presence of the simulated wind at the predicted speeds, and the performance of the MCS is then analyzed and the controller is improved. The tracking accuracy at different speeds is calculated and compared. The final controllers are tuned in Matlab, and errors and noises are applied in the simulation environment. A simple optical instrument is also simulated to estimate the image quality in the image plane. Then, after development of the structure of the telescope, in the integration phase, the appropriate controller is implemented in the real controller, and the real results are recorded from the telescope. During integration, a test camera is placed in the telescope to check the primary image quality and compare the results with the encoder's recorded data. In this paper, we discuss the design and development approach for axis controllers and provide the related results together with the future upgrades necessary for enhancing telescope performance.
The Active Optics System (AOS) of the Iranian National Observatory 3.4 m telescope (INO340) is designed to support and deform the M1 and to adjust the position of the M2 with the purpose of optical aberrations’ compensation. Sixty active axial pneumatic actuators and 32 passive lateral actuators support M1 axially and laterally, respectively. The arrangement and force vectors of the lateral actuators are optimized in such a way that minimum deformation on M1 occurs. There are 3 axial and 3 lateral fixed-points as positioning detectors for M1, and an accurate hexapod keeps M2 in the appropriate position. M1 surface shape and M2 positions are actively controlled by AOS during telescope operations using either a look-up table in open-loop control or the wavefront error in closed-loop control to achieve the best image quality. There are three levels of the control loop in AOS: 1- A proportional controller for a single actuator, 2- Inner-loop control to equilibrate M1 within the bandwidth of 1 [Hz], 3- Outer-loop control to remove optical aberrations within the bandwidth of 0.01 [Hz]. A test setup for the axial actuator and an Alt-simulator setup are provided to design and optimize a proportional controller for a single actuator and to test the inner-loop control. In this paper, the mechanical, control, and software designs for INO340 AOS are presented.
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