The Architecture and Initial Results of the Large Millimeter Telescope Control System

As the Large Millimeter Telescope (LMT) has continued to progress towards scientific operations, some preliminary commissioning of the telescope control system has taken place. We present the architecture of the LMT control system along with initial commissioning results of the LMT servo and drive system. The LMT azimuth drive system is a wheel-on-track mechanism with sixteen individually driven wheels on a circular track. The elevation drive system consists of two main gear arcs, each driven by two pinions. All twenty of the drives (sixteen in azimuth and four in elevation) consist of a motor and a gearbox. These drives are controlled by a fully digital servo system that is divided into a drive control unit which consists of the servo amplifiers and an embedded PLC that implements torque sharing and safety interlocks, and an antenna control unit that implements the servo control loops and astronomical tracking. The results of the initial commissioning of the LMT servo and drive system include full range motion in azimuth and elevation, azimuth track welding effects, elevation gear rims alignment effects, elevation balance, friction contribution to servo errors, and initial tracking accuracy.