14 July 2008 Design and field performance of the KVN main axis control system
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Abstract
In early December 2007, the first of the three Korean VLBI Network (KVN) 21m diameter telescopes was brought under servo control of the main axes. In addition to the usual slewing and tracking modes common to most radio telescopes, the KVN antennas will be used extensively for VLBI and thus also have a requirement to permit them to move and settle rapidly during fast switching motions to improve phase stability. These requirements place substantial demands on the controller. To reach the required precision, a digital Drive Control Unit (DCU) is coupled with a digital Antenna Control Unit (ACU). The control law incorporates a state space controller with a full state estimator, combined with a trajectory generator and both velocity and acceleration feedforward to improve tracking performance during fast switching motions. We discuss the design of the DCU, ACU, and the control algorithm, and we present the initial results for the encoder-based pointing accuracy during calm and windy conditions while tracking, as well as the path tracking and settling performance during fast switching.
© (2008) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
David R. Smith, Kamal Souccar, Jeff Kendall, "Design and field performance of the KVN main axis control system", Proc. SPIE 7019, Advanced Software and Control for Astronomy II, 701906 (14 July 2008); doi: 10.1117/12.790263; https://doi.org/10.1117/12.790263
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KEYWORDS
Control systems

Fast packet switching

Telescopes

Antennas

Servomechanisms

Computer programming

Control systems design

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