Al-based control of a space station Freedom prototype thermal bus

A multilayered approach to the symbolic control of complex electromechanical assemblies, such as spaceborne thermal, power, and life support subsystems, is discussed. An example of this approach in the development of successive adaptive expert controllers capable of real-time monitoring and control of a prototype two-phase space station Freedom thermal bus is presented. The thermal bus application requires read-update-act cycles of under a minute and is subject to dynamic reconfiguration while operating. These performance requirements are addressed by layering model-based expert system software on a conventional numerical data acquisition and control system. Test results demonstrate both nominal control and fault recovery actions with the ground-based thermal bus prototype. A dynamic modification of the symbolic model used in this approach is compared to that of a classical numerical adaptive controller. The monitoring and control capabilities of this hybrid Al-based control approach may be useful in other complex process control problems