The University of Texas, Center for Electromechanics (UT-CEM) is making a major upgrade to the robotic tracking
system on the Hobby Eberly Telescope (HET) as part of theWide Field Upgrade (WFU). The upgrade focuses on a
seven-fold increase in payload and necessitated a complete redesign of all tracker supporting structure and motion
control systems, including the tracker bridge, ten drive systems, carriage frames, a hexapod, and many other subsystems.
The cost and sensitivity of the scientific payload, coupled with the tracker system mass increase, necessitated
major upgrades to personnel and hardware safety systems. To optimize kinematic design of the entire tracker, UT-CEM
developed novel uses of constraints and drivers to interface with a commercially available CAD package (SolidWorks).
For example, to optimize volume usage and minimize obscuration, the CAD software was exercised to accurately
determine tracker/hexapod operational space needed to meet science requirements. To verify hexapod controller models,
actuator travel requirements were graphically measured and compared to well defined equations of motion for Stewart
platforms. To ensure critical hardware safety during various failure modes, UT-CEM engineers developed Visual Basic
drivers to interface with the CAD software and quickly tabulate distance measurements between critical pieces of optical
hardware and adjacent components for thousands of possible hexapod configurations. These advances and techniques,
applicable to any challenging robotic system design, are documented and describe new ways to use commercially
available software tools to more clearly define hardware requirements and help insure safe operation.