The GTC main axes servos and control system

The GTC azimuth and elevation axes control systems employ large custom direct-drive motors operated by means of embedded fully-digital current loops. A high-performance position loop has been developed based on sinusoidal encoder feedback with interpolation error compensation. Real-time servo feedback and trajectory tracking is implemented by object-oriented software components at CPU-level which trigger encoder sampling, interpolate the remote CORBA demands and perform high-frequency setpoint streaming for the servo controller.